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/ ~-'/~ COMPARISON OF NATURAL AND ALTERED ESTUARINE SYSTEMS The Field Data-Volume I Center for Coastal and Environmental Studies Rutgers-The State University of New Jersey New IJersey Department of Environmental .Protection, Division of Fish, Game, and Shellfisheries, and Division of Coastal Resources September 1979 COMPARISON OF NATURAL AND ALTERED ESTUARINE SYSTEMS: The Field Data - Volumes I and II U.S. DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON, SC 29405-2413 This report was prepared by the Center for Coastal and Environmental Studies Rutgers - The State University of New Jersey in cooperation with The Division of Fish, Game, and Shellfisheries, and the Bureau of Coastal Planning and Development of the New Jersey Department of Environmental Protection and funded by The New Jersey Department of Environmental Protection: Division of Fish, Game, and Shellfisheries, and Division of Coastal Resources The United States Department of the Interior: Fish and Wildlife Service under the Dingell-Johnson Act (P.L. 81-681) The United States Department of Commerce: National Marine Fisheries Service under the Commercial Fisheries Research and Development Act (P.L. 88-309) and Office of Coastal Zone Management under Section 306 of the Federal Coastal Zone Management Act (P.L. 92-583) as amended and Rutgers - The State University of New Jersey: Center for Coastal and Environmental Studies Contract No. C29358 CCES Pub. No. NJ/RU-DEP-11-9-79 Property of CSC Library COMPARISON OF NATURAL AND ALTERED ESTUARINE SYSTEMS: The Field Data - Volumes I and II Edited by: Teruo Sugihara Norbert P. Psuty James B. Durand Cartography by: Janice Limb Lesley Ogrosky Norbert P. Psuty, Director Center for Coastal and Environmental Studies Rutgers - The State University of New Jersey Doolittle Hall, Busch Campus New Brunswick, New Jersey 08903 ACKNOWLEDGEMENTS The editors wish to express their thanks to the numerous persons in the University and State govern- ment who provided assistance and direction in the preparation of this report. Within the New Jersey Department of Environmental Protection, special thanks are extended to Mr. Russell Cookingham who had the foresight to identify the need for this type of study and to Mr. A. Bruce Pyle and Mr. Paul Hamer for their guidance of the overall project. Thanks also to the many persons cited in the individual reports who worked on the various aspects of this study. The assistance of Ann Bonner, Leslie MacLardy, Gene Cass, Chuck Savrda, Michael Siegel, Joann Mossa, Maureen Dunphy, and Ralph Alvarez in the preparation of the cartographic work is acknowledged. Melinda Bellafronte, Joy Nakashima, Edith Byrnes, and Krysia Janisch are to be particularly acknowledged for their dedicated efforts in accomplishing the difficult job of producing the manuscript. v USERS GUIDE TO THE FIELD DATA - VOLUMES I AND II The Estuarine Evaluation Project was a cooperative venture by Rutgers - the State University and the New Jersey Department of Environmental Protection. Its purpose was to study how a lagoon home development built on a salt marsh would affect the processes, functions, and conditions normally found in such an area. I ~~The specific site chosen is presently known as Village Harbour; however, at the time of the study, it was called Beach Haven West. It is located in Ocean County near Manahawkin, New Jersey. The investigation was multifaceted and was conducted from 1973 through 1977. The results of this study are presented in a two-part format. The first part is a two volume set which is titled "The Field Data". The data represent a compilation of the documents submitted by the principal investigators in fulf ill- ment of their project responsibilities. The purpose of these reports is to es- tablish data sets of the many components forming the estuarine system and to in- vestigate the individual units. The second part entitled "Analysis", draws upon selected portions of the field data to evaluate the effects of and the changes brought about by the lagoon development's presence. In assembling the two volumes of field data, certain guidelines were employed. The principal objective was the preservation of the intent and meaning of the orig- inal investigator. To accomplish this, the two volumes were organized as a compil- ation of the original research reports with a minimum of editing or modification. This was to ensure the integrity and logic of each report was retained as the author intended. In general, changes were made only to maintain a standard format. MM- jor changes were subject to the approval of the original authors. This guideline served to reinforce the direct connection between the report and the researcher who authored it. It also assured the scientific validity of the subsequent analy- sis. One consequence of this minimum change policy was the retention of the units system employed by the investigator. The problem of dealing in the British and metric systems concurrently was not deemed significant enough to warrant the ex- tensive changes required. Another guideline concerned the choice of documents in the field data volumes. If a number of reports were produced over the course of the investigation, the summary versions of the reports were included. If such superseding documents were unavailable, all available reports were appended and placed in the compilation. It is intended that the contents of the reports in the two field data volumes are the responsibility of the original authors. All manuscripts were subject to author review and approval prior to publication. The compilers of the field data assume responsibility only for the accurate transferal of text from the submitted original reports into the final format. Within the field data volumes, the taxonomic nomenclature follows Gosner (1971) for the estuarine benthic invertebrates and Bailey et al. (1960) for the fish. Note that the editors consider Nassarius ob~soletus and Ilyanassa obsoleta synonymous as are Phragmites communis and Phragmites australis. Because the report sizes in the field data volumes varied considerably, two types of organization were employed. Those reports under 30 pages were written in a condensed format. Features such as separate title pages, table of contents, vii list of figures, list of tables, and separate acknowledgement and abstract pages (when requested), were used only in the larger reports. Condensation of the for- mat size was a primary objective in the smaller reports. Appendices are found in reports of all sizes and were employed to includeI (1) additional data not referred to in the report itself (see the Durand et al. and Good et al. reports); (2) raw data (see the Haskin and Ray report); and (3) figures and/or tables which would disrupt the text if placed in the body of the report because of the number of pages involved (see McClain et al. report). The specific organization of the field data contribution is as follows: 1) Users Guide 2) Order of Reports 3) Abstracts 4) Compiled Reports The order of the abstracts and the compiled reports followed as much as pos- sible their sequence of use in the analysis. This order follows. viii ORDER OF REPORTS Report No. 1 J. Durand, T. Sugihara, and ESTUARINE EVALUATION STUDY: PRIMARY C. Yearsley AQUATIC PRODUCTION AND NITROGEN. FOUR YEAR REPORT, 1973-1977. 2 R. Good and B. Frasco ESTUARINE EVALUATION STUDY: A FOUR YEAR REPORT ON PRODUCTION AND DECOMPOSITION DYNAMICS OF SALT MARSH COMMUNITIES OF THE MANAHAWKIN MARSHES, OCEAN COUNTY, NEW JERSEY. 3 D. Slate MARSH PRODUCTIVITY: SUBMERGED SALT POND VEGETATION. 4 H. Haskin and G. Ray ESTUARINE EVALUATION STUDY: BENTHIC INVERTEBRATES. FOUR YEAR REPORT, 1973- 1977. 5 F. Ferrigno, L. Widjeskog, MARSH PRODUCTIVITY: SURFACE INVERTEBRATE and E. Tomlin POPULATION INDICES. 6 J.R. Trout MARSH PRODUCTIVITY: SURFACE INVERTEBRATE POPULATION INDICES. 7 J. McClain, J. Makai, and STUDIES OF THE MANAHAWKIN BAY - LITTLE P. Himchak EGG HARBOR SYSTEM: (1) FINFISH STUDY: (2) PHYSICAL - CHEMICAL STUDY; AND (3) USE STUDY. 8 P. Festa ANALYSIS OF THE FISH FORAGE BASE IN THE LITTLE EGG HARBOR ESTUARY. 9 R. Bosenberg RODENT POPULATIONS. 10 J. Penkala and J. Sweger WILDLIFE INDEXES: AVIAN DENSITY AND DIVERSITY. 11 L. Widjeskog and F. Ferrigno WILDLIFE INDEXES: NESTING SURVEY. 12 J.R. Trout WILDLIFE INDEXES: STATISTICAL ANALYSIS OF THE NESTING SURVEY DATA. 13 W. Shoemaker and F. Ferrigno WILDLIFE INDEXES: WATERFOWL USE AND HARVEST. 14 J. Applegate, S. Salmore, and RECREATIONAL USE OF NEW JERSEY'S WET- J. Blydenburg LANDS BY THE CITIZENS OF NEW JERSEY. 15 J. Applegate and S. Sterner A STUDY OF THE RECREATIONAL USE OF NEW JERSEY'S MARINE ENVIRONMENT. 16 S. Sterner and J. Applegate ESTIMATES OF THE 1975 SPORT HARVEST OF MARINE FISHES. ix ABSTRACTS The abstracts are short, generally less than 250 words, and are intended to speed access by the reader to the individual reports of interest. The abstracts cover discrete research areas and may draw upon more than one report in the col- lation for their basis. Abstract of the Primary Aquatic Productivity and Nitrogen: Four Year Report 1973-1977 study prepared by James Durand, Teruo Sugihara, and Charles Yearsley. This study compares aspects of stratification, the nitrogen cycle, and pri- mary production in a salt marsh system and an adjacent developed area near Mana- hawkin, New Jersey. Greater and more prolonged stratification is associated with the increased depths found in the lagoon development. The lower portions of the stratified water columns are subject to periodic anoxia and high ammonia-N levels. In all areas, the organic nitrogen fraction is the dominant nitrogen form found generally followed by ammonia-N, nitrate-N, and nitrite-N. In addition to nitro- gen standing stocks, processes such as nitrogen fixation, excretion, and ammonifi- cation were also studied and partial nitrogen budgets constructed. Primary pro- duction studies were done on the microflora associated with the marsh surface, intertidal zone, and benthic sediments as well as the phytoplankton. The phyto- plankton community is the greatest importance in both the natural and developed areas. Enrichment studies show the summer phytoplankton productive capacity to be nitrogen limited. High rates of production are also associated with the bulk- head algae community; however, its limited distribution minimizes its absolute total contribution. The productive capacity of the marsh surface edaphic algae community is directly related to light incidence. Consequently, the habitats with decreased grass canopy densities, like the Spartina alterniflora forms, have higher rates of primary production. In addition, the S. alterniflora short form occupies 60% of the marsh surface which magnifies the contribution of its edaphic algae to the total salt marsh productivity. As in the rest of this study, water column depth is stressed as a critical factor to production because of its rela- tionship to the size of the euphotic zone, turbidity, and the type of biological activity possible in the benthos. Abstract of the research on the production and decomposition dynamics of the salt marsh communities of the Manahawkin marshes performed by Ralph Good, Barry Frasco, Kay Smith, and William Brown. In the Manahawkin salt marsh-estuarine ecosystem, vascular plant primary production and the fate of this biomass were studied from 1973 to 1976. All phases of both processes were subsequently related to environmental parameters. Using the harvest method, estimates of annual aboveground net production (g dry wtm-2 yr-1) are as follows: tall form Spartina alterniflora, 825-735; short form S. alterniflora, 444-574; S. patens, 535-618; and Distichlis spicata, 613-644. Below- ground production is generally about 5 times greater than aboveground. Total net primary production of short form S. alternatiflora on an energy basis is estimated at 16.0 kcal'm-2'yr-1, or 5.12 x 109 kcal for the entire marsh. These figures compared favorably with results for the world's most productive ecosystems. Standing crops of crude fiber, nitrogen-free extract, crude fat (aboveground ma- terial only), and crude protein (belowground material only) are shown to be a function of dry matter biomass. The accumulation of crude protein in aboveground xi material at the beginning of the growing season is thought to be a storage mechanism for potentially limiting nitrogen. Approximately 90% of the annual net primary production of the vascular plants remained at the end of the growing season. Based upon the analyses of plant material placed in litter bags and left on the marsh, a general decomposition pattern is described for the majority of study sites. Decomposition rates, however, vary with the type of plant material and the environmental regime. The amount of aboveground material in g dry wt-m-Z-month-1 entering the detrital food chain during the first year of de- composition is as follows: tall form S. alterniflora, 44 (6.0%); short form S. alterniflora, 20 (4.5%); and S. patens, 8 (1.5%). Additional biomass losses during the growing season are estimated from phenological studies, and are probably about 10% of the net aboveground production. Chemical analyses of de- compositional material reveal at nearly all study sites, percent crude fat de- creased and percent crude protein increased with time. The latter is attributed to colonization of the plant material by bacteria and fungi. The balance of production, decomposition, detrital export, accumulation, and incorporation into peat with seasonal tidal fluctuations and sea level changes are discussed in their relation to marsh stability. Abstract of the 1976 Submerged Salt Pond Vegetation study prepared by Dennis Slate. The purpose of the salt pool submerged vegetation study is to delineate the physical and chemical parameters which could be used to predict the presence or absence of Ruppia maritima and to measure the production of Ruppia in the salt pools of the Manahawkin marsh. Three parameters, depth, salinity, and surface area, accurately predicted 21 or 24 attempts. Ruppia occurs generally in ponds of large surface area, increased depth, and lower salinity. Peak Ruppia biomass occurs in late July - early August. The biomass estimates range from 0.04 to 79.60 g dry wt'm-2 with an overall mean of 30.2 g dry wt.m-2. Abstract of the Benthic Invertebrates: Four Year Report 1973-1977 study pre- pared by Harold Haskin and Gary Ray. During July 1973 - February 1975, an inventory of natural or undisturbed creeks, partially disturbed waterways, and fully lagooned waterways in the Mana- hawkin, New Jersey area quantified the distribution of benthic invertebrate species within the study area. During July 1975 - March 1977, emphasis was placed on the study of distribution, population structure, growth, production, and food web relationships of the dominant benthic species. All sampling was done on a seasonal basis using a ponar dredge (0.05 m2). A total of 185 species were collected. The two major dominant species are Ampelisca abdita and Streblospio benedicti. These two account for approximately 60 and 9% of all the organisms collected, respectively. The 20 most numerous species account for approximately 90% of the total collection. Of the taxonomic groups, the Crustacea are the most numerous, followed by the Polychaeta and the Mollusca. Total species listings for each waterway type are nearly identical; however, species in the dredged and partially disturbed waterways were lost and replaced at a greater rate than in the natural creeks. Numbers of individuals and biomass xii estimates are inversely related to degree of development or disturbance. The creeks have 9 times the individuals and 25 times the biomass of the lagoon com- munity. Species distribution is apparently affected by hydrographic factors, sediment characteristics, and distance from the bay. Seasonal fluctuations in species, number of individuals, and biomass seem related to reproductive pat- terns of the dominant species and also to predation pressure. Production for the natural creek and lagooned waterways is estimated at 3.0 and 0.3 kcal.m-2' year-1, respectively. Abstract of the research on surface invertebrate populations in the Cedar Run area performed by Fred Ferrigno, Lee Widjeskog, Earl Tomlin, and J. Richard Trout. A preliminary study was conducted during August 1974 on the marsh surface invertebrate populations inhabiting 10 major cover types within the Cedar Run marsh evaluation study area. Point and interval estimates of the population densities within each cover type as well as total yield for the marsh complex were obtained for the following invertebrates: Modiolus demissus, Melanpus bi- dentatus, Uca pugnax, Philoscia vittata, Orchestia grillus, ants, true bugs, crickets, grasshoppers, leaf-hoppers, and spiders. The most prevalent inverte- brates in terms of density and frequency of occurrence are Melconpus, PhiZoscia, leaf-hoppers, Orchestia, and the spiders (in decreasing order of importance). These account for approximately 99% of the total yield (6,327,992 organisms, SD = 456,175) from the study area. About 96% of this total marsh population occurs within the extensive Spartina alterniflora (short form) and S. patens covers types. Invertebrates are scarce in stands of Phragmites australis, Scir- pus olneyi, and Panicum virgatum, and also in the incompletely lagooned area at Popular Point. Abstract of the 1976 Manahawkin Bay - Little Egg Harbor System: Finfish Study; Physical-Chemical Study, and Use Study prepared by John McClain, John Makai, and Peter Himchak. The purpose of the finfish study is to inventory the fish inhabiting the Manahawkin Bay - Little Egg Harbor system. The combined data of all the collec- tion methods (seine, trawl, and gill net) indicate the five most numerous species in decreasing order are the bay anchovy, the Atlantic silverside, the fourspine stickleback, the mummichog, and the tidewater silverside. Together they com- prise 80% of the total catch. Altogether 66 species of finfish were collected. The purpose of the physical-chemical study is to describe the Manahawkin Bay - Little Egg Harbor system in terms of its morphology, biota, and physico- chemical factors. Water quality in the system is good. In general, reduced oxygen levels are not found in the bay but are found in some of the creeks and especially in the lagoons. The dissolved oxygen levels in the lagoons are mani- festations of temperature stratification. The bay lacks both temperature and salinity vertical gradients. Horizontal salinity gradients and seasonal salin- ity variation are greatest in the creeks. The data indicate high coliform counts of unknown origin in certain areas (most of these areas were in the de- veloped sites). DDT, DDT metabolites, and certain heavy metals are present in animal tissue samples with higher levels found in the sediments tested. xiii The purpose of the use study is to determine the ways in which the Mana- hawkin Bay - Little Egg Harbor system is used by man. During the first study period (July 1973 - February 1974), it is estimated over 1.58 x 105 man-days of activity occurred in the study area with a resulting harvest in excess of 4.4 x lO5 fish, 1.4 x 107 shellfish, and 300 waterfowl. Between June 1974 and May 1975, excluding November and December 1974, an estimated 2.3 x 105 mandays of activity produced a harvest of over 4.5 x 105 fish and over 1.9 x 107 clams. Abstract of the 1978 Analysis of the Fish Forage Base in the Little Egg Harbor Estuary study prepared by Patrick Festa. The purpose of this study is to identify the forage base and the allocation of this forage base among the Little Egg Harbor fish through stomach contents analysis. The forage base consists of 142 taxa which support at least 64 fish species. The trophic relationships present are complex because of the flexible dietary habits of the fish surveyed (55 species). Forage populations of partic- ular importance include the class Polychaeta, the order Calanoida, the suborder Gammeridea, the order Mysidacea, the infraorder Panaeidae, and the class Osteich- thyes. Some of the food chain associations indicated are Mercenaria-winter flounder; Cymadusa-pipefish; and calanoid copepod-sand lance-striped bass. The utilization of the forage base is analyzed in terms of use of a given forage item and also in terms of forage items consumed by a given fish species. Habi- tat area and seasonal aspects are also examined. Abstract of the 1977 Rodent Populations study prepared by Robert Bosenberg. Trapping of the rodents on the Cedar Run marsh was conducted periodically from April 1975 to June 1977. Total trapping effort using both live and killing traps amounted to 18,610 trap nights. Rodent species captured include the meadow vole (Microtus pennsylvanicus), muskrat (Ondatra zibethica), house mouse (Mus musculus), Norway rat (Rattus norvegicus), and the meadow jumping mouse (Zapus hudsonius). Microtus was the only mouse species captured in sufficient numbers to permit population density estimates. Peak densities of this species occur in July. Densities are greater in the incompletely lagooned section than in either the mosquito-ditched or natural marsh areas. Population densities are similar for the latter two sections. Densities within different vegetation cover types are related to the marsh alteration type in which they occur. A significant decline in Microtus numbers occurred in the incompletely lagooned area due to the effects of Hurricane Belle. The relation between Microtus populations and topographic relief, cover effects, predation, availability of nesting sites, and food resources are discussed. Muskrats are found to be restricted to the Scirpus-dominated vegetation located near the marsh-upland ecotone. The average number of huts observed in November of 1975 and 1976 was 21.5. Estimates of muskrat density for the area of marsh bordering and upland exceed five animals per hectare, and the total population for the Cedar Run study area probably exceeds 114 individuals. Due to the low capture success for the Norway rat, no reliable population estimates are possible. xiv Abstract of the 1976 Wildlife Indexes: Avian Density and Diversity study pre- pared by Joseph Penkala and Joseph Sweger. Bird censuses were conducted during the spring and fall migration periods within the following major vegetational associations of the Cedar Run marsh: up- land-marsh ecotone, Iva frutescens - Spartina patens, S. alterniflora, and the marsh interface with Cedar Run and Little Egg Harbor. Six visits were made during the period 20 April - 8 August 1975 and the line transect - mean flushing distance method used to determine the diversity and density of the avifauna. A total of 976 birds comprised of 87 different species were observed during the study period. Species which are typically considered to be summer residents are most prevalent. Sharp-tailed sparrows have the highest density of any species, followed by the red-winged blackbird and barn swallows. The laughing gull is the most abundant of the larger species. Reliable density estimates of most species are not possi- ble due to their infrequent occurrence. The S. aZternifZora habitat accounts for the greatest number of birds observed and has the highest species diversity, averaging 68.3 individuals and 17 species observed per visit. The upland-marsh ecotone has the lowest diversity and density. Abstract of the research on bird nesting in the Cedar Run area performed by Lee Widjeskog, Fred Ferrigno, and J. Richard Trout. During August 1974, nine major vegetation cover types of the Cedar Run marsh study area were surveyed to determine the species and density of nesting birds. Point and interval estimates of the number of nests for each species within a cover type as well as estimates of the total number of nests for each cover type and for the entire marsh were obtained. A total of 149 nests were actually observed, and the estimated number for the entire marsh is 2,739.5 (SD = 361.0). Nesting spe- cies, in decreasing order of importance, include the sea-side and sharp-tailed sparrows (Amnospiza maritima and A. caudacuta), clapper rail (Rallus longirostris), willet (Catoptrophorus semipalmatus), long-billed marsh wren (Teimatodytes palus- tris), red-winged blackbird (Agelaius phoeniceus), and the black duck (Anas ru- bripes). Sparrows account for 64% of the estimated total. Nests occurring with- in the extensive areas of short form Spartina alternifZora and S. patens account for 44% (1,213.9 nests) and 40% (1,099.6 nests), respectively, of the total marsh estimate. Although the density of clapper rail nests is high (13.29 nests'ha-1) in tall form S. alterniflora, the overall importance of this cover type is mini- mized by its small areal contribution. Very little nesting occurred in stands of Scirpus olneyi, Panicum virgatum, or Distichlis spicata, and no bird species were observed to be utilizing either Phragmites australis or dredge spoil areas. Abstract of the 1974 Wildlife Indexes: Waterfowl Use and Harvest study prepared by William Shoemaker and Fred Ferrigno. During the fall and winter of 1973-74, waterfowl utilization and harvest data were obtained for the Cedar Run study area. Monthly aerial waterfowl counts were carried out from September to January. Hunter counts and bag checks were conduc- ted on Saturdays and one day of each week from October to January. Waterfowl populations in the immediate study area increase from 800 in September to a maxi- mum of 3,200 in December with a grand tally of 9,270 birds. This represents an increase from 1.46 to 5.86 birds per hectare of marsh. Black ducks are the most xv abundant, accounting for 35.3% of the total. Greater and lesser scaup are next in importance (20.5%). Within the surrounding ecosystem of Little Egg Harbor and its bordering salt marshes, the waterfowl population increases from 1,600 in Sep- tember to 20,000 in December, with a total count of 50,050 birds. Dominant spe- cies are the brant (21.8%), greater and lesser scaup (21.0%), black ducks (19.2%), and bufflehead (15.0%). Hunter use of the study area amounts to 874 man-days and 1.61 hunters per hectare of marsh for a total harvest of 2,407 waterfowl. Hunter success was 2.65 birds per hunter-day and 4.4 waterfowl per hectare of marsh. Diving ducks, primarily the scaup, are the preferred species. The greater scaup accounts for 76.8% of the total estimated harvest. These results demonstrate the Cedar Run marsh and adjacent bay to be a prime wintering area for waterfowl and also one with a considerable recreational value in terms of hunter use and success. Abstract of the 1974 and 1975 annual reports submitted on the Recreational Use of New Jersey's Wetlands by New Jersey Citizens prepared by James Applegate, Stephen Salmore, and John Blydenburg and James Applegate and Stephen Salmore, respectively. The primary objective of this study is to quantify the recreational benefits provided by New Jersey's wetlands to New Jersey residents. Univariate analysis indicates wildlife observation is the most popular salt marsh activity in which 15% of the New Jersey population participated. It is followed by crabbing (12%), picnicking/other (12%), fishing (10%), clamming (5%), and hunting (3%). Subse- quent cluster analysis divided the salt marsh users into grouping which could be combined into more inclusive categories. The activity categories chosen were extractive (fishing, hunting, crabbing, and clamming), appreciative (wildlife observation and picnicking/other), and nonexclusive (occasional participants but not exclusively in one activity). Of the approximately 19% of the New Jersey population which utilized the wetlands (under this analysis), 6.6, 5.6, and 7.2% belong to the appreciative, nonexclusive, and extractive categories, respectively. Other more restrictive groupings were examined as were the origin of the partici- pants in the various activities and man-day estimates of marine environment use. The estimated means of man-days of recreation (in millions of man-days) provided by crabbing, estuary fishing, ocean fishing, surf fishing, and clamming are 2.5, 2.0, 1.7, 1.1, and 1.0, respectively. Abstract of the Estimates of the 1975 Sport Harvest of Marine Fishes prepared by Stephen Sterner and James Applegate in 1976. Utilization of the stocks of bluefish, weakfish, fluke, white perch, striped bass, mackerel, whiting, cod, pollack, winter flounder, and tuna were estimated for either the 1 January - 1 June 1975 period for the 1 July - 20 December 1975 period. These estimates were referenced to the type of fishing done (ocean, river/bay, or surf) and who the fishing was done by (those who fish 10 days or less annually or those who fish more). During the 1 January - 1 June 1975 period estimates were made on the striped bass, mackerel, whiting, cod, pollack, winter flounder and weakfish harvests. Winter flounder (1.62 x 105 fish), mackerel (1.19 x 10� fish), and striped bass (9.9 x 103 fish) lead the combined fishing effort (for both types of fishermen) for the bay/river, ocean, and surf fishing categories, respectively. xvi During the 1 July - 20 December 1975 period estimates were made on the blue- fish, weakfish, striped bass, tuna, fluke, and white perch harvests. Bluefish, with a mean combined catch of 3.44 x 105 are taken most frequently by ocean fisher- men. Striped bass (5.8 x 104 fish) dominate the surf fishing while fluke (1.85 x 105 fish) lead the harvest by bay and river fishermen. xvii 1. ESTUARINE EVALUATION STUDY: PRIMARY AQUATIC PRODUCTION AND NITROGEN. FOUR YEAR REPORT, 1973 - 1977. James B. Durand, Teruo Sugihara, and Charles E. Yearsleyl 'The first author is a Professor with the Department of Biology, Camden Col- lege of Arts and Sciences, Rutgers University. The other authors are graduate students also associated with that department. This report was prepared for the New Jersey Division of Fish, Game, and Shellfisheries with funds provided in part by the New Jersey Division of Marine Services during the period 1973 to 1977. TABLE OF CONTENTS Page LIST OF FIGURES ............................ iv LIST OF TABLES ............................. vi INTRODUCTION . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 1.1 METHODS . . . . . . . . . . . . . . . . . . ............. 1.1 Physical Factors . . . . . . . . . . . . . . . . . . . 1.1 Station Locations . . . . . . . . . . . . . . . . . 1.1 Study Area Statistics . . . . . . . . . . . . . . . 1.3 Temperature, Salinity, Transparency, and Dissolved Oxygen . . . . . . . . . . . . . . . . . . ........ 1.5 Nitrogen . . . . . . . . . . . . . . . . . .......... 1.6 Nutrient Series . . . . . . . . . . . . . . . . . . 1.6 Nitrogen Fixation . . . . . . . . . . . . . . . . . . 1.7 Excretion . . . . . . . . . . . . . . . . .. ....... 1.7 Ammonification . . . . . . . . . . . . . . . ..... 1.9 Runoff ............................ 1.9 Primary Productivity . . . . . . . . . . . . . . . . . . 1.10 Oxidizable Carbon . . . . . . . . . . . . . . . . . 1.10 Seston . . . . . . . . . . . . . . . . . . ......... 1.10 Plant Pigments . . . . . . . . . . . . . . . . . . 1.10 Community Production . . . . . . . . . . . . . . .. 1.10 Phytoplankton . . . . . . . . . . . . . . . . 1.10 Benthic Algae . . . . . . . . . . . . . . . . . 1.11 Marsh Surface Algae . . . . . . . . . . . . . ...... 1.11 Bulkhead Algae . . . . . . . . . . . . . . .. 1.11 RESULTS . . . . . . . . . . . . . . . . . . ............. 1.11 Physical Factors . . . . . . . . . . . . . ...... 1.11 Study Area Statistics . . . . . . . . . . . . . . . 1.11 Temperature . . . . . . . . . . . . . . . .. ..... . 1.14 Salinity . . . . . . . . . . . . . . . . . . ........ 1.15 Transparency . . . . . . . . . . . . . . . . . . . 1.18 Dissolved Oxygen . . . . . . . . . . . . . . . . . . 1.18 Nitrogen . . . . . . . . . . . . . . . . . . .......... 1.22 Nutrient Series . . . . . . . . . . . . . . . . . . 1.22 Ammonia-N .. . . . . . . . . . . . . . . . . . . . . 1.22 Nitrite-N . . . . . . . . . . . . . . . . . . 1.28 Nitrate-N . . . . . . . . . . . . . . . . . . 1.28 Organic-N . . . . . . . . . . . . . ..... 1.32 Nitrogen Fixation . . . . . . . . . . . . . . . . . 1.33 Excretion . . . . . . . . . . . . . . . . .. ...... . 1.37 Ammonification .. . . . . . . . . . . . . . . . . . . 1.40 Runoff . . . . . . . . . . . . . . . . . . ......... 1.42 Productivity ................ . . ........ 1.42 Oxidizable Carbon . . . . . . . . . . . . . . . . . 1.42 Seston . . . . . . . . . . . . . . . . . . ......... 1.44 Pigments . . . . . . . . . . . . . . . . . . ........ 1.48 Bulkhead Algal Production . . . . . . . . . . . . . .... 1.48 Marsh Surface Algal Production . . . . . . . . . . . ..... 1.52 iii Page Benthic Algal Production. ...................1.55 Phytoplankton Production. ...................1.55 DISCUSSION .. ..............................1.60 General. ..............................1.60 Nitrogen. .............................1.64 Inorganic and Organic Fractions. ...............1.64 Nitrogen Fixation. ......................1.66 Excretion. ..........................1.69 Axmmonification. ........................1.69 Runoff. ............................1.70 Nitrogen Budget. .......................1.71 Productivity. ...........................1.78 REFERENCES CITED .. ...........................1.83 APPENDIX A - Tables and Figures from the June 1974 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity .. .........1.85 APPENDIX B - Tables and Figures from the June 1975 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity .. .........1.119 APPENDIX C - Tables and Figures from the June 1976 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity and Nitrogen . . ..1.167 iv LIST OF FIGURES Figure Page 1 Station locations . . . . . . . . . . . . . . .. . . 1.2 2 Sampling schedule . . . . . . . . . . . . . . . . . . . . . . . 1.4 3 Cross sections of the natural and lagoon systems . . . . . ... 1.5 4 Longitudinal sections of lagoons in Lagoon System . . . . .. 1.12 5 Lagoon System A and Meyers Creek system. High and low water volumes and tidal prisms . . . . . . . . . . . . . ...... 1.14 6 Water temperatures at the surface of M 21 and Meyers Pond and vertical profiles of Lagoons A02 and A08 in C . . . . . ... 1.16 7 Temperature stratification (OC): (Surface temperature minus bottom temperature) in the lagoon systems on 9 July 1974 . .. 1.17 8 Temperature stratification (OC): (Surface temperature minus bot- tom temperature) in the lagoon systems on 8 February 1975 . 1.17 9 Monthly mean surface salinity at the mouths of the major sys- tems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.18 10 Salinity at the surface of M 21 andMeyers Pond and vertical profiles of Lagoons A02 and A08 in /oo . . . . . . . .... 1.19 11 Salinity at the surface and bottom of Lagoon B24 . . . . . ... 1.20 12 Salinity stratification: (Bottom salinity minus surface sa- linity) in the lagoon systems on 9 July 1974 . . . . . . ... 1.21 13 Salinity stratification: (Bottom salinity minus surface sa- linity) in the lagoon systems on 8 February 1975 ....... 1.21 14 Secchi disc readings at M 21, Meyers Pond, and A08 ....... 1.22 15 Dissolved oxygen concentrations at the surface of M 21 and Meyers Pond and vertical profiles of Lagoons A02 and A08 in ml 021-1 . . . . . . . . . . . . . . . . . . . ...... 1.23 16 Dissolved oxygen concentrations at the surface and bottom of Lagoons B24 and A08 . . .. . . . . . . . . . . . . . .. . 1.24 17 Dissolved oxygen concentrations at the bottom of the lagoon systems on 9 July 1974 . . . . . . . . . . . . . . . 1.25 18 Dissolved oxygen concentrations at the bottom of the lagoon systems on 8 February 1975 . . . . . . . . . . . . . . . . . . 1.25 19 Ammonia-N contours for Lagoon B24 in jg-atom NH3-N1-1 . . . . . 1.29 20 Ammonia-N contours for Lagoon A08 in pg-atom NH3-N-1-1 . . 1.29 21 The ammonia-N seasonal patterns for the E system . . . . . ... 1.30 22 The seasonal nitrate-N pattern for the E system . . . . . ... 1.31 23 The seasonal patterns for salinity and nitrate-N at the surface of B24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.31 24 Total organic nitrogen seasonal patterns in the Dinner Point Creek system . . . . . . . . . . . . . . . . . . . . . . . . 1.34 25 Monthly mean organic-N concentrations in Lagoons B24 and A08 . 1.35 26 The seasonal variation in the nitrogen fixation rates of the S. alterniflora (short form) communities . . . . . . . . . . . 1.35 27 The seasonal nitrogen fixation rates in the upper bulkhead algal communities within the Lagoon System A in pg-atom NH3- Nh-lm-2103 . . . . . . . . . . . . . . . . . . . . . . . . 1.37 28 Ammonification rates for study year III in pg-atom NH3-N-m-2' day-l103 . . . . . . . . . . . . . . . . . . . . . . . . . . 1.43 29 Oxidizable carbon concentrations . . . . . . . . . . . ..... 1.45 30 Phytoplankton net production and chlorophyll a values ..... 1.49 v Figure Page 31 Plant pigment levels (mg-m-3) at Lagoon A08 contoured . . . . . 1.50 32 Plant pigment levels (mg-m-3)at Lagoon A02 contoured . . . . . 1.50 33 Net community production and respiration of the bulkhead algal community from July 1975 to May 1977 . . . . . . . . . 1.51 34 Net community production and respiration of the marsh surface algal community from December 1974 to May 1977 . . . . . . . 1.54 35 Benthic sediment respiration: Meyers Pond, Meyers Creek mouth, A08 mouth, A12 mouth, and ABD . . . . . . . . . . . . 1.56 36 Phytoplankton production and nutrient enrichment experiments at M 21, Meyers Pond, A02, and A08 . . . . . . . . . . . . . 1.59 37 Phytoplankton gross production and respiration, ml 02'm-2 day-1 . . . . . . . . . . . . . . . . . . . . . . . 1.63 38 The relationship between gross production (GP) and respira- tion (R) for different communities of primary producers . . . 1.81 vi LIST OF TABLES Table Page 1 Sampling sites for all 4 study years . . . . . . . . . . . . . . 1.3 2 Ilyanassa population estimates . . . . . . . . . . . . . . . . . 1.9 3 Bathymetry and other features of the Meyers Creek system and Lagoon System A . . . . . . . . . . . . . . . . . . . . . 1.13 4 Drainage areas in the marsh and lagoon systems . . . . . . . . . 1.15 5 The proportion of the total inorganic nitrogen (TI-N) composed of ammonia-N (NH3-N) . . . . . . . . . . . . . . . . . . . . 1.26 6 Monthly mean ammonia-N concentrations in jg-atom NH3-N'1-1 . . . 1.27 7 Nitrogen standing stocks in pg-atom-106 for the Meyers Creek and lagoon systems during study year III . . . . . . . . . . . 1.32 8 Nitrogen inputs resulting from nitrogen fixation in igat NH3-N- day-1 l10 for study year III . . . . . . . . . . . . . . . . 1.38 9 Total daily ammonia-N contribution by the Meyers Creek system Modiotus demissus population in pgat NH3-N-day-1.106 . . . . . 1.40 10 Ilyanassa obsoleta excretion summary table . . . . . . . . . . . 1.41 11 Ammonia-N excretion rates for mixed natural zooplankton popu- lations in pg-atom NH3-N.l-l'day-l103 . . . . . . . . . . . . 1.42 12 Summary of nitrogen inputs resulting from precipitation in pg-atom day-l10 . . . . . . . . . . . . . . . . . . . . . . . 1.44 13 Suspended particular matter (mg.1-1) from May 1976 to May 1977, all surface values . . . . . . . . . . . . . . . . . . . 1.46 14 Marsh surface soil temperatures (�C) and percent incident light (%Io) that penetrates the vegetation . . . . . . . . . . 1.53 15 Respiration/gross production values . . . . . . . . . . . . . . 1.57 16 Average compensation depths (Dc) and compensation light in- tensities (Ic) for phytoplankton from 24 July 1975 to 16 March 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . 1,60 17 Summary of production data in ml 02'm-2'day-l . . . . . . . . . 1.61 18 Nitrogen fixation rates on the marsh surface . . . . . . . . . . 1.68 19 Benthic sediment nitrogen fixation . . . . . . . . . . . . . . . 1.68 20 Nitrogen budget for Lagoon A02 . . . . . . . . . . . . . . . . . 1.72 21 Nitrogen budget for Lagoon A08 . . . . . . . . . . . . . . . . . 1.73 22 Nitrogen budget for Meyers Creek . . . . . . . . . . . . . . . . 1.74 23 Nitrogen budget for Meyers Pond . . . . . . . . . . . . . . . . 1.75 24 Nitrogen requirements in 106 pg-atom per day based on net oxygen production by water column related plant communities exclu- sive of rooted vegetation . . . . . . . . . . . . . . . . . . 1.77 25 Ratio of the nitrogen requirements of the water related plant communities (exclusive of rooted vegetation) and their nitro- gen supply . . . . . . . . . . . . . . . . . . . 1.78 vii INTRODUCTION The purpose of this study was to ecologically evaluate the natural marshes and adjacent developed areas at Beach Haven West near Manahawkin, New Jersey. This report deals with studies of primary productivity and nitrogen in the salt marshes and lagoons of the system. Our efforts, therefore, have been focused on proces- ses of fundamental importance at the base of the trophic series. Primary production, especially that of the phytoplankton, provides a major source of organic materials for the aquatic systems. Tietrital output from sur- rounding salt marsh surfaces is probably of less significance in this area than in areas subjected to a greater tidal range. The major rooted vegetation is the short form of Spartirna alterniflora. The presence of this form indicates regular tidal flooding occurs but subsequent drainage is poor. Consequently, the main mechanism for transport from the marsh surface is of reduced effectiveness. The tall form of S. alterniflora is restricted in distribution to a narrow band along the edges of creeks. Good drainage is also restricted to that limited area. Nitrogen was studied as the nutrient of importance because other work of ours has shown nitrogen to be the nutrient most often present in limiting concentrations. Phosphorus has been shown to be limiting only rarely or only in nitrogen enriched experiments. Modification of the cycling of nitrogen, therefore, could be of sig- nificance to the energy flow through the system. In this report, we present an overall view of the system documented by selec- ted data collected during the 4 years of the study. METHODS The term of study was from June 1973 through June 1977. In this report, June 1973 to June 1974 is referred to as year I; June 1974 to June 1975, as year II; June 1975 to June 1976, as year III; and June 1976 to June 1977, as year IV. The early part of the study consisted of a broad sampling program covering the area shown in Figure I for an entire year. The study provided background data on the area and led to the identification of smaller systems on which later studies were concentrated. In this report, we have used only selected data from earlier years. Some figures and tables have been taken directly from the annual reports. In some cases, new figures and tables have been constructed. All figures and tables from the annual reports are appended to this report. Physical Factors STATION LOCATIONS -- Figure I and Table I show all stations sampled during the 4 years of the study. Stations were visited according to various schedules. Sta- tions of year I were distributed over the entire area from Dinner Point Creek on the south through Beach Haven West on the north. The same stations were used in year II. In that year, stations were classified as major or minor. Major sta- tions were located in the Meyers Creek System and in Lagoon System A. The other stations in Lagoon Systems B and E and in Dinner Point Creek were classified as minor stations. Major stations were sampled about twice a month; minor stations, once a month. In year III, stations were located only in the Meyers system and in Lagoon System A. In this year, sampling of thevarious parameters occurred according to the schedule shown in Figure 2. All samples in the groups between vertical bars were pooled. Such pooled measures were used in an analysis on a 1.1 f 3 2 4 - Oyster. PO 0 Pt yster Point Mouth Mid C,,e Meyer Mid' 04 Pond e er C eek, L I T T L E eek E G G Uoer-Dinner Poih ree HARBOR Mile Kiwmeter n r Point Took F I I Station locations. 1.2 quarterly basis. In year IV, stations in Lagoon System B were added to those of year III. Table 1. Sampling sites for all 4 study years. Year I II III IV Station Station II Ill IV number name 73-74 74-75 75-76 76-77 1 M 21 x x* x x 2 ABD x x* x x 3 A02 x x 4 A08 x x* x x 5 B17 x 6 B24 x x* x 7 Mill Creek Mouth (E Mouth) x x 8 E68 x x 9 E87 x x 10 Oyster Point Creek Mouth x 11 Oyster Point Creek Pond x 12 Meyers Creek Mouth x x* x x 13 Mid Meyers Creek x* x x 14 Meyers Pond x x* x x 15 Dinner Point Creek Mouth x x 16 Upper Dinner Point Creek x x * An asterisk (*) indicates a particular station was sampled more frequently than stations without an asterisk for that year. STUDY AREA STATISTICS-- Surface dimensions of lagoon and marsh systems were ob- tained from aerial photos. Vegetation coverage was determined by analysis of aerial photos. Bathymetry of Lagoon Systems A and B was measured with a "Shakes- peare" fish finder by recording depths on the longitudinal and transverse lines. Soundings were recorded to the nearest 0.3 m and were referenced to high water. Bathymetry of Meyers Creek and Pond was measured with a graduated pole, and the measures were referenced to mean high water. 1.3 1 2 3 NH4-N, NO2-N, NO3-N . . . . . . _ �- e- _ - - - -- Organic-N, Vertical series . . . _ _ Runoff .. . ... . . . . . . . - I Excretion-N . ........ . : ; Ammonification . . . . . . . . . _- - . . -. Bulkhead algae ....... . - . . -. Benthic . .. -- . ... . . ... .. Marsh algae - S. alt. (Tall) . . - - a Marsh algae - S. alt. (Short) .- -- -- -- -- 0-- -- -- --I-- -- --0 Marsh algae - S. patens . . . . x Marsh sediment - S. alt. (Tall) 4 -- -- -- - - -- _ - � -- - Marsh sediment - S. alt. (Short) _ a Marsh sediment - S. patens . . . --- -- - _ LWater Column .......... Phytoplankton . -. . . . . . .. . - - -- IL-- I _ >- Benthic . . . . . . . . . . . . > Bulkhead algae . . . . . . . . .-- Marsh algae - S. alt. (Tall) :: - a o Marsh algae - S. aZt. (Short) . - -- -- -- -- -- -- . . . - 0_ Marsh algae - S. patens . . . . J J A S 0 N D J F M A M 1975 I 1976 Fig. 2. Sampling schedule. The columns labeled I through 4 represent pooled data periods. J , A S O N , .~. 2 ;..... . Sapn shdl. ,h colmn laee .. thog .. rereen pooled In Figure 3 is a diagram to show the terminology used in this report with respect to general sampling sites. NATURAL SYSTEM I I I II I I I W 'i%:..~. Water /..' .~~~~I I"'''' oun Marsh uI MMarsh Surface Bank Flat Benthic Bank Surface LAGOON SYSTEM _ _ _ 7 / / ~~~~~~~~~~/ /~~~~~~~~~~~ / Algal band / Bulkhead ;\ /; / -.' / ~~L W/ Water *Water column ' Surface - bottom 'I Benthic Fig. 3. Cross sections of the natural and lagoon systems. TEMPERATURE, SALINITY, TRANSPARENCY, AND DISSOLVED OXYGEN -- At all stations, water temperature was measured at the surface each time a station was visited and at 1.0 m intervals to the bottom where the water was sufficiently deep. On occasion, sampling programs were carried out which included a large number of stations located throughout all the lagoon systems, A through E, of Beach Haven West. Temperature was measured with a Yellow Springs Instrument thermistor. Salinity was determined according to the method described in Harvey (1955). Surface samples were taken at all stations each time they were visited. Bottom 1.5 samples were routinely taken except at shallow stations. Salinity samples were frequently taken at 1.0 m intervals to the bottom at A08, A02, and B24. Water transparency was routinely estimated by Secchi disc. Occasionally, a Whitney underwater photometer was used. In later years, a Licor underwater photo- meter was used to measure the amount of photosynthetically active solar radiation, 300 - 700 nm, in the water column. Dissolved oxygen samples were taken according to a schedule similar to that for salinity. The azide modification of the Winkler method was used to determine dissolved oxygen. Nitrogen NUTRIENT SERIES -- Surface samples for analysis of ammonia-N (NH3-N), nitrite-N (NO2-N), nitrate-N (NO3-N), organic-N (Org-N: total, soluble, and particulate forms) and total phosphorus (Tot-P) were taken in an acid cleaned bucket. Sub- surface samples were taken by Van Dorn bottle. Surface and bottom samples were taken routinely. Frequently, samples were taken at 1.0 m intervals from surface to bottom in the lagoons. Within the lagoons, sampling was done at both the mouth and upper ends. In this study, the upper end data were used to confirm the mouth data trends. Samples were stored in the dark in insulated acid cleaned containers until filtered a short time later. Either glass fiber (GF/C) or Millipore filters were used. Filtrates were frozen and stored in acid cleaned Nalgene bottles. Samples were frozen in the Nalgene bottles without filtration for analysis of total or- ganic-N and total phosphorus. Chemical analyses were made by the following methods: N03-N Wood, Richards, and Armstrong (1967); Jenkins and Medsker (1964) N02-N Bendschneider and Robinson (1952) NH3-N Solorzano (1969) Org-N Kjeldahl digestion after Strickland and Parsons (1968), followed by Solorzano's NH3-N method Total Persulfate digestion (Menzel and Corwin 1965) followed by the Phosphorus ascorbic acid method of Murphy and Riley (1962) Once the concentrations were determined, the appropriate volumes for the layers sampled were applied to calculate the total amount present at the site. This necessitated a "bottom to top" approach in applying the volumes. Tidal fluctuations involved changes only in the top layer volume while the bottom layer volumes remained unchanged. Sampling at a low tide stage sometimes caused the number of layers sampled to be less than the number of layers dictated by the bathymethy work. When this occurred, the surface layer volume was omitted. 1.6 NITROGEN FIXATION-- The acetylene reduction procedure (after Stewart, Fitzgerald, and Burris 1967) with certain modifications (Waughman 1971; Schell and Alexander 1970) was employed in the estimation of nitrogen fixation rates. The theoretical conversion of 3 moles C2H4 to 2 moles NH3-N was applied to convert ethylene pro- duction to nitrogen fixation. A standard field incubation time (1300 hours) was established. This was to minimize the interfering rate changes resulting from differing intensities and angles of illumination occurring over the course of the day. The light intensities were also adjusted by screening to duplicate the in situ radiation for each site sampled. The sample analysis was done with a flame ionization detector equipped gas chromatograph. A'1.8 m stainless steel column with a 3.2 mm inside diameter was packed with 80/100 mesh Poropak N and utilized in the analysis of ethylene levels. The samples were calibrated against pure ethylene standard curves. Because the acetylene reduction rates were on an hourly basis, it was neces- sary to extend the rates for 24 hours to calculate a nitrogen contribution. This actually produced a minimum estimate of nitrogen fixation since the standard in- cubation time was at a period of minimal activity. This deduction was based on literature references and limited diel work by our group which indicated high light intensity could suppress the midday rates below the 24 hour mean rate. Samples of known surface area were taken from the communities listed below except in the case of the water column communities where volume served as the reference base. These referenced rates were then applied to the existing distribution of their particular communities. Communities tested in Lagoons A02 and A08 were: 1) Upper bulkhead algal community 2) Lower bulkhead algal community 3) Lagoon water column community 4) Benthic sediment community Communities tested in the natural marsh system were: 1) Spartina alterniflora (short form) algal community 2) Spartina alterniflora (short form) substrate community 3) Spartina patens/DistichZis spicata algal community 4) Spartina patenslDistichlis spicata substrate community 5) Spartina alterniflora (tall form) bank algal community 6) Spartina alterniflora (tall form) bank substrate community 7) Creek water community 8) Benthic sediment community 9) Salt pool community Representative sites for the above communities were selected in the Meyers Creek system and in the lagoons. Samples within these sites were randomly chosen. Sampling was done according to the schedule shown in Figure 2. EXCRETION-- In this study, excretion was defined primarily as the elimination of metabolic waste products. Because the majority of the organisms in both the lagoon and creek systems were ammonotelic, excretion would affect primarily stocks of ammonia-N. This neglected solid fecal matter except for that fraction which rapidly converted to inorganic ammonia-N. While nitrogenous compounds in fecal matter would eventually be coverted to ammonia-N, the short term 1.7 (approximately 24 hours) contribution an organism made to the available nitrogen pool was measured in these experiments. Only for a limited number of experiments were total organic-N contribution and, therefore, fecal deposition measured. Since it was not possible to evaluate all organisms, certain species were selected. Modiolus demissus, Ilyanassa obsoleta, and mixed natural zooplankton populations (primarily Acartia sp.) were chosen for study. Excretion in this study, there- fore, represented only a fraction of the actual amount of nitrogen recycled by organismal metabolism. Excretion rates by Modiolus demissus, Ilyanassa obsoleta, and mixed natural zooplankton populations were determined for various sites in the Meyers Creek system and Lagoon System A. Ammonia-N was measured by the phenol hypo-- chlorite method (Solorzano 1969). Total organic-N levels were also measured for some of the Modiolus and lZyanassa samples. The Kjeldahl digestion procedure of Strickland and Parsons (1968) followed by a Solorzano ammonia-N determination was used. The major portion of the ammonia-N work was done in the third study year on a quarterly basis (Figure 2). Organic-N experiments were confined to the latter quarter of year III. The Modiolus sampling was restricted primarily to the Mid Meyers Creek sta- tion. There was no need for a Lagoon System A station because Modiolus was not present in the lagoon system to any significant extent. The Modious were selec- ted using a randomly knotted cord laid perpendicular to the creek bank at random- ly chosen intervals. Specimens closest to each knot on the cord were used. I1yanassa obsoteta were collected from Mid Meyers Creek, Meyers Pond, Mid Lagoon A02, and Mid Lagoon A08 by means of a dip net dragged along the sediment surface perpendicular to the water current direction. Zooplankton were collected using 2 methods. Prior to April 1975, the site water was poured through a plankton net using a bucket of known volume. From April 1975 on, diagonal tows with a Clarke Bumpus plankton sampler equipped with a #20 net were used. The main sites sampled were Mid Meyers Creek, Lagoon A02, and Lagoon A08. Meyers Pond was too shallow to tow the Clarke Bumpus sampler without considerable bottom influence and was therefore discontinued as a sampling site. The data selected for this report were those whose filter volumes were approximately 200 liters. Occasionally, smaller volumes were filtered to deter- mine the effects of crowding on excretion. The Modiolus and l1yanassa were washed and scrubbed with a wire brush to remove all epiphytic algae. Organisms were placed in glass fiber filtered site water and allowed to acclimate. Subsequently, the mussels and snails were trans- ferred to acid cleaned vessels containing known amounts of filtered site water. The organisms were again allowed to acclimate prior to the beginning of the incu- bation. It was not possible to separate the zooplankton from the epiphytic algae and detritus collected with the zooplankton. To minimize this problem, collec- tions were made avoiding unnecessary entrapment of these materials. The sample brought to the laboratory was resuspended in a known volume of filtered site water and placed in an acid cleaned container prior to incubation. Initial ammonia-N samples were taken from each bottle. After a 24 hour incubation at ambient temperature and light, ammonia-N samples were taken again. Controls consisting of filtered site water were similarly run. Changes in 1.8 ammonia-N concentration in the experimental bottles were corrected for changes in the control bottles. The rates were used to calculate the contribution each population made to the nitrogen levels at the respective sites. ModioZus and 1lyanassa rates were extrapolated using estimates of the number of organisms present. The Modiolus population was estimated to be 1,653,453 for the entire Meyers Creek system. This value was derived from the data of Ray and Kiesel (pers. comm.).2 The lZy- anassa estimates were based on a dredge survey made on 19 February 1976 (Table 2). Table 2. Ilyanassa population estimates. Snails per Total estimated m2 m2 population Meyers Creek 24.40 23,000 5.612 x 105 Meyers Pond 24.00 43,000 1.032 x 106 Lagoon A02 36.70 6,763 2.482 x 105 Lagoon A08 40.00 9,067 3.627 x 105 The zooplankton rates were extrapolated using the volume of water filtered through the Clarke Bumpus or the plankton net and the volume of the water at the site as determined by the bathymetry work. AMMONIFICATION --Ammonification is usually considered to be the return of ammonia- N to the system through the biological processes that lead to the breakdown of organic nitrogenous compounds. Such processes are generally carried out by micro- organisms, such as bacteria. In these experiments, ammonification is the result of the activities of the entire benthic community - bacteria as well as protozoa, nematodes, and whatever else might have been there. For the most part, the or- ganisms were small; few large organisms were found in the sediments used in the experiments. Benthic sediments of given area from a given site were suspended in a series of BOD bottles. After a period of equilibration, ammonia-N concentrations in a pair of bottles was measured. This was taken as the initial ammonia-N concen- tration. The remaining BOD bottles were incubated in the dark for 24 hours at ambient temperature. At that time, the ammonia-N concentration was determined in the remaining bottles. The difference between initial and final ammonia-N concentrations was taken as the ammonification rate per unit area. RUNOFF --Runoff in the lagoon system had four basic sources: rain falling direct- ly on the lagoon water surface; precipitation channeled into the lagoon via road drainage systems; rainfall delivered by drainage pipes into the lagoon from the roofs of individual homes; and rain flowing into the lagoon after impinging on unpaved land. Sampling was conducted on a quarterly basis at the locations where z This work was done in connection with the benthic invertebrate population study done for this project. 1.9 owner permission was given for access to the above types of runoff. Only the first three runoff sources were tested. Coincident with these sampling trips, direct rainfall was also collected in the area of Lagoon System A. Attempts at measuring marsh drainage unfortunately were unsatisfactory. Therefore, rainfall data will be applied to the marsh system in an attempt to pro- vide an estimate of the nitrogen input by precipitation. j Based on precipitation records and surface area, the volume of rainfall in- volved with a given type of runoff was calculated and used to extrapolate the con- centration of the relevant nitrogen fraction. This method underestimated nitrogen input because the sampling evaluated the middle of a storm period. This "clean- sing" effect of the rainfall was not sampled. Primary Productivity OXIDIZABLE CARBON -- Oxidizable carbon was measured by the wet oxidation of resi- dues contained on glass-fiber filters (Reeve - Angel, 0.1 p), according to the method of Strickland and Parsons (1968). SESTON-- Seston was determined according to the method of Strickland and Parsons (1968). Residue retained on glass-fiber filters were dried at 1000C for a mea- sure of total dry weight. Ignition at 5000C for one hour was used in estimating combustible organic matter. w PLANT PIGMENTS --Plant pigments were estimated according to the method of Strick- land and Parsons (1968), using 0.8 i pore size Millipore filters. COMMUNITY PRODUCTION -- Phytoplankton-- The primary productivity of surface phy- toplankton populations was measured using a light-dark bottle technique and chan- ges in dissolved oxygen concentration. Incubations were carried out in a lighted BOD incubator at ambient temperature for 24 hours. After study year I, subsamples of surface populations were also subjected for 24 hours to a graded light inten- sity series of natural radiation, either in a tidal'creek at the Little Egg Station or in an outside water bath with a flow-through circulation of creek water. Bottles incubated in the creek were placed at varying depths corresponding to a relative intensity range of 100%, 50%, 25%, 10%, and 1% surface intensity. Bot- tles incubated in the water bath were also subjected to this range of natural illumination by using light attenuators made of plastic screening. The results of the graded light intensity series (expressed in terms of ml 02-1-1'day-1l) were then plotted against the depth to produce a productivity profile. Subsequent planimetry permitted an estimate of productivity and respiration on an areal basis (ml 02-m-2,day-1). The depths assigned to the transparency series were approximated from Secchi disc readings using the following relationships: k = 1.7/S (Poole and Atkins 1929), where k is the extinction koefficient (m-1) and S is the depth (m) of the Secchi reading (S); and I = Ioe , where D is the depth (m), and e is the base of the natural logarithms. Io and I are the light intensities at the surface and at depth, D, of the water column. The response of phytoplankton to various nutrient enrichments was determined using a modified Ryther and Guillard (1959) enrichment mixture. Bottles were incubated both under natural light conditions (50% Io) and artificial illumination, together with nonenriched controls. 1.10 Benthic Algae--- Production by the benthic microflora was examined at the following stations: Meyers Creek mouth, Mid Meyers Creek, Meyers Pond, A12 mouth, ABD, and A08 mouth. Pyrex tubes (30.5 cm long, 3.8 cm inside diameter) were used to obtain cores of the sediments. The water overlying the cores was retained since earlier experiments on replacing the water column with filtered water resulted in excessive disturbance of the mud-water interface. The cores were incubated for 12 hours in laboratory incubators, both in the light and in the dark and were periodically shaken on a specially designed shaker mechanism in order to insure a homogeneous water column above the sediment. After incubation, subsamples of the water column were withdrawn and Winkler titrations performed. Marsh Surface Algae-- The productive capacity of the marsh surface algal communi- ties was examined in stands of Spartina alternifzora (tall and short forms), S. paztens, and from an exposed mudflat located at the Mid Meyers Creek location. Using a specially constructed coring device, marsh surface cores were obtained in Pyrex tubes. The experimental design was basically the same as that employed in the benthic studies, except that the marsh surface cores were covered with filtered creek water of known oxygen content. Bulkhead Algae --Bulkhead algal production was examined along the main channel of Lagoon System A (upper, mid, and lower main channel). Circular mats of the algal community of known surface area were removed from the bulkheads and placed in light-dark BOD bottles. These were later filled with filtered lagoon water of known oxygen content and incubated for 12 hours in the laboratory incubators. Changes in the oxygen content of the water column over a known surface area of benthic, marsh surface, and bulkhead community were then converted to ml02m2 24h-1. The respiratory rates so measured are indicative of total community re- sponse and incorporate algal, bacterial, faunal, as well as sediment chemical de- mands. In addition, such production estimates are necessarily "potential"1 rates, due to the use of artificial illumination and the stimulation of only submerged conditions. Measures of light penetration through the three dominant plant canopies of the marsh surface were obtained with a Whitney Underwater Meter (LMA-8A) prior to 17 February. A Licor quantum meter (LI-170) and sensor (LI-190S) subsequently were used to estimate the photosynthetically active radiation. The sensor of the latter instrument was much smaller and the disruptive influence upon placement under a plant canopy was greatly diminished. RESULTS Physical Factors STUDY AREA STATISTICS -- In Figure 4 are shown the longitudinal plots of depths measured along the central axis of each lagoon in Lagoon System A. In Table 3, selected calculated features for Lagoon System A and the Meyers Creek system are compared. An. important feature is the irregularity of the bottom topography of lagoons. Numerous potholes, coupled with the presence of slow currents, tend to trap water and thereby lead to stagnation. In addition, the mean depth of the lagoons is generally greater than that of the neighboring bay. In effect, the lagoon system comes to represent one large pothole as long as the sill depth is less than that of the lagoon system. The sill depth of Lagoon System A is 2 mn. Mean depth of the system is 3 mn. 1.11 Depth A08 3L 3.2 �- 3.6 Mean Depth (m) 100m A05 A09 3.72 - - --" - 3. A04 AlO z - -2.9 3.2/ - -- ---25z A03 All �~~~-2.5 3.8--- A02 A12 3.0---- 2.1 \AO1 A13 1.7---\ i .---.2.6 Fig. 4. Longitudinal sections of lagoons in Lagoon System A. Whereas the tidal prism volume of the lagoons is about 25% of the high water volume, for Meyers Pond and Creek, it is about 50% (Figure 5). Tidal flushing of the Meyers Creek system therefore, is greater than that for the lagoon sys- tem. Another important point is that the tidal prism volume of Meyers Pond is approximately the low water volume of Meyers Creek. Essentially, Meyers Creek at low water is filled with Meyers Pond water. Therefore, at high water, a substantial fraction of Meyers Creek must be bay water. A lesser fraction, but still appreciable fraction, of Meyers Pond at high water is bay water since mixing of Creek and Bay water must occur in Meyers Creek during flood tide. 1.12 Table 3. Bathymetry and other features of the Meyers Creek system and Lagoon System A. Meyers Meyers Lagoon Parameter Pond Creek A08 A02 System A Mean depth (m) .42 1.2 3.6 3.0 3.0 Perimeter (m) 1,255 2,348 445 619 8,287 Tide range (m) .46 .46 .46 .46 .46 Area water 43,000 23,000 6,763 9,067 148,566 surface (m2) Drainage area (m2) 200,365 223,517 18,208 26,941 284,720 Volume (m3): High water 18,000 22,000 14,800 16,000 190,100 Low water 7,500 12,600 11,700 12,500 147,504 Tidal prism 10,500 9,400 3,100 3,500 42,596 Volume (m3) for the interval: 0.0-0.5 m 12,800 3,600 4,200 71,000 0.5-1.5 m 5,200 4,900 5,800 102,000 1.5-2.5 m 3,400 3,600 58,000 2.5-3.5 m 2,300 1,600 24,000 3.5-4.5 m 500 600 7,000 4.5-5.5 m 100 200 1,000 Percent volume greater than 3 m 10.1 8.8 6.5 Though the ratio of (tidal prism volume/high water volume) of A08 and A02 are similar (Table 2), A02 is undoubtedly influenced by bay water to a greater degree than A08 because A02 is nearer the entrance to the lagoon system. In Table 4, data for the drainage of Meyers Creek system and Lagoon System A are given. The drainage for Lagoon System A is from roof tops, gravel yards, and black top road surfaces. Much of this drainage flowed through drain pipes and storm sewer pipes into the lagoons. In contrast, the Meyers Creek system drainage area was salt marsh. The greatest area was covered by Spartina alterni- flora (short form). The next greatest area was covered by S. patens. Spartina 1.13 Lagoon Meyers System A Creek 260 -26 HW 240 -24 220 -22 o HW // / 200-20 / / 0 / .LW 180- 18 / a ntance ae/ 160-tb~~~~~~~~~ / / A02-12 160 - 16/ X/ no /y ' 140 - 14 / A03-11 E I ~~~~~~~~~~A04-t0 /) / E 120-12 / 0 1 - 10 LW too -to 80-8 /// ~~~~09/ / A05-09 - 60 - 6 / //0 o / /0~~ - ~ (Meyers Pond Tidal Prism 40 - 4 / _� 96% Meyers Creek LW Volume) / /g 20 - 2 / A06-08 A7 200 400 600 800 1000 1200 Length im) Prism volume/High water volume = .17 .26 .21 .28 .27 .29 .25 .46 .51 .51 .51 .51 .51 Fig. 5. Lagoon System A and Meyers Creek system. High and low water volumes, and tidal prisms. (Meyers System = o---o, Lagoon System A = .- ). aZternifZora (tall form) was found only along the edge of the creek and accounted for only about 1% of the drainage area. TEMPERATURE--Water temperature data are given in Figures 6, 7, and 8. Surface temperatures were essentially the same at all stations. At low temperatures, around 50C, temperatures in the ponds and lagoons were slightly higher than those in the bay. This probably reflected daytime warming of the smaller water volumes in the ponds and lagoons. Seasonal variation was from a winter low of -0.2oC to a summer high of slightly over 300C. In Figure 6, water temperatures have been contoured for Lagoons A02 and A08. Thermal stratification was marked at A08 for an appreciable part of the year in the spring and summer. Stratification was less well developed at A02, nearer the junction of the lagoon system with the bay. The extent of development of thermal stratification throughout all lagoon systems is shown in Figures 7 and 8. Surface temperatures were higher than bottom temperatures in the summer. Bottom tempera- tures were higher than surface temperatures in the winter. Inverse thermal strati- fication was common in the winter. Some of the stations sampled for Figure 8 were covered by about 5 cm of soft ice. Thermal stratification appears to be a feature of lagoons, even in the winter months. 1.14 Table 4. Drainage areas in the marsh and lagoon systems. Area Percent of total Site (m2) (%) Meyers Creek system: Total marsh surface 448,259 100.0 Spartina patens 169,561 37.8 Spartina alterniflora (short) 278,698 62.2 Spartina alterniflora (tall) 4,070 .9 Lagoon System A: Total drainage area* 284,720 100.0 Lagoon A02 drainage area 26,941 9.5 Lagoon A08 drainage area 18,208 6.4 * The term drainage area within the lagoon system refers to the sum of road, ground, and roof surface present. SALINITY -- In Figure 9 are plotted the surface salinity values from stations near the mouths of the lagoon systems, the creeks, and for the bay (M 21) for year I. The seasonal pattern is clear. The lowest salinities occurred during the winter; the highest salinities, in late summer and early fall. Measurements in the summer of 1976, not shown here, gave a record high salinity for A08 of more than 30 0/oo. This occurred during a period of very low rainfall. The occurrence of Hurricane Belle resulted in a return to lower, more normal, salinities. It is also seen in Figure 9 that E Mouth (Mouth of Mill Creek) exhibited the lowest salinities and the greatest seasonal variation of all the stations plotted. These data reflect the influence of fresh water flow through Mill Creek. On the other hand, rather high salinities were observed at Dinner Point Creek Mouth, frequently higher than those recorded for other stations. Apparently, little fresh water enters through Dinner Point Creek. In Figure 10, the salinity data of Meyers Pond, M 21, A02, and A08 are plotted. Meyers Pond salinities are generally lower than those of M 21 because of upland drainage. Maximum differences, as might be expected, occurred at the time of maximum precipitation. Salinities at A02 and A08 are contoured in Figure 10. Marked salinity stratification occurred at both stations in early fall and late spring. During the summer and fall, salinity stratification was the rule below about the 2-3 m depth. At the deeper station, B24, the difference between surface and bottom salinities was pronounced during the greater part of the year (Figure 11). Bottom salinities at this station varied very little during the year. However, station B24 is extremely isolated from the entrance to the Lagoon System B. Also, a large storm sewer pipe enters the lagoon next to station B24. 1.15 30 - ~ ~ ~ ~ ~ ~ ~ - Meyers Pond 00M21 E J A S 0 N D J IF M A M A02 0 I 'lo I 21- . ..... ----- ICEI~ 3~~~~~~~~~ I A- . .. ... I 2 5 J __2_0 7 1 1 0-L 15-~~~~~~~~~~~I 2~~~~~~~~~~~~~~~~~~ ICE 6 I~~~~~............ --1----- J OL D T~~~~~~~ I_ 2- I I......j 3 15 -I J J ~~A S 0 N DI J F M A M 1975 I1976 Fig. 6. Water temperatures at the surface of M 21 and Meyers Pond and verti- cal profiles of Lagoons A02 and A08 in OC. 1.16 ~~~~~~~~~~~~~~~~~~~~~~~~cc � <1 M 21 I >5 (Surface Temperature minus Bottom Temperature) (Surface Temperature minus Bottom Temperature) NOTE Bottom Temperatures > Surface Temperatures Fig. 7. Temperature stratification (�C): Fig. 8. Temperature stratification (�C): (Surface (Surface temperature minus bottom temperature) temperature minus bottom temperature) in the lagoon sys- in the lagoon systems on 9 July 1974. terns on 8 February 1975. Absolute value of the differ- ence is indicated. 250- 0 .415- 'E CD ~Dinner Point Greek =:~/ 10 - 'Meyers CreekO _ - \ Mouth E Mouth ~- ABD o- - a 5 - M 21= d A S 0 N 0 J F M A M 1973 1974 Fig.9. ontly eansurface salinity at the mouths of the major systems. In Figures 12 and 13, the extent of salinity stratification throughout the lagoon systems is shown. Stratification is most common at those stations that are most removed from the lagoon system entrance to the bay except for System C. Greatest stratification was observed in Lagoon System E. The main axis of Lagoon System E is Mill Creek. Undoubtedly, the fresh water flow in Mill Creek accentu- ates the salinity stratification in those lagoons. Stratification, by preventing vertical mixing, insures that water below sill depth for the lagoon system is trapped within the system. TRANSPARENCY--- Secchi disc measurements of water transparency are plotted on a time line in Figure 14. Data are plotted for two years and for stations repre- sentative of the bay, a salt marsh pond, and a lagoon. A period of relatively high transparency occurred at the bay station, M 21, in the summer and early fall. Generally, lower transparency occured after that. Little seasonal variation occurred in the salt marsh pond which was characterized by lowest transparency of all areas. Maximum transparency in the lagoon occurred in late fall and early winter. DISSOLVED OXYGEN--In Figure 15, surface dissolved oxygen concentrations for Meyers Pond and M 21 are plotted on a time line, and vertical profiles of dissolved 1.18 30 - 0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~0 _ 20- C 0-O ~~Meyers Pond J J ~A S 0 N DI J F M A M A02 0j V ___~~2 20 21 2 2 f 2 4 2~~~2---- - K-------- 2~~~~ - ~~~~~IC 3 -r --- - - - - - - - -- - - - - - - - - ---~~~- 2 _ ~~~------I. -_ 1- --22 21- 24 22 21 --22-- _4:"H+- IA 2-~~~~---- -_ -- __M 2I 6~~~~~~~~~C -4: Iz:2 _23 - 2----- --- 5 ~ ~ ~ ~ ------- - - -------- 1975----- 1976---- Fig.~~~~~~~~~~~~~~~~~~~ 1.SlntattesraeoM21adMyrPodadvriapo----- fie2fLgon 0 n A8i /0 1.19~~~~~~~------ 5-0 20 - B24 E -.- Surface 15- o--o Bottom 10 10I I I I I I I iII II JA S O N D J F 1975 1974 1975 Fig. 11. Salinity at the surface and bottom of Lagoon B24. oxygen are contoured for lagoons A02 and A08. Surface dissolved oxygen concen- trations were maximum in the winter and minimum in the summer. Meyers Pond surface values were especially low in the summer though no zero concentrations were observed. Dissolved oxygen concentrations in the lagoons fell to less than 1 ml 02-1-1 frequently at bottom depths and remained low for appreciable periods of time. The periods of low dissolved oxygen occurred both in the summer and in the winter. In Figure 16, zero oxygen concentrations are shown for long periods at A08 and B24. Lagoon B24 is deeper than A08 and is further from the entrance to the lagoon system. The extent of the development of low oxygen concentrations at bottom depths throughout all the lagoon systems is shown in Figures 17 and 18. It is clear in the July survey low dissolved oxygen levels occurred at bottom depths at most lagoons. In contrast, oxygen levels at stations along Mill Creek are not low. Though fewer stations were 3ampled in the February survey, low dissolved oxygen concentrations were often found at lagoon stations. Again, it appeared that, the more remote the station from the lagoon system entrance, the greater the chance that bottom dissolved oxygen would be low. 1.20 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ M21 <1~~~ ~ ~ ~~~~~~~~~~ M21 < <1 I-"~~~~~~~15I ~~~~~ 5 ~~~ ~ ~ ~ 0 W5 Bottom Salinity minus Surftace Salinityy) Fig. 12. Salinity stratification: (Bottom Fig. 13. Salinity stratification: (Bottom salinity minus surface salinity) in the lagoon salinity minus surface salinity) in the lagoon systems on 9 July 1974. systems on 8 February 1975. 4- M21 o---o 1976 3 1975 E 3- > Total Depth o 2 % 0 J J A S O N D J F M A M 4 A08 3 3- 2 - I II I I I I I I I I J J A S O N D J F M A M 1975 1976 Fig. 14. Secchi disc readings at M 21, Meyers Pond, and A08. Nitrogen NUTRIENT SERIES -- Ammonia-N -- Ammonia-N was the predominant inorganic nitrogen compound found in the study area waters (Table 5). Only occassionally did the pro- portion of the remaining inorganic nitrogen compounds exceed the proportion of ammonia-N present. The prevalence of ammonia-N was particularly noticeable at the deeper lagoon stations such as B24 bottom, A08 mouth bottom, and A02 mouth bottom where anaerobic or low oxygen conditions were often present. Ammonia-N concentrations at Marker 21, the bay control station, were general- ly 1.0 p1-atom NH3-Nl-11 or less and only on rare occasions exceed 2.0 Vg-atom NH3-N 1 . This was typical of the study area as generally low ammonia-N levels were found at the surface at all stations. The upper stations in the Meyers, Dinner Point, and Mill Creek (E) systems had the highest surface ammonia-N con- centrations. Excluding station E68, which was influenced by a nearby sewage out- fall, surface ammonia-N concentrations ranged as high as 23.9 vg-atom-ll1 but were usually 10.0 pg-atom-1-1 or less. Concentrations at the creek mouth stations, while somewhat higher than at M 21, were generally lower than the upper end con- centrations and were usually less than 5.0 pg-atom NH3-Nl-11 (Table 6). This apparently resulted from the mixing of nitrogen poor bay water with the ammonia- N enriched creek water. The only vertical sampling in the creeks was done at the 1.22 - Meyers Pond C 10 0--a M21 xT 0io ' __, -0T 5ICE o..~~~~~~ -oo - - --a- C -- o~ 5 ,--- -. /iI I I I Ii I I I 75; J J A S O N D IJ F M A M A02 0 / 1- 5 6 2I ~~~~~2- JI~~~~ I ~ICE E 3- - 7 7 6 0. r~ a,~/ 24- I I IC 6- 5x 7 I I76 4~ J J A S 0 N D J F M A M A08 6 7 20 i I ~~~~~~~~I6 E 2~~~~~~~~~-4~~ ?jICE E - I 5 I //Y J J A S O N D J F M A M 1975 1976 Fig. 15. Dissolved oxygen concentrations at the surface of M 21 and Meyers Pond and vertical profiles of Lagoons A02 and A08 in ml 02'1-1 1.23 9- B 24 8- Surface Bottom o- - - 7- 6- 5- 0 4- 3- 0 2- X 1- C( 0.0--0-00-0-0--0- -0-0---0 0-0-0- -0--- 0 > J A S 0 N 0J F M A M 0 1 973 1974 09 A08 08- C,, 0~~~~~~~~~~~~~ 6- 0 5- X 4- Ix hII I\i 1 2- 1 Ig 0 2 - 1- 0 /0 0 ' - I ~~~ ~ ~~~~~~~~~~~~~~~~~I I I C, 0-6-0 ' J A S 0 N 0 J F M A M 1 973 1974 Fig. 16. Dissolved oxygen concentrations at the surface and bottom of Lagoons B24 and A08. 1.24 Bottom Dissolved Oxygen \ Bottom Dissolved Oxygen ( ml O,1- ) W (ml O'1I") M 21 > 3.5 0 >3.5 1.0 -3.5 .-35 * 10-35l* 10-3.5 >1 0 <1.0 Fig. 17. Dissolved oxygen concentrations at Fig. 18. Dissolved oxygen concentrations at the the bottom of the lagoon systems on 9 July 1974. bottom of the lagoon systems on 8 February 1975. Table 5. The proportion of the total inorganic nitrogen (TI-N) composed of ammonia-N (NH3-N).* Study Station Study year: I II III mean Dinner Point Greek mouth surface .66 .63 .65 Upper Dinner Point Creek surface .85 .84 .85 Meyers Creek mouth surface .52 .64 .82 .66 Mid Meyers Creek surface .84 .84 Meyers Pond surface .86 .77 .81 .81 M 21 surface .42 .52 .83 .59 ABD surface .64 .47 .76 .62 A02 mouth surface .57 .57 A02 mouth bottom .97 .97 A08 mouth surface .53 .52 .74 .60 A08 mouth bottom .99 .97 .98 .98 B24 surface .62 .54 .58 B24 bottom 1.00 1.00 1.00 The proportions were calculated by dividing the annual mean NH3-N concentra- tion by the annual mean TI-N concentration. Annual means were based on all available monthly means. E mouth and E68 stations. The creek water was found to be moving downstream in a layer on top of the penetrating bay water. The deeper bay-related water was nitrogen poor compared to the upper layer. This lack of mixing also helped explain why the E mouth surface values were so rich in ammonia-N compared to the other creek mouths. Probably, the creeks serve as an ammonia-N source for the bay. There was no suggestion of a similar function in the lagoons where ammonia- N levels were comparable to those of M 21 and there was no evidence of a concen- tration gradient leading to the bay. Aside from the lack of a concentration gradient, vertical sampling showed the ammonia-N distribution in the lagoon systems differed in other ways from that in the creek systems. Because the lagoons were deeper and vertical mixing forces were reduced compared to those in the creeks, stratification in the water column occurred. Ammonia-N accumulated at these deeper sites in proportion to the length and degree of stratification. The A02 mouth station was infrequently stratified and showed only slightly raised ammonia-N levels. In contrast, the B24 station had some concentrations in excess of 200 pg-atom NH3-N-1 I because of the nearly continuous stratification (Figure 19). The A08 mouth station was intermediate 1.26 Table 6. Monthly mean ammonia-N concentrations in Pg-atom NH3-N-1-1. Dinner Upper Meyers Point Dinner Marker Creek Meyers Creek Point E Date 21 mouth Pond mouth Creek mouth E68 E87 6/73 1.3 1.9 6.2 7.2 7.4 3.0 7/73 0.7 1.3 2.5 0.8 3.6 2.6 13.6 2.3 8/73 0.8 0.6 0.8 0.5 1.8 2.1 5.9 1.3 9/73 0.6 0.5 0.8 0.8 1.3 2.3 2.7 2.6 10/73 0.4 0.9 0.5 0.4 0.4 0.7 3.1 2.3 11/73 1.4 1.9 4.6 2.7 12.0 0.9 3.2 3.3 12/73 0.3 1.5 6.7 0.5 4.3 0.8 27.1 5.4 1/74 0.4 2.2 1.8 1.5 1.4 5.0 8.9 7.7 2/74 0.6 0.0 6.6 0.1 11.5 5.1 8.4 5.4 3/74 0.1 0.2 10.0 0.0 6.2 0.8 8.7 5.5 4/74 0.1 0.6 0.5 0.1 5.2 3.3 2.9 4.2 5/74 0.2 0.3 0.8 0.1 1.7 0.0 12.3 1.3 6/74 0.0 0.0 0.4 0.0 1.7 0.0 0.0 0.0 7/74 0.8 0.8 2.0 0.7 5.2 0.4 1.0 2.1 8/74 0.7 1.5 1.0 3.0 6.6 1.3 0.6 1.1 9/74 1.3 4.7 6.6 5.9 5.8 0.5 3.3 1.4 10/74 0.7 0.9 2.5 0.8 5.4 5.0 8.3 4.2 11/74 0.8 1.5 1.8 0.9 16.7 6.8 12.1 7.7 12/74 0.5 1.6 1.0 0.1 1.6 0.6 0.0 2.5 1/75 0.7 3.0 4.2 3.6 5.6 5.8 6.6 4.5 2/75 0.5 0.9 1.6 0.3 2.7 8.8 9.8 8.0 3/74 0.4 1.1 0.6 0.5 2.7 7.5 10.9 5.7 4/75 0.6 0.4 5.2 3.0 10.2 3.2 17.2 5.5 1.27 to these two sites with respect to stratification and ammonia-N concentrations (Figure 20). High concentrations of ammonia-N were confined to within 2.0 meters of the bottom at B24 and 1.0 meter at A08 mouth. At B24, peak ammonia-N concentrations occurred at the bottom in the late sum- mer - early fall. Concentrations dropped to levels below 20 Vg-atom NH3-N-1-1 at B24 when stratification broke down in late fall. Following the fall overturn, concentrations again increased to the late summer levels. The main periods of stratification at A08 were during the summer, when it was strongest, and during the winter. Peak bottom concentrations ranged as high as 265 pg-atom NH3-N--17 in the summer and 66.3 pg-atom NH3-N'1-1 in the winter. Concentrations were generally below 5 pg-atom NH3-N'-11 for the remainder of the year. The nearly year round low surface concentrations in the lagoons resulted from several pro- cesses including photosynthetic demand and nitrification. At the B24 station, the surface values did increase during the periods of destratification. Appar- ently, the bottom ammonia-N enriched the entire water column. The relation be- tween lower surface salinities and increased surface ammonia-N concentrations also suggested there was an input from runoff. The overall increase amounted to an additional 5 to 10 pg-atom'1-1 at the surface. At the A08 mouth site, no simi- lar increase was detected. For the most part, surface concentrations remained below 2.0 pg-atom NH3-N'-11. The seasonal ammonia-N trends for the creek systems were subject to variation from year to year. There was a relationship between increased upper end ammonia- N concentrations and reduced surface salinities. Increased concentrations resulted from either storm activity and/or normal upland drainage and could account for the variation observed in seasonal patterns. At E87, the highest ammonia-N concentra- tions were observed in the winter and reached values around 8.0 pg-atom-1-1. Con- centrations at E68 were often the highest measured for the E System and showed a more irregular seasonal pattern than that observed at E87. The mouth of the E System approximated the pattern at E87 but incorporated some of the peaks from E68 (Figure 21). The general pattern was for concentrations as high as 13.0 pg-atom NH3-N'-11 at Meyers Pond and 7.5 pg-atom NH3-N.1-1 at the mouth station to occur in the fall to early winter period and lower levels to occur for the remainder of the time. Nitrite-N-- Nitrite-N occurred in low concentration and had little effect on the level of available nutrients. Concentrations were usually below 0.5 pg-atom NO2- N- 1-1 and frequently were zero. The presence of nitrite-N, however, did indicate periods of nitrification. The simultaneous presence of increased levels of both compounds strongly implicated nitrification as the causative process. Nitrifica- tion occurred primarily during September to February but was also indicated in June at some sites. Nitrate-N-- Nitrate-N was the second most abundant inorganic nitrogen compound. In general, most systems had concentrations of less than 1.0 pg-atom NO3-N-1-1. Most of the nitrate-N was associated with the E System. Elevated values at E87 suggested a connection between nitrate-N and upland drainage (Figure 22). Again, the sewage plant at E68 probably accounted for the higher and more irregular values found at the E68 site. Disregarding extreme values, similarities between the E68 and E87 seasonal patterns suggested the outfall represented an addition to the up- land source of nitrate-N. Nitrate-N was also associated with periods of destrati- fication at B24. The elevated nitrate-N levels could have resulted from nitrifi- cation. Because the increased N03-N concentrations were coincident with reduced 1.28 0 I 1- < e I <1 2-. E '-I------ I-3---- -------- H- I~~~~~~~~* I C~ S 0 N D J F M A M J 19 74 I1975 Fig. 19. Ammonia-N contours for Lagoon B24 in pg-atom 0- 2 - 6~~~~~~~r~~f~~~t~~a~~~l ~I- I S 0 N D J F M A M J 0. 197 5 197 6 Fig. 20. Ammonia-N contours for Lagoon A08 in pg-atom NH3-N-11. O~~~~~~~~~~~~~C 3457 54.2 24.5 15 - 10 - 5 - I/~~~ N m~~~~~~~~~~ U 4- 0 'C- ~ '~ i A S 0 N DI j F M A M ;L ~~~~~~~1973 19 7417 10 - ~-----oE M- o E68 �----�E87 5 - 0 5 3;/,* J A S 0 N D J F M A M 197A 1975 Fig. 21. The ammonia-N seasonal patterns for the E system. 1.30 18.7 57.6 15 , I I I 77- EI 17 6 - 30 I' li ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~ � I 10 I I 5 - 25 , \ X 4- ,, '- -20 5vNI I I~~~~~~~~~ 3- 15 2 2- 10 -5 A Os N D J F M A M J J A S O N D J J F M A M 0w 6 971973 1974 Fig. 22.2The seasonal nitrate-N pattern for Fig. 23. The seasonal patternsforsalinity8- theIs~~~~~~~~~~ E Sytm anNitrate-N 'hr e-. 7i m o----o Salinity %. -. E87 o----o E Mouth 6 -30 �m----. E68 10 - r 5- -25 4 - 20 5- 2- 10 - 5 0 C U 0 J J A S O N D J F M A M J J A S O N D J F M A M 1974 1975 1974 1975 Fig. 22. The seasonal nitrate-N pattern for Fig. 23. The seasonal patterns for salinity the E System. and nitrate-N at the surface of B24. surface salinities, the nitrate-N could have also resulted in part from storm drainage (Figure 23). Seasonal trends at all the stations tended to be variable from year to year, but there was a general tendency for winter values to exceed summer values. Organic-N --Total organic nitrogen was the most abundant form of nitrogen in both the marsh and lagoon systems. In study year III, total organic-N composed over 82 % of the nitrogen present within the Meyers Creek system and Lagoon System A (Table 7). Table 7. Nitrogen standing stocks in hg-atom. 106 for the Meyers Creek and lagoon systems during study year III. Org-N Total Org-N Site Quarter NH3-N N02-N NO-N (total) N Total N Meyers Creek 1 42.9 0.0 2.2 1,084.6 1,129.7 .96 2 152.9 2.2 28.6 841.5 1,025.2 .82 3 5.5 2.2 4.4 804.1 816.2 .99 4 22.0 0.0 2.2 711.7 735.9 .97 Meyers Pond 1 31.1 0.0 2.7 918.5 952.3 .96 2 120.6 1.8 22.5 982.8 1,127.7 .87 3 21.6 2.7 14.4 720.9 759.6 .95 4 22.5 0.0 1.8 629.1 653.4 .96 Lagoon A02 1 13.9 0.2 4.7 655.6 674.4 .97 2 32.7 0.5 22.6 567.6 623.4 .91 3 6.9 2.8 9.0 619.2 637.9 .87 4 0.6 0.0 0.2 568.9 569.7 1.00 Lagoon A08 1 44.2 0.1 4.0 684.0 732.3 .93 2 20.0 0.0 8.8 506.0 534.8 .95 3 13.2 0.8 2.7 679.8 696.5 .98 4 6.5 0.0 0.7 690.8 698.0 .99 1.32 Seasonal patterns at the surface at M 21 and the creek system stations were similar. Typically, in study year I, the sites had relatively uniform levels of total organic-N from June 1973 to January of 1974. However, at some sites, the values from the latter part of the period showed a tendency to be slightly lower than in the first part. A peak in total organic-N was recorded at many of the systems from January through March, but the peak was irregular with respect to time and magnitude. Following this, another increase of longer duration and higher concentrations occurred in the summer and extended into the early fall. A decrease in concentration then occurred after which concentrations leveled off and remained relatively uniform through the winter of study year II. This level was maintained through study year III within the Meyers Creek system and at M 21. In the E System, there was a decrease rather than a "January-March peak" in study year I. In addition, no summer peak was detected at E87, and the aver- age total organic-N concentration at E87 were the lowest found in the study area. Normally, the E87 values were less than 30 jg-atom Org-N--1 and averaged around 10 to 20 jg-atom Org Ni-1- for the entire year. The remaining E System sites had total organic-N values averaging as follows: 30 to 40 Og-atom-1-1 from the summer through the fall of study year I; around 20 pg-atom 1-1 during the January- March 1974 period; 60 to 70 Vg-atoml-l1 in the summer of study year II; and 20 to 30 pg-atom-1-1 thereafter. In contrast, the upper end of Dinner Point Creek system had slightly higher organic-N values. The seasonal pattern of the mouth site averaged 30 to 40 ig- atom Org-N'1-1 from June 1973 to June 1974; had a 1974 summer maximum around 60 Pg-atom-l-1; declined to less than 20 pg-atom-l-1; and were around 30 to 40 pg- atom Org-N.1-1 thereafter. While the values for the last phase were similar, the upper end concentrations for the June to January period in study year I were ap- proximately 40 to 70 jg-atom Org-N-1-1 and 60 to 80 jg-atom Org-N'1-1 in the summer of 1974. The upper end peak occurred in late December and the mouth peak in the end of February (Figure 24). The Meyers Creek system stations were comparable to each other except for some additional minor peaks during study year III and the end of study year II at Meyers Pond. The Meyers Creek stations and especially the mouth site were similar in magnitude as well as pattern to Dinner Point Creek mouth. The major difference was a more extended and slightly higher 1974 summer maximum (60 to 100 Pg-atom Org-N.1-1) at the Meyers Creek stations. The seasonal trend at Mar- ker 21 also approximated that of the Dinner Point Creek mouth. The only differ- ence between these two was the absence of the irregular presummer peak in the M 21 pattern. The seasonal total organic-N pattern for the lagoon surface sites appeared to be high, variable summer peaks followed by relatively stable levels for the remainder of the year. This trend was well illustrated by the first two years at the A08 and B24 sites (Figure 25). However, in study year III, the summer peak really was not evident. The lagoon bottom stations showed the same pattern as the corresponding surface sites. A summer peak of limited duration was detec- ted in the bottom layer in the third study year; the peak was observed only at A08 and not A02 or B24. NITROGEN FIXATION--Terrestial marsh sites were subdivided into algal and substrate (nonalgal) communities according to whether algae were or were not 1.33 6n 0 - Dne on re ot 70 60- 50- 40 - 30- 20 - o-o Dinner Point Creek Mouth �O~~ *- Dinner Point Creek Upper lo .- 10 - J J A S 0 N D J F M A M n~t A 1973 1974 70- � 60- 50 40 - 30' 30 - 20 to 0 J J A S 0 N D J F M A M 1974 D 1975 Fig. 24. Total organic nitrogen seasonal pat- terns in the Dinner Point Creek system. visible to the naked eye on the surface. Typically, higher rates of ethylene pro- duction (i.e. nitrogen fixation) were associated with the algal mats than the sub- strate (Figure 26.). Rates were computed to be as high as 303 pg-atom NH3-N'h'-l �m-2 in certain areas. Algal mats were most often found in the Spartina aZterniflora short form (SAS) areas. Maximum algal cover occurred in the spring and fall quarters. Min- imum cover occurred in the winter quarter. Although the winter minimum algal cover coincided with the seasonal low for nitrogen fixation rates, times of max- imum algal cover did not coincide with times of maximum nitrogen fixation rates. Peak nitrogen fixation rates occurred in the latter part of the summer. The Spartina patens/Distichlis spicata (SP/DS) areas generally lacked algal mats on the marsh surface. Apparently, the grass cover prevented the sunlight from pene- trating,eliminating the possibility of algal growth. Only in the limited areas where the macrophyte cover was degenerating were algae present. The Spartina alterniflora tall form/bank (SAT/B) zone on Meyers Creek had little algae asso- ciated with it. Meyers Pond bank areas, however, had large algal bands which were active nitrogen fixers. 1.34 >100 80 B, 24 70 \ I - Surface Total 11 \o-o Soluble 60- }*--* Bottom Total ,-- Soluble ~~~~50 ) ~~- \ 0.20- S.alterniflora (short form) algal community g 0 I I I / Ix Z 0 - o 80 '--. tA0// -"&,, 0.15- o 7c,0_ 10 - _ J J A S O N D| J F M A M ' J S u 80- A083~ ~ ~ ~ ~ ~ ~ ~ 5 _0.06- ~~~~~~o~~~~~~ ~~0.05 Saterniflora (70-ort form) 60- ubtrate Community 0.02.. 3 0 < / ', f 00 S.lrniora (short form) communities. 5 O 0.02 / 01 . F J F M A M J J .AS O N DIJ FM AMJ J AS Fig. 25 Monthly mean organic-N concen- Fig. 2_. The seasonal variation in the fZora (short form) communities. The nitrogen fixation rates for the corresponding substrate communities were low, usually below 5 jig-atom NH3-N-h-i'm-2. Only twice did the rates exceed 50 vg-atom NH3-N-h-l.m-2 at any marsh site. These occurred during the fall quarter in the bank community at Meyers Pond and in the SAS community. On an annual basis, nitrogen fixation by the benthic sediment community and the water column community were the lowest encountered in marsh systems. The water column community had the lower rate, essentially zero. The lagoon system differed from the marsh system because most marsh surface fixation was eliminated by housing and associated construction. The SAS algal mats were replaced by paved surfaces and house lots and the SAT/B zone communi- ties by bulkheading. Algal communities were present on the intertidal portion of the bulkheading, and we considered them to correspond to the SAT/B zone algal communities. These bulkhead associations dominated the nitrogen fixation process in the lagoon system. The upper portion of this zone was primarily a blue-green algal crust and had a fixation rate as high as 575 pg-atom NH3-N.h-1-m-2. As with the marsh surface algae, minimum rates were detected in the winter quarter (Figure 27). The lower part of the zone, which was mostly green algae, had a peak rate of onl1y96 pg-atom NH3-N-h.-1.m-2 and, generally, did not exceed 30 pg-atom NH3-N-h- m . Nitrogen fixation rates for the benthic sediments and water column communities were minimal. The SAS zone contributed the greatest amounts of newly fixed nitrogen not only because it had the highest combined algal/substrate fixation rate, but also because it was the dominant cover type (Table 8). This contribution was pre- dominantly from the algal community which fixed 2.5 times more nitrogen annually than the substrate community (7.1 to 2.8 pg-atom NH3-N-day-l.107 respectively for the Meyers Creek system). The relatively low rate of the SP/DS substrate community was also magnified by the areal importance of its cover type. This community was third highest in the contribution of fixed nitrogen with 5.0 x 106 pg-atom NH3-N.day-1 despite its low fixation rate. The remaining communi- ties, the SAT/B zone, benthic sediments, and water column were considered to contribute nitrogen to the water column. The input from each of these types was much lower with a combined total input of 4.4 x 106 pg-atom NH3-N.day-1. Again, distribution either moderated or increased the significance of these pro- cesses. Only because the low benthic sediment and water column community rates were applied to a large portion of the system were they significant. Because the SAT/B zone rates were representative of a relatively small region, the amount of nitrogen fixed was low. 1.36 .6 Lagoon A02 upper bulkhead community .5. .4. * /*3. O .2- Z z E 0 J J A S 0 N D J F M A M x .4- Lagoon A08 3- upper bulkhead community .2� .1 ,./.\4 J J A S 0 N D J F M A M 1975 1976 Fig. 27. The seasonal nitrogen fixation rates in the upper bulkhead algal communities within the Lagoon System A in pg-atom NH3-N-h-l-m-2'103. The algal SAS community fixed 2.5 times more nitrogen annually than the substrate community in the Meyers Creek system. Similarly, in the SAT/B zone, the algal components fixed twice as much as the substrate community along Meyers Creek despite very limited abundance and nearly 7 times as much along the Meyers Pond perimeter where algal mats were prevalent. The high rates of the bulkhead algal community were applied to relatively small areas. This minimized the importance of this type of nitrogen fixer. On the other hand, the importance of the low benthic sediment and water column rates was probably overmagnified as it was in the creek system. Nonetheless, algal nitrogen fixation still dominated the nitrogen contributions to the system (Table 8). EXCRETION-- ModioZus excretion data indicated minimum rates occurred in the warmer months and maximum rate� in the cooler months. The range was from 1.6 to 12.1 pg-atom NH3-N-organism- *day-1. Using a population estimate of 1,653,453 1.37 Table 8. Nitrogen inputs resulting from nitrogen fixation in Vgat NH3-N. day-1. 104 for study year III. Annual Site Quarter: 1 2 3 4 mean Meyers Creek: S. alterniflora short form: Algal community 6,061 10,824 0 798 4,421 Substrate community 3,693 2,493 274 286 1,687 S. patens/D. spicata Substrate community 702 44 0 28 194 S. alternifZlora tall form/bank zone: Algal community 0 7 0 0 2 Substrate community 2 0 0 0 1 Benthic sediment community 73 18 8 7 27 Water column community 0 0 0 159* 40* Meyers Pond: S. alterniflora short form: Algal community 3,711 6,628 0 489 2,700 Substrate community 2,261 1,445 301 292 1,075 S. patens/D. spicata Substrate community 1,125 71 0 44 310 S. alterniflora tall form/bank zone: Algal community 993 79 3 6 270 Substrate community 23 114 0 17 39 Benthic sediment community 165 233 0 24 106 Water column community 0 0 253* 0 63* * The data with a * are probably artifacts of the extrapolation and should more properly be considered as zero. 1.38 Table 8. Continued. Annual Site Quarter: 1 2 3 4 mean Lagoon A02: Bulkhead algal community: Upper zone 24.4 58.7 7.5 84.6 43.8 Lower zone 5.0 7.5 0.5 32.3 11.3 Benthic sediment community 18.4 14.7 0.0 3.8 9.2 Water column community: 0-2 m 0.0 0.0 0.0 154.0* 38.5* Greater than 2 m 0.0 46.0* 17.3* 15.8* Lagoon A08: Bulkhead algal community: Upper zone 18.2 20.3 0.4 15.1 13.5 Lower zone 1.9 0.8 0.4 4.5 1.9 Benthic sediment community 8.1 5.6 2.5 4.9 5.3 Water column community: 0-2 m 0.0 0.0 9.4* 105.0* 28.6* Greater than 2 m 0.0 11.4* 0.0 2.9* *The data with a * are probably artifacts of the extrapolation and should more properly be considered as zero. organisms in the Meyers Creek system the total daily contribution of ammonia-N could be extrapolated (Table 9). Organic-N excretion rates were determined for the April 1976 sampling. The mean rate was 9.4 Vg-atom Org-N.organism-1 day-1. This accounted for over 60% of the nitrogen excreted by the mussels on this sampling. Extrapolation of the data yielded a total organic-N contribution of 15.58 x 106 ig-atom.day-l in the Meyers Creek system. If this estimate is taken as representative of the entire year, this would add 5.69 x 109 pg-atom Org-N to the 3.31 x 109 Vg-atom NH3-N ex- creted per year by Modiolus in this system. Ilyanassa obsoleta excretion data indicated maximum rates occurred around April, while minimum rates were found around the October period. The rates ranged from around 0.4 to 2.8 ug-atom NH3-N.organism-lday-1. The seasonal pattern was 1.39 Table 9. Total daily ammonia-N contribution by the Mgyers Creek system Modiolus demissus population in vgat NH3-N'day- 10 . Study Meyers Meyers year Quarter Creek Pond Total II 2 4.8 2.1 6.9 3 8.6 3.7 12.3 4 7.9 3.4 11.3 III 1 1.8 0.8 2.6 2 4.7 2.0 6.7 3 14.0 6.1 20.1 4 4.8 2.1 6.9 Overall Mean* 6.3 2.8 9.1 Mean # 6.7 2.9 9.6 * These values are the average of the quarterly values for study year III. These values are the average of all available quarterly values. quite similar at all stations, and the rates at all stations were also similar as seen in Table 10. The data on organic-N, as in the case of Modiolus, indicated a significant portion of the excreted nitrogen was in the organic-N form (Table 10). Extrapola- ting the data for the entire year suggested 70 to 75% of the excreted nitrogen was in that form. The zooplankton excretion data were fairly consistent for the three experi- mental sites with regards to seasonal trends. Excretion rates were highest in the summer and spring quarters with the spring generally having the highest rates associated with it. Minimum excretion rates were found in both the fall and winter. The rates ranged from 0 to 140 ag-atom NH3-N'11-.day-l.10-3 (Table 11). AMMONIFICATION -- Within their respective systems, the Meyers Pond and Mid Lagoon A02 sites generally had the highest ammonia-N production rates (Figure 28). Seasonal trends were similar for stations in the Meyers Creek system. Mini- mum ammonification rates occurred in the winter followed by higher rates in the spring and summer. This pattern was not as evident in the lagoons because the A02 site showed a spring increase in ammonification prior to the other stations while the A08 site failed to show any increase at all. The highest rates were found in the spring of 1976. The spring increase was greatest at the Lagoon A02 1.40 Table 10. IZlanassa obsoZleta excretion summary table. Total NH3-N Total Org-N contributed at contributed the site in at the site Study pg-atom'day-l- in Vg-atom Total Org-N Site year Quarter 105 �day-l.105 Total-N Meyers II 2 2.4 Creek 3 5.1 4 7.7 III 1 5.7 2 3.0 3 7.5 7.2 .49 4 9.2 21.4 .70 III Mean 6.4 14.3 .69 Meyers II 4 15.5 Pond III 1 10.5 2 5.8 3 8.9 11.1 .56 4 22.4 52.2 .70 III Mean 11.9 31.7 .73 Lagoon II 3 4.1 A02 4 4.1 III 1 2.3 2 2.0 3 4.8 4 7.4 13.9 .65 III Mean 4.1 13.9 .77 Lagoon II 4 3.8 AO8 III 1 3.1 2 1.5 3 2.7 4 7.7 12.4 .62 III Mean 3.8 12.4 .77 1.41 Table 11. Ammonia-N excretion rates for mixed natural zooplankton populations in Pg-atom NH-N-l1-lday-l.10-3. Date Mid Meyers Creek Lagoon A02 Lagoon A08 10/74 1.6 11/74 0.2 1.1 1.0 12/74 0.9 1.2 0.5 4/75 18.5 55.1 110.5 7/75 27.2 0.8 10.9 10/75 4.3 2.7 2.4 2/76 0.0 12.0 3.0 4/76 57.7 139.9 86.1 Note: Ice prevented sampling from late December 1975 to mid February 1976. site where a study high rate of over 6.0 x 103 pg-atom NH3-N'm-2.day-1 was reached. The maximum rate at this time in the Meyers Creek system was much less at 3.5 x 103 pg-atom NH3-N'm-2-day'l. RUNOFF -- The data in Table 12 show the amounts of nitrogen introduced via pre- cipitation and/or runoff. Although referenced to a daily time frame, the values were actually based on a calculated annual sum. This was in turn derived from the actual rainfall and the mean concentrations of ammonia-N, nitrite-N, nitrate-N, and organic-N for each quarter. Total organic-N data were not available for direct rainfall due to insufficient sample volume. Productivity OXIDIZABLE CARBON -- Oxidizable carbon data for the study years I-IV at A08, B24, M 21, ABD, Meyers Pond, and Meyers Creek mouth are presented in Figure 29. Natural creek areas, including Oyster Point and Dinner Point, were characterized by considerable seasonal fluctuation. A predominant seasonal cycle was not ob- served at these stations since peak concentrations were often recorded several times throughout the year. Meyers Creek system, for instance, had high carbon levels during several seasons at the creek mouth and pond. The upper end of Dinner Point Creek did not have such a pronounced seasonal variability or the ex- ceptionally high carbon values recorded for the other natural areas. Record lev- els greater than 104 mg m-3 were observed in February 1974 at Dinner Point Creek mouth and Meyers Creek mouth; and also in September 1976 at Meyers Pond. Various seasonal peaks were also observed in the bay (M 21) where high con- centrations were frequent during the winter and spring. Annual variation was also noted. Summer peaks were recorded in 1974 and 1976, while carbon levels were consistently less than 2.0 x 103 mg.m-3 during the summers of 1973 and 1975. 1.42 4 . Meyers Creek System: o-o Meyers Pond 3- ___* Mid Meyers Creek 2- 0 ~~~~~~~~~~~~~ICE >-1- - --- ON J J A S 0 N D J F M A M z 0 W 6 Lagoon System A: * g] I o oMid Lagoon AO8 5- *---* Mid Lagoon A02 / 0 - 4 I I 1- 3- 3 < of < X s ~~~~~~I CE 0~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~' -f J J A S O N D J F M A M 1975 1976 Statistical data: Annual means + I SE Mid Meyers Creek 0.8 + 0.3 Meyers Pond 1.3 + 0.6 Mid Lagoon A02 2.5 + 0.9 Mid Lagoon A08 0.9 + 0.2 Fig. 28. Ammonification rates for study year Ill in jg-atom NH3-N-m-2' dayl103. Values for the major stations (ABD, A02, A08, B17, and B24) did not demon- strate the great yariability observed in the creeks. These stations generally had higher concentrations during the summer, especially in 1976 when exceptional carbon levels were noted throughout the entire lManahawkin area. Peaks during other times of the year were infrequent, such that a seasonal pattern was more pronounced in the lagoons than in the shallower natural areas. The Mill Creek system had the lowest carbon levels, with E87 frequently less than 103 mg-m-3. Higher values were observed downstream. Summer peaks were re- corded at E68 and E mouth, and spring minima consistently occurred throughout the creek. 1.43 Table 12. Summary of nitrogen inputs resulting from precipitation in pg-atom' day-l.105. Input Total In- Total In- Total Site Type organic-N organic-N Nitrogen Meyers Creek: Water column Direct 11.4 Meyers Creek: Marsh surface Direct 110.9 Meyers Pond: Water column Direct 21.3 Meyers Pond: Marsh surface Direct 99.3 Lagoon A02: Water column Direct 4.5 Roof runoff 1.2 0.7 1.8* Road runoff 1.2 1.7 3.0* Lagoon A08: Water column Direct 3.4 Roof runoff 0.9 0.6 1.5 Road runoff 0.9 1.3 2.3* * Total nitrogen was not computed by adding the two preceding columns. A * in- dicates there was a roundoff difference between the method used and the sum of the preceding columns. SESTON -- Measures of suspended particulate matter (total seston, combustible or- ganic matter, and residual ash) were begun in May 1976 and were continued on a regular basis until May 1977. The surface total and organic seston data for all stations are given in Table 13. Though considerable fluctuations occurred in the concentration of total seston, especially in the shallow Meyers system, seasonal patterns were similar at all stations. The pattern was characterized by maximal levels during June-July-August and minimal levels during March-April-May. For any particular sampling date, concentrations throughout the Meyers system were gen- erally very similar, as were those throughout the lagoons. The Meyers Creek system with an annual range of 5.8 - 161.0 mg-1-1, frequently had much higher seston levels than the lagoons, which had an annual range of 3.8 - 39.0 mg'1-1. The seasonal pattern of suspended organic matter at all stations followed closely that of the total seston, with highest concentrations appearing during the summer. However, concentrations of suspended organic matter in the lagoons and in the Meyers system were more similar. The annual range in the Meyers Creek system and in the lagoons was 2.0 - 30.5 mg11 and 2.1 - 23.0 mg.1-, re- pectively. 1.44 120- - A08 -o -- --o B24 100- 60 - rJ 40 :P 20 J A SO N DI F M AMJJAS NDIJFMA M : J A S 0 N DIJ F M A M J J N DIJNMA -e 60- M 21 4 1\ 09 I o----o ~~~~~~~~~~ABD a 40- 0 0 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 20 JA S O N DIJ M A M J J A S 0 N DIJ F M A M J J A S 0 N DIJ F M A M J J A S N DIJ F M A M 100- - Meyers Pond o----o Meyers Mouth 80 - 2' I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ : 60- - 10,~~~~~~~~~~~~~~~~~~~~~~~~~~ JASON~~ D IFA J AO 1 MA AO DJMMJAS DJMA 20--I J S0NDJF S 0 N DI J F M A M J J A 5 0~ N D J F M A M J J A S 0 NDJFMAM 1973 1974 1975 1976 1977 Fig. 29. Oxidizable carbon concentrations. Table 13. Suspended particular matter (mg'1-1) from May 1976 to May 1977. All surface values,. Meyers Mouth Mid Meyers Meyers Pond M21 ABD Date Total Ore Total Org Total Ore Total Ora Total Ora 5/12/76 63.4 11.3 29.0 8.0 5.8 3.3 6/9 23.2 7.4 22.4 6.8 22.1 5.5 16.2 5.6 16.4 8.0 6/30 34.2 9.2 32.2 9.0 26.4 6.2 26.5 6.8 18.2 6.2 7/15 33.7 9.4 40.6 8.2 44.4 8.6 27.1 6.2 45.2 11.5 7/28 51.2 16.8 42.6 13.4 54.0 16.4 29.8 10.7 43.0 16.0 8/3 55.0 11.0 66.5 13.5 161.0 30.5 15.5 7.0 9.2 4.4 8/18 23.0 7.1 23.9 9.2 25.8 9.2 26.2 8.4 25.8 7.6 8/31 24.8 11.8 34.8 15.5 32.0 13.5 22.9 10.3 17.4 10.0 9/28 18.4 11.6 30.4 12.8 46.2 14.9 19.8 9.6 22.1 10.7 10/11 29.7 11.4 30.0 8.9 21.0 8.4 26.5 10.0 19.8 8.8 11/2 19.7 8.9 19.8 9.5 22.0 10.3 22.6 7.7 20.3 8.0 2/23/77 22.0 5.4 15.6 7.0 15.2 6.2 3/8 7.6 2.8 7.9 2.7 6.1 2.0 10.3 4.7 6.1 2.4 3/16 49.2 12.4 52.8 11.6 30.0 5.6 13.4 3.8 10.4 3.4 4/13 27.6 5.2 42.2 8.0 24.0 5.8 4/19 27.2 5.8 57.0 9.0 5/12 24.0 6.2 10.8 3.2 5.8 2.2 16.6 4.6 6.0 4.2 Note: Total = Total suspended particulate matter; Org = Combustible organic matter Table 13. Continued. A02 A08 B17 B24 Date Total Org Total Org Total Org Total Org 5/12/76 3.8 2.9 7.9 3.5 6/8-6/9 11.0 7.1 15.2 9.3 32.2 13.2 19.4 10.4 6/30-7/1 12.3 7.8 17.3 11.8 23.4 9.0 39.0 21.6 7/15 25.4 10.4 25.1 10.6 7/28 26.2 15.3 24.8 15.4 8/3 11.2 6.6 37.0 23.0 33.8 20.8 35.5 22.5 8/18 11.2 7.0 12.0 7.9 8/31 18.3 11.8 18.3 11.2 14.0 7.3 14.0 7.0 9/13 17.7 11.3 18.0 11.5 9/28 14.8 11.3 14.8 11.9 10/11 13.1 8.9 16.3 11.1 11/2 12.8 7.8 13.0 9.0 18.0 8.2 12.2 6.2 2/23/77 7.6 4.6 7.0 3.6 3/8 5.6 2.1 5.6 2.8 3/16 8.0 4.2 6.8 3.0 7.0 4.6 6.6 4.2 4/13 22.0 5.0 22.8 6.0 5/12 5.0 3.4 4.0 3.8 Note: Total = total suspended particulate matter; Org = combustible organic matter The results from this year of data have demonstrated a significant contrast in the relative proportion of surface total particulates contributed by organic and inorganic fractions for the developed and natural areas. Whereas only about 31% (annual average) of this material in the Meyers system was organic, approximately 57% was contributed by the organic fraction within the lagoons. Values for M 21 and ABD were 36% and 43%, respectively. The vertical distribution of total and organic seston in the lagoons fre- quently demonstrated discrete maxima within the water column, though not necessar- ily coinciding with each other. Vertical patterns were not as dramatic as some of the chemical data, but seemed to occur most clearly under condition of well-developed stratification. PIGMENTS -- The seasonal pattern of surface chlorophyll a concentrations at A08, N 21, and Meyers Pond are presented in Figure 30. Chlorophyll a and pheophytin concentrations at A02 and A08 from July 1975 to June 1976 are contoured in Figures 31 and 32. Nearly all stations in the Manahawkin area were characterized by rela- tively high summer concentrations. The duration of this period and the magnitude of the standing crop demonstrated a certain degree of annual variation. This was especially true for the bay, in which rather minimal levels of chlorophyll a were observed during the summers of 1973 and 1975, similar to the findings for oxidi-- zable carbon. Peak standing crops also varied from year to year in the lagoons and creeks, reaching exceptional levels at all stations during the summer of 1976. At this time, chlorophyll a frequently exceeded 20 mg~m3 for extended periods of time, and clearly surpassed the previous years of observation. A record level of 130.5 mg-m3 was noted at B24 on 30 June 1976. Other stations which typically had very high summer pigment levels included Meyers Pond, Oyster Point Pond, and E68. in contrast to the outfall site on Mill Creek, E87 had relatively low levels of chlorophyll a, similar to the results for oxidizable carbon. Such periods of high standing crop were generally followed by an abrupt decline around October. However, minimal levels were generally not extended throughout the win- ter, for winter peaks were frequently recorded. Such peaks even approached summer levels at times. Usually accompanying these increased pigment levels was a greater productive capacity of the phytoplankton, especially when measured under conditions of artificial illumination. Pheophytin, indicative of plant decomposition products, was an important component of the plant pigments throughout the study period for the entire Mana- hawkin area. Pheophytin levels were especially prominent below the euphotic zone of well-stratified lagoons during the summer (Figures 31 and 32). In addition, significant quantities of active chlorophyll a were also observed below the eupho- tic zone in regions of total darkness, low dissolved oxygen concentrations, and high NH3-N concentrations. This was most striking at B24. Rapid changes in con- centration with depth appeared to be linked to changes taking place in temperature and salinity (i.e. density) and dissolved oxygen. The lesser degree of stratifi- cation at A02 was reflected in the less frequent development of pronounced verti- cal patterns. BULKHEAD ALGAL PRODUCTION -- Seasonal patterns of bulkhead algal net production and respiration for the upper, mid, and lower sections of the Lagoon System A main channel are presented in Figure 33. The seasonal patterns were similar at each of the three stations. Net production was generally highest during the period May- September for 1976 and also demonstrated a return to such high summer levels in May 1977. Maximal rates for 1975 were observed in October-December. The low levels of net production on 7 July 1975 followed a period of heavy rainfall, 1.48 ,~~~~-------~~~~~- - ---�r--*�l----:;-- -. A08 / 0 0 0-0 J A S 0 N DIJ F M A M J JA S 0 N D J F M A M JiJ A S O N DIJ F M A M J J A S O NDIJFMAM - � 4- E EM 21 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 E 0�'0-9~~~~~~~0 H -~~3 '.0 0 J A SO0N DIJ FM AM J JA SO0 N DI JF M A M J J A SO0N DIJFM AM J J A S 0 N DIJ F M A M CL 7- 6 Meyers Pond 0 5- II 4- 3 - 2- Cr ,0---9 ~ ~~~~~~~~~~ O ,0, -o O Oo 0 A j A S O N D�IJ FM~ A M J J A 5 0 N D1DJ F MJ A MN J IJFMAM J JA 0 N OJJFMA M 1973 1974 1976 1977 Fig. 30. Phytoplankton net production ( -.) and chlorophyll a (O---o) values. A02 Chlorophyll a J A S 0 N J F M A M J 0~~~~~~~~~~~ A08 Chlorophyll a1 i~~~~~~~~~~~~~~~~~~~~~~~~~~ A S 0 N DM M J 0 2 2~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 5 -10I Ei 2 2- 4-' -- ~~~~~~~~~~~~ICE__ Cil 3 - inkl ~~Y- L6,+,\ I- HIH ~ ~ ~~~~~~~~~~~- I-- 4 - n2O 6 ~ I 4++-~~~~~~~~~ -H17 196 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~iA0 PheophytJin A0 Mhephti Fig. 3~~~1.7 Plant pimn ees(gm)a aonFg.3.Patpgetlvl mm)a A08 coturd Lagoon F A0 conoued exceeding 11 cm during 11-15 July (NOAA Environmental Data Service, Tuckerton Station). The results for this sampling run are possibly not representative. 2000 ~~~~~~~~~~UPPER MAIN CHANNEL 2000 10 0 AS ON D1 F M A M J J A S DiJ F M A M 2000~ MID MAIN CHANNEL 'I\' m 9-~~~~- '1 000 MD LMAIN CHANNEL '~ 1000 ', / respiration (U---a) of the bulkhead algal communi- ty from July 1975 to May 1977. Vertical lines represent 2 SD. Respiration rates were maximal during May and July of 1976 when water temper- atures were approximately 150C and 260C, respectively. The results for early July 1976 at the mid station may reflect the abnormal conditions at this time as a result of an extensive period of negligible rainfall and high salinities (>29 O/oo). During the summer, respiration of the bulkhead algal community accounted for approximately 50-60% of the gross production on a 24 hour basis. Minimal rates were observed during the winter of 1975-76 and also in November 1976 when water temperatures had already declined to less than 0.0�C. Though the seasonal patterns and magnitude of net production and respiration were similar at each station, considerable variability did occur on certain occa- sions. To what extent this reflects a nonuniform distribution in the standing crop crop of the algal community at a particular station or a varied physiological re- sponse is not known. 1.51 The development and rejuvenation of these mats in the spring of 1976 and 1977 appeared to be delayed as a result of extensive ice cover in the lagoons. It is believed that the physical stress of this ice and its denuding action upon the bulkheads severely affected this algal community during this period. MARSH SURFACE ALGAL PRODUCTION -- Seasonal sail temperatures and light penetration for the three dominant plant canopies and an exposed mudflat are presented in Table 14. Soil temperatures followed closely the trend in water temperature of the near- by Meyers Creek. These values demonstrated significant differences at thimes and would be influenced by such factors as relative isolation, air temperature, shading, and greenhouse effects. Those recorded in the S. patens zone, often the lowest values observed on any particular data, were sometimes as much as 50C lower than in the S. alternifZlora (short form) zone. In February 1975 and November 1976, the soil surface was almost completely frozen. In February 1976, ice was still present in patches under the dense canopy of S. patens, but had already disappeared from the other stands. Since the mudflat area was always sampled at times of near or complete expo- sure, the percentage of incoming radiation (%Io) reaching the surface is given as 100%. This would necessarily change with varying tidal stages and turbidity con- ditions. Very little solar radiation was capable of penetrating the S. patens canopy throughout the year (0-5%) and visible a~jgal mats were generally absent. The presence of such mats under canopies of S. aZternifl-ora (tall and short form), however, appeared indicative of the more favorable light conditions there. During the period of February 1976 to September 1976, light penetration through these stands progressively diminished from 30-60% Io to 6-16% Io as a result of Spartina growth and canopy closure. Net community production and respiration for the four experimental sites are presented in Figure 34. Net production was highest during the summers of 1975 and 1976 at all stations, though the magnitude and duration of this active period varied considerably. The net production of the S. patens-zone was characteristically negligible during the summer and negative during the rest of the year. These findings indicate the overriding influence of total community respiration upon any photosynthetic capability of the microflora. The absence of any significant autotrophic activity (Gross production/Respiration > 1) probably reflects the limiting light conditions persistent throughout the year. The level of net production and its seasonal pattern in the two S. alterniflora zones were very similar. Maximal rates of 200-300 ml 02-m-224 h-l were typical from May to September of 1975-76. Negligible activity was recorded during the winter when freezing of the marsh surface occurred. The net productivity of the mudflat community was approximately 4 - 5 times greater than the S. alternifZorca zones during the summer, exceeding 800 ml 02m224 h-l. Such high rates were comparable to those recorded for the bulkhead algal communities. The most active period for the mudflat microflora was not reached until July of each year, in contrast to April-May for the S. alterniflora edaphic communities. At this time of considerable growth, large populations Ilyanassa sp. were observed grazing upon the surface. Respiration of the marsh surface communities generally followed the seasonal trends described for net production. This was most clearly seen in the S. 1.52 Table 14. Marsh surface soil temperatures (�C) and percent incident light (% Io) that penetrates the vegetation. * Spartina alternifZora Spartina alternifZora Spartina patens Mudflat tall formin short form Date Temp. %Io Temp. %Io Temp. %I, Temp. %In 5/20/76 14.4 18 16.9 34 11.4 < 1 14.7 100 7/15 24.7 10 25.7 23 21.7 < 1 23.0 100 9/13 18.7 6 20.5 16 19.9 < 1 19.3 100 11/24 0.4 20 0.0 15 0.4 < 1 0.0 100 5/12/77 11.8 30 11.7 35 9.5 < 1 13.2 100 * All values represent the average of five observations. S. alterniflora (short) 500- S 5. patens 500 '~~~~~~~~~~~ ~300- 3~~500- 10 40- /", 400- 8l00 4/".DT 0o, - 3'.- 400- -~3200- DIJ F M J J A N DIJ F M AM J A S F A A M J FM A M J J A S 0 N M A M J J A S 0 IJ F M A M from 5DecemrS. alterniflora TX~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~(tall) Ooo000- Mudflat 500- 800- 400- . -- , 600- g 300- , 200 200 JJ F M A M J J A S 0 N Dl MA J J A S 0 IJ F M A M D J F A M J J A S 0 N D M A M J J A S 0 DIJ F M A M 1975 1976 1977 19751976 1977 Fig. 34. Net community production (-- ) and respiration (.---u) of the marsh surface algal community from December 1974 to May 1977. Vertical lines represent + 2 SD. alternijflora (short form) zone and in the mudflat, where clearly defined summer peaks were recorded each year. Typical summer levels approximated 400 ml 02.m-2'24 h-1 in the S. alterni- flora stands, while considerably greater rates were noted for the mudflat in 1975, exceeding 800 ml 02,m-2'24 h-1. Since October 1975, the marginal photosynthetic activity of the S. patens station has been accompanied by rather substantial respiratory levels, especially during the summer of 1976. The difference between the two summers cannot be ex- plained at this time. In contrast to the minimal net production rates during the winter, signifi- cant rates of oxygen uptake were often recorded. Microbiota respiration accounted for a large proportion of the gross productivity (usually greater than 50%) of these communities all year round. BENTHIC ALGAL PRODUCTION -- Seasonal patterns of benthic respiration are presented in Figure 35. Negative net productivity was generally observed at all stations throughout the study period and appears indicative of a major proportion of non- photosynthetic microbiota present in the sediments. Even in the Meyers system where favorable light conditions would seem to provide a relatively favorable habitat for benthic microflora, only occasional periods of net production were observed. Such results emphasize the overriding importance of total community respiration upon the photosynthetic capacity of the algae. A period of pronounced summer activity was observed at ABD, A12, and in the Meyers system, typical summer levels approached 700 ml 02-m-2'24 h-l at these lagoon stations and at Meyers Creek mouth. Higher rates (exceeding 103 ml 02� m-Z-24 h-1) were observed at Meyers Pond. Respiration rates in the pond were considerably greater than at the mouth, especially from April to October of 1975. The relatively low activity at the mouth during this period compared to the sum- mer of 1976 cannot be explained. The decline in benthic respiration at Meyers Pond on 17 July 1975 may reflect the unusual amount of rainfall prior to this sampling run. Uptake rates during the winter at these stations were greatly diminished. The results for A08 were complicated by the presence of anaerobic conditions during the summer. Under such conditions, no changes in oxygen concentration could be detected in either light or dark-incubated cores. During the winter, however, relatively high rates of oxygen uptake were noted at A08, especially in December 1975. Respiratory rates at this time approximated summer levels at Meyers Creek mouth, ABD, and A12. It is significant that just prior to the development of a well-stratified water column and anaerobic conditions at the lagoon bottom, very high sediment respiration rates were recorded. PHYTOPLANKTON PRODUCTION -- A general seasonal trend in phytoplankton production was observed in the entire Manahawkin area. This was characterized by a rela- tively pronounced period of summer activity usually followed by an abrupt decline around October, similar to the results for chlorophyll a. Minimal rates for production, on a per unit volume basis, were recorded during the winter, though significant winter activity was sometimes observed. Annual variations also occurred and were expecially noticeable in the magnitude and duration of the sum- mer growth period. The seasonal patterns of net productivity at A08, M 21, and 1.55 (a) 1000 900 800 700 500 / 400- E 100- / o~~~~~~~~~~~~~~~ E J FM A M J J A S0 N IJ F M A M J J A S 0 N DJ F M A 701 6- 000 300- 4' oo ? 700- ~: 600-\ I ~~// a ~~~~// -5 00- /V 400 -/ ~~~~~~~~~ / 0 'f / ~- 200 - anaerobic anaerobic anaerobic i's #~~~~~~~~I J F M A M J J ASOAN DIJF J SM AO N D M J FM A 1975 1976 1977 Fig. 35. Benthic sediment respiration: (a) Meyers Pond (. -) and Meyers Creek mouth ( --- ); (b) A08 mouth ( -- ), A12 mouth (A----), and ABD (m---m). Vertical lines represent + 2 SD. Meyers Pond for the study years I-IV are presented in Figure 30. Such seasonal patterns correlated fairly well with the seasonal distribution of standing crop. The bay station was only moderately active during the summers of 1974 and 1976 with net productivity rates of 1.0-2.0 ml 02-1-1.day-1. Phytoplankton production at this station was greatly diminished during the rest of the study period such that net productivity levels less than 1.0 ml 02'1l1-day-l were common. The summer productive capacity of the natural creeks was much greater than the bay, on a per unit volume basis. Tremendous bursts of activity were re- corded in the shallow, turbid ponds located at the upper ends of the creek sys- tems. Net productivity rates exceeding 3.0 ml 02-1-1day-1 at Meyers Pond and Oyster Point Pond were frequent, and even rates as high as 7.0 ml 02-1i.day- were observed. The phytoplankton production in the Meyers system was felt to be typical of a tidal creek in the Manahawkin area based upon additional results gathered from the Dinner Point and Oyster Point Creeks. This system also had a certain degree of annual variation in the magnitude of the summer peak, with ex- ceptional activity noted during the summer of 1976. 1.56 The phytoplankton production in the lagoons was also very high during the summer, especially at the remote station B24. Though the record levels of photo- synthesis occurring in the ponds were not observed, net productivity levels of 2.0-3.0 ml 02-1-1'day-1 were common. Usual departures from the general seasonal trend were noted at B24 (22 October 1974) at the end of October turnover, and at A08 on 26 February 1976 when exceptionally high growth rates were recorded. The results for Mill Creek, which received sewage effluent from a secondary treatment plant, varied along the length of the system. High net productivity was observed from May to September at the mouth and at E68, which is adjacent to the outfall site. The summer rates at the latter station were comparable to those in the ponds. Negligible production occurred throughout the year at the oligoha- line station, E87. The respiration of the phytoplankton community also had a pronounced seasonal pattern with highest levels occurring during the summer. An interesting contrast was observed during this period between the lagoon stations and Meyers Creek sys- tem in terms of the fraction of incorporated photosynthetic products being required for self-maintenance, i.e. (Respiration/gross production or R/GP). During the summer of 1974, for example, the following values of R/GP were observed (Table 15). Table 15. Respiration/gross production values. Station Range Average Meyers Creek mouth 0.19-0.42 0.31 Meyers Pond 0.19-0.36 0.29 A08 0.36-0.54 0.47 B24 0.39-0.72 0.52 These values were greater than the 5-15% range commonly described as characteris- tics of healthy algal cultures with no gross nutrient deficiencies (Strickland 1960). A measure of phytoplankton respiration independent of other organisms was not possible. A distinct correlation was noted between net production (NP) and gross production (GP), approximating a 1:1 relationship. High rates of gross pro- ductivity were generally not a result of aberrantly high respiration rates, but high photosynthetic rates. If respiration was largely nonalgal, high GP rates with low NP rates would have been observed. Potential phytoplankton production measured in a lighted, constant tempera- ture incubator showed good agreement with the seasonal patterns determined under conditions of natural illumination. However, net productivity during the fall and winter was significantly higher under artificial illumination and would appear to substantiate the relatively good photosynthetic potential of the phytoplankton during such periods of low temperature, low light intensity, and short daylight periods. Such a contrast was not observed in respiration when measured under con- trolled laboratory conditions and in the outside water bath. This enhanced photo- synthetic response was particularly noticeable during December 1974 at M 21 when 1.57 net productivity levels approached those of the previous summer. This enhancement accounts for the general observation made in the first annual report on the abili- ty of the Manahawkin phytoplankton populations to maintain positive NP rates throughout the year, since only laboratory incubations were carried out in study year I. This ability was later shown to be less likely under conditions of natural winter illumination. The summer productive capacity in the bay, lagoons, and creeks was affected by the addition of inorganic nitrogen (NO3 - N + NH3-N) as presented in Figure 36. Severalfold increases in net productivity after nitrogen enrichment were com- mon at all stations during the summer. Such effects were usually not observed in the fall or winter, whether measured under natural or artificial light condi- tions. Indications of other limiting nutrients, including phosphorus, were rare. Exp'eriments on the response of the surface phytoplankton populations to varying degrees of natural light attentuation demonstrated maximum photosynthetic rates at 50% I.~. Surface (100% IO) inhibition was common at all stations. The productivity profiles which were constructed permitted the calculation of compen- sation depths (Dc), expressed on a 24 hour basis. These values are listed in Table 16 and represent the depth at which total photosynthesis equals respiration, i.e., zero net carbon assimilation or growth. The light intensity at this depth is referred to as the 'compensation light intensity', IC. The data indicate a greater average depth of the euphotic zone in the lagoons. Though greater light attenuation in the turbid, shallower areas is a major factor, it should also be pointed out that such Dc values are theoretical, since the euphotic zone can only be as deep as the total depth of the area in question. Whereas the average depth of the euphotic zone at M 21 and in the Meyers system was greater than the mean depth, in the lagoons it only lies within the top 2.0 meters of the water column. The relationship between Dc and the total depth will be shown to be crucial in the overall balance between photosynthesis and respiration beneath a square meter of water surface. The similarity in Ic values (Table 16) suggests a similarity in the photosyn-I thetic behavior of the phytoplankton communities at-these different stations in relation to the reduction in light intensity. These values were considerably greater than the theoretical values of 1% I. commonly employed as an approximation of the compensation depth. Phytoplankton production per unit area (ml 02 m-2dayl1) is presented in Table 17 and Figure 37. These figures reflect not only the variation in per unit volume rates in the graded light intensity series, but also the differences in mean depth to which a productivity profile is extended. The seasonal patterns of gross productivity were generally similar to those previously described for per unit volume rates, with highest rates occurring during the summer. Net produc- tivity was frequently negative in the deep lagoon stations. This resulted from an inability of the phytoplankton to compensate for very high respiratory demands. Such demands resulted not only from high per unit volume respiration rates, but also from the relatively greater depths to which such rates had to be extrapolated, and the significant proportion of the water column lying in an aphotic zone. Negative net production was not entirely restricted to the summer, for it was also frequently observed during the fall and winter at A08 and B24. The shallower lagoon stations of B17 (2.4m) and ABD (3.0m), maintained positive net production during the summer. 1.58 M 21 6/5 6/26 7/8 7/24 9/25 10/15 12/17 2/26 4/20 6/8 Meyers Pond - I n 1. d-b c I 6/5 6/26 7/8 7/24 9/25 10/15 11/11 12/17 2/26 4/20 6/8 A02 a- 7/24 9/25 10/15 12/17 2/26 4/20 6/8 A08 6/5 6/26 7/8 7/24 9/25 10/15 11/11 12/171 2/26 4/20 6/8 1975 1976 IJJ5 Enrichment Series l l I - "Al I" (NH3-N + NO3-N + PO4-P) (NH -N + NO -N) PO -P Control Fig. 36. Phytoplankton production and nutrient enrichment experiments at M 21, Meyers Pond, A02, and A08. 1.59 Table 16. Average compensation depths (De) and compensation light intensities (Ia) for phytoplankton from 24 July 1975 to 16 March 1977. Mean depth De D e ___IC_ Stations (in) (in Mean depth (%To) Meyers Pond 0.42 1.08 2.57 10 M 21 1.00 1.55 1.55 13 ABD 2.00 1.57 0.78 11 A08 3.60 1.72 0.48 12 B24 4.00 1.60 0.40 11 Seasonal patterns of photosynthesis and respiration per square meter in the Meyers system were very similar to those rates on a per unit volume basis. Sub- stantial amounts of net production occurred during the summer, especially in Meyers Pond, when very high photosynthetic rates compensated, to some extent, for the very shallow depth. In constrast to the deep lagoon stations, negative net production occurred infrequently. DISCUSSION General In this marsh system, there are basically two types of creek drainages. Creeks with upland sources generally show a marked axial salinity gradient because of fresh water input. Those that do not extend into the upland show a reduced salinity gradient because they drain only marshland. Usually, the water draining from a marsh is tidal in origin. Rainfall in the immediate vicinity would account for only a small part of the marsh drainage over the course of a year. In the Manahawkin area, Mill Creek is an example of the first type of creek drainage; Dinner Point Creek and Meyers Creek are examples of the second type. In both cases, tidal flow is the major hydrologic force rather than fresh water input. Apparently, it matters little, as far as stratification is concerned, whether a lagoon is in communication with a reasonably fast flowing creek or with the bay where currents are reduced. Stratification is as common and severe in the lagoons of E system as in the other lagoons systems. There is no justification in locating lagoons in upstream areas just because there is a high flow rate in the creek. As a matter of fact, locating the lagoons upstream increases their remoteness from the bay. In those systems communicating directly with the bay, e.g. Lagoon Systems A and B, severity of stratification seems to be related to the remoteness of location. On the other hand, the shallowness of Meyers Pond results in almost complete flushing into the creek each tide. The short length of Meyers Creek and the completeness of vertical mixing permit a high exchange of water with the bay; water does not tend to become trapped in the Meyers Creek system. The high ben- thic respiration requirements in the summer are met in part by the import of oxy- gen rich water. Such water is brought into the pond with each flood tide. A 1.60 Table 17. Summary of production data in ml 0?'m-2'day-1. Meyers Pond Mid Meyers Creek M21 ABD Date ~P R NP GP R NP ~P R NP GP R NP 9/25/74 722 168 554 787 260 527 2,526 1,280 1,246 10/15 213 142 71 279 240 39 689 400 289 10/22 213 126 87 435 260 175 927 640 287 11/4 312 168 144 418 200 218 738 680 58 11/19 49 50 -1 90 120 -30 221 440 -219 12/3 25 17 8 98 80 18 394 280 114 12/27 336 126 210 492 280 212 820 560 260 1/21/75 16 76 -60 197 240 -43 197 400 -203 2/18 107 0 107 320 120 200 164 80 84 3/18 74 76 -2 221 140 81 402 240 162 4/1 287 360 -73 1,788 680 1,108 4/22 131 58 73 385 100 285 1,025 200 825 6/5 369 176 193 927 520 407 3,649 2,880 769 6/25 869 344 525 1,041 480 561 1,960 1,120 840 7/8 754 462 292 1,050 880 170 2,649 2,320 329 7/24 2,345 336 2,009 1,886 576 1,310 541 240 301 2,780 1,520 1,260 9/25 230 110 120 344 192 152 394 200 194 836 560 276 10/15 262 0 262 697 96 601 230 0 230 812 0 812 12/17 459 126 333 1,099 432 667 574 320 254 959 600 359 2/26/76 328 68 260 754 264 490 738 220 518 861 480 381 4/20 558 252 306 1,132 432 700 525 300 225 1,328 840 488 6/8 853 210 643 2,353 768 1,585 1,558 380 1,178 2,878 1,080 1,798 8/3 1,779 470 1,309 1,435 1,176 259 1,164 1,040 124 3,149 2,520 629 8/31 3,018 454 2,564 2,845 1,152 1,693 1,263 1,000 263 3,780 2,280 1,500 9/13 2,624 520 2,104 3,255 1,344 1,911 1,394 1,200 194 2,575 2,520 55 11/2 574 210 364 1,214 504 710 1,099 320 779 984 680 304 3/16/77 271 59 212 344 192 152 336 20 316 599 80 519 Table 17. Continued. A02 A08 B17 B24 GP R NP GP R NP GP R NP GP R NP 9/25/74 3,460 2,160 1,300 2,124 2,160 -36 10/15 1,615 1,872 -257 1,419 3,040 -1,621 10/22 1,509 1,224 285 4,330 2,960 1,370 11/4 1,115 2,016 -901 1,804 2,080 -276 11/19 640 1,224 -584 558 1,280 -722 12/3 574 288 286 1,337 800 537 12/27 820 864 -44 886 1,200 -314 1/21/75 279 720 -441 148 400 -252 2/18 418 144 274 262 160 102 3/18 853 720 133 1,279 960 3Q9 4/1 2,025 1,800 225 1,886 1,360 526 4/22 1,591 432 1,159 1,000 480 520 6/5 2,731 2,880 -149 1,681 2,080 -399 6/25 2,862 2,592 270 2,280 3,200 -920 7/8 2,936 4,464 -1,528 2,886 6,080 -3,194 7/24 2,107 2,340 -233 3,460 5,040 -1,580 9/25 2,739 1,200 1,539 4,477 1,440 3,037 10/15 853 60 793 877 432 445 12/17 1,542 1,020 522 2,025 792 1,233 2/26/76 1,041 780 261 4,674 2,304 2,370 4/20 1,681 1,140 541 1,968 1,152 816 6/8 4,772 2,760 2,012 4,346 3,888 458 8/3 3,821 4,140 -319 2,919 5,256 -2,337 4,395 3,360 1,035 4,936 6,240 -1,304 8/31 3,050 4,320 -1,270 2,132 5,472 -3,340 3,313 3,120 193 4,576 6,080 -1,504 9/13 3,895 4,200 -305 3,387 5,472 -2,085 4,149 3,360 789 4,567 6,080 -1,513 11/2 1,082 1,320 -238 1,320 2,016 -696 1,591 960 631 1,386 2,400 -1,014 3/16/77 812 300 512 853 360 493 1,214 336 878 1,164 560 604 5 -I A08 Meyers Pond 4- 2 - 3- o 0 0~~~~~~~~~~~~~~~~~~~ 2- SN DJ- F M Ao~ MJ A S O 0 S 0 iJ F M A MJ J DI5 N D J F M A M J J A S 0 N 0 J F M A M a -2 1- I\ / M 21 \0 W o ~~~~~~~~~~~~~~~~~~~~~~~~~I~~~~ .~~~~~~~~~~~ Ii a S ON DoiJ F M A M J J A M 0 N DIJ F M A M J F MA M ar ..o-~ -o~ "0.. ~ 1974 5- 1975 1976 1977 A o. . . .. ... S 0 9 N n JJ F M A M j J A S 0 N 0 IJ F AM AM J J A S O NDIJFMAM 4- 0 I I. 9 I\ 3- 3- 0 0 S 0 N Di J F M ~ ~ ~AMJJA NDIJFMAMJJAS 0 N DJFMAMJ A SONDJiF M AM J JA SO0NODJFMA 1974 1975 1976 1977 F ig - 37. Phytoplankton gross production (*--.) and respiration (o --- o) in ml 02-m-2 -day-l103. portion of this water originates in the bay. Such an exchange does not occur in the lagoon systems. Poor flushing, increased depth, and stratification all tend to magnify the effects of benthic respiration demands on the water column in the lagoons. The bottom water is retained in the lagoons, and since the compensation depth is usually less than the depth of stratification, photosynthetic oxygenation is restricted to the surface layers. In the same way, metabolic products can accumulate on the bottom during periods of stratification. Buildings along the lagoons offer protection from wind stirring and thereby reduce mixing. Such pro- tection is not provided the shallow marsh ponds. The rich benthic fauna of ponds contributes to the cycling of materials. The periodic creation of anaerobic conditions on the bottom in lagoons certainly must prevent the development of an equally rich benthic community. The degree to which this interferes with cycling is not known. The occurrence of a seasonal cycle in lagoon salinity values indicates that even though flushing is low, exchange with the bay does occur. The return of salinity levels to high values after periods of high runoff requires an input of higher salinity water from the bay. The creeks are bordered to varying degrees with Spczrtina alternif'lora tall form. In some cases, the tall form border is absent. Behind the border are ex- tensive areas of short form. The presence of the short form indicates that, although tidal flooding does occur, poor drainage conditions exist. Consequently, there probably is only minimal transport of materials off the marsh surface. Nitrogen INORGANIC AND ORGANIC FRACTIONS -- The occurrence of peak inorganic nitrogen con- centrations coupled with reduced surface salinities in the creek systems suggested the inorganic nitrogen concentrations were related to storm activity and/or upland drainage. Precipitation, surface runoff, and upland drainage could have depressed the surface salinities and transported nutrients. Alternatively, storm related wind and wave disturbance of the bottom could have increased the amounts of inor- ganic nitrogen in the water column. In either case, the seasonal trend would be irregular from year to year because of the variability of storm occurrence. Any of these explanations or a combination of them could account for the elevated ammonia-N and nitrate-N concentrations seen at the upper ends of the creek systems; factors related to the individual systems would also influence the observed levels. .Such was the case in the Mill Creek System (Lagoon System E). Mill Creek was the only system studied with a continuous stream flow. Following the fall reduction of upland community primary production, increased amounts of inorganic nutrients were transported downstream by the creek. To a degree, this increased transport masked the storm-related inputs and resulted in a more extended inter- val of raised ammonia-N and nitrate-N concentrations at E87 compared to the upper ends of the other systems. The inorganic nitrogen seasonal trends were further complicated by the sewage plant at E68. The sewage outfall probably accounted for the irregular nature of the peaks and the high levels reached at the E68 site. The influence of this contribution extended downstream to the creek mouth where corresponding peaks, although diminished in size, were sometimes observed. The Dinner Point Creek drainage, while relatively large in size, was confined mainly to the marsh. Examination of U.S.G.S. topographic maps indicated there was no significant upland area within the Dinner Point Creek drainage basin. Large 1.64 differences in salinity occurred between the mouth and upper ends with some over 10 O/oo. Many of these differences were attributable to storm drainage. Other cases could be explained by the lack of complete tidal mixing at the upper end station. It was likely the observed nutrient levels resulted primarily from tidal-related forces or storm activity in the immediate area. This accounted for the more irregular nutrient peak patterns seen at the upper end site compared to E87. The lack of flow also eliminated the "salt wedge" effect seen in Mill Creek and allowed for greater mixing with the nitrogen poor bay water at the mouth site. Greater damping or alteration of upper end trends was the net effect. The lower surface values observed at Dinner Point Creek mouth relative to the E mouth sur- face station resulted from this effect as well as t'ie absence of any sewage out- fall on Dinner Point Creek. The situation in the Meyers Creek system was similar to that in Dinner Point Creek. Except for local rainfall and runoff, there was limited upland drainage. Reduction of upper end salinity variations was again seen at the mouth site. Within the lagoons, nitrate-N and ammonia-N varied in their distribution pat- terns. The anaerobic conditions during periods of stratification favored the accumulation of ammonia-N. This was best seen at station B24. Nitrate-N could be found in the lower layers when the water column was destratified; however, the main concentrations usually were in the upper part of the water column. Enrich- ment of the upper layers occurred following breakdown of stratification. At such times accumulated ammonia-N circulated throughout the water column, and nitrifica- tion resulted in elevated nitrate-N values. The situation at the A08 mouth site was different. Ammonia-N accumulated on the bottom during periods of stratification. Stratification was intermittent at the A08 mouth station and the water column vacillated between stratified and nonstratified conditions. Perhaps the similarity in trends and values for the surface and bottom nitrate-N concentrations was a result of this. Also unlike B24 the surface nitrate-N and bottom ammonia-N concentrations did not maintain an in- verse relationship. For the winter-spring periods the relation could even possi- bly be interpreted as being direct. Aside from diffusion and subsequent nitrifi- cation, a concurrent process was the nutrient addition associated with storm activity. Surface salinity reductions in the lagoons could only result from freshwater input associated with rainfall. The periods of observed salinity re- ductions in the winter and fall coincided with elevated nutrient values. The im- plication was part or all of these increased concentrations were attributed to runoff/precipitation. Such values seemed possible based on the nitrogen runoff contributions determined in this study. On a per square meter basis, the lagoons were much richer in nitrogen than the other systems because of the greater depths in the lagoons. The increased depth allowed a greater volume of water per unit area. It also permitted strati- fication which led to elevated ammonia-N concentrations in the lower part of the water column. Considering that nitrogen probably limits the aquatic primary production, this would seem to be a potentially beneficial attribute; however, the increased levels were confined to the bottom of the lagoons. The inorganic nitrogen was available neither to the bay, because of the lack of circulation, nor locally to the upper part of the water column because of the presence of a thermocline and/or halocline. 1.65 The inorganic nitrogen stocks were the net product of a number of processes and factors. It was difficult to state which process was the most responsible. The observed concentrations could have been a function of regeneration rates alone. Alternatively, photosynthetic demands greater than the existing rate of nutrient regeneration could account for low levels of a specific compound. The converse would also be true. Seasonal variations could further complicate matters. In- creased rates of summer versus winter photosynthesis and evapotranspiration would have to be recognized. The effects of a given nutrient input and salinity de- pression caused by rainfall would be moderated more rapidly in the summer than in the winter. While precipitation effects could be readily detected in the win- ter, they might be less obvious in the summer. Concurrent processes were also difficult to discriminate between. The total organic-N component was important not only because it was the lar- gest nitrogen fraction but also because it represented a major nutrient reservoir. Eventually, decomposition processes would convert the organic-N into ammonia-N. However, the release of this utilizable form would be over a long time increasing its effective availability. Not unexpectedly there was an apparent relationship between the seasonal organic-N patterns and some of the primary production factors measured. For example, the chlorophyll a variations in the lagoons seemed to be related to the total organic-N changes. While not the only source of organic- N, primary production by the phytoplankton would probably be the major source in the water column. Our research indicated the following general trends regarding nitrogen com- pounds: 1) The surface waters of both creek and lagoon systems were generally poor in all forms of inorganic nitrogen. 2) Ammonia-N was the predominant form of inorganic nitrogen, followed by nitrate-N and then nitrite-N. 3) The organic nitrogen fraction was the dominant nitrogen form in terms of abundance. 4) The bottom of the lagoons accumulated high concentrations of ammonia- N during periods of stratification. 5) The extremely high ammonia-N concentrations were applicable to a relatively small volume of the total water column. 6) The creeks, and in particular Mill Greek, were implicated as sources of inorganic nitrogen compounds based on concentration gradients. 7) Increased surface ammonia-N levels correlated with decreased surface salinities. 8) Increased nitrate-N levels could be related to nitrification and/or reduced surface salinities. NITROGEN FIXATION -- Nitrogen fixation was a significant process despite the rela- tively low rates observed. Its importance stemmed from its singular position as a mechanism for the introduction of previously nonutilizable nitrogen into the system. Other input processes functioned only as recycling mechanisms of already 1.66 fixed nitrogen. Only nitrogen fixation increased the absolute standing stocks of fixed nitrogen. The reduction of this capability in the lagoon complex was a major difference between the developed and the marsh areas and represented a dis- advantage for the lagoon systems. The importance of this difference was emphasized by the nitrogen poor condition of the surface waters in the study area and the limitation this placed on photosynthetic rates. The reduced nitrogen fixing capability was primarily related to the loss of marsh surface in the developed areas. The amount of "new" nitrogen, while not supplying the bulk of the primary production nitrogen demand, probably did much over a long time span to charac- terize the overall production types and amounts currently present. The seasonal variation observed in nitrogen fixation was not unexpected as the enzyme system is known to be cold labile. Also, the reduction of photosynthe- tic processes during the winter meant a reduction in the input of energy to the nitrogen fixation process. Within the marsh surface (SAS, SAT/B, and SP-DS) and bulkhead (lower) communities, seasonal patterns for net photosynthesis and nitrogen fixation were very similar. Minimal activity was observed in these areas during the winter period at which time visible algal cover was also at a minimum. Maxi- mum nitrogen fixation rates in the Spartina alterniflZora stands (SAS and SAT/B) occurred during the June-July period, and in May for the lower bulkhead community. High net photosynthetic rates also occurred in May but extended to September. Photosynthesis and nitrogen fixation in the benthic sediments were consistently low. Though marginal rates were observed under S. patens throughout the year, somewhat higher levels were observed in July for both nitrogen fixation and photo- synthesis. The similarity in seasonal trends is plausible since nitrogen fixation re- quires an energy input from photosynthesis. However, the correlation between these processes is dependent upon the relative proportion of the nitrogen fixers and non-nitrogen fixers in the community at any one time. The presence of non- fixing autotrophs may have been the reason the period of high photosynthetic activity was more prolonged than that for nitrogen fixation. Our nitrogen fixation data are comparable to those of Whitney et al. (1975) and Van Raalte et al. (1974) among others. Whitney et al. (1975) found nitrogen fixation rates of approximately 5 1-g-atom N'm2,h- for marsh surface sediments in the summer. This differed by only a factor of 2 from our calculated summer value of approximately 11 lPg-atom N~m-2h- for the SAS substrate community. Considering site and inherent sample variation, this was a minor difference. Our SAS substrate community values peaked in the fall of 1975 following a period of slightly elevated levels during the spring-summer period. Possibly this was due to an increase in the population or activity of the heterotrophic bacterial nitro- gen fixers present. Such an explanation was reasonable based on the data of Marsho et al. (1975) for a Typha marsh. They attributed most of the nitrogen fixation occurring in the Rhode River Estuary marsh sediments to bacterial activ- ity. In evaluating the potential nitrogen fixation capability of these sediments, they found a seasonal variation approximating our in situ trends. They suggested the fall increase was a response to accumulated organic compounds by the nitrogen fixing bacteria. Perhaps this was also what caused our fall peak in nitrogen fixation activity. The Flax Pond data_(Whitney et al. 1975) indicated a nitrogen fixation rate around 8 jig-atom NM2hI during the summer for the SAT substrate community. Our summer values for this zone ranged from less than I to about 18 pg-atom N-m-2-h1 depending on the site chosen. If all three sites were pooled with equal weight, the mean was approximately 6 pg-atom N-m-2,h_. Concerning 1.67 the algal mats on the marsh surface, the approximate summer nitrogen fixation rates found by a number of researchers are indicated in Table 18. Table 18. Nitrogen fixation rates on the marsh surface. Researchers Date Location Rate (Vg-atom N'm-2'h1) Whitney et al. 1975 New York 200 This report 1977 New Jersey 120 Van Raalte et al. 1974 Massachusetts 70 In terms of rate the algal mats were the dominant nitrogen fixers in both the developed and undeveloped areas examined in the present study. This was also true of several other studies where marsh surface substrate and algal communities were compared. Research on benthic sediment community nitrogen fixation in many different environments has indicated only low rates are generally found. The results found at Meyers Creek system also support this statement as does the following (Table 19). Table 19. Benthic sediment nitrogen fixation. Researchers Date Location Rate (pg-atom N'g dry wt-l'h-1) This report 1977 Meyers Pond, N.J. 0.000353 Meyers Creek, N.J. 0.000107 Brooks et al. 1971 Waccasassa estuary, 0.000219 Fla. Marsho et al. 1975 Rhode River estuary, 0.000171 Md. Keirn and Brezonik 1971 Various Fla. lakes 0.000024 - 0.004214 Howard et al. 1970 Lake Erie, Ohio 0.000833 The water column community in the Manahawkin area was determined to have negligible nitrogen fixation capacity. Often in freshwater studies high nitrogen fixation activity is associated with the water column, particularly with blooms of blue-green algal species like Anabaena. The only marine algal form proposed as a nitrogen fixer is Trichodesmium. Accordingly, nitrogen fixation is less frequently observed in the marine water column. In the temperate nearshore en- vironments a nitrogen fixation capacity is mainly associated with benthic or primarily terrestial communities. It is possible to transplant organisms from these zones to the water column because of the interchange that exists between terrestial, benthic, and aquatic zones in an estuarine environment. This would provide organisms capable of nitrogen fixation to be associated with the water column at least on a temporary basis. Despite this mechanism, in the Manahawkin 1.68 study area the nitrogen fixation rates were extremely low within the water column and at the limit of detection of our methodology. Because of the variation en- countered the observed rates were determined to be essentially zero. EXCRETION -- Johannes (1965) has emphasized the importance of excretion by animals versus bacterial decomposition in nutrient regeneration. In our work with animal excretion we did not differentiate between the various nitrogen loss mechanisms (removal of metabolic wastes, osmoregulation, reproduction, discharge of unassimi- lated material, etc.). We were primarily interested in the total nitrogen con- tribution made by the organisms. We also did not examine the nitrogen compounds not detected by the ammonia-N and Kjeldahl-N methods utilized. Because the liter- ature indicated aquatic invertebrates were primarily ammonotelic, we felt we detected the majority of the excreted nitrogen compounds using the above methods. Given these restrictions, it was found the total nitrogen contribution via excre- tion, as defined by us, was significant. Of this contribution, a larger than expected portion was total organic-N for Modiolus demissus and Ilyanassa obso- leta (also known as Nassarius obsoletus). Bishop (1976) indicated as a general rule ammonia-N comprised 65-70% of the total excreted nitrogen compounds for most aquatic invertebrates with urea, uric acid, amino acids, and other composing the remainder. More specifically, for Modiolus sp. Lum and Hammen (1964) found excretion rates of 3.1 ,g-atom NH3-N'9 tissue-l'day-l and 1.0 pg-atom amino acid' g tissue-l'day-1.3 They also stated their amino acid excretion rates were prob- ably low based on recovery experiments. They further indicated in several of the experiments amino acid excretion exceeded ammonia-N excretion. Corroborating data were supplied by Nicol (1969) who indicated ammonia-N composed only 10% of the total nonprotein nitrogen excreted by Mytilus edulis, a species simi- lar to ModioZus. While we feel our "excess" organic-N excretion was in part due to the broad nature of this category as defined by us, perhaps the high excretion rates we observed could be explained by the high and sometimes variable amino acid excretion encountered by Lum and Hammen. Regarding ammonia-N loss, for a time comparable to when the Lum and Hammen work was done, we obtained a rate of 2.0 Pg-atom NH3-N-g dry wt-l'day-1. In contrast to this, Nixon et al. (1976) found much higher rates, on the order of 3.6 Vg-atom NH3-N'g dry wt-l'h-1. However, their methodology, particularly their shorter incubation time, differed from that used by Lum and Hammen (1964) and us. At most stations, the zooplankton ammonia-N excretion was at a minimum in the winter and attained a maximum in the spring which extended somewhat into the summer. Possibly this spring peak was associated with the increased availability of food. In other zooplankton excretion studies, a fall excretion pulse excre- tion was detected, we did not. Sage and Herman (1972) indicated the zooplankton population in nearby Sandy Hook Bay peaks in the late spring and fall. It is therefore likely our sampling schedule missed the fall population and related excretion peak if one occurred. Like the zooplankton, Ilyanassa obsoZeta excretion peaked during the spring quarter. Perhaps this was a reflection of a postwinter increase in metabolic activity or the increase of available food amounts and/or types. This trend was consistent for all sites tested. AMMONIFICATION -- In this study, ammonification was defined as the production of ammonia-N from the degradation of organic matter. Our intent was to monitor this process and to roughly estimate its importance in nitrogen cycling. Although 3Note: It is unknown whether "tissue" is dry weight tissue or wet weight tissue. 1.69 labeled ammonification, the rates actually resulted from a variety of processes of benthic organisms. Besides decompositional processes, excretion by various benthic populations would be included. Because we were estimating a net rate, adsorption to sediment fractions by mineralized nitrogen, nitrification, and denitrification would also be a part of the rate but as losses. The ammonification rates thus represented ammonification in a very broad sense, because they reflected the net degradation of organic matter to ammonia-N on a community basis and not by micro- organismal populations alone. The data from the third study year indicated the following: 1) It was readily apparent that of the "inputs" studied ammonification was the dominant nitrogen source. 2) In general, the sites investigated showed declines in the rates of ammon- ia-N production during the winter. This suggested, as other investigators have hypothesized, the process was in part temperature related. 3) Because there was no trend relative to upper or lower ends of the systems tested, factors other than remote point distance (i.e. distance from the bay) probably determined the ammonification rate of a specific site. Although we did not ascertain the specific factors, bottom substrate composition and microorganism environment probably were involved. Conclusions must be made cautiously. Even between experimental replicates there were discrepancies caused by the inherent variability of the methodology used raising questions about the accuracy of the measurements. Because "disturbed" substrate systems were employed to derive the ammonification rates, it was diffi- cult to establish several systems with identical parameters and conditions. The use of "disturbed" sediment systems relatively soon after collection might have resulted in erroneously high initial ammonia-N concentrations caused by sampling disturbance. This could have led to the determination of artificially low ammoni- fication rates. Such an error was implied by a comparison of the Manahawkin rates to those of Rowe et al. (1975). The Manahawkin rates were lower than the mean coastal sediment ammonia-N flux rate of 3,456 lg-atom NH-N-m-2.day-1 they deter- mined. It is possible, however, these discrepancies can be explained by site differences or because the methods used to determine the rates were based on dif- ferent principles. Nixon et al. (1976) cite ammonia releases of 150 to 250 ijg- atom NH3-N~m-.h-1 for Narragansett Bay which extrapolates to 3600-6000 Vg-atom NH3-N'm-2'day-1. Rowe et al. determined a summer flux rate of 2,030 lg-atom NH3- N'm-2'day-1 for Eel Pond, presumably a salt marsh type site. Evidently, site differences cause a lot of variation in the ammonification rate. Because our mean rates differ by only a factor of 2 or 3 and our individual measures approxi- mate the published data, we are confident our figures are acceptable estimates. RUNOFF -- Based on Table 12, road runoff was a greater source of nitrogen than roof runoff. This was not unexpected as road drainage would travel farther over surfaces with potentially higher accumulations of nitrogen than roof runoff. Also road runoff carried a higher proportion of organic nitrogen than roof runoff. At Lagoons A02 and A08, 38% of the nitrogen contributed by roof runoff was organic- N while 57% of that contributed by road runoff was organic-N. Organic-N repre- sented a significant part of the total nitrogen contributed via runoff. Whipple and Hunter (1977) also emphasized the importance of imported organic matter in urban storm runoff, indicating contributions of hundreds of milligrams per liter of suspended sediments and large amounts of B.O.D. and nutrients were common. 1.70 They commented the organic shock loads to the receiving bodies of water could be massive. In studying the mineralization of this type of tranported material, Cowen et al. (1976) stressed the importance of the organic fraction because of the po- tentially large amounts of nitrogen that would be released upon decomposition. Yard runoff was not measured due to the lack of a means to collect subsurface and ground level sheet flows. Probably this type of runoff would be more similar to road runoff than roof runoff. If this were true, an additional input of 6 to 7 times the road runoff input would be expected provided all the water percolated into the lagoons. NITROGEN BUDGET -- Quarterly nitrogen budgets were organized into three sections, (1) standing stocks; (2) inputs measured; and (3) calculated requirements. Separ- ate budgets were derived for Meyers Creek, Meyers Pond, Lagoon A02, and Lagoon A08. Subdivisions were made between terrestial (the marsh surface) and aquatic (areas interfaced with or within the water column) zones where appropriate. Bud- gets were based on data from study year III (Tables 20, 21, 22, 23). Of the nitrogen standing stock categories, total organic-N was the dominant fraction at all four sites, more than 82% of the nitrogen was in this form. In general, greater levels of total organic-N were found in the Meyers Creek system than in the Lagoon A system. Although shallower than the lagoons, the larger volume of the Meyers Creek system accounted for much of the observed difference. If concentration was the sole determinant of the total organic-N present, the order would have been Lagoon A02 (37 Pg-atom Org-N'l-1), Meyers Pond (39 pg-atom Org-N1'-1), Lagoon A08 (45 pg-atom Org-N'l-1), and Meyers Creek (45 pg-atom Org- N-1-1). While the organic-N fraction is significant to the nitrogen budget on a long- term basis, the inorganic-N fraction is of greater importance in terms of daily nitrogen flux because of its availability. At both Meyers Creek system sites a large pulse of inorganic nitrogen was observed in the second quarter. This was probably a result of storm related activity and the fall shutdown of the primary producers. The lagoon sites presented a less consistent pattern. While Lagoon A02 exhibited a peak inorganic nitrogen level during the second quarter, at Lagoon A08 a first quarter peak was recorded followed by a high level of inorganic nitro- gen during the second quarter. While the fall patterns at both A02 and A08 could be explained as parallels to the creek system phenomena, the summer maximum at A08 could not. Elevated nitrate-N levels played a part in determining the sizes of the fall increases, but this was not the case at A08 during the summer maximum. Here, ammonia-N comprised over 90% of the inorganic nitrogen present as opposed to under 70% in the second quarter. The ammonia-N level was more than 2 times higher than it had been in any other period. The first quarter increase resulted from a mechanism distinct from that which produced the fall increases and which was peculiar to A03 and not A02. We believe this mechanism to be stratification. Stratification would account for the preponderance of ammonia-N in the composition of the first quarter peak, the occurrence of the increase during the summer, and the failure to observe a similar peak at A02. It is important to remember while nitrate-N assumes importance on occasion, as in the fall increases, ammonia-N is usually the most prevalent inorganic nitrogen compound found. The nitrogen input rates to the water column indicate ammonification is the dominant process followed by excretion, runoff, and nitrogen fixation. It seems, therefore, the on site nitrogen recycling processes are much more important on a 1.71 Table 20. Nitrogen budget for Lagoon A02. Classification Quarter: 1 2 3 4 Standing Stock in ig-atom N'106 Inorganic nitrogen: NH3-N 13.9 32.7 6.9 0.6 N02-N 0.2 0.5 2.8 0.0 N03-N 4.7 22.6 9.0 0.2 Sum of inorganic nitrogen stocks 18.8 55.8 18.7 0.8 Organic nitrogen: Total Organic-N 655.5 567.6 619.2 568.9 Sum of all nitrogen standing stocks: 674.4 623.4 637.9 569.7 Inputs in 106 ig-atom N'day-1l.106 Ammonification (NH3-N) 10.2 21.8 20.2 54.8 Excretion: Zooplankton (NH3-N) 0.0 0.0 0.2 2.0 Ilyanassa (NH3-N) 0.2 0.2 0.4 0.6 (Org-N) 1.4* Sum of all excretion (NH3-N) 0.2 0.2 0.6 2.6 (Total-N) 1.6 1.6 2.0 4.0 Nitrogen fixation (NH3-N): Water column 0.5 0.8 0.1 1.2 Runoff/precipitation: Inorganic-N (NH3-N + N02 -N + N03 -N) Water column 0.7# Organic-N (Total organic-N) Water column 0.2# Sum of all inputs: Water column (Inorganic-N) 11.6 23.5 21.6 59.3 (Organic-N) 1.6 1.6 1.6 1.6 * This value will be applied to the entire year. # This value is based on the data accumulated during the entire year and will be applied to the entire year. 1.72 Table 21. Nitrogen budget for Lagoon A08. Classification Ouarter: 1 2 3 4 Standing Stocks in pg-atom N-106: Inorganic nitrogen: NH3-N 44.2 20.0 13.2 6.5 N02-N 0.1 0.0 0.8 0.0 N03-N 4.0 8.8 2.7 0.7 Sum of inorganic nitrogen stocks 48.3 28.8 16.7 7.2 Organic nitrogen: Total Organic-N 684.0 506.0 679.8 698.0 Sum of all nitrogen standing stocks 732.3 534.8 696.5 698.0 Inputs in pg-atom N-day 1-106 Ammonification (NH3-N): 4.2 10.4 4.7 4.9 Excretion: Zooplankton (NH3-N) 0.2 0.0 0.0 1.2 Ilyanassa (NH3-N) 0.4 0.2 0.4 1.0 (Org-N) 1.2* Sum of all excretion (NH3-N) 0.6 0.2 0.4 2.2 (Total-N) 1.8 1.4 1.6 3.4 Nitrogen fixation (NH3-N): Water column 0.3 0.3 0.0 0.2 Runoff/precipitation: Inorganic-N (NH3-N + NO2-N + N03-N) Water column 0.5# Organic-N (Total organic-N) Water column 0.2#i Sum of all inputs Water column (Inorganic-N) 5.6 11.4 5.6 7.8 (Organic-N) 1.4 1.4 1.4 1.4 * This value will be applied to the entire year # This value is based on the data accumulated during the entire year and will be applied to the entire year. 1.73 Table 22. Nitrogen budget for Meyers Creek. Classification Ouarter: 1 2 3 4 Standing Stocks in ug-atom N,106: Inorganic nitrogen: NH3-N 42.9 152.9 5.5 22.0 N02-N 0.0 2.2 2.2 0.0 NO3-N 2.2 28.6 4.4 2.2 Sum of organic nitrogen stocks 45.1 183.7 12.1 24.2 Organic nitrogen: Total organic-N 1,084.6 841.5 804.1 711.7 Sum of all standing stocks: 1,129.7 1,025.2 816.2 735.9 Inputs in 106 ]jg-atom N'day- 1106 Ammonification (NH3-N): 28.9 25.2 1.5 39.8 Excretion: Zooplankton (NH3-N) 0.6 0.1 0.0 1.3 Modiolus (NH3-N) 1.8 4.7 14.0 4.8 (Org-N) 10.9* IZyanassa (NH-N) 0.6 0.3 0.8 0.9 (Org-N) 1.4* Sum of all excretion (NH3-N) 3.0 5.1 14.8 7.0 (Total-N) 15.3 17.4 27.1 19.3 Nitrogen fixation (NH3-N): Marsh surface 104.6 133.6 2.7 11.1 Water column 0.8 0.3 0.1 0.1 Runoff/precipitation: Inorganic-N (NH3-N + N02-N + N03-N) Marsh surface 11.1* Water column 1.1* Sum of all inputs: Marsh surface (Inorganic-N) 115.7 144.7 13.8 22.2 Water column (Inorganic-N) 33.8 31.7 17.5 48.0 (Organic-N) 12.8 12.3 12.3 12.3 *This value is based on all the available data and will be applied to the entire year. 1.74 Table 23. Nitrogen budget for Meyers Pond. Classification Quarter: 1 9 A Standing stocks in ug-atom N.106 Inorganic nitrogen: NH3-N 31.1 120.6 21.6 22.5 N02-N 0.0 1.8 2.7 0.0 N03-N 2.7 22.5 14.4 1.8 Sum of inorganic nitrogen stocks 33.8 144.9 38.7 24.3 Organic nitrogen: Total Organic-N 918.5 982.8 720.9 629.1 Sum of all standing stocks 952.3 1,127.7 759.6 653.4 Inputs in 106 vg-atom N'day-l'106 Ammonification (NH3-N): 54.1 59.4 0.0 155.3 Excretion: Zooplankton (NH-N) 0.5 0.1 0.0 1.0 Modiolus (NH3-N) 0.8 2.0 6.1 2.1 (Org-N) 4.7* Ilyanassa (NH-N) 1.1 0.6 0.9 2.2 (Org-N) 3.2* Sum of all excretion (NH3-N) 2.4 2.7 7.0 5.3 (Total-N) 10.3 10.6 14.9 13.2 Nitrogen fixation (NH3-N): Marsh surface 71.0 81.4 3.0 8.3 Water column 11.8 4.3 0.0 0.5 Runoff/precipitation: Inorganic-N (NH3-N + N02-N + N03-N) Marsh surface water column Sum of all inputs: Marsh surface (Inorganic-N) 80.9 91.3 12.9 18.2 Water column (Inorganic-N) 70.4 68.5 9.1 163.2 (Organic-N) 7.9 7.9 7.9 7.9 *This value is based on all the available data and will be applied to the entire year. 1.75 short term basis than those which provide nitrogen previously unavailable or from allochthonous sources. Other workers including Hlaines et al. (1976) have conten- ded this. The only inputs to the marsh surface measured were nitrogen fixation and nitrogen from direct precipitation. Nitrogen fixation was found to exceed the precipitation contribution on an overall basis. Comparing the two systems in terms of these processes, the lack of certain components in the lagoon system is apparent. The lack of a Modiolus population in the lagoons accounts for the smaller excretion contribution made there. The contributions made by the ITZyanassa and mixed zooplankton populations were roughly equivalent both within and between systems. The lack of a biologically functional marsh surface in the lagoon system is another obvious difference between the two areas. Because of this a great deal of nitrogen fixing capability is lost. The failure for other zones to compensate represents a restriction of the introduction of "new" nitrogen into the system. In discussing the nitrogen fluxes it is important to note the various inputs and requirements derived are not all inclusive. The vast majority of the species and the number of organisms present were untested. It is, therefore, likely that a significant fraction of the total excretion was not included in the estimates of contributed nitrogen. Similar gaps exist in the net production data which were utilized to calculate the demand placed on the nitrogen resources. Production by macrophytic algae was not included. On the marsh surface production in the salt pools and certain epiphytic plant zones were also untested. The "budget" outlined then is only an estimate of the stocks and fluxes occurring in the respective systems. Within the water column, the phytoplankton exerted the greatest nitrogen demand in both systems. The limited distribution of the bulkhead algal community in the lagoon system negated to an extent its high rate of nitrogen demand. The bank zone algal community was a parallel to this in the creek system. Reflecting the importance of their microbial populations, the benthic algal communities in both systems generally exhibited a negative net production throughout the year. This represented a contribution of nitrogen shown -as a reduced demand rather than an input. It meant microbial respiration returned more nitrogen than the primary producers incorporated. The microbial component was also a factor in the phyto- plankton community. At the surface a 1:1 ratio of net production to gross produc- tion was typically observed. However, on a water column basis, the 1:1 ratio was not maintained, and negative net production values were sometimes detected during the year. These values resulted from high respiratory activity which occurred primarily in the lower water column. This in turn suggested the respiration was nonalgal in nature and would logically be microbial in origin. Table 24 shows the total nitrogen demand of the bulkhead algal, bank zone algal, benthic algal, and phytoplankton communities at their respective sites. The nitrogen demand was greatest in the Meyers Creek system, particularly in the summer and spring quarters. The total available inorganic nitrogen supply would have been depleted within one day at these times if there were no inputs into the standing stock compartment. It was the high phytoplankton production that created the bulk of this nitrogen demand. In the lagoons relatively low nitrogen demand were exerted during the summer season. This resulted in part from the depth of the lagoon sites. The compensation depth in the lagoons during the summer was around 2.0 m or less. This meant a significant portion of the water column was exerting a respiratory demand offsetting the effect of high production rates in the surface layers; and resulting in a low overall net production and nitrogen requirement. Downward shifts of the compensation depth appeared to increase the nitrogen demand 1.76 in the fall at the lagoons. In addition, there was a major increase in the rates of bulkhead algal production at this time. The negative fall quarter value at Meyer's Pond was due to exceptionally high benthic respiration. A high respiration I ~rate also caused a low nitrogen demand value at the Meyers Creek site. The large nitrogen requirement at A08 during the winter was the result of a major burst of phytoplankton production, observed only at A08, and continued bulkhead community I ~activity. In the spring, the lagoon values were again unexpectedly low considering I ~the trends shown in the Meyers Creek system. The Meyers Creek system sites showed increases in nitrogen demand because of rising primary production rates I ~in both phytoplankton and bank zone algal communities. At A08, this was not the case as benthic respiration and the loss of bulkhead algal and phytoplankton com- munity production caused a reduced nitrogen requirement. Subsequent primary pro- I ~duction increases during the period after the fourth quarter indicated the spring I ~increase in the lagoons was delayed in comparison with the creek system pattern. Table 24. Nitrogen requirements in 106 pig-atom per day based on net oxygen produc- I ~~tion by water column related plant communities exclusive of rooted vegetation. Site Quarter 1 2 3 4 I ~~Meyers Creek 67.3 5.5 27.7 35.2 I ~~Meyers Pond 84.8 -35.3* 18.5 24.5 Lagoon A02 6.4 19.5 4.2 5.8 Lagoon A08 3.3 26.6 33.2 5.5 *A negative value indicates an input of nitrogen to the system. I ~~~Analysis of the nitrogen demand in relation to the nitrogen supply is shown I ~in Table 25. Where the values exceed 1.00 the estimated demand exceeds the mea- sured supply. I ~~~In the Meyers Greek system, summer was a period of high nitrogen require- I ~ments. Despite relatively high nitrogen inputs, this demand exceeded the supply capabilities. In the second quarter, the supply exceeded the demand, probably because production fell off sharply in October while high inputs of nitrogen I ~continued. In addition, extremely high benthic respiration rates were recorded. In the winter period, large decreases in ammonification reduced the total inorganic nitrogen input. There was also a reduction of the "nitrogen input" attributable to benthic community respiration. In the spring, increases in primary production were outweighed by increased nitrogen input. Of particular importance was the return of high rates of ammonification. In the lagoons, nitrogen supply exceeded demand during the summer because of the high respiration values shown by the combined water column communities. The higher nitrogen requirements during the fall at A02 and during the fall and winter at A08 were a reflection of a decrease in microbial respiration relative to the gross primary production. of particular interest was the fact that the bulkhead algae, benthic algae, and phytoplankton all reached maximum rates during 1.77 Table 25. Ratio of the nitrogen requirements of the water related plant communi- ties (exclusive of rooted vegetation) and their nitrogen supply. The ratio is calculated by dividing the demand by the supply. Site Quarter 1 2 3 4 Meyers Creek 1.99 0.17 1.58 0.73 Meyers Pond 1.20 -* 2.03 0.15 Lagoons A02 0.55 0.83 0.19 0.10 Lagoon A08 0.59 2.33 5.93 0.71 * The negative value indicates there is a net contribution of nitrogen. the winter quarter at A08. The low demand/supply ratio in the winter quarter at A02 resulted not only from a low primary production nitrogen demand but an unusu- ally high benthic community respiration. The spring period ratios were mainly attributable to ammonification rate increases at A02 and high benthic respiration at A08. The nitrogen supply and demand values discussed here do not take into account nitrogen uptake by the Spartina alterniflora tall form which is also associated with the water column. Doing so would place an additional 2.0 x 107 pg-atom N. day-i requirement at the Meyers Pond site and 4.0 x 107 pg-atom N-day-1 at the Meyers Creek station for the late spring to early fall period. This was calcu- lated from the data of Good and Frasco (1977) assuming a growing season of 182.5 days and using their estimate of the nitrogen content of the plant material for the fall time period. Because net production belowground was estimated to be 5 times the aboveground, a factor of 6 was applied to this derived figure to give the total net production of both above and belowground compartments. Similar calculations for the Spartina aZterniflora short form and Spartina patens/DistichZis spicata marsh surface communities led to an estimated demand of 4.2 x 109 -pg-atom N.day-1 for the same period of time. This far exceeds the estimates of nitrogen supply and indicates on site recycling must provide most of the nitrogen required. Productivity Seasonal patterns in several standing crop indices, including chlorophyll a, oxidizable carbon, particulate organic nitrogen, and organic seston, occurred in both natural and developed areas. These patterns, though more pronounced for some parameters and some stations than others, occurred with some degree of regu- larity from year to year. Concentrations generally were found to be highest during the active summer period of the phytoplankton and were primarily attributed to local production. The resuspension of bottom deposits by wind stirring is believed to be a factor in the fluctuation of such particulates in the shallow creeks and bays. The high levels of oxidizable carbon recorded during the winter in such areas may be of importance to higher trophic levels. 1.78 In addition, annual variation was noted in the summer magnitude of the standing crop parameters and coincided with similar changes in phytoplankton pro- F ~ductivity. This was especially noticeable in the bay during the summers of 1973 and 1975 when phytoplankton standing crop and productivity were greatly diminished. Preliminary statistical analysis for study year IV indicate that although surface chlorophyll a is not a good indicator of the suspended organic matter, it was significantly correlated with the amount of available energy stored in the crop, i.e., oxidizable carbon (correlation coefficients of +.83 and +.88 in the Meyers and lagoon systems, respectively). The seasonal distribution of chloro- phyll a also coincided especially well with phytoplankton net productivity. F ~~~Measures of total seston incorporated a large array of possible sources (plankton, detritus, suspended organisms from benthic and fouling communities, resuspended minerals, etc.). it was observed that the relative proportion contri- buted by organic and inorganic sources was significantly different in the natural and developed areas. This would seem to reflect the importance of depth and the susceptibility to resuspension of bottom deposits, thereby increasing dispropor- tionately the inorganic material in the water column. This wind stirring effect was believed to account for not only the wide fluctuation of total seston in the natural creek but also for the relative predominance of inorganic matter in the water. The presence of such suspended material could have an important effect upon the transparency of the water, and therefore on the productive capacity of the phytoplankton. From the results for the quarterly periods during study year III, the pro- ducers of the aquatic system were rated according to the percentage of total production they accounted for. According to those findings, it was clear that the producer category of greatest importance was the phytoplankton in both developed and natural areas. The summer productive capacity of the phytoplankton throughout the Manahawkin area was shown to be nitrogen limited, as determined by a nutrient enrichment technique. Such limitation occurred at times when the productive capacity of the phytoplankton was high, especially in the ponds. Such responses were not observed during the winter and probably reflected the effects of reduced light intensity and duration, lower phytoplankton standing crop, and increased stocks of inorganic nitrogen. In contrast, phosphorus was rarely limiting. The turbidity in the creeks was often greater than in the lagoons. Average compensation depths for the Meyers Creek system and for the bay were greater than the total depth, thereby placing the entire water column within the photic zone. Thus, the overall shallowness of such areas permitted net production throughout the water column. One might even consider such extremely shallow depths as at Meyers Pond (0.42 in) to be suboptimal, since the phytoplankton are capable of carrying out net production at over twice that depth (D.c 1.08 in). Such a limita- tion is counteracted, to some extent, during the very active summer periods when high photosynthetic rates per unit volume occur. Total depth was also a critical factor in the lagoon systems where a signifi- cant proportion of the water column lay in the aphotic zone. This placed a con- siderably greater respiratory burden upon the actively growing populations located within the top 2.0 m. As a result, negative net production per square meter was common at the deeper lagoon stations, especially during the summer. 1.79 Such depths affected not only the areal production of the phytoplankton but also placed strict limits on the type of biological activity possible in the ben- thos. The aphotic conditions which generally prevailed ruled out benthic pro- ducers, while the high benthic respiration rates were probably a major factor in the frequent development of anaerobic conditions. In addition, no compensatory input of oxygen by the phytoplankton was possible below the euphotic zone. The high oxygen uptake rates accorded in the sediments of Meyers Pond also had an effect upon dissolved oxygen levels in the overlying water. Low oxygen concentrations were characteristic of the pond during summer. High rates of phyto- plankton production throughout the entire water column could not compensate for the high demands of the benthos,and considerable undersaturation occurred. Aerobic conditions prevailed as a result of the high degree of tidal flushing and the in-- put of bay water during the flood tide. The respiration of the sediment biota exceeded photosynthetic activity of the microalgae such that sediment cores exposed to the light demonstrated a de- cline in oxygen content. This phenomenon was even observed at the very shallow Meyers Pond station where favorable light conditions at the bottom persisted throughout the year. Based upon preliminary studies involving the addition of antibiotics to dark cores, a large proportion of this respiration is bacterial activity. The importance of this benthic metabolism lies not only in its effect upon the oxygen levels in the overlying water column, but also in its role in- volving nutrient regeneration and mineralization. The efficiency of this cycling by the benthic communities will of course depend upon the availability of the released nutrients for further utilization. In contrast to the benthic subsystem, some of the marsh surface edaphic com- munities were capable of net productivity during the summer. Such a productive capacity was directly related to the amount of light penetrating the canopy of marsh grass. Another important factor affecting the total contribution of algal mats in the salt marsh was the areal distribution of the canopy types. Whereas Spartina patens accounted for about 38% of the marsh surface, the importance of the microflora would be minimal since algal growth was limited by light penetra- tion. Significant net production was recorded for the S. aZternifZora (tall form) and mudflat communities,but the areal distribution of each area only accounted for less than 1% of the marsh surface. Algal production in the S. aZternifZora (short form) zone was similar to that in the tall form, and reflected more favor- able light conditions. Since the short form zone accounted for about 60% of the marsh surface, such algal mats would make a significant contribution to the total primary productivity of the salt marsh. The production of the bulkhead algal community was comparable to the high levels observed in the mudflat community. However, the distribution within its respective system was also limited, and, therefore, its contribution to the total system production was small. The relative contribution of autotrophic and heterotrophic metabolism in these productive subsystems is shown in Figure 38, in which total community respir- ation is plotted against total production (Odum 1956). Values of GP/R> 1 are characteristic of an autotrophic-dominated metabolism and involve a net storage of organic matter. Values of GP/R <1 are characteristic of an heterotrophic- dominated metabolism and involve a net loss of organic matter. The diagonal line 1.80 3- 3- 5- 2- 2- 4- 0 GP 3 1 - / Meyers Pond 1 M 21 2- * A08 * * / Phytoplankton * / Phytoplankton Phytoplankton - (9/74 3/77) *(9/74 3 177) (9/74 3/77) C 1 2 3 1 2 3 1 2 3 4 5 .3 R *R R 3 e OD1 A0 Lt-~ .�~ / 1.o- 1.0- L / /Meyers System I/ Benthics � 2- (1/75 -4/77) GP . 0 t v~ v/0.5- A*A 0.5- 0*v / *Bulkhead A */-* (7/75 0 5/77) el a S .. alt. (short) 00 AS. alt. (tall) A^tP hAtMudflat eS. patens (12/74- 5/77) SA (12/74 - 5/77) 1 2 3 0.5 1.0 0.5 1.0 R R R Fig. 38. The relationship between gross production (GP) and respiration (R) for different communities of primary producers. All units: ml 022m92dayl--103. represents a GP/R ratio of 1, and the departure of points above this line repre- sents positive net productivity. The respiration of the phytoplankton communities was probably due in large part to the phytoplankton themselves, as previously mentioned. This was more than compensated for by photosynthesis in the shallower stations such as Meyers Pond and M 21. However, values of GP/R < 1 were frequent in the deeper lagoon stations, especially during the summer. Such a heterotrophic metabolism was prevalent at all benthic stations and in the Spartina patens zone. The algal communities asso- ciated with S. alterniflora, lagoon bulkheads, and the Meyers Creek mudflat were generally autotrophic, but became heterotrophic during the colder parts of the year when photosynthesis was negligible. 1.82 REFERENCES CITED Bendschneider, K. and R. J. Robinson. 1952. A new spectrophotometric determina- tion of nitrite in sea water. J. Mar. Res. 11: 87-96. Bishop, S. H. 1976. Nitrogen metabolism and excretion: Regulation of intracel- lular amino acid concentrations, p. 414-431. In M. Wiley (ed.), Estuarine Processes Vol. 1. Academic Press, New York. Brooks, R., P. Brezonik, H. Putnam, and M. Keirn. 1971. Nitrogen fixation in an estuarine environment: The Wacasassa on the Florida Gulf Coast. Limnol. Ocean- ogr. 16: 701-710. Cowen, W. F., K. Sirisinha, and G. F. Lee. 1976. Nitrogen availability in urban runoff. J. Water Pollut. Control Fed. 48 (2): 339-345. Haines, E., A. Chalmers, R. Hanson, and B. Sherr. 1976. Nitrogen pools and fluxes in a Georgia salt marsh, p. 241-254. In M. Wiley (ed.), Estuarine Processes Vol. 2. Academic Press, New York. Harvey, H. W. 1966. The chemistry and fertility of sea waters. Cambridge Uni- versity Press, London. 240 p. Howard, D., J. Frea, R. M. Pfister, and P. R. Dugan. 1970. Biological nitrogen fixation in Lake Erie. Science 169: 61-62. Jenkins, D. and L. L. Medsker. 1964. Brucine method for determination of nitrate in ocean, estuarine, and fresh waters. Anal. Chem. 36: 610-612. Johannes, R. E. 1968. Nutrient regeneration in lakes and oceans. Adv. Microbiol. Sea 1: 203-213. Lum, S. C. and C. S. Hammen. 1964. Ammonia excretion of LinguZa. Comp. Biochem. Physiol. 12: 185-190. Marsho, T. V., R. P. Buchard, and R. Fleming. 1975. Nitrogen fixation in the Rhode River estuary of Chesapeake Bay. Can. J. Microbiol. 21: 1348-1356. Menzel, D. W. and N. Corwin. 1965. The measurement of total phosphorus in sea- water based on the liberation of organically bound fractions by persulfate oxidation. Limnol. Oceanogr. 10: 280-282. Murphy, J. and J. P. Riley. 1962. A modified single solution method for the de- termination of phosphate in natural waters. Anal. Chim. Acta. 27: 31-36. Nicol, J. A. C. 1967. The biology of marine animals. John Wiley and Sons, Inc., New York. 699 p. Nixon, S. W., C. A. Oviatt, J. Garber, and V. Lee. 1976. Diel metabolism and nutrient dynamics in a salt marsh embayment. Ecology 57 (4): 740-750. Poole, H. H. and W. R. G. Atkins. 1929. Photo-electric measurements of submarine illumination throughout the year. J. Mar. Biol. Assoc. U.K. 16: 297-324, 1.83 Rowe, G. T., C. H. Clifford, K. L. Smith Jr., and P. L. Hamilton. 1975. Benthic nutrient regeneration and its coupling to primary production in coastal waters. Nature 255: 215-217. Ryther, J. H. and R. R. L. Guillard. 1960. Enrichment experiments as a means of studying nutrients limiting to phytoplankton production. Deep-Sea Res. 6: 65-69. Schell, D. M. and V. Alexander. 1970. Improved incubation and gas sampling tech- niques for nitrogen fixation studies. Limnol. Oceanogr. 15: 961-962. Solorzano, L. 1969. Determination of ammonia in natural waters by the phenol- hypochlorite method. Limnol. Oceanogr. 14: 799-801. Stewart, W. D. P., G. P. Fitzgerald, and R. H. Burris. 1967. In situ studies on N2 fixation using the acetylene reduction technique. Proc. Nat. Acad. Sci. U.S.A. 58: 2071-2078. Strickland, J. D. H. and T. R. Parsons. 1972. A practical handbook of seawater analysis. Fisheries Research Board of Canada, Ottawa. 310 p. Van Raalte, C. D., I. Valiela, E. J. Carpenter, and J. M. Teal. 1974. Inihibition of nitrogen fixation in salt marshes measured by acetylene reduction. Estua- rine Coastal Mar. Sci. 2: 301-305. Waughman, G. J. 1971. Field use of the acetylene reduction assay for nitrogen fixation. Oikos 22: 111-113. Whipple, W. Jr. and J. V. Hunter. 1977. Nonpoint sources and planning for water pollution control. J. Water Pollut. Control Fed. 49 (1): 15-23. Whitney, D., G. Woodwell, and R. Howarth. 1975. N2 fixation in Flax Pond: A Long Island salt marsh. Limnol. Oceanogr. 20: 640-643. Woods, E. D., F. A. J. Armstrong, and F. A. Richards. 1967. Determination of nitrate in seawater by cadmium-copper reduction to nitrite. J. Mar. Biol. Assoc. U. K. 47: 23-31. 1.84 APPENDIX A Tables and Figures from the June 1974 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity LIST OF FIGURES Figure Page 1 Station locations . . . . . . . . . . . . . . . . . . . . . . . 1.89 2 Surface water temperature: B24, E87, Meyers Pond compared to M 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.89 3 Seasonal water temperature at M 21 surface . . . . . . . . . . . 1.89 4 Temperature and salinity vertical distributions . .... 1.89 5 Temperature stratification; (surface temperature minus bot- tom temperature) in the lagoon systems on 26 June 1973 . . . . 1.90 6 Temperature stratification; (surface temperature minus bot- tom temperature) in the lagoon systems on 7 March 1974 . . . . 1.90 7 Monthly mean surface salinity values at the mouths of the major systems . . . . .... .... 1.90 8 Surface salinity (O/oo); spatial distribution in the lagoon systems on 26 June 1973 . . .. ..... 1.90 9 Monthly mean surface salinity values for Mill Creek and Dinner Point Creek . . . . . . . . . . . . . . . . . . . . . . . . . 1.91 10 Salinity stratification; (bottom salinity minus surface sa- linity) in the lagoon systems on 26 June 1973 . . . . . . . . 1.91 11 Monthly mean dissolved oxygen values at the surface and bottom of Lagoons B24 and A08 . . . . . . . . . .1.91 12 Dissolved oxygen values at the bottom of the lagoon systems on 26 June 1973 . . . .. . . . . . . . . . . . 1.91 13 Secchi disc readings . . . . . . . . . . . . . . . . . 1.92 14 Monthly mean ammonia-N concentrations in the Dinner Point and Meyers Creek systems . . . . . . . . . .. 1.92 15 Monthly mean ammonia-N concentrations in the E system (Mill Creek). ........ ...... . . . 1.92 16 Monthly mean ammonia-N concentrations at Lagoons B24 and A08 . . . . . . . . . . . . . . . . . . . ........ 1.92 17 Monthly mean ammonia-N concentrations at M 21 and ABD . . . . . 1.93 18 Monthly mean nitrate-N concentrations in the Dinner Point and Meyers Creek systems . . . . . . . ... 1.93 19 Monthly mean nitrate-N concentrations in the E system (Mill Creek) . . . . . . . . . . 1.93 20 Monthly mean nitrate-N concentrations at B24, A08, M 21, and ABD . . . . . . . . . . . . . . . . . .... . 1.93 21 Monthly mean organic-N concentrations in the Dinner Point and Meyers Creek systems . . . . . . . . . . . . . . . . . . . 1.94 22 Monthly mean organic-N concentrations in the E system (Mill Creek) . . . . . ..... 1.94 23 Monthly mean organic-N concentrations at ABD and M 21 . . . . . 1.94 24 Monthly mean organic-N concentrations in Lagoons B24 and A08 . . ...... . . . . . . . . . . . . . . .. 1.94 25 Particulate organic-N concentrations in the Dinner Point and Meyers Creek systems ..1.95 26 Particulate organic-N concentrations in the E system (Mill Creek) . . . . . . . . . . ...... ..... . . . . . . . . . 1.95 1.85 Figure Page 27 Particulate organic-N concentration in Lagoon B24 and A08 . . ...1.95 28 Particulate organic-N concentrations at ABD and M 21 .. .....1.95 29 Monthly mean oxidizable carbon concentrations in the Dinner Point and Meyers Creek systems .. ...............1.96 30 Monthly mean oxidizable carbon concentrations in the E system (Mill Creek) .. ........................1.96 31 Monthly mean oxidizable carbon concentrations at Lagoon B24, Lagoon A08, M 21, and ABD .. ..................1.96 32 Chlorophyll a concentrations in the Dinner Point and Meyers Creek systems .. ........................1.96 33 Chlorophyll a concentrations in the E system (Mill Creek) . . ...1.97 34a Chlorophyll a concentrations at Lagoon B24 .. ..........1.97 34b Chlorophyll a concentrations at Lagoon AOS8.. ..........1.97 35 Chlorophyll a concentrations at M 21 and ABD .. .........1.97 36 Net productivity values in the Dinner Point and Meyers Creek systems .. ...........................1.98 37 Net productivity values in the E system (Mill Creek) .. .....1.98 38 Net productivity values at Lagoons B24 and A08 .. ........1.98 39 Net productivity values at M 21 and ABD .. ............1.98 40 Net production versus gross production at Meyers Creek mouth . . 1.99 41 Net production versus gross production at Meyers Pond .. .....1.99 42 Net production versus gross production at Lagoon AO08.. .....1.99 43 Net production versus gross production at M 21 .. ........1.99 1.86 LIST OF TABLES Table Page 1 Surface water temperature (�C) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . 1.100 2 Surface salinity (�/oo) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . . . . . 1.101 3 Surface dissolved oxygen (ml 02-1-1) except where noted. Month- ly averages for all stations from June 1973 to May 1974 . . . 1.102 4 Surface NH3-N (pg-atom NH3-N'-1) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . 1.103 5 N03-N as proportion of total inorganic-N . . . . . . . . . . . . 1.104 6 Surface N03-N (pg-atom N03-N.1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . 1.105 7 Surface N02-N (pg-atom N02-N.-l-1) except where noted. Monthly averages for all stations from June 1973 to Mal 1974 . . . . . 1.106 8 Surface total organic nitrogen (pg-atom Org-N-1- ) except where noted. Monthly averages for all stations from June 1973 to May 1974 .................-... 1.107 9 Surface soluble organic nitrogen (pg-atom Soluble Org-N. 1 l) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . . . . . . . . . . . . . . . . 1.108 10 Surface particulate organic nitrogen (jg-atom Particulate Org-N.1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . . . . . . . . . 1.109 10a Surface particulate organic nitrogen (pg-atom Particulate Org-N-1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . . . . . . . . . 1.110 11 Surface particulate oxidizable carbon (mg-m-3 ) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . . . . . . . . . . . . . . . . . . . . . 1.112 12 Surfade chlorophyll a-(mg.m-3) except where noted. Monthly averages for all stations from June 1973 to May 1974 . . . . . 1.113 12a Surface chlorophyll a (mg.m-3) except where noted, from June 1973 to May 1974 . . . . . . . . . . . . . . . . . . . . . . . 1.114 13 Surface net productivity (ml 02.1-1.24h-1) except where noted. Monthly averages for all stations from July 1973 to May 1974....... . . . . . . . . .. . . . . . . . . . 1.116 13a Surface net production (ml 02.1-1-24h-1) except where noted, from June 1973 to May 1974 ................... . 1.117 1.87 4 , "~ '~ ' M 210 30 - . B24 ___ ABO1 o E87 _____ ABD ~~25 - x Meyers Pond mouth Oyster Point Pond ( 20 - Oyster Point Ctr Meyers ., mou th Pond 15 ,Meyers C r . mouth 10 Upper End Dinner Point Cr. 5 Iv R / ..... Diner Point 5 10 15 20 25 30 r Cr mouth Temperature at M 21 (�C) Fig. 1. Station locations. Fig. 2. Surface water temperature: B24, E87, Meyers Pond compared to M 21. Temperature (�C) and Salinity (/0) 10 15 20 25 o Salinity 2 �- Temperature 4 6 B24 23 July 1973 10 15 20 25 E 2k - A08 25- . a M 21 X _23 July 1973 25- a M 21 020- L 15- / 10 5 10 25 10- aa10-~~~~~~~~~ It~~~~~~~~~~~~~~~ v19.2 S%� E ~~~~~~~~~~5-~~~~ B22 , , , 17 January 1974 J J A S 0 N D J F M A M 0 1973 1974 o 23.7 S%. Fig. 3. Seasonal water temperature at M 21 Fig. 4. Temperature and salinity vertical distri- surface. butions. (from June 1974 Annual Report) 1.89 gC X ~~~~~~~~~~~~~~oC OC < ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I � 1 1-5 o5 0>5 > 5 (Surface Temperature minus (Surface Temperature minus Bottom Temperature) Bottom Temperature) Fig. 5. Temperature stratification; Fig. 6. Temperature stratification; (surface temperature minus bottom temp- (surface temperature minus bottom temp- erature) in the lagoon systems on 26 erature) in the lagoon systems on 7 March June 1973. 1974. Absolute value of the difference is indicated. 30- *X>5 X A0 Dinner Point\ \ / 20> / v) Creek Mouth *-* \ , %. 10 _-M ey ers C reek B-o \ 21 2e-at (srfc teprtrDinusbtonapsraetmeratr Poinusbtto ep 10- Meyer~~~~~~~~~~~s dCateekd Mouth ~- 13,0 E Mouth --~ 25 - 0 ABD O O A M 21 .... 20- A \ /201 2090. ~~~~J JF A S N D J F M A M . 1 973 1974 Fig. 7. Monthly mean surface salinity values at Fig. 8. Surface salinity (�/oo); spa- the mouths of the major systems. tial distribution in the lagoon systems on 26 June 1973. (from June 1974 Annual Report) 1.90 30- -�"�'~ '~ ~ Dinner Point 25 , /'0 Mouth 25 /- , ,, X 2 / E Mouth S Dinner Cek20 n DnePoint - 'Upper End 15 '~. ; ~E 68 10 - ABD 10~~~~~~~~~~~~~ 5 e<l � 1-5 E 87 >5 ity) in the lagoon systems on 26 June 1973. 9- B -B24 7 - 6- 5- 74. -3- o3-< ~~~~~~~Surfaced+ I 1 -(Bottom Sanit J J A S O N D J F M A M Bt iy ~~~~~~~~~~~~~~~~~~~~~~~A08 (21973 1974 Fig. 11. Monthly mean dissolved oxygen values Fig. 12. Dissolved oxygen values at at the surface and bottom of Lagoons 824 and A08. the bottom of the l agoon systems on 26 June 1973. (from June 1974 Annual Report) .91 :}- B24~ 2- S~~~~~~~~~~~~~~~ urfae 193 ~. B o t t ~ ~ ~~~~~~~fom Jn 194Aua Reo---o 79-~~~~~~~19 ~~~4-~~~~~~~~~12 43- AO8 12 Dinner Point 10 . Upper End 2 o--o Mouth 3.5 . 8 J J A S O N D J F M A M 4 E3AM2J A S O N D|J F M A M 4t~ ' A \ \~ ----------2.2 J A S O N DJ F M 21 M Meyers E - PondA 3 Meyers Pond 6J- A f 2- ''- 2.2 12 -o- J J A S 0 N D J F M A M Meyers 1973 1974 1973 1974 Fig. 13. Secchi 3tions in the Dinner Point and Meyers Pond 6Creek 2- 4- 28-2.2 In Excess JJ ASO ND J FM AMJ J A S O N DJ F M A M 1973 1974 1973 1974 Fig. 13. Secchi disc readings. Fig. 14. Monthly mean ammonia-N concentra- tions in the Dinner Point and Meyers Creek systems. 924 28-\~~~~~ -.E87 20 In Excess 8 26- .. E68 -of 225 24 ~,~~l- 10 4 I 2 1I - ?974 1973 1974 E �Surf ace ,14 - 35-, + I 0-fOA08 -. 12- ; 90.41 10 /s\ '0 E' J J ASO N DIJ F M A M J J ASO N DIJ F M A M 1 9 73 1974 1973 1974 Fig. 15. Monthly mean ammonia-N concentra- Fig. 16. Monthly mean ammonia-N concentrations tions in the E system (Mill Creek) at Lagoons B24 and A08. (from June 1974 Annual Report) 1.92 Dinner Point Upper End . 5 Mouth o-.--o 4- 3 o J J A S O N D J F MA M z 12- m ' M 21 - * Meyers Creek M21 6 z 10- ABD 6- I lo- ABD o----o 6- o ~ 5 - Pond a8- ? Mouth ---- l- �. 4- 6- 3 - ,q 4- 2- E 2- o J J A S O N D J F M A M J J A S O N DIJ F M A M 1973 1974 1973 1974 Fig. 17. Monthly mean ammonia-N concentrations at Fig. 18. Monthly mean nitrate-N concentra- M 21 and ABD. tions in the Dinner Point and Meyers Creek systems. 5- B24 15- 1':l , Surface \ B '20.0~ 4 Bottom o--/, - ' I ~~~~~~~~~~~~3- I x E68 I I 0- , I I ', J J A S O N D J F M A M 10\- I 1 - - I3 - -/ \ E a Surface. A08 J J A S O N D J F M A M J J A S N D J F M A M 1973 1974 1973 1974 Fig. 19. Monthly mean nitrate-N concentrations in the E Fig. 20. Monthly mean nitrate-N concentra- system (Mill Creek). tions at B24, A08, M 21, and ABD. (from June 1974 Annual Report) 1.93 Upper End) Total Dinner Point Upper End) Ta : 90- Soluble 50 . Total E87 Total ..... 40 Soluble Mouth) T - 70- 60 350 - E68 � ) J A S O N D | J F M A M - . / 40- --A 20- '.... c 90 PO d} Total az ' Pond- rw Soluble so* E Mouth s o - Mouth) Total *. 0 O 20 J A S O N DI J F M A M 2973 1 974 o )TSurface Fig. 2. Monthly mean organic- c oncentrations in Soluble , ii , i i , i I , , the Dinner Pont and M eyers Creek systems. 70 A--- o l Bttm 950 -~~~~~~~~~~~~~~50 60- < son - Total 30 0 Soluble 30 - 7 20 XE J J A S 0 N D Ji F M A M 30 21 -�' 1973 1974 Mouth 1974 ) IS\urfa=ceSoluble Surfac o 0 Total 1 4 a ~~J ~ ~ ~ ~ ~ ~ J A S O N D |J F M A M 1973 1974 at ABD and M 21. Lagoons B24 and A8. J J A O SN DIJ FM AM 1973 1974 Fig. 23. Monthly mean organic-N concentrations Fig. 24. Monthly mean organic-N concentrations in at ADo and M 21. Lagoons B24 and A-S. (from June 1974 Annual Report) 1.94 Dinner Point It68 4t 40- Upper End Mouth o--o 30- E87 v 20- to, ' 20- oE o - It Pond ..... i \1 3 40- ~i ~ ~~ 'IX~~ ~2 i Mouth o- *-o 10 ! I /\ IJ~ 0 10 IDl ~ J J A S O N D F M A M A N D J F M A M 1973 1974 1973 1974 Fig. 25. Particulate organic-N concentrations Fig. 26. Particulate organic.-N concentra- in the Dinner Point and Meyers Creek systems. tions in the E system (Mill Creek). 50- - B24 40- 7 30 o J o b E J J A S O N DIJ F M A M 10 - 3 100-10 o I J J A S O N DIJ F M A M 1973 1974 Fig. 27. Particulate organic-N concentra- Fig. 28. Particulate organic-N concentra- tion in Lagoons B24 and A08. tions iat ABD and M 2 1.re (from June 1974 Annual Report) 1.95 50 104 Dinner Point . ' E87 Upper End , - 600 Mouth --o 20 40- 1 - 0 E30t .No ~~~~J J A S O N Di J F M A M 250-, 50 40 ' 40 E J J J A SO N D J F MA M Meyers Creek systems. 2,., 19.5 Poin 40 SuraceE Mouth o 030: . . 30- 2- 20 J 2 A Q /" N EIJ F J J A S O N D J F M A M 1973 1974 1973 1974 Meyers Creek systems. 1,42 Surface M - CMBottom B2--- J J A S O N D J F M A M J Upper End J Bottom 0-__ 30 - , a-- A te b._ .' *019.6 lo - J JJ A S O N D171 F M AM M o0 M21 3- 0 40 AB o-.o ', 0 30 .- 10 ~ * -0.* b Pond Mouth I I I ,m , J J A S O N DI1J F M A M J J A S O N D J F M A M 1973 1974 1973 1974 Fig. 31. Monthly mean oxidizable carbon Fig. 32. Chlorophyll m concentrations concentrations at Lagoon B24, Lagoon A08, in the Dinner Point and Meyers Creek sys- M 21, and ABD. tems. (from June 1974 Annual Report) 142 15 - ~-o t' o~~~~ 9 49.8 3+ .3 56.5 35 x 35-, E87 B24 E68 x-- -x I Surface 30- 30- e0 i) E Mouth -...o Bottom .....o ,- 25- H 25- I1 I- C II 20- , E 20 - -I , - 15. 15 - U0 I 01 -1 0 l, ,( ,, i,, . .0 ;I 0 -d - b J J A S O N DlJ F M A M J J A S O N D J F M A M 1973 1974 1973 1974 Fig. 33. Chlorophyll a concentrations Fig. 34a. Chlorophyll a concentrations in the E system (Mill Creek). at Lagoon B24. 15- ABD CO 10 - ~01 30-- tif A08 5- 25-- Surface = : ~-'m~ ~ Bottom ,-, ' , J J A SO N DIJ F MA M 20-- 20.1 m 15-- / " 0 o - io ~ J J A S O N D J F M A M J J A S O N DIJ F M A M 1973 1974 1973 1974 Fig. 34b. Chlorophyll a concentrations Fig. 35. Chlorophyll a concentrations at at Lagoon A08. M 21 and ABD. (from June 1974 Annual Report) 1.97 Dinner Point Upper End E87 Mouth o--- 3- 2- -P J-- s J A S O N DiF A M 2-' 'N ,. o'N 6 �D-~ 3- E68 2- o J J A S O N D J F M A M > Meyers Pond . . U 3- ~ Mouth o---o J J A S 0 N DI J F M A M u 3- E Mouth z 2- s_ iiN < 2- 4- I I24 10 I Surface J J A S O N D J F M A M 1973 1974 J J A S O N D J F M A M Fig. 36. Net productivity values in the Dinner Point and Meyers Creek systems. Fig. 37. Net productivity values in the E system (Mill Creek). 4- B24 Surface *-. 4- Bottom - - --o 3- 3 IABD .?\ 2- 2 1- J J A S O N DIJ F M A M 1973 1974 I Surface :- I -o Bottom e---o I I Fig. 39. Net productivity values at M 21 3- II I z a 3- II I I 3- It I P9 1- Fig. 38. Net productivity values at Lagoons and ABD. B24 and A8 (from June 1974 Annual Report) rI JASON 0 J FMA M J J A S O N D0J F M A M 1973 1974 Fig. 39. Net productivity values at M 21 Fig. 38. Net productivity values at Lagoons and ABD. B24 and A08. (from June 1974 Annual Report) 1.98 5- 5 Meyers Creek Meyers Pond Mouth - 4 4- * 3- 73 I N �0 o CE 2 - - 2 - - - . 1 2 3 4 5 2 3 4 5 �4 . .I I z z Gross Productivity (ml 021-1 24h 1) Gross Productivity (ml 021 *24h) Fig. 40. Net production versus gross pro- Fig. 41. Net production versus gross pro- duction at Meyers Creek mouth. duction at Meyers Pond. 45-/ A08 M 21 _43 / As, 3 - / 2 2 / * E o4 - - ' 3 - N , 3 - 0 a. 2 - - - - - - - - - - - - 1 2 3 4 5 1 2 3 4 5 Gosrdcvt(l0 24h Gross Productivity (ml 021 24h) Fig. 42. Net production versus gross pro- Fig. 43. Net production versus gross pro- duction at Lagoon A08. duction at M 21. (from June 1974 Annual Report) 1. 99 Grs Prdciiy(l01*4 rosPoutvt m 4 �Y 1 j��� � U~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fig 42 e rdcinvru rs r-Fg.4.Ntpouto essgospo Table 1. Surface water temperature (�C) except where noted. Monthly averages for all stations from June 1973 to May 1974. E5i P. 4 .4 )4 co~ ~4 o oJ o 0 o 0 o - c E ~ oW ) W a) T 0 ) P 0 ; 0 o 0 o 0 P 0)0 Q44- P- P.I4 0) 0) C) C Cl) o z U P - , WH 1r C W e4 -. 00 0 .M~ Q~o 0) o) m ~0 .fo 00 0 c ~ Jun 23.0 20.9 20.8 23.0 22.7 2i.2 22.8 23.2 19.2 22.0 10.5 Jul 23.6 22.8 23.9 23.8 23.4 24.0 23.9 24.7 24.1 23.3 24.0 24.8 20.0 24.9 10.6 Aug 24.8 24.6 24.9 24.4 24.9 24.7 24.4 24.5 24.8 24.5 24.3 25.5 21.9 25.0 10.8 Sep 19.2 18.9 19.8 19.3 19.4 18.5 19.7 18.6 19.3 20.0 19.8 21.5 21.0 20.2 10.3 Oct 12.9 13.0 15.5 15.3 15.7 15.0 16.0 15.9 16.1 15.1 15.2 16.5 16.4 15.8 11.6 Nov 5.2 4.4 5.7 5.3 5.3 3.9 5.9 5.6 6.6 6.6 6.0 7.6 8.0 7.9 8.7 Dec 5.8 7.6 6.0 7.7 6.0 7.8 6.0 6.1 7.5 8.4 6.2 7.3 5.0 7.3 6.5 Jan 2.0 2.0 1.5 1.5 1.5 1.5 1.9 2.5 3.5 1.2 1.2 6.0 2.5 8.0 Feb 3.6 4.0 3.2 5.0 2.5 3.6 0.5 2.5 3.5 3.8 1.4 2.5 2.5 2.5 5.5 Mar 5.0 4.8 5.0 5.8 4.5 4.0 6.5 7.8 8.1 6.1 7.6 6.7 7.4 6.3 Apr 10.2 10.5 10.0 11.0 9.0 10.0 7.0 9.5 9.7 9.8 7.8 8.8 8.0 8.5 7.6 May 18.5 22.6* 19.2 19.4 18.7 22.3 16.0# 21.7 21.3 20.5 20.7 20.9 18.2 17.0# 8.5# * No 5/2/74 sample # No 5/23/74 sample (from June 1974 Annual Report) Table 2. Surface salinity (�/oo) except where noted. Monthly averages for all stations from June 1973 to May 1974. oD4~ 0 o o 0 0 9140 H 4 P 91 U 4OJ r= 1 u 1d r . C4 - o 4' H 4 W ~ ~ 0 co 0 o > s o o 4J a) a 4-J a) ,: Jun 22.30 10.71 22.83 16.83 13.72 0.43 21.73 21.36 22.66 20.72 23.39 Jul 23.69 16.91 23.43 20.46 21.87 22.77 22.68 20.21 6.16 0.59 21.88 20.61 22.72 19.26 24.80 Aug 26.48 22.57 24.18 22.68 24.11 22.96 25.16 22.34 9.99 1.41 24.42 23.94 24.78 22.83 25.57 i-r Sep 27.36 25.61 24.91 24.71 24.37 23.45 24.93 23.95 12.01 0.83 24.43 23.98 24.51 23.97 25.01 r Oct 28.13 26.80 24.56 23.39 24.22 22.68 24.85 23.78 12.43 2.69 25.07 24.75 24.81 23.66 24.76 Nov 26.87 20.86 25.37 22.50 23.50 21.81 24.29 21.06 10.28 1.69 24.04 24.03 24.42 23.44 23.67 Dec 25.25 14.66 22.72 19.14 22.06 20.24 24.90 21.84 11.49 1.02 22.80 22.58 24.37 19.51 23.49 Jan 22.22 16.10 18.64 17.63 18.90 20.45 13.97 6.79 2.12 19.51 19.90 23.35 19.19 23.68 Feb 22.76 11.07 19.70 16.86 20.04 18.31 22.64 8.44 8.03 1.72 22.05 21.96 22.44 20.88 23.40 Mar 22.87 13.29 22.97 18.23 23.16 25.34 18.39 9.17 2.33 23.45 22.81 23.26 21.92 24.20 Apr 20.90 8.81 20.00 20.23 19.78 14.46 22.77 8.79 5.57 0.69 21.23 21.36 22.68 19.70 23.62 May 26.24 21.10 23.99 22.91 25.73 25.31 25.93 24.68 11.53 0.85 25.21 25.04 25.23 22.92 24.19 (from June 1974 Annual Report) Table 3. Surface dissolved oxygen (ml 02.1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. 4.J 4- 4~j 'w * Hmo .l ... U Wo --A 4- j H -4 W0o 0 Ca 4 PJ ,0 -H $ 4- L)P- P40 O. 4-0 .W 4 0 rd P U 1G o A4 4 4 k4 a) -11 a) co~p 4J 0 W a ) 4J W -Z Wj -0 0 W aC) P, ;>, c a) C C 0coo o -r $ 0~ a)0 8P 8, 0 c 0 C)4 C' Jun 5.67 5.40 5.13 5.56 5.01 5.53 5.51 5.43 2.65 5.45 0.08 Jul 4.91 2.08 4.63 3.51 4.96 4.08 5.08 4.68 4.50 4.76 4.77 5.28 0.90 4.80 0.00 Aug 4.58 2.83 4.40 3.42 4.59 4.22 5.01 4.52 5.02 5.44 4.16 4.89 0.14 4.58 0.00 Sep 5.23 4.50 5.04 4.52 4.93 4.30 5.70 4.87 4.95 6.22 4.49 4.66 2.79 3.89 0.00 Oct 5.27 6.34 6.18 4.98 6.02 5.10 6.64 5.50 5.95 6.52 5.94 5.34 4.86 5.51 0.00 Nov 7.09 6.83 6.93 7.30 7.35 4.92 7.70 7.31 7.59 7.97 7.25 7.65 6.91 5.84 5.05 Dec 7.88 8.36 7.75 6.03 5.88 6.99 8.24 8.12 8.35 7.94 8.13 7.72 6.18 6.96 4.33 Jan 8.68 7.05 8.10 7.71 8.65 8.79 8.52 8.17 8.03 8.93 8.59 1.01 8.17 0.00 Feb 7.67 6.58 7.89 7.05 8.31 6.81 8.35 12.15 8.29 8.44 8.00 7.77 6.43 7.67 0.00 Mar 7.84 7.77 7.94 7.19 7.93 7.79 7.65 7.62 7.92 7.32 7.24 6.64 7.08 0.00 Apr 7.52 5.19 7.53 7.44 7.53 4.69 7.11 7.33 7.39 7.43 7.32 7.60 1.53 7.59 0.00 May 5.55 3.28 5.03 4.21 5.26 2.86 5.74 5.30 6.25 6.23 5.53 5.84 2.62 5.94 0.00 (from June 1974 Annual Report) Table 4. Surface NH3-N (pg-atom NH3-N.1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. ~c J"� 0) .H J 4 o 0) . -- *H o o .a) 0 0 V 0 c 0 0.4 ) $.4 P.I 4-4 0 0 ~4 co W P co :3 o m � o a) 0J4 ~ -4- 4J ~ ~4 Wa 0) ai) mf Cl 4..) ~ W 0J~ 0)4~J a 0) 4-0) 4--Jd0 o .H r. O o o co C' CO rao C00 o co -t - 0 - ~4 0 a) 0 Q)o co 0 CD C l Jun 1.9 6.2 1.3 7.2 7.4 3.0 1.1 1.9 2.5 0.9 70.3 Jul 0.8 3.6 1.3 2.5 0.6 0.2. 0.7 2.6 13.6 2.3 1.3 0.1 90.4 0.2 247.2 Aug 0.5 1.8 0.6 0.8 0.8 0.4 0.8 2.1 5.9 1.3 0.7 0.3 33.2 0.2 690.7 Sep 0.8 1.3 0.5 0.8 0.7 1.5 0.6 2.3 2.7 2.6 0.7 0.3 0.6 0.6 254.9 Oct 0.4 0.4 0.9 0.5 0.8 1.1 0.4 0.7 3.1 2.3 0.2 0.5 0.6 0.1 102.3 Nov 2.7 12,0 1.9 4.6 1.2 41.2 1.4 0.9 3.2 3.3 0.6 0.1 0.1 3.9 6.8 Dec 0.5 4.3 1.5 6.7 1.0 10.0 0.3 0.8 27.1 5.4 0.8 0.8 3.1 7.6 8.4 Jan 1.5 1.4 2.2 1.8 1.2 0.4 5.0 8.9 7.7 1.8 0.9 20.3 6.5 57.1 Feb 0.1 11.5 0.0 6.6 0.2 15.3 0.6 5.1 8.4 5.4 0.5 0.1 0.3 2.7 42.4 Mar 0.0 6.2 0.2 10.0 0.0 0.1 0.8 8.7 5.5 0.0 0.0 0.5 4.8 71.7 Apr 0.1 5.2 0.6 0.5 0.4 9.0 0.1 3.3 2.9 4.2 0.1 0.0 20.6 0.4 117.1 May 0.0 0.0 0.7 0.0 0.2 0.0 24.5 2.2 0.3 0.0 0.0 0.0 110.7 No true mean can be calculated as some sample values exceeded the 350 pg-atom NH3-N.1-1 limit of the method. (from June 1974 Annual Report) Table 5. N03-N as proportion of total inorganic-N. Mean NO3-N Mean Mean Mean total N03-N NH3-N Station inorganic-N (pg-atom N03-N-1-1) (Hg-atom NH3-N-1-1) E87 0.56 5.1 3.8 E68 0.45 7.9 10.0 E mouth 0.36 1.6 2.6 Meyers Creek mouth 0.44 0.7 1.0 M 21 0.42 0.7 0.6 Oyster Point Creek mouth 0.37 0.5 0.7 A08 surface 0.31 0.3 0.5 B24 surface 0.28 1.3 2.5 ABD 0.25 0.3 0.7 Dinner Point Creek mouth 0.28 0.3 0.9 Upper Dinner Point Creek 0.17 0.8 5.1 Meyers Pond 0.19 0.5 3.2 Oyster Point Pond 0.11 0.7 9.9 (from June 1974 Annual Report) 1.104 Table 6. Surface NO -N (pg-atom N03-N.1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. o U � O o o o ;: O 4 W 0 O 0 a) W Jun 0.2 0.1 03.2 2.32.22.8 0.0 0.0 0.3 0.6 0 Jul 0;3 0.0 0.4 0 .0 0.1 0.0 0.2 0.1 4.5 1.4 0.2 0.1 0.0 0.2 0.0 Aug 0 .0 0 0.3 1.8 1.3 0.1 0.2 0.0 0.1 0.1 0 , -H 4 P- WO PA 4 OH Jun 0.2 0.1 0.2 2.3 2.2 2.8 0.0 0.0 0.3 0.6 0.0 Jul 03 0.0 0.4 0.0 0.1 0.0 0.2 0.1 4.5 1.4 0.2 0.1 0.0 0.2 0.0 Aug 0.0 0.0 0.1 0.0 0.1 0.0 0.4 0.3 1.8 1.3 0.1 0.2 0.0 0.1 0.1 Sep 0.1 0.2 0.3 0.5 0.3 0.5 0.3 0.3 2.7 4.4 0.2 0.1 0.1 0.1 0.0 Oct 0.4 0.3 0.3 0.2 0.1 0.5 0.1 0.4 10.4 3.4 0.3 0.2 0.1 0.0 0.0 Nov 0.8 1.2 0.8 0.8 0.8 0.8 0.5 0.8 4.9 6.0 0.2 0.0 0.0 0.7 1.6 Dec 1.2 1.3 1.1 0.7 1.2 1.2 0.1 1.2 29.0 8.0 0.5 0.7 0.4 5.1 2.0 Jan 0.3 1.0 0.9 0.9 1.2 4.7 4.6 8.7 9.4 1.3 0.9 0.0 6.3 0.0 Feb 0.1 1.7 2.8 0.5 0.4 1.2 0.2 4.0 6.2 7.5 0.2 0.1 0.0 0.7 0.0 Mar 0.0 2.4 0.5 0.8 0.5 0.7 0.6 6.4 6.5 0.0 0.0 0.0 1.7 0.0 Apr 0.7 1.0 0.6 0.6 0.5 1.2 1.2 4.2 5.4 5.6 0.7 1.5 0.6 0.5 0.1 May 0.0 0.3 0.3 0.0 0.3 0.1 13.0 5.3 0.0 0.0 0.0 0.0 0.3 (from June 1974 Annual Report) Table 7. Surface N02-N (jig-atom N02-N-1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. GP -i -UWU *H4-i~~~Q -r-4 -W *H1J U 04 O 0 0 P-,0 -H~ c.4 P-10 N 4- 4.4 - rz p )9: r 4 .4l-W ~~~4e $- 4 1.4 ~ 0 %4 ~~~4 ~~4 a) -14 e a) 9z 04.i wj a ) 4-d '1 0 P, .H :j eW W n OD 00 -.COt 0 PH 0 O wO N i>1. 9O CO -: <~ PC' Jun 0.1 0.1 0.2 0.2 0.3 0.1 0.2 0.2 0.2 0.3 0.6 Jul 0.1 0.0 0.1 0.0 0.0 0.0 0.1 0.2 0.2 0.0 0.1 0.1 0.2 0.1 0.5 Aug 0.0 0.0 0.1 0.0 0.0 0.1 0.0 0.1 0.1 0.0 0.1 0.0 0.0 0.0 0.0 Sep 0.0 0.0 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.6 CD Oct 0.0 0.0 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Nov 0.2 0.1 0.2 0.1 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 Dee 0.1 0.0 0.3 0.0 0.2 .0.2 0.1 0.1 0.8 0.1 0.1 0.1 0.1 0.3 0.3 Jan 0.1 0.1 0.1 0.0 0.2 0.0 0.1 0.0 0.1 0.0 0.1 0.4 0.3 0.0 Feb 0.0 0.0 0.1 0.0 0.0 0.1 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 Mar 0.1 0.0 0.1 0.1 0.0 0.1 0.0 0.2 0.0 0.0 0.0 0.0 0.1 0.0 Apr 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 May 0.0 0.0 0.0 0.1 0.0 0.1 0.9 0.0 0.0 0.0 0.0 0.0 0.0 (from June 1974 Annual Report) Table 8. Surface total organic nitrogen (pg-atom Org-N1-l1) except where noted. Monthly averages for all stations from June 1973 to May 1974. o-, 4 U P - o 0 o 4 o rz U r Ci 4 P s4 s a) -: $- 4j a) s 4 a) a ) 0 u - Qa) 9 *r W4 W Q) 4J a � 5 4 - AH v > 0 0 9 0 g 0 0 o o > o P 0 o o 49 CI ; il ) . a W O . O P �� Jun 31.8 49.9 38.8 33.8 28.9 16.8 37.5 41.7 39.3 83.0 * Jul 37.6 63.0 38.5 48.2 33.5 87.4 31.3 36.5 36.9 22.0 39.0 47.7 63.2 63.0 * Aug 36.2 60.1 38.3 39.5 28.9 77.1 31.1 28.2 37.3 28.4 43.6 58.2 60.6 61.7 * Sep 35.7 46.0 47.9 47.6 42.9 61.7 30.3 43.3 28.9 14.0 42.0 45.1 47.3 61.6 Oct 38.5 42.8 33.0 36.9 31.5 43.2 29.2 34.7 47.3 21.6 31.6 38.6 34.3 57.5 43.6 Nov 40.3 46.4 32.1 34.3 30.1 34.5 37.8 35.4 28.5 5.5 26.2 28.2 31.0 43.0 51.3 Dec 34.4 61.8 36.7 31.6 35.7 38.4 37.2 41.1 29.9 9.9 25.6 27.3 29.5 34.4 31.0 Jan 36.6 45.8 39.3 38.7 28.0 53.5 21.1 14.3 14.2 30.3 27.9 36.9 34.2 33.2 Feb 86.1 44.2 86.2 50.1 63.8 64.0 24.5 19.8 14.0 9.6 24.9 30.0 27.5 36.5 33.1 Mar 62.0 54.9 46.5 70.6 48.8 61.0 35.0 23.4 35.5 35.2 34.8 31.2 31.5 20.2 Apr 43.2 49.1 51.6 43.8 37.3 48.8 37.2 25.4 18.5 12.5 31.2 29.0 33.8 31.6 24.0 May 40.6 35.7 45.1 32.2 36.2 31.9 38.6 15.1 38.6 29.8 47.8 37.9 16.5 � No true mean can be calculated as some sample values exceeded the 350 pg-atom Org-N.1-1 limit of the method. (from June 1974 Annual Report) Table 9. Surface soluble organic nitrogen (Cg-,atom Soluble Org-N.1-1) except where noted. Monthly averages for all stations from June 1973 tQ May 1974. .H ,4J ~ � W . H4 H .U o oc cw 0 0 o 0 0 ~ d) ~ ~ ~~ rJ) rJ, ~ -I r- 00 4-' ~ ~ ~ W W W- -WW -W~ r o '~ ~ o o o- d ) w C co co co o- 0 r4~Pl P~0 Wj fr> P ta 0 0O 0C 0 C q Jun 24.3 45.5 25.0 28.3 23.7 15.1 23.6 27.2 27.5 43.2 Jul 26.9 52.1 31.0 42.4 30.5 61.1 25.9 31.6 28.6 19.7 30.4 36.6 51.2 41.5 * Aug 26.0 42.2 31.1 33.2 23.2 48.3 31.4 31.8 30.0 20.5 36.0 33.5 35.8 37.7 * Sep 20.1 28.8 33.4 29.3 31.6 40.8 28.4 32.2 15.0 7.5 32.0 36.7 30.1 36.5 * o CO Oct 27.3 25.5 25.4 29.2 26.3 30.3 25.9 32.1 30.9 13.3 26.6 27.5 26.8 33.5 19.7 Nov 19.7 31.1 24.4 21.7 21.3 19.3 22.9 27.0 23.0 4.9 21.4 27.2 27.2 28.3 31.9 Dec 14.8 31.8 17.3 25.6 16.1 23.9 29.2 23.4 11.2 8.7 10.1 17.2 22.3 19.9 20.1 Jan 13.2 23.4 29.9 26.7 18.3 18.5 10.2 14.8 9.5 17.3 17.8 22.0 19.5 22.0 Feb 18.0 35.2 22.1 26.8 13.8 43.4 15.1 9.7 9.1 6.2 16.5 15.9 14.4 22.2 22.8 Mar 13.2 28.5 29.8 22.4 15.1 15.7 12.1 10.3 11.0 19.3 12.8 14.0 15.2 18.1 Apr 16.4 33.5 13.2 21.2 15.4 30.1 15.9 15.2 11.2 9.0 17.6 10.7 20.6 12.2 16.7 May 25.9 28.4 37.7 26.2 27.3 19.3 25.5 7.6 34.2 24.3 23.7 23.4 11.2 No true mean can be calculated as some sample values exceeded the 350 g-atom Soluble Org-N-1-1 limit of the method. (from June 1974 Annual Report) Table 10. Surface particulate organic nitrogen (pg-atom Particulate Org-N'1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. w o ~~U W.~ 0) -d U 0 O0 ~W 4 0 0L O L PL4 .y4- Q P. Pj 0 $44. 4-1~~~~~~~~~o 0 ~ o 4J (V W W 0) 4.JO) OJQ- 0 0 �rlP C O 04 0) 90 PIZ 4, c a) c LI~ c) PO wQ W Jun 7.5 4.5 13.9 5.5 11.2 5.3 14.0 14.5 11.8 39.8 Jul 10.7 10.9 7.6 5.9 3.1 26.3 5.3 5.6 8.3 2.3 9.0 11.2 12.0 21.6 * Aug 10.3 17.9 7.2 6.4 5.7 28.8 1.0 0.0 14.2 7.9 12.4 24.7 24.8 24.0 * Sep 15.6 17.2 14.5 18.3 11.3 20.9 2.3 � 11.1 14.0 6.5 9.5 8.4 17.2 25.1 * o 10 Oct 11.3 17.3 7.6 7.7 5.2 12.9 3.9 2.9 16.4 8.3 5.6 11.2 7.5 24.0 24.0 Nov 20.6 15.3 7.8 12.6 8.8 15.3 15.4 8.5 5.6 0.6 4.9 5.7 5.0 14.8 19.4 Dec 19.6 30.1 19.4 7.5 19.6 14.5 8.1 17.7 18.7 2.4 15.5 10.1 7.2 14.5 10.9 Jan 23.4 22.4 9.4 12.0 9.7 35.0 10.9 0.0 4.7 13.0 10.1 14.9 14.7 11.2 Feb 68.1 9.0 64.1 23.3 50.0 20.6 9.4 10.1 4.9 3.4 8.4 14.1 13.1 14.3 10.3 Mar 48.8 26.4 16.7 48.2 33.7 45.3 22.9 13.1 24.5 15.9 22.0 17.2 16.3 2.1 Apr 26.8 15.6 38.4 22.6 21.9 18.7 21.3 10.2 7.3 3.5 13.6 18.3 13.2 19.4 7.3 May 14.7 7.3 7.4 6.0 8.9 12.6 13.1 7.5 4.4 5.5 24.1 14.5 5.3 No true mean particulate organic nitrogen can be calculated because some total and soluble organic nitrogen values exceeded the limits of the method. Note: Individual negative values of particulate organic nitrogen between 0 and -3.5 were taken as 0 in calculating the means, while all negative values were discarded. (from June 1974 Annual Report) Table 10a. Surface particulate organic nitrogen (pg-atom Particulate Org-N-1-1) except where noted. Monthly averages for all stations from June 1973 to May 1974. -W $-4 , W - o C a) 14 0 0 CD 4r-i 4J W 4j .r r o 4-1J I4 o U4 0 Ce 0 - 4.i 0 0 � m c a) J QJ 4j 0 4 4 -? -I >* m C W PI rz 0- la -t 4 . a 40 oo o , C D � ,C 6/13 10.1 3.0 1.2 16.5 4.9 6.8 13.8 6/20 9.3 5.2 30.3 10.4 5.8 5.6 21.9 23.2 13.0 29.3 14.9 6/25 3.1 3.7 8.3 4.8 -6.7 -5.5 6.0 13.5 8.6 50.3 66.0 7/2 11.7 1.8 4.3 10.9 2.5 1.6 20.0 5.2 8.2 7.8 7/17 9.8 2.3 4.1 11.5 7.7 7.0 0.4 -0.7 2.9 2.6 27.2 -42.2 7/23 7/23 13.5 17.3 4.4 2.4 0.6 10.5 7.0 3.9 28.7 3.2 22.7 11.5 7/24 7/30 7.9 13.2 10.7 9.3 2.0 26.3 7.4 -2.8 8.1 5.5 18.6 28.3 28.1 96.8 7/31 8/6 3.2 13.8 6.4 10.1 2.6 -2.4 -6.8 -13.6 1.1 6.7 19.0 22.7 13.5 25.4 8/7 8/13 13.6 29.6 15.1 3.9 6.6 32.6 -2.7 -2.5 13.0 9.5 8.5 30.3 34.5 36.5 25.0 8/14 8/20 10.0 9.8 2.3 7.9 8.5 48.8 3.9 -1.4 22.8 22.0 16.0 10.3 20.4 9.6 8/21 8/27 14.2 18.3 5.0 3.5 5.1 5.0 0.2 -3.5 6.7 13.0 - 6.6 33.5 31.8 25.4 -25.4 8/28 9/11 18.8 19.6 11.0 9.2 11.9 28.6 -0.8 12.9 24.0 9.1 6.5 6.1 14.3 30.1 24.3 9/13 Table 10a. Continued. pco ~ ~ � ~ o o e o X o cc a ) 0) -H 4J -rJ ~ *4J � H o0 0: : I 0 c o Uo PO UD Q PL P- 4-4 .J '4 4J- 0) a)X o wo- A w ,0 4a 0 X X D X d r44 O )0 m) w O C U 0 c 9/25 12.3 14.7 18.0 27.4 10.7 13.2 4.6 9.3 3.9 3.8 12.4 10.6 20.1 20.0 -23.3 9/26 10/9 10/9 8.7 10.4 9.9 6.1 22.0 7.7 5.7 15.1 4.9 11.2 5.2 10.5 28.0 9.5 10/10 10/24 13.8 17.3' 4.8 5.4 4.2 3.8 -1.1 -0.5 17.6 11.7 -1.3 17.1 4.4 19.9 33.7 10/25 11/7 15.0 7.1 3.3 6.4 3.0 22.5 30.8 5.8 3.5 0.3 4.7 5.7 9.9 15.3 22.1 11/8 11/19 26.1 23.5 12.2 18.8 14.5 8.0 -1.0 11.1 7.6 0.9 5.0 -3.6 -2.3 14.2 16.7 11/20 12/4 9.6 17.9 6.5 15.0 10.8 13.5 14.3 6.2 19.9 -2.2 19.7 11.2 8.5 19.1 18.0 12/27 29.6 42.2 32.2 -2.9 28.3 15.5 1.8 29.1 17.5 4.7 11.3 9.0 5.9 9.8 3.7 1/17 23.4 22.4 9.4 12.0 9.7 35.0 10.9 -0.5 4.7 13.0 10.1 14.9 14.7 11.2 2/28 68.1 9.0 64.1 23.3 50.0 20.6 9.4 10.1 4.9 3.4 8.4 14.1 13.1 14.3 10.3 3/14 48.8 26.4 16.7 48.2 33.7 45.3 22.9 13.1 24.5 15.9 22.0 17.2 16.3 2.1 4/11 26.8 15.6 38.4 22.6 21.9 18.7 21.3 10.2 7.3 3.5 13.6 18.3 13.2 19.4 7.3 5/2 14.7 7.3 7.4 6.0 8.9 12.6 13.1 7.5 4.4 5.5 24.1 14.5 5.3 (from June 1974 Annual Report) Table 11. Surface particulate oxidizable carbon (mg-m-3) except where noted. Monthly averages for all stations from June 1973 to May 1974. o~ o @o o ~ o oo O r0 0 0 O : 0 � Jun 2,018 1,770 1,649 2,629 1,637 852 2,017 2,342 2,123 14,206 2,666 Oct 3,698 4,783 1,341 2,171 1,616 2,959 417 1,113 1,201 384 1,244 507 913 Nov 3,644 2 ,762 2,907 2.671 2,670 1,411 376 Jun 2,018 1,770 1,649 2,629 1,637 852 2,017 2,342 2,123 14,206 2,666 Jul 2,261 1,858 1,174 2,705 2,489 2,814 1,587 1,753 2,023 1,341 1,735 3,067 3,652 3,410 2,612 Aug 1,813 2,271 1,906 1,346 1,049 3,905 1,106 1,508 1,855 984 1,519 2,411 2,969 3,187 2,725 Sep 2,615 3,286 2,822 3,843 2,853 3,434 1,214 2,042 3,019 375 1,998 1,717 1,776 3,322 2,206 Oct 3,698 4,783 1,341 2,171 1,616 2,959 417 1,113 1,201 384 1,244 507 913 2,966 3,946 Nov 3,644 2,762 2,907 2.671 2,670 4,422 1,889 1,720 1,411 376 1,246 1,720 2,697 2,544 2,623 Dec 2,335 1,407 2,336 2,199 1,667 2,178 1,945 1,883 1,740 662 1,671 1,626 1,282 1,675 1,221 Jan 3,031 2,378 2,564 3,031 979 7,087 2,072 785 785 2,198 2,104 2,407 2,261 2,355 Feb 10,418 3,201 12,125 2,894 2,199 3,909 2,189 923 171 684 2,633 1,334 1,607 1,925 1,847 Mar Apr 3,660 3,172 4,793 3,813 3,348 2,507 4,793 1,495 1,037 1,464 4,104 3,821 3,222 3,630 2,867 May 2,257 1,434 2,135 1,525 1,739 1,098 1,342 427 1,007 1,708 2,776 1,830 1,708 (from June 1974 Annual Report) Table 12. Surface chlorophyll a (mg-m-3) except where noted. Monthly averages for all stations from June 1973 to May 1974. 4-J 4 i 4. 4 n 6.0 7 5 c C1 . 0 - 4.4 4 0 2 Aug 5.88 9.96 4.68 7.27 8.13 23.41 2.63 3.83 16.27 10.70 4.07 10.94 29.92 20.32 22.00 Sep 11.13 12.98 10.49 8.46 6.61 10.06 268 4.74 8.52 2.21 4.74 7.90 7.55 17.57 11.71 Oct 10.67 7.75 1.59 1.89 2.5 4 2.86 1.08 2.72 8.43 4.62 1.64 2.06 2.47 11.42 10.38 Jun 6.07 5.31 1.90 4.15 9.07 1.34 6.46 10.66 6.99 17.50 25.40 Jul 10.85 8.79 5.7514 6.53 7.08 5.29 7.50 7.69 12.00 0.52 2.42 5.77 10.37 96.11 25.34 38.40 Aug 5 9.51 96 4.68 7.27 8.13 23.41 2.63 3.83 16.27 10.70 4.07 10.94 29.92 20.32 22.00 Sep 11.13 12.98 10.49 8.46 6.61 10.06 9.68 4.74 8.52 2.21 4.74 7.90 7.55 17.57 11.71 Oct 10.67 7,75 1.59 1.89 2.54 2.86 1.08 2.72 8.43 4.62 1.64 2.06 2.47 11.42 10.38 Nov 7.76 7.00 5.29 4.40 3.74 4.93 4.01 5.14 4.24 1.15 3.22 3.54 6.46 11.05 10.64 Dec 11.62 6.18 10.14 6.53 7.08 5.29 7.50 7.69 12.00 0.58 6.35 5.56 5.83 7.59 8.49 Jan 19.51 11.79 12.14 13.03 9.52 20.08 7.72 2.69 1.40 9.15 6.90 9.32 7.41 4.99 Feb Mar 11.58 5.95 6.26 10.08 6.96 5.08 4.71 2.45 2.56 4.66 5.74 6.31 4.54 0.43 Apr 6.86 4.02 8.18 6.21 6.95 4.04 7.85 5.76 3.89 2.17 9.45 7.10 16.30 5.81 3.06 May 7.08 10.20 5.53 5.82 4.07 9.12 3.07 5.00 9.51 1.81 4.92 5.55 10.04 3.89 1.60 (from June 1974 Annual Report) Table 12a. Surface chlorophyll a (mg'-m3) except where noted, from June 1973 to May 1974. 0o .: r4 ( .4 o W 0 co F41 0 -HP ~ ~0 ~: P O $, 0 4 C)4 $44 ) c )C .l 6/13 6.15 1.79 4.23 19.21 2.09 12.99 4.43 6/20 6.61 4.73 1.97 3.66 4.21 1.05 5.75 10.57 3.49 12.91 37.11 6/25 5.44 5.89 1.93 4.56 3.79 0.88 7.16 8.42 13.04 22.08 13.68 7/2 14.78 0.73 3.18 6.60 1.41 1.59 5.61 11.06 53.25 25.41 7/17 14.98 9.50 5.71 1.15 4.27 19.34 4.69 2.97 10.22 163.84* 10.47 49.75 7/23 3.57 9.45, 3.92 5.26 3.89 1.95 6.68 1.17 13.13 14.11 125.85 19.32 56.50 7/24 7/30 10.05 7.43 7.58 19.59 6.55 30.86 0.97 3.14 11.61 5.38 11.52 83.68 18.30 21.93 7/31 8/6 2.89 10.95 4.27 5.86 1.87 1.45 3.41 6.68 1.47 5.44 4.24 70.79 7.92 32.36 8/7 8/13 9.17 14.51 6.48 15.03 21.94 7.50 2.57 4.63 34.77 2.22 5.78 21.98 12.66 26.94 19.97 8/14 8/20 4.89 8.80 5.56 5.06 6.41 58.22 2.19 3.52 18.34 3.91 13.83 11.59 31.52 16.77 8/21 8/27 6.56 5.59 2.39 3.12 2.30 4.52 4.29 3.74 5.28 28.41 1.15 3.72 24.62 14.90 18.90 8/28 9/11 11.54 21.69 6.33 4.32 4.11 10.84 2.37 7.05 12.26 4.41 4.24 11.92 9.79 25.13 18.74 9/13 Table 12a. Continued, 4J ~ 4-1 4.J .-W o D w (D U o o a d;0 9 ~- * r 0 o 0 c o 0 O.~ 0 ~ o0 oo o~ ~ c-~ ~ oo4J -o.. .U p o 44 44 4-o 4 w 0) r, 4j a)~- 0J 0 '"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~f ,f .0 , r 4j ~ ~ W w- a) 47W -HS M 0)M000 rI o o0 Qo ro >o CO c~~~~~ *H-- I? O) u 0$- PO Pq C) w' P, ~~~ �rl U P CU F' 9/25 10.72 4.26 14.65 12.59 9.10 9.28 2.99 2.42 4.78 0.00 5.24 3.87 5.31 10.00 4.68 9/26 10/9 0.37 0.58 2.43 1.80 0.54 2.65 6.75 1.39 1.60 1.91 1.29 7.23 5.76 10/10 10/24 10.67 7.75 2.81 3.19 2.64 3.91 1.62 2.79 10.11 7.84 1.67 2.21 3.65 15.60 15.00 10/25 11/-7 5.09 2.66 2.92 2.47 1.77 2.84 3.66 4.09 2.81 1.10 2.27 3.44 7.88 13.44 11.97 11/8 11/19 10.42 11.34 7.65 6.33 5.71 7.01 4.36 6.18 5.66 1.19 4.16 3.64 5.03 8.65 9.30 11/20 12/4 8.08 6.30 3.82 3.67 4.54 3.96 4.43 7.30 22.65 1.15 4.86 8.25 6.38 14.41 14.45 12/27 15.16 6.06 16.45 9.38 9.62 6.62 10.52 8.08 1.34 .00 7.83 2.86 5.28 0.77 2.52 1/17 19.51 11.79 12.14 13.03 9.52 20.08 7.72 2.69 1.40 9.15 6.90 9.32 7.41 4.99 2/28 3/14 11.58 5.95 6.26 10.08 6.96 5.08 4.71 2.45 2.56 4.66 5.74 6.31 4.54 0.43 4/11 6.86 4.02 8.18 6.21 6.95 4.04 7.85 5.76 3.89 2.17 9.45 7.10 16.30 5.81 3.06 5/2 4.26 5.16 5.53 3.11 3.07 3.59 4.46 1.92 3.76 2.84 9.94 3.89 1.60 5/23 9.89 10.20 5.90 6.10 5.03 9.12 6.41 14.55 1.70 6.08 8.25 10.14 Limits of method exceeded. (from June 1974 Annual Report) Table 13. Surface net productivity (ml 02.1-1-24h-1) except where noted. Monthly averages for all stations from July 1973 to May 1974. 4J : 4J 4J *r *II4 U -W a * 4 L 4 P40 .H P L_) P -: o 4-A 4J 4 $ 4 4J 0 0 , W 0)� P44 $ 4 Id w 5 0L S W 0 *i $4 w P o 0 M C) o Jul 1.52 1.52 1.06 2.99 1.30 3.22 0.38 2.13 3.27 -0.06 0.95 1.35 0.96 1.70 0.00 Aug 1.59 1.93 1.01 2.09 1.18 4.62 0.33 1.66 1.03 0.43 1.30 1.81 1.56 2.16 0.00 Sep 1.97 2.12 1.11 1.87* 1.91 2.87 0.81 1.24 2.02 0.52* 1.21 1.63 1.74 2.78 0.00 Oct 1.37 0.94 0.34* 0.58* 0.77 0.02 -3.12* 0.60 1.56* 0.95 1.00 0.23 0.49 2.70 1.27 Nov -0.53 2.07 1.74 1.34 1.19 1.68 0.27 1.15 1.16* 0.62 1.24 0.97 1.50 2.17 2.17 Dec 1.50 0.45 0.96 0.35 1.25 0.87 0.98 1.31 0.88 -0.08 1.16 0.93 0.94 0.73 1.15 Jan 1.95 0.60 1.10 0.65 1.13 1.63 0.36 -0.20 -0.50 0.65 0.76 0.65 0.38 -0.01 Feb 2.46 * 2.00 0.38 1.00 0.58 0.54 0.40 0.02 -0.82 0.70 0.46 0.76 0.76 -0.14 Mar 1.50 0.23 0.55 -0.10 0.84 0.99 0.88 0.17 -0.14 0.83 1.35 1.05 1.29 -0.55 Apr 0.98 0.09 0.90 0.98 0.76 0.20 1.26 1.50 0.56 0.11 1.33 1.05 4.48 1.50 0.00 May 2.31 1.81 0.58 1.15 0.68 2.00 0.61 0.79 1.36 -0.08 0.71 0.71 1.89 0.24 0.00 Production experiments with respiration values less than -0.12 ml 02-1-1-24 h-l were discarded from monthly mean determinations. (from June 1974 Annual Report) Table 13a. Surface net production (ml 02-1-1-24h-1) except where noted, from June 1973 to May 1974. o D o o - o x H 4J 0 4* HJ *r - ) o v:1 r : a) r4l 0 I- I v C 0 E 7/23 1.01 2.56 0.74 2.26 0.14 3.09 3.24 -0.06 0.98 2.11 0.00 0.52 0.00 7/24 7/30 2.03 1.06 1.38 3.71 1.30' 3.22 0.61 1.17 3.29 0.91 0.59 1.91 1.88 0.00 7/31 8/6 1.53 1.30 0.19 3.26 0.44 0.44 2.08 2.23 -0.62 1.55 1.37 0.15 1.27 0.00 8/7 13 1.60 3.21 1.89 1.64 7.07 0.76 1.98 2.26 0.28 1.50 3.17 1.00 2.58 0.00 8/14 8/20 0.75 0.58 0.75 1.14 1.18 2.56 0.01 0.67 4.24 0.81 1.60 0.68 3.46 0.00 8/21 8/27 2.48 2.63 1.20 1.87 1.46 4.22 0.10 1.90 4.07 1.63 1.33 1.10 4.41 1.34 0.00 8/28 9/11 1.71 3.00 0.49 2.56 1.71 3.55 0.00 1.02 1.80 0.52 1.05 2.18 1.70 3.53 0.00 9/13 9/25 2.22 1.24 1.73 1.87 2.11 2.18 1.61 1.46 2.24 -0.37 1.37 1.07 1.78 2.03 0.00 9/26 10/9 0.34 0.58 0.22 0.90 -3.12 1.48 2.08 0.33 1.20 0.25 0.67 2.51 0.00 10/10 Table 13a. Continued. cO~ j .,4 w O, o 0 o o U . oo : o 4 O , c 10/24 1 a) O Q) 5 4 w F4 0 4 4J 10/24 1.37 0.94 0.81 0.90 1.31 -0.87 2.8 1 -0.28 1.56 1.56 0.79 0.20 0.30 2.88 2.53 10/25 11/7 -026 11/7 2.66 0.65 0.733 .23 0.57 -0.21 0.55 0.88 4.82 -0.07 1.17 0.96 1.40 3.21 3.04 11/8 11/19 1.60 3.48 2.75 2.45 1.80 3.57 -0.02 1.41 1.16 1.31 1.31 0.98 1.60 1.13 1.29 11/20 12/4 1.04 0.99 0.70 0.85 0.61 0.54 0.57 0.81 1.89 0.04 0.72 0.92 0.93 1.26 1.69 12/27 1.95 -0.09 1.22 -0.15 1.88 1.20 1.38 1.80 -0.14 -0.19 1.59 0. 20 0.95 0.20 0.61 1/17 1.95 0.60 1.10 0.65 1.13 1.63 0.36 -0.20 -0.50 0.65 0.76 0.65 0.38 -0.01 2/28 2.46 4.78 2. 2.00 0.38 1.00 0.58 0.54 0.40 0.02 -0.82 0.70 0.02 -0.82 0.70 0.46 0.76 0.76 -0.14 3/14 1.50 0.23 0.55 - 0.1 4 0.99 0.84 0.99 0.14 0.83 1.35 1.05 1.2 -0.8355 4/11 0.98 0.09 0.90 0.98 0.76 0.20 1.26 1.50 0.56 0.11 1.33 1.05 4.48 1.50 0.00 5/2 1.14 1.00 0.99 0.53 0.61 0.88 -0.08 -0.04 0.73 0.54 2.13 0.24 0.00 5/23 3.47 1.81 0.16 1.30 0.83 2.00 0.69 2.80 -0.11 0.69 0.88 1.65 (from June 1974 Annual Report) APPENDIX B Tables and Figures from the June 1975 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity LIST OF FIGURES Figure Page 1 Station locations ........................ 1.123 2 Surface water temperature: Meyers Pond, A08, B24, E87 versus M 21 ............................. 1.123 3 Seasonal water temperature at M 21 surface ........... 1.123 4 Surface salinity levels at the mouths of the major systems . 1.123 5 Salinity levels at Meyers Pond, Meyers Creek mouth, A08, and ABD .............................. 1.124 6 Salinity levels at the surface and bottom of Lagoon B24 . . . 1.124 7 Dissolved oxygen concentrations at Meyers Pond, Meyers Creek mouth, A08, and ABD .................. 1.124 8 Dissolved oxygen concentrations at M 21 and Lagoon B24 . .... 1.124 9 Secchi disc readings at M 21, Meyers Pond, and Lagoon A08 . . 1.125 10 Temperature stratification (surface temperature minus bottom temperature) in the lagoon systems on 9 July 1974 ....... 1.125 11 Salinity stratification (bottom salinity minus surface salinity) in the lagoon systems on 9 July 1974 ............. 1.125 12 Dissolved oxygen concentrations at the bottom of the lagoon sys- tems on 9 July 1974 ...................... 1.125 13a Surface NH3-N concentrations in the lagoon systems on 9 July 1974 .......................... 1.126 13b NH3-N concentrations at the bottom of the lagoon systems on 9 July 1974 .......................... 1.126 14 Temperature stratification (surface temperature minus bottom temperature) in the lagoon systems on 8 February 1975 . .... 1.126 15 Salinity stratification (bottom salinity minus surface salinity) in the lagoon systems on 8 February 1975 ........... 1.126 16 Dissolved oxygen concentrations at the bottom of the lagoon systems on 8 February 1975 .................. 1.127 17a Surface NH3-N concentrations in the lagoon systems on 8 February 1975 ....................... 1.127 17b NH3-N concentrations at the bottom of the lagoon systems on 8 February 1975 ........................ 1.127 18 Total organic-N concentrations at M 21 and Lagoon B24 ...... 1.127 19 Vertical distribution of temperature, salinity, dissolved oxygen, and ammonia-N at Lagoon B24 .............. 1.128 20 Cross sections of the natural and lagoon systems .. 1.128 21 Chlorophyll a concentrations in the Meyers system, Lagoon A08, and Lagoon B24 ........................ 1.128 22 Vertical distribution of temperature, salinity, dissolved oxygen, and chlorophyll a at Lagoon A08 and B24 ............ 1.129 23 Net productivity values in the Meyers system, ABD, M 21, A08, and B24 ........................... 1.129 1.119 LIST OF TABLES Table Page 1 Surface water temperatures (DC), except where noted, from June 1974 to May 1975 . . . . . . . . . . . . . . . . . . . . . . 1.130 2 Surface salinity (0/oo), except where noted, from June 1974 to May 1975 . . . . . . . .. . . . . . . . . . . . . . . . . . . 1.132 3 Surface dissolved oxygen (ml 02.1-1), except where noted, from June 1974 to May 1975 . . . . . . . . . . . . . . . . . . 1.134 4 Secchi disc measurements (m) from June 1974 to May 1975 . . . . . . 1.136 5 Vertical distribution of temperature (0C), salinity (O/oo), and dissolved oxygen (ml 02.1-1) at A08 and B24 . . . . . . . . . . . 1.137 6 Surface NH3-N (pg-atom NH3-N.l-l), except where noted, for all stations from June 1974 to April 1975 . . . . . . . . . . . . . . 1.140 7 Surface N02-N (pg-atom N02-N1l-1), except where noted, for all stations from June 1974 to April 1975 ....... ......1.142 8 Surface N03-N (pg-atom N03-N.l-1), except where noted, for all stations from June 1974 to May 1975 . . . . . . . . . . . . . . . 1.144 9 Surface total organic nitrogen (pg-atom Org-N-l-1), except where noted, for all stations from June 1974 to May 1975 . . . . . . . 1.146 10 Vertical distribution of NH3-N, N02-N, and N03-N in (Vg-atom- 1-1) A08 and B24. . . . . . . . . . . . . . . . .......1.148 11 Acetylene reduction (V1 C2H4.min-1 m-2) by algae and associated substrate.. . . . . . . . . . . . . . . . . . . . . . . . . ...1.150 12 Acetylene reduction rate (V1 C2H4.min-lm-2) in substrate sam- ples . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.152 13 Acetylene reduction rate (p1 C2H4.min-l1-1l) in the water col- umn . . . . . . . . . . . . . . . . . . . . . . ........1.154 14 Invertebrate excretion of inorganic ammonia. Average value per sampling date is indicated ................... 1.154 15 Surface particulate oxidizable carbon (mg.m-3), except where noted, for all stations from June 1974 to April 1975 . . . . . . 1.155 16 Surface chlorophyll a (mg.m-2), except where noted, from June 1974 to April 1975 . . . . . . . . . . . . . . . . . . . . . . . 1.157 17 Chlorophyll a (mg.m-3) and acid-factor ratio. Lagoon verti- cal distribution from September 1974 to April 1975 . . . . . . . 1.159 18a Surface phytoplankton net production (ml 02.1-1-day-1l) from June 1974 to April 1975 . . . . . . . . . . . . . . . . . . . . . 1.161 18b Phytoplankton production (ml 02.m-2.day-1) at Meyers Creek mouth and Lagoon A08 from September 1974 to April 1975 . . . . . 1.163 19 Net production and respiration of marsh surface algal mats (ml 02.m-2-12 h-l) from December 1974 to April 1975 . . . . . . . 1.164 20 Net production and respiration of benthic microflora and fauna (ml 02.m-2-12 h-l) from January to April 1975 . . . . . . . 1.165 21 Sample calculations for daily system totals of nitrogen processed or present in Meyers Creek system and Lagoon A in April . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.166 1.121 21 A ,E8 25 xE87 Meyers 5 Pond t ers Cr -5 Mouth A Upper End <a MhTempeyerature at M 21 (, Fig. 1 Station locations. Fig. 2. Surface water temperature: Meyers Pond, A08, B24, E87, versus M 21. 30- 25-- 10- 2 1--- Meyers Creek Mouth - 20- M 21 A-- ABD L-115- 1974 1975 1974 1975 Fig. 3. Seasonal water temperature at M 21 Fig. 4. Surface salinity levels at the surface. mouths of the major systems. 1. 123 1.123 25- o 2s- ~",~" "~, X 15- s__Meyers Pond o-o Meyers Creek Mouth J J A S O N DIJ F M A M 25 - 25- -- o.'� -. . - -------- 20. .- ~ /t 20. : '- B24 .-. A08 Surface * o---o ABD 15 ._. Surface a---- A08 Bottom o---o Bottom 10 ' 10 J J A S O N D | J F M A M J J J S O N D|J F M A M 1974 1975 1974 1975 Fig. 5. Salinity levels at Meyers Pond, Fig. 6. Salinity levels at the surface and bot- Meyers Creek mouth, A08, and ABD. tom of Lagoon B24. 9- 9- M 21 8- 8- 7- 7- 6- � � o6- 5- 25- ,-3-. 'i . 3- 2 *---. Meyers Pond 2- o O--O Meyers Creek Mouth 1- 1- E , J J A S O N D J F M A M J J A S O N DJ F M A M >. 9- .- A08 Surface B 824 o 8 O--o ABD 9- Surface o-8- Bottom .a---a A08 Bottom Bottom - 7- 7- 6- 6- 5- i~~ 5 4- 4- I - 3- I ' ! 3- ' 2- I 2 - , /i I, i I i .o I, A I, I i1 '".J J J A S 0 N D i F M A M J J A S O N D J F M A M 1974 1975 1974 1975 Fig. 7. Dissolved oxygen concentrations at Meyers Fig. 8. Dissolved oxygen concentrations at M Pond, Meyers Creek mouth, A08, and ABD. 21 and Lagoon B24. 1.124 2F 21 3 L 6.8 2.7 1.9 J J A S O N D|J F M A M F~~~~~~~ E 3 Meyers Pond ~ ~ .-2_ o = > Total Depth -I _2 ___ .,I A. J J A S O N DI J F M A M M 21 A08 2 3 3-4.3 C �<1 1.9 * ;1-5 * >5 .I JA S'O N D I J F M A M (Surface Temperature minus I1974~ 1975 ~~Bottom Temperature) 1974 1975 Fig. 9. Secchi disc readings at M 21, Fig. 10. Temperature stratification Meyers Pond, and Lagoon A08. (surface temperature minus bottom tempera- ture) in the lagoon systems on 9 July 1974. 0% @1-< I (ml 02I) � >3.5 @ -1-3.5 * < 1.0 (Bottom Salinity minus Bottom Dissolved OxygenC Surface Salinity) Fig. 11. Salinity stratification (bot- Fig. 12. Dissolved oxygen concentra- tom salinity minus surface salinity) in tions at the bottom of the lagoon sys- the lagoon systems on 9 July 1974. tems on 9 July 1974. 1.125 M 21 N2, N 21 0~~~~~~~~~~~~~~~~~~~~~~~~~~ < 0.5 -< (vig-atom NI-3 -N* j1) Gi 2 g-atom NH3-N 11) A M2 * 05< 1 / * 1 10 1 < 5 lo 10v 50 * 5 S10 0 501 ' 00 * >10 C >100 Surface Ammonia-N Bottom Ammonia-N Fig. 13a. Surface NH3-N concentra- Fig. 13b. NH3-N concentrations at tions in the lagoon systems on 9 July the bottom of the lagoon systems on 9 1974. July 1974. / ~~~~ *2 1 M 21 NM2 oc * <1 & ' I~~~~~~~~~~~~~~~ * 1-5 * <1 * >5 I1-5 l >5 (Surface Temperature minus (Bottom Salinity minus Bottom Temperature) Surface Salinity) Fig. 14. Temperature stratification (sur- Fig. 15. Salinity stratification (bottom face temperature minus bottom temperature) salinity minus surface salinity) in the in the lagoon systems on 8 February 1975. lagoon systems on 8 February 1975. Absolute value of the difference is indica- ted. 1.126 M 21 1 21 Bottom (jig-atom NH3-NI1) N. (ml 02.1 1) > 3.5 . 0.5- 1 * < 1.0 5 �10 >10o Bottom Dissolved Oxygen Surface Ammonia-N Fig. 16. Dissolved oxygen concentra- Fig. 17a. Surface NH3-N concentrations tions at the bottom of the lagoon systems in the lagoon systems on 8 February 1975. on 8 February 1975. 80 - M 21 60 40 20- ro J J A S O N D J F M A M p 120- 824 0 1 ~ 0 49100 - 'gA/~ : Surface o--2o Bottom (ug-atom NH -NI1) 3 60- - �0.5 0.5-< 1I0 � 1 - 5 20- � 5 <10 >10 J JASON D J F MA M Bottom Ammon i a-N 1974 1975 Fig. 17b. NH3-N concentrations at the Fig. 18. Total organic-N concentrations at M 21 bottom of the lagoon systems on 8 February and Lagoon 824. 1975. 1.127 NATURAL SYSTEM 0 5 10 15 20 25 30 0 5 10 20 25 0 50 100 150 200 250 2l00 50#1 0 .0 p ' , 5%oOC 1 , Marsh Mud2 Marsh ANH-i I Surlace B sank Flat Benthic sank Surface Ir I E 61 | 6!1 !I' LAGOON SYSTEM 8 Oct 19743 30 Oct 1974_ a) .o 50 100 150 200 250 3U0+o0 50 100 150 200 HW_ 2 ! o | 1t 2o 4uc \ B Algal band . Suilead 2t i / L 3 5 L (�---�),and a ia at Lagon24 Surface - bottom K:.. 4Nov 1974 4 FebM1975 21[0'�et h Po slid svoxygen systems. (0 --- o), and ammonia-N (A-~-A) at Lagoon B24. 30 - , '� I I I I I I IaMeyers I Pond I F0a 6 I r'I 0 - 0 J A S. ND J F M A I A Surfaco- bottomI 4 Nov 1974 4 Feb 1975 Fig. 19. Vertical distrabution oc temperature Fig. 20. Cross sections of the natural and lagoon (o---o), and ammonia- (20) at : Lagoon 824. 30- o 10- /r l, / .EE J J A S O N D J F M A 1.128 Temp (�C), Salinity (%.), Oxygen (ml 02.1-1 Chlorophyll a (mg.m-3) 0 5 10 15 20 25 30 0 5 10 15 20 25 30 ~~~~~~~~~05O150 ,25 3 0 1- Ili= ?Ii 0 0 2- A08 2 - C~ 02d �1,i 2 bc I �~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I 3- o 3 0 ~~~~~~~~~~~~~~~I A - ' 41 3- O : B214 4. b LI 5- 0 Oct 1974 41 Feb 1975 Fig. 22. Vertical distribution of temperature (.-.) salinity (---), dissolved oxygen (o---o), and chloro- phyll a (---) at Lagoon AO8 and B24. 4- Meyers IR i Pond 3- ' Mouth -o 2 - 0, q')~~~b 1- ro~~~~~~~~~~P- ~ J J~ A S 0 N D J- F A 4 - ABD C14 M 21-0 3- 2- PI P,, 4 - IJ 0 / 4- I ,A08 3, B240---o z3- o2 I I' 1- 'bh I J J A SO N D FM A 1974 1975 Fig. 23. Net productivity values in the Meyers system, ABD, M 21, A08, and B24. 1.129 Table 1. Surface water temperatures (�C), except where noted, from June 1974 to May 1975. 0 C w S1 o a 0 mo o D o a x kx 3 m m 6/20/74 23.8 22.7 22.1 24.0 25.0 18.0 25.5 14.0 7/3 25.0 24.8 24.5 25.2 26.5 19.0 26.5 15.0 7/9 27.6 27.5 29.7 20.0 31.0 11.2 7/17 25.0 24.8 23.8 25.5 27.0 17.8 25.8 12.0 8/1 26.8 26.0 27.0 27.0 27.9 20.6 27.9 12.1 8/13 23.0 22.6 22.0 23.0 24.5 20.8 24.2 15.5 8/27 24.6 24.0 23.6 25.0 26.7 23.5 26.2 15.9 9/10 21.0 21.3 21.0 21.1 22.2 21.2 23.0 13.5 9/25 16.3 16.0 15.0 16.7 18.5 18.2 19.0 18.7 10/8 13.9 13.6 13.6 13.4 14.4 13.6 14.9 15.4 10/15 16.8 8 16.9 16.8 16.9 16.9 16.0 17.2 14.2 10/22 6.4 7.9 7.7 8.2 11.2 10.1 12.2 11.7 10/30 14.1 11.5 14.7 12.0 11/4 16.5 16.8 17.5 16.7 17.0 12.0 16.5 12.1 11/19 6.5 7.0 7.0 6.6 8.7 7.7 9.8 9.3 12/3 4.3 3.9 3.5 4.1 3.9 4.5 4.3 5.3 12/27 3.8 3.5 3.0 4.0 44.6 7.6 4.6 6.6 1/21/75 0.0 < 0 < 0 0.0 0.5 7.2 1.2 6.6 2/4 0.0 < 0 0.8 1.1 6.3 1.5 6.5 2/8 1.0 1.0 3.0 7.2 2/18 3.2 4.2 5.1 3.5 3.0 2.1 5.5 7.8 3/4 3.5 4.0 4.9 5.4 5.2 4.5 9.0 3/18 5.3 5.9 5.6 5.6 6.0 5.0 5.9 8.1 4/1 5.7 5.9 8.1 6.7 7.7 6.5 7.8 8.2 4/22 8.9 9.0 8.5 9.7 10.4 9.8 9.8 8.4 5/15 20.3 9.0 5/25 22.0 16.8 1.130 Table 1. Continued. U 0~~~ 6/20/7~4 2 .2 2 022 2314 2 4.1 2 4.02. 7/9~~ 27. 27. 28 . 274 29.1 0~~~~~~0 8/27 2~4 . 2 .24. 1 243 2.254-23. 9/0 �rl~ ~ ~ ~ U 0, 11/j o c o4 4-'~~~~~~ 0 1/970) .0 7364.75 06. 6/20/74 23.0 22.0 23.2 23.1 24.1 24.0 24.0 7/3 24.4 24.5 25.0 24.8 25.0 24.5 25.7 7/9 27.7 27.5 28.2 27.4 29.1 7/17 8/1 27.0 25.0 26.1 26.5 26.0 27.0 25.1 8/13 8/27 24.1 23.7 24.1 24.3 25.0 25.4 23.8 9/10 9/25 16.2 14.5 16.2 16.2 18.3 17.7 16.0 10/8 10/15 10/22 8.1 8.3 9.0 8.0 9.9 10.5 7.5 10/30 11/4 11/19 7.0 8.0 7.3 6.4 4.7 5.0 6.0 12/3 12/27 4.0 3.0 3.5 3.7 4.6 4.0 6.1 1/21/75 < 0 < 0 0.0 < 0 0.5 1.0 1.0 2/4 2/8 1.5 1.7 3.1 2.8 4.1 2/18 4.5 5.5 4.0 3.2 5.0 3.0 6.0 3/4 3/ 18 5.7 5.2 5.7 5.2 6.1 5.9 6.7 4/1 4/22 9.2 7.9 10.0 9.8 11.0 11.0 11.0 5/15 5/25 (from June 1975 Annual Report) 1.131 Table 2. Surface salinity (O/oo), except where noted, from June 1974 to May 1975. To 6/20/74 26.40 24.10 22.91 24.95 24.50 24.50 25.00 7/3 24.44 22.30 20.55 23.88 24.47 25.18 24.02 24.90 8/27 23.40 20.59 18.95 21.30 21.35 26 .00 20.88 24.81 9/10 23.49 19.60 16.41 22.58 23.19 24.20 22.29 24.90 9/25 24.34 C24.60 24.09 23.46 23.43 23.60 22.10 24.94 10/8 24.98 23.99 23.20 24.49 24.50 24.71 23.25 24.99 6/20/74 26.40 24.10 22.91 24.95 24.50 26.30 24.50 25.00 7/3 24.44 22.30 20.55 23.88 24.47 25.18 24.02 24.90 7/9 24.33 23.75 24.50 25.19 23.80 25.34 7/17 24.95 24.42 23.86 23.74 23.63 24.64 23.21 25.13 8/1 26.39 24.79 24.57 25.32 25.35 25.11 23.90 25.02 8/13 25.80 24.60 22.28 25.39 26.34 26.42 24.99 25.10 8/27 23.40 20.59 18.95 21.30 21.35 26.00 20.88 24.81 9/10 23.49 19.60 16.41 22.58 23.19 24.20 22.29 24.90 9/25 24.34 24.60 24.09 23.46 23.43 23.60 22.10 24.94 10/8 24.98 23.99 23.20 24.49 24.46 24.71 23.25 24.99 10/22 25.52 23.57 21.99 24.93 24.93 24.53 23.62 24.60 10/30 24.56 24.65 23.77 23.94 11/4 25.31 25.143 17.99 21.763 9 24.41 24.63 23.84 24.6154 11/19 25.559 4 18.87 12.95 21.62 21.95 22.34 20.18 24.316 12/3 25.88 22.70 21.18 26.00 25.69 24.32 12/272 23.86 2.9856 21.86 23.07 22.46 22.98 23.15 24.83 1/21/75 21.03 18.61 15.75 20.30 20.38 23.77 19.68 24.84 2/4 22.35 19.58 20.8 0 20.77 24.15 20.0 24.6984 2/18 21.00 21.21 17.20 20.34 20.46 24.09 19.88 24.70 3/4 23.72 20.58 22.55 22.90 22.92 19.84 24.60 3/18 23.28 21.43 17.99 21.76 21.91 22.94 21.43 24.54 4/1 22.94 18.87 12.95 21.62 21.95 22.34 20.18 24.36 4/22 23.26 21.98 18.21 22.63 22.08 22.25 20.37 24.30 5/15 14.76 10.81 18.01 24.69 1.132 Table 2. Continued. o 0 6/20/74 26.01 21.24 24.09 12.60 1.79 7/3 24.2 18.21 22.5o 11.90 16.67 0.91 7/9 23.59 23.81 9.82 15.4 2 1.20 'IO 00 .o -oo 6/20/74 26.01 21.24 24.09 12.60 1.79 7/3 24.20 18.21 22.50 11.90 16.67 0.91 7/9 23.59 23.81 9.82 15.42 1.20 7/17 8/1 27.09 22.60 25.57 25.81 11.10 20.07 2.72 12.32 8/13 8/27 24.29 12.72 20.35 20.87 9.31 13.40 1.59 9/10 9/25 26.08 20.19 23.09 23.08 12.99 18.82 2.17 12.38 10/8 10/22 23.55 14.14 15.83 23.67 7.47 18.63 1.31 14.13 10/30 11/4 11/19 25.74 17.71 15.55 23.70 8.11 17.78 3.47 12/3 12/27 25.65 23.56 22.44 14.29 20.81 6.14 1/21/75 20.91 9.16 12.11 20.05 4.28 16.87 0.52 2/4 2/18 22.70 13.35 12.94 20.27 4.86 17.90 3/4 3/18 20.35 11.75 12.63 20.68 6.26 16.52 1.11 4/1 4/22 24.78 16.89 17.49 21.27 9.15 15.70 1.00 5/15 (from June 1975 Annual Report) 1.133 Table 3. Surface dissolved oxygen (ml 02-1-1), except where noted, from June 1974 to May 1975. 7 P A 4.7 4 41 04 7/17 4 .79 4.32 3.61 4.59 4.0 0 4! N h h oco co D; 6/20/74 4.91 4.07 2.78 4.77 5.17 0.10 5.40 0.00 7/3 4.75 4.16 2.08 5.30 6.30 0.00 6.44 0.00 7/9 4.75 4.38 7.26 0.00 6.16 0.00 7/17 4.79 4.32 3.61 4.59 4.09 0.00 4.92 0.00 8/1 4.35 3.96 1.69 4.35 4.97 0.00 5.45 0.00 8/13 5.21 3.90 2.79 4.51 5.41 0.00 5.74 0.00 8/27 4.30 4.04 3.28 4.36 5.82 0.00 5.88 0.00 9/10 5.70 2.53 0.81 5.61 6.35 0.00 6.29 0.00 9/25 6.29 5.11 4.64 5.17 4.12 2.65 4.89 0.00 10/8 6.15 6.60 6.28 6.05 6.34 4.68 5.07 0.00 10/22 7.06 7.24 6.28 7.04 6.09 6.25 5.56 0.00 10/30 6.50 5.67 7.38 3.63 11/4 5.62 5.62 5.91 5.65 6.15 3.05 6.23 0.00 11/19 7.13 7.25 6.78 6.91 6.58 6.31 5.28 0.41 12/3 6.72 5.32 5.00 6.50 7.32 7.80 12/27 7.74 7.68 7.48 7.68 7.49 0.14 7.48 0.93 1/21/75 8.38 7.88 7.01 8.06 7.95 1.94 7.81 0.00 2/4 8.51 8.22 8.07 7.74 0.00 7.18 0.00 2/18 8.43 7.85 6.49 8.31 8.24 0.00 7.88 0.00 3/4 7.80 7.82 7.67 7.49 7.53 7.73 0.00 3/18 7.53 7.55 6.60 7.54 7.86 7.59 7.49 0.00 4/1 7.46 7.21 3.94 7.41 7.39 6.08 7.46 0.00 4/22 6.69 6.34 4.86 6.40 6.28 3.95 6.27 0.00 5/15 5.17 0.00 1.134 Table 3. Continued. U I 0 UU sq 4 o 0 0 0) Y 0 4P 4-) qj (oo . ,-. C C) H4 P0 00 0 CO 6/20/74 4.55 2.34 4.55 5.04 5.72 7/3 4.32 1.74 4.88 5.53 4.18 5.65 7/9 5.02 3.66 6.71 4.56 5.51 7.20 7/17 8/1 3.94 1.45 3.87 3.86 5.66 3.23 5.94 8/13 8/27 4.33 2.53 4.38 4.04 5.40 3.95 5.35 9/10 9/25 5.25 4.05 5.58 5.48 4.96 4.42 6.35 3.71 10/8 10/22 7.41 4.81 6.71 6.90 7.18 5.84 7.64 5.86 10/30 11/4 11/19 7.45 5.13 6.73 6.76 7.34 5.96 7.38 12/3 12/27 7.47 7.68 7.75 7.82 8.61 7.68 8.46 1/21/75 8.16 6.08 8.08 8.18 7.88 7.68 8.38 2/4 2/18 7.89 5.79 7.96 8.09 7.48 8.10 7.62 3/4 3/18 7.00 6.03 7.40 7.22 7.41 7.15 7.50 4/1 4/22 6.04 5.35 6.62 6.48 6.78 6.44 6.83 5/15 (from June 1975 Annual Report) 1.135 Table 4. Secchi disc measurements (m) from June 1974 to May 1975. o X3 44 � j C~ d> ,1 4 X- 0 . a; P< aJ a) *H 6/20/7 4 0.7 0.3 0.4 0.5 0.6 0.3 0.2 0.4 0.4 0.6 0.7 7/3 0.8 0.8 >0.3 0.6 0.7 0.7 0.7 0.7 0.7 0.9 1.0 7/9 0.7 0.7 0.6 0.7 0.5 0.9 0.6 7/17 0.7 0.8 >0.6 0.6 0.7 0.6 8/1 0.7 0.7 0.6 0.6 0.7 0.7 0.9 0.8 0.7 0.8 0.8 8/13 0.7 0.6 >0.4 0.6 0.7 0.6 8/27 1.1 0.2 0.4 0.5 0.5 0.6 0.5 0.4 0.5 0.7 0.6 9/10 0.9 >0. >0.5 0.8 0.9 0.8 9/25 1.4 0.9 >0.6 0.9 0.8 0.8 0.6 0.8 0.9 1.2 1.2 10/8 1.1 0.9 >0.9 0.9 1.1 0.8 10/15 1.7 0.7 >0.6 0.9 1.2 0.9 10/22 1.0 >0.5 >0.5 1.0 0.8 0.6 0.9 0.5 0.7 0.9 0.9 10/30 1.2 0.9 11/4 2.4 0.8 1.7 1.6 1.1 11/19 2.5 1.2 >0.5 1.8 1.2 1.1 >1.0 0.5 1.8 1.3 0.9 12/3 0.2 0.5 0.4 0.5 1.0 1.0 12/27 0.3 0.2 0.6 1.0 1.7 1.5 0.5 0.6 0.6 1.0 0.8 1/21/75 0.5 0.5 0.5 0.6 0.9 1.4 0.4 0.4 0.7 0.8 0.8 2/4 0.9 0.6 1.0 0.9 1.3 2/8 0.9 1.1 1.2 1.2 1.3 2/18 1.4 0.9 0.9 1.1 1.1 1.4 0.6 0.7 1.3 1.3 3/4 1.0 0.3 1.3 1.4 1.5 3/18 1.0 0.7 0.7 0.8 1.2 1.5 0.2 0.3 0.9 0.9 0.9 4/1 1.6 0.2 0.3 1.4 1.3 1.3 4/22 1.5 1.1 0.8 1.3 1.0 1.2 0.6 0.3 1.2 1.0 1.0 5/15 0.9 0.3 1.0 (from June 1975 Annual Report) 1.136 Table 5. Vertical distribution of temperature (OC), salinity (0/oo), and dissolved oxygen (ml 02-1-1) at A08 and B24. Depth Lagoon A08 Lagoon B24 Date (m) (�C) (O/oo) (ml 02.1-1) (OC) (0/00) (ml 02-1-1) 9/10/74 0.5 22.2 23.19 6.35 23.0 22.29 6.29 1.0 22.2 23.22 5.85 22.8 22.39 6.15 2.0 21.6 23.60 4.95 22.0 22.48 4.58 3.0 21.2 23.75 1.87 22.0 23.11 0.00 4.0 21.2 24.20 0.00 20.6 24.60 0.00 5.0 17.8 24.64 0.00 6.0 15.0 24.90 0.00 7.0 13.5 10/8 0.5 14.4 24.50 6.34 14.9 23.25 5.07 1.0 14.4 24.60 6.28 15.0 23.45 4.42 2.0 14.4 24.58 6.00 15.1 23.70 3.28 3.0 14.1 24.60 5.21 15.5 23.71 3.16 4.0 13.7 24.71 4.68 15.6 24.33 0.00 5.0 13.6 16.3 24.92 0.00 6.0 15.4 24.99 0.00 10/30 0.5 14.1 24.56 6.50 14.7 23.77 7.38 1.0 13.6 24.39 6.64 13.0 23.79 7.49 2.0 13.3 24.47 6.70 12.3 24.12 5.12 3.0 12.2 24.62 6.64 12.1 24.03 4.99 4.0 11.5 24.65 5.67 12.1 24.12 5.34 5.0 12.0 24.04 5.34 6.0 12.0 23.94 3.63 11/4 0.5 17.0 24.41 6.15 16.5 23.84 6.23 1.0 16.2 24.24 6.10 16.2 23.85 6.29 2.0 16.1 24.32 5.88 15.4 23.91 6.24 3.0 13.2 24.43 5.28 12.3 24.04 4.64 4.0 12.1 24.63 3.05 12.2 24.02 2.91 5.0 12.0 12.2 24.14 2.24 6.0 12.0 23.99 1.58 7.0 12.0 24.61 0.00 8.0 12.1 12/27 0.5 4.6 23.46 7.49 4.6 23.15 7.48 1.0 4.6 23.42 7.54 4.6 23.03 7.55 2.0 4.6 23.40 7.48 5.1 23.42 7.08 3.0 5.8 24.85 4.87 6.4 24.40 2.96 4.0 6.7 25.98 0.14 6.6 24.65 2.01 5.0 7.1 6.7 24.75 1.25 6.0 7.6 6.7 24.83 0.93 7.0 6.6 8.0 6.6 1.137 Table 5. Continued. Depth Lagoon A08 Lagoon B24 Date (m) (�C) (O/oo) (ml 02-1-1) (�C) (O/oo) (ml 09.1-1) 1/21/75 0.5 0.5 20.38 7.95 1.2 19.68 7.81 1.0 0.6 20.43 7.84 2.0 20.81 7.34 2.0 2.0 21.54 7.25 4.2 22.09 6.55 3.0 2.8 21.70 6.99 6.0 24.06 0.69 4.0 5.5 23.77 1.94 6.2 24.79 0.06 5.0 7.2 6.2 24.79 0.00 6.0 6.5 24.84 0.00 2/4 0.5 1.1 20.77 7.74 1.5 20.03 7.18 1.0 1.3 20.76 7.80 2.1 20.20 7.32 2.0 1.5 20.80 7.73 2.1 22.37 3.26 3.0 1.5 21.04 7.60 5.0 24.15 0.00 4.0 4.9 24.15 0.00 5.4 24.55 0.00 5.0 6.3 5.6 24.69 0.00 6.0 5.7 24.84 0.00 7.0 6.5 2/18 0.5 3.0 20.46 8.24 5.5 19.88 7.88 1.0 3.0 20.60 8.20 3.2 20.10 7.81 2.0 2.0 20.95 7.94 2.8 20.28 7.75 3.0 1.0 21.10 7.88 5.0 23.49 0.00 4.0 2.1 24.09 0.00 7.7 24.27 0.00 5.0 7.8 24.55 0.00 6.0 7.8 24.70 0.00 7.0 7.8 8.0 7.8 3/4 0.5 5.4 22.90 7.49 4.5 19.84 7.73 1.0 5.3 22.85 7.53 4.3 19.88 7.75 2.0 5.2 22.82 7.47 6.0 20.77 7.23 3.0 5.2 22.92 7.53 8.2 23.25 0.20 4.0 5.2 8.9 24.14 0.00 5.0 9.0 24.39 0.00 6.0 9.1 24.60 0.00 7.0 9.0 8.0 9.0 3/18 0.5 6.0 21.91 7.86 5.9 21.43 7.49 1.0 5.9 21.97 7.96 5.9 21.51 7.48 2.0 5.9 22.00 7.22 5.9 22.49 7.47 3.0 5.5 22.94 7.59 6.0 21.61 7.05 4.0 5.0 6.1 23.84 0.19 5.0 7.6 24.01 0.00 6.0 8.0 24.54 0.00 7.0 8.1 1.138 Table 5. Continued. Depth Lagoon A08 Lagoon B24 Date (m) (Oc) (O/oo) (ml 02'-11)i (�C) (0/oo) (ml 02'1-1) 4/1/75 0.5 7.7 21.95 7.39 7.8 20.18 7.46 1.0 7.6 21.90 7.34 7.8 20.40 7.52 2.0 7.1 22.02 7.32 8.0 21.03 7.00 3.0 6.8 22.34 6.08 8.0 21.09 7.19 4.0 6.5 8.0 22.38 1.80 5.0 8.0 24.07 0.00 6.0 8.1 24.26 0.00 7.0 8.2 8.0 8.2 4/22 0.5 10.4 22.08 6.28 9.8 20.37 6.27 1.0 10.2 22.12 6.33 10.1 20.77 6.70 2.0 10.2 22.04 6.00 10.3 20.84 6.76 3.0 10.2 22.28 5.63 9.0 21.26 6.57 4.0 10.2 22.25 3.95 8.0 21.40 4.46 5.0 9.8 8.0 23.70 0.00 6.0 8.2 24.30 0.00 7.0 8.4 7.5 8.4 5/15 0.5 20.3 18.01 5.17 1.0 21.3 20.00 5.24 2.0 18.9 20.98 5.40 3.0 15.0 21.58 4.40 4.0 12.1 22.03 0.56 5.0 10.0 24.05 0.00 6.0 9.2 24.69 0.00 7.0 9.2 7.5 9.0 (from June 1975 Annual Report) 1.139 Table 6. Surface NH3-N (Pg-atom NH3-N-l-1), except where noted, for all stations from June 1974 to April 1975. co) 0 20/740 0 6/20/74 0.0.0 0.4 0.0 0.0 7.0 0.3 53.2 7/3 1.4 0.9 3.6 1.0 0.9 27.8 0.7 86.2 7/17 0.1 0.7 0.4 0.0 0.0 61.6 0.1 133.9 8/1 0.3 0.6 0.0 0.2 0.3 15.7 0.3 109.2 8/13 0.3 1.5 0.6 0.2 0.1 50.2 0.5 140.9 8/27 1.5 2.4 2.3 0.2 0.7 79.1 1.2 206.6 9/10 2.0 7.3 10.5 1.6 0.7 11.4 1.2 164.2 9/24 0.5 2.0 2.7 0.2 0.3 4.8 1.3 227.5 10/8 0.7 1.0 1.3 0.7 0.6 3.1 0.1 260.9 10/22 0.6 0.7 3.7 0.5 0.9 06.6 2.6 294.6 11/4 0.8 1.9 1.0 0.6 0.3 1.9 0.7 129.7 11/19 0.7 1.1 2.5 1.5 1.1 1.8 8,0 42.7 12/3 0.9 3.1 1.7 0.5 0.3 1.1 12/27 0.0 0.0 0.2 0.2 0.0 2.9 3.2 6.3 1/21/75 0.7 3.0 4.2 2.3 3.3 19.0 4.9 22.6 2/4 0.5 0. 7 0.6 0.5 66. 3 4.0 74.6 2/18 0.4 1.1 1.6 1.3 1.0 55.6 3.1 43.8 3/4 0.5 1.6 0.1 0.1 0.4 1.6 35.4 3/18 0.2 0.5 . 0.2 0.4 1.8 2.2 91.6 4/1 1.2 0.6 8.0 0.0 2 0.5 86.9 4/22 0.0 0.1 2.4 0.1 0.0 4.4 1.3 118.9 1.14 0 3/18 ~ ~ ~ ~ ~ ~ ~S 04J 0. 0JJ. . 18 22 9. 7/3 1.4 0.9 3.6 ~1.10 0.278 .762 Table 6. Continued. v 0 ,U h( 4J P L. -14 4- 6/2:474 0.0 1.7 0.4 0.) 0 7/3 0.7 Sk2 4.4 1.U ,fl C 0 4J 7 u~ AsH g g -40 o ~1 � P0 4.1 0. c o 6/20/74 0.0 1.7 0.0 0.0 0.0 7/3 0.7 5.2 0.4 1.0 2.3 2.1 7/17 8/1 3.6 1.9 0.4 0.6 0.5 1.9 0.6 8/13 8/27 2.3 11.3 2.1 4.2 0.6 5.2 1.5 9/10 9/24 5.9 5.8 0.5 0.2 3.3 5.7 1.4 10/8 10/22 0.8 5.4 5.0 1.6 8.3 4.9 4.2 11/4 11/19 0.9 16.7 6.8 2.4 12.1 6.2 7.7 12/3 12/27 0.1 1.6 0.6 0.4 0.0 3.5 2.5 1/21/75 3.6 5.6 - 5.8 1.5 6.6 3.8 4.5 2/4 2/18 0.3 2.7 8.8 0.9 9.8 4.4 8.0 3/4 3/18 0.5 2.7 7.5 1.9 10.9 6.7 5.7 4/1 4/22 3.0 10.2 3.2 0.9 17.2 5.3 5.5 (from June 1975 Annual Report) 1.141 Table 7. Surface N02-N (jig-atom N02-N-1-1), except where noted, for all sta- tions from June 1974 to April 1975. U30 0 0 W Pq ~~~~~0 0q 6/20/74 0.1 0.1 0.0 0.1 0.0 0.1 0.1 0.0 7/3 0.0 0.0 0.1 0.0 0.1 0.1 0.0 0.2 7/17 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 8/11 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 8/13 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 8/27 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 9/10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 9/24 0.1 0.1 0.2 0.0 0.1 0.0 0.0 1.1 10/8 0.1 0.1 0.1 0.3 0.0 0.0 0.0 0.3 10/22 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.5 11/4 0.1 0.0 0.1 0.2 0.2 0.0 0.0 0.2 11/19 0.0 0.1 0.0 0.0 0.0 0.0 0.2 0.4 12/3 0.0 0.0 0.0 0.0 0.0 0.0 12/27 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 1/21/75 0.3 0.0 0.0 0.1 0.2 0.1 0.5 0.0 2/4 0.1 0.0 0.2 0.2 0.0 0.4 0.0 2/18 0.0 0.2 0.1 0.0 3/4 0.0 0.0 0.0 0.0 0.0 0.1 0.1 3/18 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 4/1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.142 Table 7. Continued. 0 0 4.J ~~~~L', 4-j 4J 0)~~~~~ ~~~4 ~ 4 4 0 0)~~~~~~~~~~~~~~~0 00)0 6/20/74 0.1 0.0 0.0 0.2 0.0 0.0 7/3 0.0 0.1 0.0 0.1 0.0 7 /17 8/1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 8 /13 8/27 0.0 0.0 0.0 0.0 0.0 0.0 0.0 9 /10 9/24 0.6 0.2 0.0 0.0 0.0 0.0 0.0 10 /8 10/22 0.2 0.0 0.0 0.0 0.0 0.0 0.0 11/4 11/19 0.0 0.0 0.0 0.0 0.1 0.1 0.0 12/3 12/27 0.0 0.0 0.0 0.0 0.3 0.0 0.0 1/21/75 0.4 0.0 0.0 0.1 0.0 0.1 0.0 2/4 2/18 0.1 0.1 0.1 0.1 0.0 3/4 3/18 0.0 0.0 0.1 0.0 0.0 0.0 0.0 4/1 (from June 1975 Annual Report) 1.143 Table 8. Surface N03-N (pg-atom N03-N-1-1), except where noted, for all stations from June 1974 to May 1975. 4-i 0 a 0. U U u u 4c c co 6/20/74 0.7 1.0 0.9 1.0 0.6 1.0 1.0 0.1 7/3 0.2 0.5 0.0 0.3 0.5 0.6 1.0 0.0 7/17 0.4 0.8 0.7 1.3 0.0 1.0 0.2 1.9 8/1 0.5 1.0 1.1 0.5 0.7 0.3 0.9 0.0 8/13 0.7 0.9 0.4 0.8 0.5 0.1 0.7 0.2 8/27 0.6 1.7 1.3 0.9 0.7 0.0 1.2 0.4 9/10 0.8 0.3 0.0 0.2 0.1 0.2 0.5 0.2 9/24 0.3 1.1 0.9 0.5 1.3 0.7 0.7 1.1 10/8 0.3 0.2 0.4 0.2 0.3 0.3 0.4 0.3 10/22 0.4 0.5 0.7 0.3 0.4 0.3 1.9 0.5 11/4 0.6 0.9 0.5 0.3 0.5 0.4 0.4 0.2 11/19 0.2 0.4 0.3 0.3 0.2 0.0 1.4 0.4 12/3 0.1 0.4 0.6 0.3 0.1 0.1 12/27 0.2 0.2 0.3 0.3 0.2 0.7 1.2 0.4 1/21/75 1.2 1.8 1.6 1.7 1.8 0.7 5.1 0.3 2/4 0.3 0.4 1.6 0.8 0.4 4.8 0.0 2/18 0.1 0.6 0.5 0.5 3/4 0.6 0.7 0.5 0.5 0.4 3.1 0.4 3/18 0.6 0.4 0.6 0.5 0.5 0.5 1.5 0.4 4/1 0.5 0.7 0.2 0.5 0.5 0.4 0.5 0.5 1.144 Table 8. Continued. o LI o *H 594 L4 0 U.,0 - J ~ m a� o o 4$a O A.S g4 4J 03 c a ~ ~ o -, Po o o 6/20/74 1.1 0.7 0.9 0.8 2.9 7/3 0.5 0.0 0.3 0.7 0.3 3.0 7/17 8/1 0.4 0.4 0.7 1.0 0.7 0.8 0.9 8/13 8/27 0.9 2.2 1.1 0.9 0.3 1.0 5.3 9/10 9/24 1.7 1.6 0.8 1.2 3.5 1.6 4.3 10/8 10/22 0.4 1.0 3.4 0.7 10.1 2..7 5.7 11/4 11/19 0.4 0.9 1.6 0.5 3.7 0.9 5.5 12/3 12/27 0.1 0.2 0.1 0.1 2.1 0.7 4.4 1/21/75 2.2 2.7 4.3 1.6 6.3 2.6 5.9 2/4 2/18 4.2 0.9 7.1 1.0 7.5 3/4 3/18 0.7 0.9 3.8 0.9 5.4 2.5 6.4 4/1 (from June 1975 Annual Report) 1.145 Table 9. Surface total organic nitrogen (hg-atom Org-N-l-1), except where noted, for all stations from June 1974 to May 1975. S 0 0 0 M Pco Co co -o 6/20/74 51.8 71.1 64.8 85.2 65.3 45.4 69.1 89.4 7/3 69.8 60.4 62.4 65.5 82.1 94.3 61.6 94.4 7/17 70.7 72.7 104.6 92.6 97.5 50.2 99.2 31.6 8/1 57.1 64.6 77.1 76.6 108.2 76.4 108.9 8/13 69.3 69.4 68.1 79.1 64.5 137.8 70.7 91.7 8/27 44.4 79.6 80.3 70.3 63.7 26.0 72.8 35.4 9/10 32.4 60.9 32.6 50.4 65.0 75.7 52.1 9/24 29.7 25.5 25.4 34.3 38.2 39.7 43.8 10/8 27.9 31.7 27.1 28.8 42.1 33.3 47.6 10/22 30.0 15.1 25.0 24.3 25.9 35.8 44.2 11/4 19.1 21.9 23.8 23.7 30.3 10.2 27.8 120.7 11/19 27.5 21.0 17.9 21.5 24.1 25.8 27.1 12/3 34.5 22.6 26.9 32.4 21.9 29.0 12/27 37.8 38.2 34.2 24.3 20.0 24.3 38.4 33.1 1/21/75 33.1 38.2 39.5 27.2 28.9 24.4 28.8 38.5 2/4 31.6 38.8 40.0 35.3 30.7 33.5 13.4 2/18 34.3 35.3 26.1 39.3 28.1 42.2 26.2 32.5 3/4 25.4 34.0 23.4 30.9 30.5 18.1 52.4 3/18 26.9 38.2 33.7 21.8 24.4 34.4 25.7 14.9 4/1 93.8 49.7 31.1 9.1 31.8 56.0 4/22 31.4 35.5 59.4 44.3 51.6 48.0 37.8 87.6 1.146 Table 9. Continued. �0 ; l 2 o 0 r o . 4 4j a) - c o 1o 4- ; U D A X X X 6/20/74 63.9 62.0 61.9 52.8 40.5 7/3 61.2 64.6 73.1 60.1 77.4 16.5 7/17 8/1 58.8 84.6 70.8 65.9 47.0 29.6 8/13 8/27 41.6 72.9 63.2 60.7 48.3 48.8 9/10 9/24 29.0 26.2 30.4 4.0 28.9 2.8 13.6 10/8 10/22 17.0 34.3 29.9 27.2 14.5 33.8 10.5 11/4 11/19 16.6 19.2 18.4 19.9 6.9 39.7 23.1 12/3 12/27 34.9 30.8 33.5 37.2 22.1 19.9 30.0 1/21/75 36.7 43.6 27.9 27.3 21.6 26.5 13.7 2/4 2/18 24.0 37.2 25.7 40.0 20.7 37.1 23.9 3/4 3/18 42.0 30.8 11.8 22.2 13.5 10.3 18.7 4/1 4/22 44.9 69.4 38.7 38.1 35.9 30.6 17.4 (from June 1975 Annual Report) 1.147 Table 10. Vertical distribution of NH3-N, N02-N, and N03-N in (vg-atom.1-1) A08 and B24. Lagoon A08 Lagoon B24 Date Depth NH3-N N02-N N03-N NH3-N N02-N N03-N 9/10/74 0.5 0.7 1.2 1.0 1.2 2.0 3.4 1.5 3.0 1.7 4.7 4.0 11.4 40.8 5.0 6.0 164.2 10/8 0.5 0.6 0.0 0.3 0.1 0.0 0.4 1.0 1.2 0.0 0.3 0.7 0.0 0.3 2.0 0.7 0.0 0.2 5.0 0.0 0.4 3.0 0.6 0.0 0.2 7.0 0.0 0.3 4.0 3.1 0.0 0.3 46.7 0.0 0.1 5.0 194.1 0.0 0.0 6.0 260.9 0.1 0.3 10/30 0.5 0.6 0.1 0.3 1.1 0.1 0.2 1.0 0.7 0.1 0.3 0.8 1.7 0.9 2.0 0.7 0.2 0.4 0.7 0.1 0.2 3.0 0.7 0.2 0.3 0.7 0.2 0.2 4.0 0.7 0.1 0.5 0.6 0.2 0.2 5.0 0.8 0.1 0.3 6.0 5.6 0.2 0.2 11/4 0.5 0.3 0.2 0.5 0.7 0.0 0.4 1.0 0.4 0.1 0.4 0.7 0.0 0.4 2.0 0.7 0.0 0.4 0.7 0.0 0.4 3.0 0.5 0.0 0.5. 1.0 0.0 0.4 4.0 1.9 0.0 0.4 1.1 0.0 0.5 5.0 7.2 0.0 0.5 6.0 9.0 0.0 0.3 7.0 129.7 0.0 0.2 12/27 0.5 0.0 0.0 0.2 3.2 0.1 1.2 1.0 0.0 0.0 0.3 2.5 0.0 1.1 2.0 0.0 0.0 0.2 0.4 0.0 0.7 3.0 0.0 0.0 0.1 2.6 0.1 0.6 4.0 2.9 0.1 0.7 2.0 0.0 0.5 5.0 5.4 0.0 0.4 6.0 6.3 0.0 0.4 1.148 Table 10. Continued. Lagoon A08 Lagoon B24 Date Depth NH3-N N02-N N03-N NH3-N N02-N N03-N 1/21/75 0.5 3.3 0.2 1.8 4.9 0.5 5.1 1.0 3.9 0.1 1.9 5.9 0.3 3.8 2.0 3.1 0.3 1.1 3.5 0.3 3.0 3.0 4.3 0.1 1.3 15.0 0.0 0.5 4.0 19.0 0.1 0.7 14.5 0.0 0.3 5.0 24.3 0.0 0.3 6.0 22.6 0.0 0.3 2/4 0.5 0.5 0.2 0.8 4.0 0.4 4.8 1.0 0.3 0.1 0.8 3.0 0.5 4.4 2.0 0.3 0.1 0.9 2.6 0.2 2.5 3.0 1.2 0.0 0.6 3.8 0.0 0.1 4.0 66.3 0.0 0.4 5.3 0.0 0.1 5.0 72.7 0.0 0.0 6.0 74.6 0.0 0.0 2/18 0.5 1.0 0.1 0.5 3.1 1.0 1.4 0.1 0.3 3.5 2.0 1.4 0.1 0.4 2.6 3.0 2.0 0.0 0.5 28.5 4.0 55.6 30.4 5.0 37.5 6.0 45.8 3/4 0.5 0.1 0.0 0.5 1.6 0.1 3.1 1.0 0.0 0.0 0.5 1.5 0.2 2.9 2.0 0.1 0.1 0.6 -2.2 0.1 1.6 3.0 0.4 0.0 0.4 25.5 0.0 0.5 4.0 1.6 20.9 0.0 0.5 5.0 28.5 0.0 0.4 6.0 35.4 0.1 0.4 4/1/75 0.5 0.2 0.0 0.5 0.5 0.0 0.5 1.0 0.0 0.0 0.4 0.0 0.0 0.4 2.0 0.1 0.0 0.3 0.1 0.0 0.4 3.0 0.0 0.0 0.4 0.2 0.0 0.4 4.0 25.8 0.0 0.6 5.0 57.9 0.0 0.3 6.0 86.9 0.0 0.5 (from June 1975 Annual Report) 1.149 Table 11. Acetylene reduction (P1 C2H4-min-1-m-2) by algae and associated sub- strate. Lagoon o) Meyers system System A o Ov Xd ko a) 11/30/74 7.0 0.5 153.6 151.5 13.1 4.3 1.1 Y = 0.50* Y = 64.72 12/21/74 5.2 4.4 18.4 0.1 7.7 0.5 Y = 2.25 Y= 8.87 1/14/74 -1.5 0.7 108.1 0.0 52.0 4.6 4.5 Y = 0.35 Y = 42.30 2/15/75 7.8 1.5 0.0 15.8 0.3 0.4 0.0 0.0 0.0 Y = 0.60 Y= 0.0 Y= 4.05 3/1/75 7.2 19.7 3.8 0.7 0.1 0.0 0.0 Y = 4.05 1.150 Table 11. Continued. ~- ULagoon g o Meyers system System A 4J Q) 0) O4-J Y-J UCB -4 3/8/75 7.0 0.3 0.2 0.0 0.0 0.0 Y = 0.10 3/25/75 15.7 532.9 336.4 248.4 Y - 372.57 4/12/75 9.5 7.1 (0.8)# 18.8 (0.1) 365.9 0.0 (0.4) 92.5 0.0 (0.2) 56.0 41.8 40.5 5.5 Y 2.37 (0.47) Y = 18.80 (0.10) Y 100.37 4/26/75 18.5 12.2 (5.6) 7.9 (2.7) 4.7 (0.9) Y - 8.26 (3.07) 5/25/75 16.0 26.6 134.5 24.0 69.6 46.3 1.0 (0.5) 35.4 Y = 1.00 (0.5) Y = 25.30 Y = 71.45 * Y indicates the mean of the values for that date. # The parentheses indicate the substrate acetylene reduction value associated with the adjacent algal value. (from June 1975 Annuat Report) 1.151 Table 12. Acetylene reduction rate (P1 C2H4'min-l.m-2) in substrate samples. Vegetation zone Incubation Date or location temperature (OC) Rate Marsh surface soil subsamples: 9/28/74 S. patens 25.5 0.9* DistichZis sp. 4.2* S. alterniflora 0.3* 1/24/75 S. aZternifZora 7.8 0.0 tall form 0.2 S. alternifZora 0.0 short form 0.6 S. patens 0.0 0.0 Distichlis sp. 0.3 0.0 3/1/75 Nonvegetated 7.2 12.7 mudflat 3/8/75 S. alternifZora 7.0 0.9 short form 4/26/75 S. patens 18.5 0.3 0.0 1.152 Table 12. Continued. Vegetation zone Incubation Date or location temperature (OC) Rate Benthic sediment samples: 2/9/75 Lower third 2.8 0.1 Meyers system Mid third 0.0 Meyers system Upper third 0.2 Meyers system Lower third 0.5 Lagoon System A Mid third 0.0 Lagoon System A Upper third 0.0 Lagoon System A 3/25/75 Lower third 11.3 0.0* Meyers system Mid third 0.3* Meyers system Upper third 0.1* Meyers system Lower third 0.2* Lagoon System A Mid third 0.2* Lagoon System A Upper third 0.1* Lagoon System A *Assumed sample area of 6.25 cm2 with negative values assumed to be 0. (from June 1975 Annual Report) 1.153 Table 13. Acetylene reduction rate (P1 CH4.min'l-1-1) in the water column. Incubation Date Location Depth (m) temperature (�C) Rate 8/8/74 Meyers Pond surface 26.0 0.0 10/12/74 Upper Meyers surface 18.5 0.0258 Creek Pool 10/27/74 B24 1.0 11.2 0.0051 3.0 11.1 0.0036 5.0 11.1 0.0133 12/21/74 A08 1.0 5.2 0.0 3.0 5.2 0.0028 Table 14. Invertebrate excretion of inorganic ammonia. Average value per sam- pling date is indicated. Zooplankton Ilyanassa obsoleta Modiolus sp. (jg-atom (jg-atom (ig-atom NH3-N.m-3.24 h-l) NH3-N-org-l124 h-1) NH3-N-org-l124 h-1) Meyers Lagoon Meyers Lagoon Meyers Date system system system system system 10/19/74 1.6 0.0 0.43 3.4 11/16/74 0.3 1.5 0.44 9.2 12/14/74 1.7 0.9 0.90 1.2 7.3 4/19/75 28.1 75.4 1.40 1.3 5.2 (from June 1975 Annual Report) 1.154 Table 15. Surface particulate oxidizable carbon (mg.m-3), except where noted, for all stations from June 1974 to April 1975. GO 4. 4O) 0 0 6/20/74 3,788 7,979 3,512 4,494 7,704 3,531 5,044 3,820 7/17 3,105 4,005 3,948 4,106 4,950 4,158 4,786 1,575 8/1 2,571 4,415 3,497 5,231 5,426 4,651 5,275 757 8/13 4,128 3,784 3,784 5,332 3,937 6,433 5,663 1,514 9/24 1,803 2,093 1,674 3,459 2,834 2,640 2,981 2,061 11/19 1,170 1,650 1,590 1,560 2,100 1,650 1,800 1,680 12/3 3,430 3,262 4,167 2,596 2,441 4,450 12/27 5,314 6,000 4,286 2,580 2,040 2,520 3,180 1,890 1/21/75 3,617 2,303 2,170 2,524 1,488 1,963 1,860 1,705 2/4 2,201 1,976 2,480 2,077 3,035 1,684 3,410 2/18 1,581 1,581 1,612 2,139 1,178 2,635 1,891 2,914 3/4 1,469 3,940 1,683 1,928 1,928 1,346 1,836 4/1 6,219 2,794 2,387 1,744 2,387 2,387 1.155 Table 15. Continued. c o *r44 04 U 4 a) O rlS 4-3 0 a)) 0 0 o cU *H A z Qo �4 0 c 6/20/74 7,704 3,072 5,200 3,264 1,086 7/17 8/1 860 3,096 3,727 4,243 2,339 3,876 1,564 8/13 9/24 4,186 1,771 2,576 2,290 2,397 2,157 926 11/19 1,410 2,250 1,800 1,710 1,530 3,960 900 12/3 12/27 5,150 2,700 3,600 3,480 2,400 2,880 2,820 1/21/75 3,978 2,303 1,594 2,945 974 2,170 531 2/4 2/18 1,488 1,333 1,612 3,333 1,054 1,798 217 3/4 4/1 (from June 1975 Annual Report) 1.156 Table 16. Surface chlorophyll a (mg.m-2), except where noted, from June 1974 to April 1975. 4__ 0n o c0 o 0 o 6/20/74 10.6 12.7 15.9 16.7 14.0 25.5 10.7 11.9 7/3 14.5 21.2 19.2 20.7 18.6 20.2 14.0 15.4 7/17 12.5 28.9 11.8 24.9 25.6 23.2 22.1 13.3 8/1 15.5 19.0 21.4 24.8 22.5 22.4 16.5 13.4 8/13 14.5 16.2 10.6 20.1 17.2 18.0 20.3 12.6 8/27 10.0 27.4 27.0 22.6 23.9 21.4 25.4 10.1 9/10 14.3 14.0 8.7 16.9 15.8 23.1 18.7 15.2 9/25 3.9 8.5 6.2 10.8 20.8 11.9 16.6 10.9 10/8 3.7 5.7 6.6 6.2 9.1 11.0 18.0 11.0 10/22 4.4 4.5 4.0 4.3 9.5 ll.2 30.1 9.5 10/370 . 0 7.8 13.6 22.0 11/4 2 .1 5.2 6.9 3.9 4.9 625.5 10.7 11. 1 1/519 2.3 2.8 2.1 322.4 16.5 5.8 5.8 9.5 7.5 12/3 9.1 3.9 5.2 5.9 8.7 11.9 12327 13.9 15.5 9.7 20.1 17.2 4.9 4.0 4.7 4.7 1/21/75 8.2 6.7 5.0 5.8 3.5 2.4 4.8 0.6 2/4 6.2 5.6 7.3 8.8 2.9 5.2 1.0 2/18 3.9 4.1 2.6 3.5 3.4 2.6 4.0 0.9 3/4 3.2 4.5 4.3 5 .3 7.0 1.3 5.7 3/18 3.1 6.0 3.4 4.7 5.8 5.8 9 .5 7 .5 4/1 1.3 10.5 3.42 4.9 4.0 4.5 5.2 4/22 3.4 4 4.4.4 4.6 7 .0 12.4 5 . 4/1 1.3 10.5 3.4 4.4 4.5 5.2 6.2 8.0 1.157 Table 16. Continued. o n4J 1:4 P4 4J 7/17 8/1 18.0 17.7 22.0 17.8 37.0 34.0 14.5 8/13 8/27 17.0 18.4 26.5 22.3 45.3 40.9 7.5 9/10 9/25 8.4 4.7 11.0 11.2 14.4 12.7 8.0 10/8 710/22 3.9 3.4 7.6 5.6 5.3 8.3 2.6 10/22 3.9 3.4 7.6 5.6 5.3 8.3 2.6 11/4 11/19 2.8 4.4 3.0 2.8 2.6 19.7 2.2 12/3 12/27 16.2 11.5 10.1 9.4 13.3 11.3 28.6 1/21/75 7.8 4.1 4.9 6.6 3.1 7.7 1.4 2/4 2/18 4.3 2.5 2.4 4.3 0.6 2.2 0.4 3/4 3/18 10.8 3.2 3.1 4.7 1.3 3.8 0.4 4/1 4/22 4.6 9.5 5.1 4.8 6.3 7.6 4.0 (from June 1975 Annual Report) 1.158 Table 17. Chlorophyll a (mg-m-3) and acid-factor ratio.* Lagoon vertical distribution from September 1974 to April 1975. Lagoon A08 Lagoon B24 Depth 665/ 665/ Date (m) Chl a 665a Chl a 665a 9/10/74 0.5 15.8 1.31 18.7 1.28 1.0 20.6 1.31 2.0 18.8 1.26 26.0 1.27 3.0 20.1 1.27 35.9 1.30 4.0 23.1 1.26 38.9 1.22 5.0 6.0 15.2 1.26 10/8 0.5 9.1 1.23 18.0 1.41 1.0 8.8 1.47 18.9 1.31 2.0 9.4 13.5 1.28 3.0 11.2 1.40 16.2 1.30 4.0 11.0 1.37 21.8 1.19 5.0 15.6 1.21 6.0 11.0 1.20 10/30 0.5 7.0 1.41 13.6 1.43 1.0 7.6 1.32 19.4 1.35 2.0 6.7 1.44 25.5 1.38 3.0 7.4 1.43 20.2 1.35 4.0 7.8 1.35 19.4 1.35 5.0 20.1 1.32 6.0 22.0 1.37 11/4 0.5 4.9 1.21 9.7 1.37 1.0 6.5 1.46 8.5 1.35 2.0 4.1 1.29 10.1 1.32 3.0 3.7 1.33 11.2 1.22 4.0 6.8 1.26 10.8 1.21 5.0 9.7 1.24 6.0 9.5 1.24 7.0 11.3 1.29 12/27 0.5 4.9 1.38 4.7 1.40 1.0 3.4 1.36 5.1 1.44 2.0 4.9 1.29 7.3 1.45 3.0 5.1 1,.44 8.1 1.38 4.0 4.0 1.64 6.5 1.38 5.0 4.3 1.46 6.0 4.7 1.31 1/21/75 0.5 3.5 1.27 4.8 1.53 1.0 3.2 1.44 11.2 1.51 2.0 3.5 1.39 10.2 1.52 3.0 4.1 1.45 5.6 1.33 1.159 Table 17. Continued. Lagoon A08 Lagoon B24 Depth 665/ 665/ Date (m) Chl a 665a Chl a 665a 1/21/75 4.0 2.4 1.30 1.5 1.00 5.0 0.7 6.0 0.6 2/4 0.5 8.8 1.37 5.2 1.37 1.0 8.5 1.45 9.0 1.54 2.0 8.6 1.42 30.3 1.54 3.0 9.6 1.47 2.9 1.55 4.0 2.9 1.13 1.2 1.50 5.0 1.1 1.33 6.0 1.0 1.17 2/18 0.5 3.4 1.38 4.0 1.31 1.0 4.9 1.35 9.0 1.39 2.0 5.8 1.40 5.0 1.33 3.0 6.6 1.62 2.6 1.19 4.0 2.6 1.17 1.2 1.13 5.0 1.0 1.17 6.0 0.9 1.25 3/4 0.5 5.3 1.27 1.3 1.00 1.0 5.2 1.37 2.1 1.07 2.0 6.3 1.41 5.1 1.33 3.0 7.0 6.7 1.26 4.0 2.8 5.0 1.2 1.00 6.0 5.7 1.00 4/1 0.5 4.5 1.50 6.2 1.50 1.0 4.8 1.48 8.3 1.44 2.0 6.3 1.45 13.5 1.39 3.0 5.2 1.43 16.0 1.50 4.0 21.1 1.46 5.0 16.9 1.25 6.0 8.0 1.40 4/22 0.5 7.0 1.23 5.0 1.29 1.0 7.1 1.31 6.7 1.45 2.0 9.8 1.42 8.5 1.42 3.0 10.6 1.41 11.2 1.43 4.0 12.4 1.31 16.6 1.45 5.0 70.0 1.35 6.0 30.0 1.35 * 665/665a represents the change in absorption of an acetone extract of plant pigment measured at 665 nm before and after dilute acid treatment. A ratio of 1.00 indicates only chlorophyl degradation products are present; a ratio of 1.70 indicates the absence of such phaeo-pigments. (from June 1975 Annual Report) 1.160 Table 18a. Surface phytoplankton net production* (ml 02.1-1-day-1l) from June 1974 to April 1975. 7/17 1.65 2.24 2.19 2.05 2.54 1.78 04 8/1 1.3 0 1.81 2.77 2.15 1.58 1.15 8/13 2.17 2.55 1. 2.2. 2.2.16 1.01 8/27 1.84 3.59 3.02 2.53 1.43 1.92 9/10 1.50 3.11 2.06 1.49 1.12 0.63 9/25 0.55 1.51 1.29 1.17 2.19 0.88 10/15 0.03 0.40 0.13 0.48 0.38 0.47 10/22 0.21 0.26 0.23 0.24 0.63 3.17 11/4 0.21 0.32 0.42 0.15 0.12 0.73 11/19 -0.02 -0.11 0.00 -0.05 0.15 0.22 12/3 0.27 0.00 0.02 0.27 0.34 0.42 12/27 0.56 0.51 0.46 0.20 0.04 0.05 1/21/75 0.04 -0.21 -0.17 0.05 -0.03 -0.01 2/4 0.00 -0.12 -0.06 0.07 -0.07 2/18 0.15 0.30 0.23 0.16 0.35 0.20 3/4 0.10 -0.19 0.20 0.13 -0.01 3/18 0.07 0.14 -0.02 0.21 0.16 0.38 4/1 -0.05 0.59 -0.93 0.60 0.27 0.29 4/22 0.21 0.56 0.16 0.43 0.56 0.31 1.161 Table 18a. Continued. r4 4- �c o: X4 co F " 6/20/74 1.92 1.70 2.01 3.19 0.78 7/3 2.23 2.03 2.44 3.27 0.28 7/17 8/1 1.58 2.09 2.21 2.31 0.47 8/13 8/27 1.90 4.92 3.15 4.68 -0.42 9/10 9/25 1.52 0.95 1.14 2.99 0.91 10/15 10/22 0.28 -0.03 0.41 0.17 0.14 11/4 11/19 -0.07 -0.13 -0.14 -0.09 -0.08 12/3 12/27 0.81 0.73 0.35 0.50 0.90 1/21/75 0.01 -0.38 -0.08 0.24 -0.09 2/4 2/18 0.23 0.19 0.09 -0.04 -0.07 3/4 3/18 0.30 0.00 0.03 -0.01 0.10 4/1 4/22 0.37 0.00 0.38 0.08 0.21 * Data for 6/20-8/13/74 are taken from January from laboratory incubations. All other values are natural light incubations at 50% of the incoming radiation. (from June 1975 Annual Report) 1.162 Table 18b. Phytoplankton production (ml 02.m-2.day-1) at Meyers Creek mouth and Lagoon A08 from September 1974 to April 1975. Meyers Creek mouth Lagoon A08 Date GP* RI NPt GP R NP 9/25/74 1,607 361 1,246 3,395 2,411 984 10/15 500 262 238 1,615 2,878 -1,263 10/22 1,509 1,363 156 11/4 467 287 180 1,173 2,804 -1,631 11/19 49 197 -148 640 1,673 -1,033 12/3 74 90 -16 574 328 246 12/27 336 525 -189 820 1,369 -549 1/21/75 8 98 -90 279 1,009 -730 2/4 107 172 -65 369 1,312 -943 2/18 476 213 263 426 148 278 3/4 98 205 -107 1,263 1,353 -90 3/18 344 189 155 828 779 49 4/1 410 115 295 2,066 1,984 82 4/22 681 107 574 1,591 549 1,042 * GP = Gross production. # R = Respiration. t NP = Net production. (from June 1975 Annual Report) 1.163 Table 19. Net production and respiration of marsh surface algal mats (ml 02'm-2.12 h-l) from December 1974 to April 1975. Meyers Spartina S. S. Creek alternifZora alterniflora patens mouth Date tall form short form mudflat 12/12 NP* 18 44 35 96 RTotal# 13 13 75 31 RBactt 4 9 22 9 % Bacterial 31 69 29 29 % 0Io** 17 41 2 100 2/13 NP 132 RTotal 70 3/12 NP 40 68 -4 191 RTotal 88 114 13 154 RBact 58 83 4 77 % Bacterial 66 73 31 50 % Io 36 51 5 100 4/9 NP 180 206 13 246 RTotal 48 132 31 193 % Io 7 68 4 100 *NP = Net production. #RTotal = Total community respiration. t RBact = Bacterial respiration. ** % Io = % incoming radiation reaching marsh surface. (from June 1975 Annual Report) 1.164 Table 20. Net production and respiration of benthic microflora and fauna (ml 02-m-2.12 h-l) from January to April 1975. Meyers Creek Meyers Lagoon Date mouth Pond ABD A08 1/14 NP* -18 22 13 -136 RTotal# 75 92 39 144 2/13 NP 0 79 13 -219 RTotal 118 92 53 202 3/26 NP 140 48 4 -272 RTotal 39 88 48 294 RBactt 22 53 158 % Bacterial 25 >100** 54 4/30 NP 167 83 26 -316 RTotal 96 382 149 329 RBact 31 158 39 158 % Bacterial 32 41 26 48 * NP = Net production. # RTotal = Total community respiration. t RBact = Bacterial respiration. ~* Due to the limits of the method, this value probably indicates only bacterial respiration was taking place. (from June 1975 Annual Report) 1.165 Table 21. Sample calculations for daily system totals of nitrogen processed or present in Meyers Creek system and Lagoon System A in April. Rooted vegeta- tion was not included. Quantities presented as g-atom N-system-l-day-l. Meyers Creek Lagoon Parameter system A08 1. STANDING STOCK Aquatic NH3-N 0.044 0.000 N02-N 0.000 0.000 N03-N 0.044 0.290 Total organic-N 3.0* 24.0* Total standing stock 3.1 24.3 2. INPUT N fixation Bulkhead algae 0.00 9.50* Algal mat: S. alternifora short form 130.00* S. alterniflora tall form 0.23 S. patens 0.00 Soil: S. alterniflora short form 24.00* S. aZterniflora tall form 0.12 S. patens 0.00 Benthic sediments 0.18 1.00 Total input 154.53 10.50 3. EXCRETION Modiolus 1.6 Ilyanassa 52.0* 140.0* Zooplankton 2.1 44.0 Total excretion 55.7 184.0 4. N REQUIRED Phytoplankton 40.0 270.0* Algal mat: S. alterniflora short form 140.0* S. aZternifZora tall form 1.8 Benthic sediments 16.0 2.1 Total N required 197.8 272.1 * Maximum value within a category at a particular site. (from June 1975 Annual Report) 1.166 APPENDIX C Tables and Figures from the July 1976 Estuarine Evaluation Study Annual Report: Primary Aquatic Productivity and Nitrogen LIST OF FIGURES Figure Page 1 Station locations ....................... 1.171 2 Cross sections of the natural and lagoon systems ........ 1.171 3 Sampling schedule ........................ 1.171 4 Water temperature at the surface of M 21 and Meyers Pond and contoured plots for Lagoon A02 and A08 in oc ........ 1.172 5 Salinity at the surface of M 21 and Meyers Pond and contoured plots for Lagoons A02 and A08 in O/oo ............ 1.172 6 Dissolved oxygen concentrations at the surface of M 21 and Meyers Pond and contoured plots for Lagoons A02 and A08 in (ml 02.1-1) .......................... 1.172 7 Incident light energy plots from Kimball's tables (1928) and Licor measurements at the Little Egg Research Station . .... 1.172 8 Longitudinal sections of the lagoons .. 1.173 9 Lagoon System A volume to system length relationship ...... 1.173 10 Ammonia-N concentrations at the surface of M 21 and Meyers Pond and contoured plots for Lagoons A02 and A08 in pg-atom NH3-N.- ....................... 1.173 11 Gross production values at M 21 and Meyers Pond ......... 1.174 12 Gross production values (ml 02.1-1) at Lagoons A02 and A08 . . . 1.174 13 Plant pigment concentrations at M 21 and Meyers Pc-d ...... 1.174 14 Contoured plant pigment concentrations (mg.m-3) at Lagoon A02 .......................... 1.175 15 Contoured plant pigment concentrations (mg.m-3) a. Lagoon A08 .............................. 1.175 16 Production and nutrient enrichment experiments at M 21, Meyers Pond, Lagoon A02, and Lagoon A08 ............... 1.175 1.167 LIST OF TABLES Table Page 1 Secchi disc measurements (m) ................. 1.176 2 The % incident light that penetrates the marsh surface vegetation . . . . . . . . . . . . . . . . .. ...... . 1.177 3 Bathymetry and other features of Meyers system and Lagoon System A . . . . . . . . . . . . . . . . . . ........ . . 1.178 4 Nitrate-N, (ig-atom N03-N-ll) at M 21, Meyers Pond, Lagoon A02, and Lagoon A08 . . . . . . . . . . . . . . .. 1.179 5 Total organic-N (ig-atom Org-N.1-1) at M 21, Meyers Pond, Lagoon A02, and Lagoon A08 ................. 1.180 6 Nitrogen fixation rates in vg-atom NH3-N.m2'24 h-1 . . . . . . . 1.181 7 Nitrogen fixation: total fixation (mg-atom NH3-N-24 h-1) by each category in the indicated system . . . . . . . . .... 1.182 8 Ammonia-N excretion by IZyanassa, rates per organism and rates per Meyers Creek and Meyers Pond . . 1.183 9 Ammonia-N excretion by zooplankton, rates-m-3 and rates. system-1. Rates'system-1 calculated to mean depth . . . . .. 1.183 10 Ammonia-A excretion by IZyanassa, rates.organism-l and rates- systeml . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.184 11 Ammonification (ammonia-N regenerated by sediments): rates. m-2 and rates-system-1 . . . . . . . . . . . . . . . . . . . . 1.185 12 Nitrogen contribution through runoff and rainfall (mg-atom N. quarter-l-103) . . . . . . . . . . . . . . . . . . 1.186 13 Benthic algal community net production (NP) and respiration (R) (ml 02'm-2'24 h-1) . . . . . . . . . . . . . . . . . . . . . . 1.187 14 Marsh surface algal community and bulkhead algal community net production (NP) and respiration (R) (ml 02'm-2'24 h-1) . 1.188 15 Available inorganic nitrogen: Sum of ammonia-N, nitrate-N, N fixation, ammonification, and excretion . . . . . . . ... 1.189 16 Nitrogen fractions as percent of available inorganic nitro- gen ............................. 1.190 17 Available inorganic nitrogen as percent of total organic nitrogen . . . . . . . . . . . . . . . ........ 1.191 18 Nitrogen required: Calculated from net oxygen production by phytoplankton community, benthic algal community, and bulkhead or bank algal community . . . . . . . . . . .. . 1.191 19 Percent gross production according to producer community; total producer community respiration as percent gross production . . . . . . . . . . . . . . . . . . . . . . . . . 1.192 20 Gross production: Sum of the gross production by phyto- plankton community, benthic algal community, and bulkhead or bank algal community . . . . . . . . . . . . . . . . . . . 1.193 21 Respiration: Sum of the oxygen consumed by phytoplankton community, benthic algal community, and bulkhead or bank algal community . . . . . . . . . . . . . . . . . . . . 1.194 1.169 NATURAL SYSTEM I I I LW' MEYERS CREEK LAGOON Upper I ..'. ~yers ~ SYSTEM A Marsh I IMud M as.... .. ,h SYSTEM Pnd 8 outh Surface I Bank Flat Benthic I Bank Surface LAGOON SYSTEM Mid Meyers Creek A02 Upper A02 lgal ba.nd Bulkhead Mouth Mouth ,/g y'iWater ABD * M 21 Water column I lum AB Surface - bottom Benthic Fig. I. Station locations. Fig. 2. Cross sections of the natural and lagoon systems. 1 2 3 4 NH/4-N, N02-N, N03-N .. . . 0. *i.. . -- _ _ � .... Organic-N, Vertical series Runoff . ... . I . ..... -. . Excretion-N ... : Ammonification ........... _ .. .. Bulkhead algae . - Benthic ... ... . . Marsh algae - S. alt. (Tall) Marsh algae - S. alt. (Short) .- --- . - . .. --*.. M� arsh algae - S. patens . . x Marsh sediment - S. alt. (Tall) -- * - - -. 0- --0 -- z Marsh sediment - S. alt. (Short) _ Marsh sediment - 5. patens .-� . ..... . . - .. .-I - -. e _p ter Column .......... . . : Phytoplankton . ........ . . -- * Benthic . . . . . . . . . . . . > Bulkhead algae ......... -- -- .* M Harsh algae - s. alt. (Tall) . o Marsh algae - s. alt. (Short) . -- - - -- -- - Marsh algae - S. patens . ... Fig. 3. Sampling schedule. The columns labeled I through 4 represent pooled data periods. 1.171 30 --- Meyers Pond30 e 0 FL � 0---0 M21 0 0 2 = 4 �> 9 S O> d o~ ~- ------. o~ooM .... ... 2 2- r ICE L. j- 1 21C J J A S O N IJ F M A M A S N D F M A A08 0 A02 aO 8 i I--e 2 20 1 : I- iI 09-IM 2 5r Ose- : - IE 0 --- t J J A S O N D J F D I F M A M A083 I.,17 1 17 1975 1 1976 3- 4 � 7 M63 J J A S O N ' D J F M A M J J A S N j F M A M 500 A08 7 4 I CE 2 * 3 I3 J J A S O N D J F M A M J 1975 1976 Fig. 6. Dissolved oxygen concentrations at Fig. 7. Incident light energy plots from Kimball's the surface of M 21 and Meyers Pond and con- tables (1928) Meyers Pond ) and Licor measurements at the toured plots for Lagoons A02 and A08 in Little Egg Research Station. (ml 02.1-1). 1.172 E~~~~~~~~ I� J --� 2 I~,. I �--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~a 7 U 1000- ~~~~~~~~~~~~~~~~~~~~ -500 ~~~~~~~~~~~~ ~~~~~~~nso~~~~~~~~~olJF~~~~~~~~~~~~a M r L~~~~~~~~~~~~ 1.172 A 6 3. 6 Mean Depth 2 H 100m 220r 200- LW 3.7 --\361 - / Enlrance 3--0 36A2 - 1128 140 z ~3.2- =~i~c/---~~ 2 -2- /2 9 120- 680- I0--< L - - -42.1-,A07 20- A0 100 T 03 I200 400 L00 B 00 1200 1 i 7-_ A3 wPrism volume/high water volume = ---- 2.6 Fig. 8. Longitudinal sections of the lagoons. Fig. 9. Lagoon System A volume to system length relationship. High and low water volumes are indicated. T. . (MMeyers Pond '_ I- - 4 / 200 400 600 eo 000 1200 � 2.6 6E M 21 2IICE = ~J J A $ O N D J F M A M 2 - 1_ ICE <1 / I I I I I I I I I N 4 - I I ill I III1976l\ s - + + fi 5-10 Fig. 10. Ammonia-N concentrations at the surface goons J J A08 in -atoD J F M A M . _17 I I I I I I I I J J A S O N D J F M'A'M 1975 1976 Fig. 10. Ammonia-N concentrations at the surface of M 21 and Meyers Pond and contoured plots for La- goons A02 and A08 in Ig-atom NH3-N'I-I. 1.173 1975 1976 21 .. 100% Incident Light A02 J J A S O N D [ J F M A M J M21 - 25 i.5 --. Respiration k o ICE 0 E. J J A S . N D J F M A M J o 2552I7/241 Meyers Pond A J A S N D J F M A M -~~~~o~~ m~ _1*C' (, z~'~ . . . . , I i o .....Mean ICE .- / - Depth J J A S a N D J F M A M J *= Compensation Depth 1975 1976 Fig. 11. Gross production values at M 21 and Fig. 12. Gross production values (ml 02.1-1) at Lagoons A02 Meyers Pond. and A08. OM 21 20- 15 10 E ICE .Q~ ' / . w J J A S O N D J F M A MJ C Meer Pon^Chlorophylla ~' 15 ICE ~~~~~J J A S O N D J F M A M J �Compensation Depth ~~1975 1976 sFig. 13. Pva lues a ant M 21 and Figent. 12. Gross production values (ml 021-1) at Lagoons A02 ~~~~~and Meyers Pond. and A08. 20 15 5 rl hP- ICE d AS S DN J F M A M J Fig. 13. Plant pigme-n Chlorophyll a an Meyers Pond 1.174 A02 Chl-rphylle i A S 0 ~N SI J F M A e i 008 Chlorophyll 2 5 D i AtJr II' IC Ill' I II 1975 1976 J A ~~~~ I D SJ F 0 j 1975 976 I A A II J i- -I ICE t iA P I-ICI 5 I 5- 4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A02 Ph-ophytin opnato et 672 Pheophytie * Compensation Depth �AO Pheophytin Compensation Depth Fig. 14. Contoured plant pigment concentrations Fig. 15. Contoured plant pigment concentrations (mg. (mg-m3) at Lagoon A02. m-3) at Lagoon A08. M 21 6/5 6/26 7/8 7/24 9/25 10/15 12/17 2/26 4/20 6/8 -M 6eyers P-ed 615 6126 7/8 7/24 9/25 0/15 11/11 12/17 2/26 4/20 6/9 0~ 8 tLla ai~. 712 4 9/2510/14 12/17 2/26 4/20 6/8 AOS I~L aL W 6/5 6/26 7/8 7/24 9/25 10/15 11/11 12/171 2/26 4/20 6/8 1975 E 1976 LLIJJ ~~Enriohent Serie "AI I" L (NH- -N03 p04-P Control Fig. 16. Production and nutrient enrich- ment experiments at M 21, Meyers Pond, Lagoon A02, and Lagoon A08. 1.175 Table 1. Secchi disc measurements (m). Meyers Meyers Date Pond Creek A08 A02 ABD M 21 6/5/75 1.0 1.0 1.4 1.3 6/26 0.7 0.9 0.8 1.3 7/8 0.9 0.9 0.7 1.2 7/24 0.6 0.6 0.8 0.8 0.8 1.5 8/13 0.7 1.0 1.2 1.6 1.1 1.7 8/28 0.5 1.1 9/25 0.9 0.9 1.5 1.3 1.2 1.3 10/15 >0.6 2.1 1.6 1.8 1.8 2.8 11/11 0.2 0.3 1.1 1.2 1.3 1.7 12/17 0.9 0.9 1.7 1.5 1.1 0.9 2/26/76 0.7 0.8 1.2 1.5 1.1 0.9 4/6 >0.5 1.2 1.5 1.4 1.7 1.7 4/20 0.3 0.6 1.6 1.6 1.4 1.1 5/26 0.9 0.8 0.8 0.8 0.9 0.9 N 12 10 14 10 13 13 X 0.7 0.9 1.2 1.4 1.2 1.4 S D 0.25 0.48 0.32 0.33 0.34 0.51 (X.mean depth-1) 1.67 0.75 0.33 0.47 0.60 1.40 (from July 1976 Annual Report) 1.176 Table 2. The % incident light that penetrates the marsh surface vegetation. Spartina Spartina Spartina alterniflora, aZterniflora, patens Date tall form short form 7/1/75 80 68 2 7/15 33 57 5 8/6 43 83 9/10 2 6 0 9/30 5 12 4 10/23 3 12/29 1 2 0 2/12/76 20 18 0 2/17 37 57 4 4/8 11 8 3 5/10 9 22 1 5/20 18 34 0 (from July 1976 Annual Report) 1.177 Table 3. Bathymetry and other features of Meyers system and Lagoon System A. Lagoon Meyers Meyers Lagoon Lagoon System Parameter Pond Creek A08 A02 A Mean 0.42 1.20 3.60 3.00 3.00 depth, (m) Perimeter, (m) 1,255 2,348 445 619 8,287 Tide range, 0.46 0.46 0.46 0.46 0.46 (m) Area water 43,000 23,000 6,763 9,067 148,566 surface (m2) Drainage 200,365 223,517 18,208 26,941 284,720 area (m2) Volume (m3) 18,000 22,000 14,800 16,000 190,100 Tidal prism 10,500 9,400 3,100 3,500 42,596 volume (m3) Volume (m3) for interval: 0-1 m 6,300 7,700 92,600 1-2 m 4,000 4,400 57,500 2-3 m 3,000 2,500 27,600 3-4 m 1,200 1,000 10,200 4-5 m 200 300 1,800 5-6 m 100 100 400. (from July 1976 Annual Report) 1.178 Table 4. Nitrate-N, (Pg-atom NO0-N.l-1) at M 21, Meyers Pond, Lagoon A02, and Lagoon A08. Location 6/26/75 7/8 7/24 8/13 8/28 9/25 10/15 11/11 12/17. 2/26/76 4/6 5/26 M 21: Surface 0.1 0.0 0.1 0.0 0.6 0.8 0.0 0.2 0.2 0.1 Meyers Pond: Surface 0.1 0.0 0.0 0.0 0.6 1.8 0.7 1.4 0.2 0.1 0.1 Lagoon A02: Surface 0.3 0.0 2.3 0.4 0.4 0.0 0.0 0.0 0.0 1 m 0.4 0.0 1.5 0.2 0.0 0.1 0.1 0.1 0.0 2 0.5 0.0 1.2 0.2 0.0 4.4 0.1 0.0 0.0 3 0.5 0.0 0.7 0.1 0.2 0.1 0.2 0.0 0.0 4 0.5 0.0 0.5 0.2 0.0 0.0 0.2 0.0 0.1 5 0.5 0.0 0.5 0.2 0.7 0.2 0.3 0.1 0.0 Lagoon A08: Surface 0.2 0.2 0.6 0.0 0.5 0.8 0.3 0.4 0.0 0.2 0.0 0.1 1 m 0.1 0.1 0.5 0.0 0.5 0.4 0.2 0.4 0.4 0.1 0.0 0.1 2 0.1 0.1 0.4 0.0 0.7 0.4 0.0 0.4 0.3 0.2 0.0 0.1 3 0.0 0.0 0.3 0.0 0.4 1.0 1.1 0.5 0.0 0.2 0.1 0.1 4 0.0 0.0 0.2 0.0 0.0 1.4 0.0 0.1 0.1 0.2 (from July 1976 Annual Report) Table 5. Total organic-N (Vg-atom Org-N--1) at M 21, Meyers Pond, Lagoon A02, and Lagoon A08. Location 6/26/75 7/8 7/24 8/13 9/25 10/15 11/11 12/17 2/26/76 4/6 5/26 M 21: Surface 33 33 27 36 22 39 39 26 30 38 Meyers Pond: Surface 46 40 66 48 36 74 40 40 30 40 Lagoon A02: Surface 42 40 43 29 28 49 29 25 46 Go Bottom 34 42 26 34 36 34 38 37 Lagoon A08: Surface 51 41 53 44 40 34 28 39 52 43 51 Bottom 56 104 26 25 36 35 49 45 55 55 (from July 1976 Annual Report) Table 6. Nitrogen fixation rates in pg-atom NH3-N m2. 24 h-l. Quarterly period Sample July October February May Y Bulkhead algae: Upper zone 2,866 2,103 174 9,053 3,549 Lower zone 439 228 56 474 299 Benthic sediment: Lagoon Systeh A 17 13 2 3 9 Meyers Creek system 36 38 0 3 19 S. alterniflora, short form: Algal mat 2,412 501 7 32 738 Mud substrate 243 882 21 8 289 S. patens: Mud substrate 103 7 0 4 28 S. alternif~ora, tall form: Bank algal mat 7,704 669 24 1 2,100 Bank mud substrate 88 619 1 119 207 Water column: 0 0 0 0 0 * Quarterly mean value (from July 1976 Annual Report) Table 7. Nitrogen fixation: total fixation (mg-atom NH3-N.24 h-1) by each category in the indicated system. Quarterly period Sample July October February May YQ* Bulkhead algae in Lagoon System A: Upper zone 2,802 2,291 123 12,379 4,399 Lower zone 942 456 76 1,247 680 Total 3,744 2,747 199 13,626 5,079 Benthic sediment: Lagoon System A 2,482 1,907 260 464 1,278 Meyers Creek system 2,358 2,509 0 175 1,261 S. alterniflora, short form, Meyers system: Algal mat 90,080 123,108 1,331 2,321 54,210 Mud substrate 58,583 28,996 1,678 1,733 22,748 Total 148,663 152,104 3,009 4,054 76,958 S. patens Meyers Creek system: Mud substrate 17,535 1,161 0 612 4,827 S. alZternifZora, tall form, Meyers system: Bank algal mat 10,558 1,391 45 3 2,999 Bank mud substrate 255 2,271 2 335 716 Total 10,813 3,662 47 338 3,715 Water column: 0 0 0 0 0 * Quarterly mean value (from July 1976 Annual Report) 1.182 Table 8. Ammonia-N excretion by Ilyanassa, rates per organism and rates per Meyers Creek and Meyers Pond. Quarterly Period Rates July October February May Y Meyers Creek: (hg-atom NH3-N.organism-l. 24h-1) 1.56 4.06 11.95 4.19 5.44 Meyers Creek plus Meyers Pond: (mg-atom NH3-N-24 h-l) 1,949 5,071 14,925 5,234 6,795 * Population size: Meyers Pond, 3.753 x 105 organisms and Meyers Creek, 8.737 x 105 organisms. # Quarterly mean value. Table 9. Ammonia-N excretion by zooplankton, rates.m-3 and rates.system-1. Rates-system-1 calculated to mean depth. Quarterly period Rates July October February May YQ* Volume rates (jg-atom NH3-N-m-3.24 h-l): Meyers Creek 27.16 4.60 57.75 22.38 Lagoon A02 2.09 4.08 10.55 139.85 39.14 Lagoon A08 10.92 2.75 3.05 86.05 25.69 Lagoon System A 6.33 3.44 6.95 114.00 32.68 System rates (mg-atom NH3-N.system1-24 h-l): Meyers Creek 597.5 101.2 1,270.5 492.3 Meyers Creek system 1,086.4 184.0 2,310.0 895.1 Lagoon A02 30.5 59.6 154.0 2,041.8 571.5 Lagoon A08 152.9 38.5 42.7 1,204.7 359.7 Lagoon System A 1,562.2 849.0 1,715.3 28,135.2 8,065.4 * Quarterly mean value 1.183 (from July 1976 Annual Report) Table 10. Ammonia-A excretion by IZyanassa, rates-organism-l and rates. system-l.* Quarterly period Rates July October February May YQ Organism rates (pg-atom NH3-N.organism-l 24 h-l): Meyers Creek 1.02 0.53 1.34 1.59 1.12 Meyers Pond 0.58 0.86 2.10 1.18 Lagoon A02 0.69 0.58 1.44 2.15 1.22 Lagoon A08 1.13 0.54 0.98 2.75 1.35 Lagoon System A 0.88 0.56 1.24 2.41 1.27 System rates (mg-atom NH3-N.system-l.24 h-I): Meyers Creek 563.0 292.6 739.7 877.7 618.3 Meyers Pond 598.6 887.5 2,167.2 1,217.8 Meyers Creek system 891.2 1,627.2 304.9 1,854.4 Lagoon A02 237.7 199.8 496.1 740.8 418.6 Lagoon A08 290.4 138.8 251.9 706.7 347.0 Lagoon System A 4,968.0 3,161.5 7,000.4 13,605.7 7,183.9 * Population size: Meyers Creek system, 24 organisms-m-2 and Lagoon System A, 38 organisms.m-2. # Quarterly mean value (from July 1976 Annual Report) 1.184 Table 11. Ammonification (ammonia-N regenerated by sediments): rates.m-2 and rates-system-1. Quarterly period July October February May YQ* m2 rates (Pg-atom NH3-N.m-2.24 h-l): Meyers Creek 1,258.0 2,095.4 68.1 1,732.2 1,038.4 Meyers Pond 1,381.6 3,611.4 1,664.3 Lagoon A02 1,127.2 2,406.4 5,260.8 6,038.7 3,708.3 Lagoon A08 614.8 1,537.1 694.7 725.2 893.0 Lagoon System A 908.3 2,035.0 3,310.0 3,768.6 2,505.5 System rates (mg-atom NH3-N-systemnl.24 h-1.103): Meyers Creek 28.9 25.2 1.6 39.8 23.9 Meyers Pond 59.4 155.3 71.6 Meyers Creek system 84.6 1.6 195.1 93.8 Lagoon A02 10.2 21.8 47.7 54.8 33.6 Lagoon A08 4.2 10.4 4.7 4.9 6.1 Lagoon System A 134.9 302.3 491.8 559.9 372.2 * Quarterly mean value (from July 1976 Annual Report) 1.185 Table 12. Nitrogen contributed through runoff and rainfall (mg-atom N.quarter-1L 103). Quarterly period Sample July October Road runoff: Lagoon A02 5.9 2.4 Lagoon A08 4.4 1.6 Roof runoff: Lagoon A02 5.3 5.5 Lagoon A08 4.2 5.5 Lagoon surface: Lagoon A02 33.4 14.7 Lagoon A08 26.3 10.3 Total: Lagoon A02 44.6 22.6 Lagoon A08 34.9 17.4 Meyers Creek system: Water surface 248.6 105.8 Marsh surface 1,682.6 718.8 Total 1,931.2 824.6 (from July 1976 Annual Report) 1.186 Table 13. Benthic algal community net production (NP) and respiration (R) (ml 02.m-2.24 h-l). Parameter 7/17/75 10/2/75 12/11/75 3/12/76 Meyers Pond NP 159 -523 -64 -85 R 464 874 170 462 Meyers Creek NP -298 -85 -114 R 356 192 520 Meyers Creek mouth NP -85 -266 -105 -88 R 158 228 6 398 Lagoon A02* NP -32 -231 -58 R 590 198 468 Lagoon A08 NP # 120 364 -287 R 380 638 638 ABD NP -228 R 690 *Benthic data extrapolated from results for Lagoon A12 mouth. #Bottom depths anaerobic (from July 1976 Annual Report) 1.187 Table 14. Marsh surface algal community and bulkhead algal community net pro- duction (NP) and respiration (R) (ml 02,m-2,24 h,1). Parameter Sampling data Marsh surface algae zone: Date 7/1/75 9/10/75 10/23/74 2/17/76 5/20/76 S. patens NP 44 -71 -158 -79 -170 R 150 80 258 204 432 S. alternifZlora, NP 211 257 120 -53 298 short form R 324 398 182 146 316 S. alterniflora, NP 250 178 129 -85 241 tall form R 202 188 182 198 356 Bulkhead algae: Date 7/17/75 10/2/75 12/11/75 2/17/76 3/12/76 Upper main channel NP -237 1,052 1,240 149 373 R 894 550 432 550 1,438 Mid main channel NP -219 1,210 696 -47 146 R 1,042 446 380 520 422 Lower main channel NP -211 947 436 47 281 R 854 520 492 450 340 (from July 1976 Annual Report) 1.188 Table 15. Available inorganic nitrogen: Sum of ammonia-N, nitrate-N, N fixation, ammonification, and excretion. Quarterly period Rates July October February May YO* Area rate (m2-atom N.m-2): Meyers Pond 1.65 4.68 0.44 3.85 2.66 Meyers Creek 2.50 7.77 0.65 3.30 3.56 Lagoon A02 2.68 7.93 5.70 6.80 5.78 Lagoon A08 3.46 5.49 2.54 1.79 3.32 ABD 2.78 6.72 0.66 3.06 3.31 M 21 2.15 4.52 0.26 2.90 2.46 Volume rate (mg-atom N-m-3): Meyers Pond 3.95 11.18 1.06 9.19 6.35 Meyers Creek 2.60 8.13 0.68 3.45 3.72 Lagoon A02 1.52 4.49 3.23 3.86 3.28 Lagoon A08 1.58 2.51 1.16 0.82 1.52 ABD 1.39 3.36 0.33 1.53 1.65 M 21 2.15 4.53 0.26 2.90 2.46 *Quarterly mean value (from July 1976 Annual Report) 1.189 Table 16. Nitrogen fractions as percent of available inorganic nitrogen. Vo o a X t4X July quarter: Meyers Pond 16.9 0.8 3.10 76.1 3.0 Meyers Creek 42.1 1.2 2.10 50.2 4.4 Lagoon A02 39.9 13.2 3.70 42.0 1.1 Lagoon A08 60.7 16.7 2.80 17.9 1.9 ABD 36.0 14.4 46.8 2.8 M 21 32.5 4.6 60.4 2.4 October quarter: Meyers Pond 49.2 16.1 4.10 29.5 1.1 Meyers Creek 61.5 22.1 0.02 14.1 2.2 Lagoon A02 40.1 28.5 0.80 30.3 0.4 Lagoon A08 50.1 19.7 1.80 28.0 0.5 ABD 61.0 20.8 17.8 0.3 M 21 59.8 13.3 26.6 0.4 February quarter: Meyers Pond 37.8 18.9 0.30 15.4 27.6 Meyers Creek 0.0 14.7 0.00 10.5 74.8 Lagoon A02 4.4 1.9 0.03 92.3 1.3 Lagoon A08 54.7 14.5 1.70 27.3 1.7 ABD 61.0 30.5 4.6 4.0 M 21 0.0 78.1 11.7 10.2 May quarter: Meyers Pond 1.1 1.8 0.30 93.8 2,9 Meyers Creek 34.8 2.9 2.10 52.5 7.7 Lagoon A02 0.2 0.0 7.10 88.8 4.0 Lagoon A08 17.4 12.4 13.90 40.5 15.8 ABD 0.0 6.5 88.2 5.2 M 21 0.0 3.4 93.0 3.5 (from July 1976 Annual Report) 1.190 Table 17. Available inorganic nitrogen as percent of total organic nitrogen. Quarterly period Location July October February May YQ* Meyers Pond 7.8 31.3 2.6 23.0 16.2 Meyers Creek 6.0 28.9 2.2 8.6 11.4 Lagoon A02 3.6 12.4 11.1 9.2 9.1 Lagoon A08 3.3 7.1 2.2 1.6 3.6 ABD 3.2 11.6 1.1 3.7 4.9 M 21 6.9 20.2 9.8 7.6 11.1 *Quarterly mean value Table 18. Nitrogen required: Calculated from net oxygen production by phyto- plankton community, benthic algal community, and bulkhead or bank algal community. Quarterly period Location July October February May YQ * Area rates (mg-atom N.m-2): Meyers Pond 1.97 -0.82 0.43 0.57 0.54 Meyers Creek 2.93 0.23 1.20 1.53 1.47 Lagoon A02 0.71 2.14 0.45 0.63 0.98 Lagoon A08 0.49 3.93 4.91 0.81 2.54 ABD 1.40 0.70 0.85 0.78 0.93 M 21 0.30 -0.20 1.15 0.38 0.41 Volume rates (mg-atom N-m-3): Meyers Pond 4.71 -1.96 1.03 1.36 1.29 Meyers Creek 3.06 0.25 1.26 1.60 1.54 Lagoon A02 0.40 1.22 0.26 0.36 0.56 Lagoon A08 0.22 1.80 2.24 0.37 1.16 ABD 0.70 0.35 0.52 0.39 0.49 M 21 0.30 -0.20 1.15 0.38 0.41 *Quarterly mean value (from July 1976 Annual Report) 1.191 Table 19. Percent gross production according to producer community; total pro- ducer community respiration as percent gross production. 0~~~~~~~ 0 ~ o 0 0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~$4J 0~~ ~ ~ ~ ~~~ 0 0 July quarter: Meyers Pond 84 15 1 50 Meyers Creek 87 11 2 46 Lagoon A02 99 * 1 82 Lagoon A08 100 * <1 92 ABD 84 16 80 M 21 66 34 91 October quarter: Meyers Pond 41 58 1 154 Meyers Creek 85 10 5 85 Lagoon A02 68 31 1 52 Lagoon A08 78 21 1 38 ABD 105 -5 65 M 21 115 -15 121 February quarter Meyers Pond 46 53 <1 76 Meyers Creek 64 35 1 69 Lagoon A02 62 37 <1 81 Lagoon A08 91 9 <1 50 ABD 68 32 75 M 21 64 36 60 May quarter: Meyers Pond 59 40 2 76 Meyers Creek 71 25 4 62 Lagoon A02 72 28 81 Lagoon A08 78 22 80 ABD 74 26 75 M 21 63 37 83 *Anaerobic at bottom (from July 1976 Annual Report) 1.192 Table 20. Gross production: Sum of the gross production by phytoplankton com- munity, benthic algal community, and bulkhead or bank algal community. Quarterly period July October February May YO* Area rate (ml 02m2): Meyers Pond 1,581 606 708 953 962 Meyers Creek 2,177 610 1,172 1,599 1,399 Lagoon A02 1,555 1,792 1,098 1,328 1,443 Lagoon A08 2,529 2,419 3,925 1,620 2,623 ABD 2,920 780 1,270 1,170 1,535 M 21 1,340 272 1,147 834 898 Volume rate (ml 02.m-3): Meyers Pond 3,777 1,448 1,691 2,277 2,298 Meyers Creek 2,178 611 1,173 1,600 1,391 Lagoon A02 882 1,016 623 753 819 Lagoon A08 1,156 1,105 1,794 740 1,199 ABD 1,460 390 635 585 768 M 21 1,340 272 1,147 834 898 *Quarterly mean value (from July 1976 Annual Report) 1.193 Table 21. Respiration: Sum of the oxygen consumed by phytoplankton community, benthic algal community, and bulkhead or bank algal community. Quarterly period July October February May YO* Area rate: (ml 02'm-2): Meyers Pond 791 933 538 724 747 Meyers Creek 1,001 519 809 991 830 Lagoon A02 1,275 932 889 1,076 1,043 Lagoon A08 2,327 919 1,963 1,296 1,626 ABD 2,336 507 953 878 1,169 M 21 1,219 329 688 692 732 Volume rate (ml 02.m-3): Meyers Pond 1,890 2,229 1,285 1,730 1,784 Meyers Creek 1,046 542 845 1,036 867 Lagoon A02 723 528 504 610 591 Lagoon A08 1,063 420 897 592 743 ABD 1,168 254 477 439 585 M 21 1,219 329 688 692 732 *Quarterly mean value (from July 1976 Annual Report) 1.194 2. ESTUARINE EVALUATION STUDY: A FOUR YEAR REPORT OF PRODUCTION AND DECOMPOSITION DYNAMICS OF SALT MARSH COMMUNITIES OF THE MANAHAWKIN MARSHES, OCEAN COUNTY, NEW JERSEY. Ralph E. Good and Barry R. Frascol The first author is a Professor with the Department of Biology, Camden College of Arts and Sciences, Rutgers University. The second author is a grad- uate student also associated with that department. This report was prepared for the New Jersey Division of Fish, Game, and Sheilfisheries with funds provided in part by the New Jersey Division of Marine Services during the period 1973 to 1977. TABLE OF CONTENTS Page LIST OF FIGURES ............................ LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . vii ACKNOWLEDGEMENTS ............................ ix ABSTRACT/SUMMARY ............................ xi INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 ENVIRONMENTAL STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Methods . . . . . . . . . . ... . . . . . . . . . . . . . 2.4 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . 2.6 ABOVEGROUND PRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 2.10 Methods .. .......... 2.10 Results and Discussion . . . . . . . . ... 2.12 BELOWGROUND PRODUCTION . . . . . . . . ... 2.16 Methods . . . . . . . . . .... 2.16 Results and Discussion . .... . . ......... 2.18 PHENOLOGICAL STUDIES . . . . . . . ..... 2.24 Methods . . . . . . . . . . . ...... 2.24 Results and Discussion .... .. ... 2.25 DECOMPOSITION OF END OF THE SEASON PLANT MATERIAL . . . . . . . . . . . 2.30 Methods ............. 2.30 Results and Discussion . . . . .... 2.31 Percent Decomposition ..................... 2.31 Percent Ash ....... 2.39 Percent Crude Fat .. . ... 2.40 Percent Crude Fiber . . . .... 2.42 Percent Nitrogen and Percent Crude Protein . ........ 2.42 DECOMPOSITION STUDY OF LIVE (HARVESTED) ABOVEGROUND MATERIAL . . . . . . 2.44 Methods . . . . . . . . . ............. 2.44 Results and Discussion .... . . . . . . . . . . . . . . . . . . . 2.46 STUDY OF BELOWGROUND MATERIAL DECOMPOSITION .... 2.48 Methods . . . . . ...... 2.48 Results and Discussion ...... . ..... 2.48 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.50 REFERENCES CITED . . . .... ....... 2.55 APPENDIX A- Tables and Figures from the June 1974 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity . . . . . . . . . 2.59 APPENDIX B - Tables and Figures from the June 1975 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity . . . . . . . . . . . . 2.83 APPENDIX C - Tables and Figures from the July 1976 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity Decomposition . . . . . 2.103 iii LIST OF FIGURES Figure Page 1 Location of the general study area, Manahawkin marshes, between Manahawkin and Tuckerton, Ocean County, New Jersey . . . . . . 2.2 2 Map of study area and location of sampling stations for the aboveground and belowground production studies . . . . . . . . 2.4 3 Location of stations at Manahawkin used for the decomposition studies . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 4 % wt. loss vs. time for (1)PSAS . . . . . . . . . . . . . . . . 2.33 5 % wt. loss vs. time for (2)PSAM . . . . . . . . . . . . . . . . 2.33 6 % wt. loss vs. time for (3)SAS ....................... 2.33 7 % wt. loss vs. time for (4)SAM ....................... 2.34 8 % wt. loss vs. time for (5)SAT . . . . . . . . . . . . . . . . . 2.34 9 % wt. loss vs. time for (6)S. patens . . . . . . . . . . . . . . 2.34 10 % wt. loss vs. time for (7)SAS . . . . . . . . . . . . . . . . . 2.35 11 % wt. loss vs. time for (8)SAT . . . . . . . . . . . . . . . . . 2.35 12 % wt. loss vs. time for (9)SAS . . . . . . . . . . . . . . . . . 2.35 13 A model of the dynamic processes of a Spartina alternifZora salt marsh community . . . . . . . . . . . . . . . . . . . . . 2.53 v LIST OF TABLES Table Page 1 Mean mud salinity values (�/oo) for the five major vegetation types from 3 August 1973 to 21 April 1975 ......... 2.7 2 Mud salinity (�/oo) at five study sites in the Manahawkin marshes at 0 and 10 cm depths from 13 October 1975 to 26 April 1976 ....................... 2.9 3 Monthly precipitation (cm) for the Manahawkin marshes area for 1973-1976 ....................... 2.10 4 Comparison of peak aboveground standing crops (g-m-2) dry wt. for the major vegetation types at the Manahawkin marshes in 1973 and 1974 . . . . . . . . . . . . . . . . . . . . . . . . 2.13 5 Density and culm weight of representative Spartina alterniflora and Spartina patens community types found in the study area 2.14 6 Comparison of net production (g dry wt.m-2) of aboveground parts for a number of salt marsh studies . . . . . . . . . . 2.15 7 Standing crop of the current year's growth for the shrubs, Iva frutescens, Baccharis halimifolia, and minor associates . . . 2.17 8 Production in kg on an area basis (aboveground, belowground, and total) for the five major community types at Manahawkin . . . 2.18 9 Energy content (kcal.g-1) and percent crude protein for above- ground portions of SAS at stations 19, 20, and 21 from 5 June 1974 to 23 October 1974 . . . . . . . . . . . . . . . . . . . 2.19 10 Seasonal changes in belowground biomass for the major vegetation types at Manahawkin during 1974-1975 . . . . . . . 2.20 11 Maximum biomass, belowground production, and turnover rates for the major vegetation types at Manahawkin during 1974-1975 . . 2.22 12 Net annual production (kg.m-2) in 1974-1975 for the below and aboveground components of six communities and ratio of below to aboveground . . . . . . . . . . . . . . . . . . . . . . . 2.23 13 Caloric values (ash-free) and percent ash for S. alterniflora, short form, belowground material by depth at stations 19, 20, and 21 during 1974-1975 . . . . . . . . . . . . . . . . . . . 2.24 14 Percent (%) crude protein for S. alterniflora, short form below- ground material at stations 19, 20,and 21 during 1974-1975 . 2.25 15 Maximum leaf lengths obtained during the 1976 growing season at Popular Point and Mud Cove . . . . . . . . . . . . . . . . 2.26 16 Leaf lengths and leaf condition of plants from 4 June 1976 to 10 October 1976 at Popular Point and from 20 July 1976 to 10 October 1976 at Mud Cove . . . . . . . . . . . . . . . . . 2.27 17 Comparison of percent leaf loss of Spartina alterniflora during the growing season for several salt marsh studies . . . . . . 2.29 18 Study sites, locations, and vegetation used for the decomposi- . tion of end of season material study . . . . . . . . . . . . 2.30 19 Percent weight loss (+ 1 SD) for decomposition samples at all Popular Point and Mud Cove study sites from 2 December 1975 to 10 October 1976 . . . . . . . . . . . . . . . . . . . . . 2.32 20 Linear regression line equations and correlation coefficients (r) for percent weight loss of decomposition samples for the study period 2 November 1975 to 10 October 1976 at Popular Point and Mud Cove . . . . . . . . . . . . . . . . . . . . . 2.36 vii Table Page 21 Percent weight loss increments of decomposition samples at all Popular Point and Mud Cove study sites for the period 2 December 1975 to 10 October 1976 ..2.37 22 Percent ash content (+ 1 SD) of samples at all study sites from 2 November 1975 to 10 October 1976 ........... 2.41 23 Percent (%) crude fat ash-free dry weight of samples at all study sites ......................... 2.43 24 Percent (%) crude fiber ash-free dry weight of samples at all study sites from 2 November 1975 to 23 February 1976 . . 2.44 25 Percent Kjeldahl nitrogen ash-free dry wt (+ i SD) and percent crude protein ash-free dry weight (+ 1 SD) of samples at study sites (3)SAS, (4)SAM, (5)SAT, and (6)S. patens at Mud Cove from 2 November 1975 to 10 October 1976 ........ 2.45 26 Percent weight loss (+ 1 SD) of live harvested decomposition bags at Popular Point and Mud Cove ............. 2.47 27 Estimated initial dry root weight, actual dry root weight, and actual-initial dry root weight difference for belowground samples collected from 23 June 1976 to 21 November 1976 at Mud Cove .......................... 2.49 viii ACKNOWLEDGEMENTS During the 4 years of this phase of the Estuarine Evaluation Study, a number of students at Rutgers University, Camden have been involved. Katherine K. Smith served as a graduate assistant during the first 2 years and continued working on her thesis the third year which involved part of the project. The graduate assistant during the third year was William Brown who was followed by Barry Frasco during the windup period of the fourth year. Dr. Norbert Psuty (Director, Center for Coastal and Environmental Studies) has been of great assistance throughout the project. Students that should be acknowledged include Blake Anderson, Steve Auslander, Alex Burckhardt, Barbara Frasco, Joe Freeman, Steve Kavros, John Schumann and Ray Walker. Cooperation by members of the N.J. Division of Fish, Game, and Shellfisheries and by other principal investigators is gratefully acknowledged. Finally Kathy Carr and Rita Lorang should be ac- knowledged for converting all this information (during the last 4 years) into neatly typed reports. ix ABSTRACT/SUMMARY In an effort to evaluate the role of salt marsh systems in contributions to the estuary and in particular the role of a 800 ha tract in Ocean County, New Jersey known as the Manahawkin marshes, the New Jersey Department of Environmental Protection funded Rutgers University for a 4 year period be- ginning July 1973. Included in the overall study was the section on the pro- duction dynamics of the marsh vascular plant system that is reported here. This marsh plant productivity study was designed to determine the role of vascular plants in the estuarine ecosystem at Manahawkin. Investigation~of the contribution of these communities focused on two basic processes: primary pro- duction and decomposition. Photosynthetically fixed energy was traced through aboveground, belowground, and decomposing phases to determine the quality and quantity of organic matter formed. Plant tissues from each component and each community were further analyzed to measure energy transfer into various carbon pathways. Emphasis during the first 2 years of the study was placed on measurement of net primary productivity of growing plants, observations of environmental conditions, and laboratory analysis of plant tissues. The aboveground portion of the Spartina alterniflora short form (SAS) plant community, the major vegeta- tion type studied, was found to yield a total of 5 x 103 kg.ha-1 annually. The belowground portion of SAS provided an additional 30 x 103 kg'ha-1 in the top 30 cm. The total energy content, varying with component, age, and sublevel, was approximately 4.6 kcal.g-1. Total energy produced by this form of Spartina for the Manahawkin marshes was estimated at 5.12 x l09 kcal (annual net produc- tion) which amounts to 16.0 x 103 kcal.m-2; comparing favorably with the world's most productive ecosystems. Standing crops of crude fiber and nitrogen free extract (above and belowground), crude fat (aboveground), and crude protein (belowground) were found to be a function of dry weight biomass. Accumulation of crude protein in aboveground material during the early growing season may act to offset shortages of nitrogen at the peak of the growing season. The 1975-76 study emphasized the decomposition of this production. Decom- position was measured by analyzing bagged plant material left on the marsh to decompose. This material (detritus) formed in the decomposition process repre- sents an energy transfer phase from the primary producer to consumer, which pro- vides the important link in the energy flow system of the marsh. During the study it was observed that the different growth forms of S. alterniflora decom- pose at different rates, the taller forms losing material faster than the short form. There is also some indication that the belowground portions decompose at a rate of only 20% per year. Chemical analysis of decomposing aboveground material revealed an increase in percent crude protein by the end of the study period. This increase is attributed to microbial colonization of the detritus. It is felt that this colonization makes detritus a good food source for consumers in the estuarine food chain. Since this study has shown that production exceeds decomposition for the high marsh species at Manahawkin (especially S. patens) it is suggested that the net difference becomes incorporated into the marsh peat. It is concluded that marsh stability depends on a balance between production, decomposition, xi detrital export, accumulation, and incorporation, all of which must be in balance with seasonal tidal fluctuations and sea level to maintain the marsh on a long-term basis. xii INTRODUCTION Coastal New Jersey is composed of approximately 106 ha of tidal wetlands, two-thirds of which are salt marshes with the remainder in the freshwater marsh category. Up to the early part of the 20th Century very little destruc- tive use was made of these marsh areas, but as the population increased so too increased industrial, commercial, and recreational utilization. Salt marshes were utilized as sites for dredge spoil, industrial plants, and -more recently marinas and housing. Utilization of marshes for lagoon housing (waterfront living) represents New Jersey's largest loss category in recent years. New Jersey's Wetland Act of 1970 (A505) began the process of regulating the use of the wetland resources. Other Mid-Atlantic states have since enacted laws to regulate usage of their wetlands. Although little was done prior to 1970, the Federal Government had enacted the River and Harbor Act in 1899 (commonly known as the Refuse Act). House Report No. 91-917 (1970) entitled "Our Waters and Wetlands: How the Corps of Engineers Can Help Prevent Their Destruction and Pollution" analyzed how the Corps might more adequately fulfill its responsi- bilities under the Refuse Act of 1899. The early regulations were developed without strong documentation of the value of these resources. Over the years there has developed greater evidence for the necessity to preserve our wetlands. Some of the principal findings include the importance of marshes as a source of food for estuarine animals in the form of detritus and the use of the marsh proper as a habitat for a part of the life cycle of many commercial fishes (Keefe and Boynton 1973; Odum 1961; Reed and Moisan 1971). In the last 20 years ecological evidence began to point strongly to a vital link between the terrestrial and marine environments. In spite of regulations for usage of New Jersey's wetlands in 1970, a number of large salt marsh tracts were being threatened with destruction for lagoon development. The State of New Jersey, Department of Environmental Pro- tection, Division of Fish, Game and Shellfisheries was particularly concerned with a 800 ha tract of tidal marsh in Ocean County, New Jersey known as the Manahawkin marshes (Figure 1) located between Mill Creek on the north, Little Egg Harbor on the east, Cedar Run on the south, and the upland border to the northwest. The area north of Mill Creek was formerly tidal marsh and had been largely developed for waterfront living. The Manahawkin marsh tract is typical of the marshes along this area of New Jersey's coast near Atlantic City domi- nated by the short form of Spar-tina alternifZora (saltwater cordgrass) with lesser amounts of Spartina patens (salt hay) and Distichlis spicata (salt grass). Along streams and waterways where the marsh is regularly flooded, the tall form of Spartina alterniflora dominates. Thus this wetland "prairie" is dominated by relatively few species with large populations although a number of other species are present in small numbers (Appendix B). The Department of Environmental Protection asked investigators from the Marine Sciences Center, Rutgers University (presently called the Center for Coastal and Environmental Studies) to carry out a long-term study to evaluate this system under the title Estuarine Evaluation Study. The objectives of the study were to evaluate the role of a New Jersey salt marsh system in the contri- butions of the estuary: (1) to the food chains of fish and wildlife; (2) as habitat; (3) to recreation; and (4) to food for man and to document this role for use in legal actions. This report has been concerned with the Marsh Plant Productivity phase of the overall study. 2.1 *742W ' 0' /5' Barnegat :-::/ Ib Barnegat i: �t~~~~~~~~O ~~Bar negat N39*45~ Bay Light 39'45'- Harvey Cedars 4(fY Std 40'- Ship Bottom 0 35'- Beach RK. r Great I .:: -'::::~ Bay 0 -30' Little Egg ~M0 5 Inlet Miles 0 Kilometers 5s' to' DC. Fig. 1. Location of the general study area, Manahawkin marshes, between Manahawkin and Tuckerton, Ocean County, New Jersey. 2.2 Although the initial objectives of this phase were: 1) To obtain estimates of aboveground standing crop of the major communities 2) To determine coverage area of each community type and calculate total production for the study area 3) To determine the environmental factors of salinity, depth of flooding, depth of substrate, and precipitation, and determine their effect on production 4) To compare the value of these marshes with others throughout the Atlantic Coast, the study was extended to the productivity of the belowground component and its interaction with the aboveground component. This was done since it had been estimated that the belowground component may be 7-9 times the amount of above- ground (de la Cruz 1974). During the third and fourth years the study was further extended to investigate the fate of this total production; namely the decomposition phase. A special phenological study was conducted during the last year to aid in the understanding of biomass losses during the growing season. Throughout the entire study reported here an attempt was made to put the information on an energy flow basis since energy produced as a result of the photosynthetic process represents the ecosystem budgetary unit. The energy is initially in the form of plant matter making up the roots, stems, and leaves of the marsh plants. Transfer of energy in the form of plant nutrients takes place throughout the year with a large component being trans- located to the root and rhizome system at the end of the growing season where it can be used for new plant growth the following year. Some of the remaining plant material undergoes microbial decomposition making it more available to consumer organisms such as detritivores. It may remain relatively intact con- tributing to the amount of accumulated peat material or may undergo decomposi- tion, a process which represents an energy transfer phase from primary producer to consumer and thus provides the important link in the energy flow system of the estuarine ecosystem. Consequently wherever possible the samples were ana- lyzed for their caloric content and chemical composition. These are summarized by Odum et al. (1973) who indicated that the role of vascular plant detritus, is divided into four distinct processes: (1) produc- tion-the sources and quantity of annual net production; (2) degradation-decay and microbial colonization of the dead plant material and detritus formation; (3) export-movement of detritus from source to site of utilization; and (4) utilization-the ingestion and assimilation of portions of the detritial complex by consumers. The degradation process itself has several components: loss of soluble compounds, microbial colonization, and mechanical fragmentation. Since the quantity of biomass produced by coastal and estuarine salt marsh macrophyte communities is among the highest on earth, their contribution to the productivity of the coastal zone is considered to be highly significant. This report summarizes the dynamics of vascular plant production and decomposition for the Manahawkin marshes. 2.3 ENVIRONMENTAL STUDIES Methods Environmental data were collected during 1973-1974 at 18 stations and during 1974-1975 at 19 stations described in the Aboveground Produc- tion section of this report (Figure 2). In addition, environmental data were collected during 1975-1976 at the major sites (except (6) S. patens) described in the "decomposition of end of the season material" section of this report (Figure 3). Collections were made 32 times during 1973-1974, 22 times during 1974-1975, and 15 times during 1975-1976. ~-' ~ ~ ' -u ~' " $' 2 , . 3.; ,, - V _ 05s M- Fig. 2. Map of study area and location of sampling stations for the above- ground and belowground production studies. Salinity was measured by collecting surface mud samples at each station for each environmental run. During 1975-1976 samples were also taken at 10 cm depth. Using the quantitative procedure described by Good (1965), mud samples were dried, soaked, and filtered; and salinities were calculated based on readings with a RB4-250 Beckman Solubridge conductivity meter. 2.4 Fig. 3. Location of stations at Manahawkin used for the decomposition studies. Precipitation data were gathered using Taylor Instrument Company rain gauges installed in five marsh locations during 1973-1974 and 1974-1975. Precipitation differences among the five locations were generally minimal with few instances of variable local storms. Measurements were usually closely related to those of the U.S. Weather Service, Tuckerton Station (U.S. Dept. Commerce 1973-1976). During 1975-1976, the heights of the four major Mud Cove study sites relative to each other were measured during a high tide. The depth of water was measured at each site and the relative height was calculated using the deepest reading at the tall form Spartina aZterniflora (SAT) site as the zero point. An estimate was made of the number of times each site was flooded by tides. The incoming tides were measured every 15 to 20 minutes at these different sites during various times of the study. From the measurements it was possible to roughly estimate the number of high tides reaching each site by using a ratio with the tide table published for Sandy Hook, N.J. (U.S. Dept. Commerce 1976). 2.5 Results and Discussion Table 1 presents average soil salinity values for the five major vegeta- tion types from October 1973-April 1975. Soil salinity values for individual stations can be found in Appendices A, B, and C. Soil salinity results for October 1975-April 1976 are presented in Table 2. Precipitation levels for the entire study period are found in Table 3. In general, there is a relationship between mud salinity and precipitation levels. During periods of low rainfall, soil salinity increases while heavy rainfall causes a decrease in soil salinity. Variation in rainfall from month to month and year to year has an effect on soil salinity variation within a given vegetation type. (Tables 1, 2, and 3). The amount and regularity of marsh surface flooding also plays an important role in determining soil salinity. At Mud Cove, using the lowest area in the SAT site as the zero point (which was later found to roughly correspond to the mean low water mark) SAT plants were found from 0 to 15 cm above this point. Intermediate height Spartina alterniflora (SAM) plants were found between 28 and 32 cm or 13 to 17 cm above the upper limit of the SAT zone. The plants of the short form S. alterniflora (SAS) site were found between 35 and 37 cm or 20 to 22 cm above the SAT zone. A site in a Spartina patens site was also measured and was found to be at 44 cm or 29 cm above the SAT zone. Of the approximately 700 high tides of 1975 all reached the SAT site. The SAM site was covered by 600 to 700, the SAS site by 400 to 600 and S. patens by less than 100. An SAS site at Popular Point (PSAS) was found to be equivalent to the SAS site and a SAM site at Popular Point (PSAM) corresponded with the SAT site. These are very rough estimates but do give an indication that there are significant differences in tidal influence among the study sites. S. patens sites, which are flooded less than 100 times per year, have the lowest soil salinites (mean = 17.3 0/oo). Other high marsh sites (Distichlis spicata and D. spicata/Juncus gerardi also have low soil salinities (mean = 23.9 and 19.4 0/oo). Sites which are flooded more regularly (SAS, SAT) have higher soil salinities (mean = 28.2 and 32.3 0/oo). Soil salinity values taken from October 1975 to April 1976 (Table 2) are generally lower than values from 1973- 1975 (Table 1). Upon general observation it appears that soil salinities are generally lower in late autumn, winter, and early spring compared to late spring and summer. Mean salinity values for the 1975-76 study are likely lower because summer soil salinity values were not determined. It was also noticed that the greatest fluctuation in soil salinity during 1973-1975 occurred at SAT sites (Mean + SD = 32.3 + 15.8 �/oo). This is unusual because SAT sites are flooded quite regularly, therefore soil salinity should be very constant. Values presented in Table 1 are means from several stations. One SAT station (Station 5, Appendices A and B) showed much greater fluctuation soil salinity compared to the other SAT stations and is a major reason for the large fluctuation in soil salinity. If this station is not considered, SAT soil salinity at the 1975-1976 SAT and PSAM sites (Table 2) were the smallest (SD = 5.7 and 5.9 �/oo respectively). Fluctuation of soil salinity at intermediately flooded sites (SAS-SAM) should be high (longer periods of time for the marsh soil to dry), and were found to be so (Tables 1 and 2). Variation of soil salinity at infrequently flooded sites (S. patens, D. spicata/J. gerardi) was found to be low. 2.6 Table 1. Mean mud salinity values (O/oo) for the five major vegetation types from 3 August 1973 to 21 April 1975. S. S. aZterni- aZterni- S. fZora flora DistichZis D. spicata/ Date patens short tall spicata Juncus 8-3-73 16.6 26.2 37.5 22.1 8-9-73 25.1 49.9 53.6 18.5 8-16-73 12.6 23.0 22.1 21.4 13.9 8-23-73 18.0 18.4 24.0 9.5 19.7 8-30-73 18.7 24.9 36.0 24.4 21.2 9-7-73 32.6 36.0 93.3 46.4 22.9 9-12-73 30.7 38.5 61.2 58.4 26.3 9-19-73 14.9 18.7 24.0 23.4 18.1 9-26-73 13.1 19.7 20.3 22.0 18.8 10-3-73 14.8 19.8 30.6 24.1 21.3 10-20-73 25.6 43.6 67.0 31.5 35.1 10-27-73 18.6 22.3 28.8 35.7 21.3 11-3-73 19.4 25.0 30.4 26.2 18.4 11-7-73 23.1 28.0 25.3 26.4 25.8 11-14-73 15.0 21.5 31.7 22.1 17.3 11-21-73 26.0 37.3 21.9 21.3 20.0 11-28-73 16.5 20.5 24.4 19.3 18.8 12-8-73 18.6 21.5 27.1 13.7 18.5 12-12-73 15.7 20.6 22.5 33.1 20.5 12-26-73 11.6 15.4 18.2 17.3 11.5 1-17-74 9.7 14.2 12.8 15.1 10.7 1-23-74 8.9 11.1 12.5 12.7 10.4 2-20-74 10.3 13.9 15.4 14.3 13.5 3-6-74 13.5 16.9 19.5 15.2 14.3 3-27-74 11.1 23.6 33.0 10.5 15.0 4-3-74 11.2 17.2 15.7 17.1 13.2 4-17-74 10.3 24.6 33.2 18.7 15.4 4-24-74 14.9 24.7 32.5 14.4 29.1 5-7-74 20.8 25.3 29.7 11.5 16.4 5-16-74 14.5 42.5 36.7 19.4 29.3 5-23-74 16.3 48.6 27.9 18.9 20.1 5-30-74 15.1 25.9 30.5 22.7 23.0 6-5-74 14.2 26.6 23.4 21.7 6-11-74 19.1 43.5 28.1 13.8 6-17-74 29.2 58.7 55.1 31.8 6-25-74 16.1 23.4 25.7 18.0 7-1-74 15.2 19.0 28.7 23.3 7-8-74 18.1 40.7 33.3 58.7 7-15-74 20.1 56.9 56.3 22.7 7-22-74 22.3 34.9 68.3 27.4 7-29-74 28.3 52.5 61.7 29.7 8-5-74 34.3 58.3 69.8 31.5 8-14-74 15.7 29.5 24.8 23.6 8-25-74 15.9 21.4 25.6 21.8 9-9-74 11.7 18.6 17.6 23.4 10-2-74 16.6 32.3 31.5 34.5 10-20-74 16.7 24.9 28.8 32.8 2.7 Table 1. Continued. S. S. alterni- alterni- S. flora flora DistichZis D. spicata/ Date patens short tall spicata Juncus 11-6-74 11.3 25.5 20.9 27.6 11-27-74 18.7 27.5 27.6 24.6 12-30-74 18.2 21.7 23.0 25.7 1-28-75 6.8 12.7 14.9 12.0 3-5-75 11.0 21.1 22.3 4-21-75 13.3 24.1 27.7 22.2 Mean + 1SD 17.3+6.1 28.2+12.2 32.3+15.8 23.9+10.2 19.4+5.6 2.8 Table 2. Mud salinity (o/oo) at five study sites in the Manahawkin marshes at 0 and 10 cm depths from 13 October 1975 to 26 April 1976. Study sites Date Depth(cm) (1)PSAS (2)PSAM (3)SAS (4)SAM (5)SAT 10/13/75 0 25.8 23.3 24.1 28.0 21.1 10 36.6 20.2 29.1 38.3 23.4 10/23/75 0 25.7 10 35.5 10/26/75 0 16.0 18.8 20.6 10 15.7 21.2 11/11/75 0 25.3 11.7 10 30.8 32.8 11/17/75 0 17.9 17.6 17.9 10 20.2 18.9 11/25/75 0 14.0 18.1 20.3 10 17.3 16.3 12/2/75 0 17.0 15.6 16.1 18.3 16.5 10 24.2 16.8 15.0 16.8 16.1 12/16/75 0 20.8 27.0 26.4 10 20.8 19.7 12/23/75 0 23.3 21.6 10 13.2 12/30/75 0 18.5 18.8 18.0 14.0 15.0 10 24.6 20.0 15.6 16.6 20.3 1/13/76 0 6.8 9.8 8.3 6.0 12.9 10 2/9/76 0 5.7 13.2 3.4 5.9 10.7 10 2/26/76 0 26.6 23.3 21.9 10 17.7 22.6 20.6 3/25/76 0 23.6 22.3 22.5 22.1 10 24.7 21.8 22.1 4/26/76 0 58.9 25.1 34.4 49.9 32.2 10 40.6 60.0 38.1 30.2 Mean + SD 0 23.0+15.5 17.5+5.7 15.8+8.6 20.8+11.0 19.8+5.9 10 31.0+6.9 22.5+7.1 27.5+19.0 21.9+8.5 -20.8+4.0 2.9 Table 3. Monthly precipitation (cm) for the Manahawkin marshes area for 1973-1976. (Data from the U.S. Weather Service - Tuckerton, N.J.) Precipitation (cm) 1973 1974 1975 1976 January 10.03 10.52 13.77 12.93 February 10.31 7.19 8.10 7.34 March 7.67 11.48 10.46 3.86 April 15.27 5.82 10.13 3.51 May 10.52 5.44 9.96 6.91 June 16.28 8.18 8.64 1.45 July 9.73 3.96 15.88 7.44 August 4.67 20.47 3.40 16.10 September 13.84 9.50 14.10 4.42 October 6.30 4.37 7.16 17.20 November 3.43 3.43 9.93 3.48 December 15.01 10.59 6.30 5.84 Total 123.06 100.94 117.83 90.47 Soil salinity at 10 cm depth was found to be greater than surface sal- inities at intermediately flooded sites (PSAS, SAS), and only slightly higher at the more flooded sites (SAM, PSAM, SAT). Variation in soil salinity at 10 cm was less (except PSAM, SAS) than at the surface (Table 2). ABOVEGROUND PRODUCTION Methods The study of marsh plant productivity in the Manahawkin salt marshes was conducted at 18 permanent stations during 1973 and 17 permanent stations in 1974 representing five vegetation types; Spartina aZternifZora short form (SAS), S. alterniflora tall form (SAT), S. patens, Distichtis spicata, and Juncus gerardi. The emphasis placed on each was based on their occurrence and importance in the total study as seen on Department of Environmental Protection aerial maps. 2.10 The stations, shown on Figure 2, were selected in generally uniform stands of the desired vegetation type and represent both disturbed and undisturbed areas. Five stations were located on the south side of Mill Creek, opposite Beach Haven West, a former marsh. These stations included two paired stands of SAS (1, 3) and S. patens (2, 4) plus one stand of SAT (5). The latter station (5) was located on Popular Point, which was diked but subsequently was under injunction against further construction. This station was maintained for environmental data collection only in 1974. Four additional stations (6, 7, 8, 9) were estab- lished in this altered area so that comparisons could be made with similar com- munities in unaltered marshes. Stations 6 and 8 were stands of S. paztens while stations 7 and 9 were stands of SAS. Four stations (10, S. patens; 11, SAS; 12, SAT; 18, D. spicczta) were established in the Mud Cove area representing communities in their most natural condition within the study area. Three addi- tional stations (19, 20, 21) were established in 1974 to provide greater input from an undisturbed area while station 11 was maintained for the collection of environmental data only. The remaining stations (13, S. patens; 14, SAS; 15, SAT; 16, S. pa-tens; 17, D. spicata/J. gerazrdi) were at the opposite end of the study area extending along the Cedar Run Dock Road from the upland border to the bay. Stations 13, 16, and 17 were not sampled in 1974. Net aerial production was determined using the harvest method (Odum 1971; Milner and Hughes 1968). Four by eight meter plots were established at each station with the exception of SAT stations, where the linear growth pattern along the edges of ditches and streams dictated a linear plot arrangement. Each plot was subdivided into I x I m subplots and periodic clippings were conducted in alternate subplots in alternate rows to avoid prior disturbance of quadrats by field workers. During each harvest two subplots per station were clipped with hand shears at 1 to 2 cm above the soil level. Samples were collected a t approximately one month intervals between July/August to September/October in 1973 and between May/June to September/October in 1974. Average plant height was measured prior to clipping. During harvesting clipped material was separated into live and litter portions, with all nonliving matter, whether lying on the ground or standing, defined as litter. Dry weights of all harvested grass and litter were obtained after drying at 800C for 48 hours in a forced draft oven. Net aerial production of the woody shrubs Iva frutescens and Baccharis halimifolia, was determined in 1974 by the direct method (Milner and Hughes 1968). The current season's growth increment was harvested after maturity but before leaf or flower fall. -Grazing or litter fall of these species is negligi- ble. The annual amount of material incorporated into the woody stems was not estimated and was considered a minor input in terms of energy flow through the marsh ecosystem. Random meter square quadrats were selected and all current shrub growth and associated grasses or annuals were harvested with pruning shears and grass clippers. Samples were processed and stored using the same procedures accorded the grasses. These shrub species, which are traditionally treated as an entity for mapping and descriptive purposes, were identified and processed separately but combined for interpretation. Percent ash content of the live portion of all harvested samples except woody shrubs was determined by combusting I g grass subsamples, prepared with a Wiley mill, in a F-1635 Temco muffle furnace for two hours at 60000 (Reiners and Reiners 1972). In addition, caloric and crude protein analysis of above- 2.11 ground material was conducted at three SAS stations (19, 20, 21). Caloric content was measured by combusting ground material in a Parr 1221 adiabatic calorimeter with a temperature controller according to the Parr method (1968). All crude protein analyses were conducted on duplicate desiccated samples and the results presented on an ash-free dry weight basis. Crude protein content was determined by using the standard macro-Kjeldahl method for total organic nitrogen and multiplying the result by 6.25 (Assoc. Offic. Agric. Chem. 1965). In conjunction with the determination of aboveground production, a commu- nity analysis was conducted in three major marsh communities. Plant density at each of the stations was determined by counting the number of culms present in duplicate 25 cm by 25 cm quadrats. The included stations were SAS (2, 4 and 9), SAT (5, 12 and 15), and S. patens (1, 3, 6 and 8). Peak mean dry weight per culm was calculated for each station to provide a basis for comparison of stands and vegetation types. Results and Discussion Table 4 and Appendix A present 1973 and 1974 peak aboveground standing crop values for all marsh grass stations sampled. Results not only indicate a varia- tion in mean peak aboveground standing crop between vegetation types but varia- tion between stations within a given vegetation type during a given growing sea- son and between growing seasons. For the major vegetation types (SAS, SAT, and S. patens), SAT had the greatest mean peak standing crop followed by S. patens and SAS in both 1973 and 1974. Variation in peak aboveground standing crop be- tween stations within a given vegetation type, however, was large resulting in overlaps in the range of peak aboveground standing crop values of all vegetation types. Table 5 presents density and culm weight figures for several stands of the dominant vegetation types at Manahawkin. These values may help to explain some variation in aboveground biomass for the stands of SAS. For the three stands sampled, culm.m-2 varied from 960-2,000. For SAT the variation was from 496-816 culm.m-2. Variation for Spartina patens stands was even greater ranging from 3,280-11,696. Table 5 also gives the average culm weight for these stands at the densities shown. For all major vegetation types, there was a decrease in average culm weight with increasing culm density. There was, however, no apparent relationship between biomass and culm density or average culm weight. Peak standing crop values were lower in 1974 at all but one of the stations. The greatest difference between years occurred at SAS stations. Not only was there a decrease in peak standing crop in 1974 but there was also a change in the time when peak standing crop was attained. At SAS and S. patens stations, peak standing crop was reached 2-4 weeks earlier in 1974 and 2-4 weeks later at SAT sites. Two possible factors influencing'the variation in peak standing crop are precipitation and soil salinity. Good (1965, 1972) showed that increasing soil salinity places a stress on marsh vegetation resulting in reduced growth. Tables 1 and 2 present soil salinity and precipitation levels respectively for the vegetation types for the period August 1973 to April 1975. During the early summer of 1974, precipitation was considerably lower than that of 1973. This in turn resulted in high soil salinity values during July and early August of 1974 due to accumulation of salts from the evaporation of tidal water on the marsh surface. This was particularly noticeable at SAS and SAT stations. High pre- cipitation levels during August of 1974 resulted in a sharp decrease in soil salinity levels. Another possible explanation for the large decrease in above- ground biomass at some stations in 1974 is disturbance. Stations 2, 4, 7 and 2.12 Table 4. Comparison of peak aboveground standing crops (g.m-2) dry wt. for the major vegetation types at the Manahawkin marshes in 1973 and 1974. Station no. 1973 Peak 1974 Peak % Change g.m-2 Date g.m-Z Date S. alterniflora 2 669 9/7/73 374 7/3/74 -44% short form 4 484 9/7/73 280 8/5/74 -42% 7 633 9/7/73 408 8/8/74 -36% 9 442 9/5/73 290 8/8/74 -34% 11 735 9/5/73 552 8/12/74 -25% 14 483 9/5/73 19 574 7/15/74 20 512 7/31/74 21 460 7/1/74 Average peak 574 + 120 * 444 + 113 -23% S. patens 1 613 8/31/73 546 7/29/74 -11% 3 684 9/12/73 644 7/29/74 - 6% 6 519 9/4/73 478 8/28/74 - 8% 8 746 9/4/73 434 7/29/74 -42% 10 691 8/17/73 572 8/8/74 -17% 13 694 8/24/73 16 380 8/27/73 Average peak 618 + 128 535 + 82 -13% S. alterniflora tall form 5 1098 8/24/73 12 739 8/20/73 678 9/18/74 - 8% 15 639 8/6/73 669 9/26/74 + 5% 22 858 9/26/74 Average peak 825 + 241 735 + 107 -11% D. spicata 18 644 8/20/73 613 8/12/74 - 5% D. spicata/ J. qerardi 17 514 8/27/73 * one standard deviation 9 were either adjacent to lagoon development or occurred at the Popular Point location which was considered highly disturbed (Good and Smith 1974). There was visible evidence of community degradation for SAS stations 7 and 9 due to dikes which prevented tidal circulation. Station 8, S. patens, also in the disturbed area, showed a very large decrease in standing crop for 1974. Fur- thermore station 5 in the disturbed area had such poor growth of SAT that above- ground biomass could not be sampled in 1974. The percent change in peak standing crop attributable to disturbance, however, is difficult to assess. Standing crop of a salt marsh community has been considered as net produc- tion in situations where the sample is taken at the peak of development of the community and no great loss due to harvest by organisms has taken place (Good 1965, and others). A comparison of net production of the Manahawkin area marshes with other Atlantic coast marshes must be made with caution. Turner (1976) and 2.13 Table 5. Density and culm weight of representative Spartina alterniflora and Spartina patens community types found in the study area. Sample Vegetation Average (2 samples) Average Peak Culm date type, Station culm culm weight biomass density density per l/16m2 (g) (g.m-2) per m2 7/22/74 S. patens (1) 669 0.05 546 10,704 7/22/74 " " (3) 655 0.06 644 10,480 6/4/75 " " (6) 205 0.15 477 3,280 7/22/74 " " (8) 731 0.04 434 11,696 7/22/74 SAS (2) 111 0.21 374 1,776 7/22/74 " (4) 125 0.14 280 2,000 7/22/74 " (9) 60 0.30 290 960 7/22/74 SAT (5) 51 0.45 364 816 6/11/75 " (12) 49 0.86 677 784 6/11/75 " (15) 31 1.35 669 496 Kirby and Gosselink (1976) have shown that the method used in determining above- ground protection will greatly effect production values. Turner (1976) also states that changes in production values along a north-south gradient as well as local variation (e.g. tall versus short form S. alterniflora) must be taken into consideration when comparing marsh production values. In addition, as shown in this study, yearly variation must also be considered. With this in mind, Table 6 presents a comparison of net aboveground production values found in several marshes in the Mid-Atlantic region. In general, the production values of Manahawkin marshes are comparable to other marshes in this region, especially other New Jersey marshes. The only major exception is net production values for SAT. Peak standing crop values at Manahawkin are similar to those obtained at Great Egg Harbor but are much lower than that of Great Bay. This lower value may be due in part to the lack of extensive stands of the tall form in addition to the apparent lower density of the individual stems in this study area. Turner (1976) has shown that there is a local variation in net production estimates. This variation is best shown in production values for Spartina alterniflora found along stream and creek banks (SAT) compared to S. alter- nifZora found on higher marshland away from the creek banks (SAS). Several fac- tors have been suggested which might influence such variation in production. A number of workers have shown that nitrogen is a major nutrient limiting the growth of short form S. alterniflora but not tall form (Sullivan and Daiber 2.14 Table 6. Comparison of net production (g dry wt-m-2) of aboveground parts for a number of salt marsh studies. Production (g dry wt-m-2) Date Location Author(s) Spartina alterniflora 827 1969 Long Island, N.Y. Udell et al. tall form 1700 1972 Great Bay, N.J. Good 1592 1974 Great Bay, N.J. Squiers and Good 850 1977 Great Egg Harbor, N.J. Good 825 1973 Manahawkin, N.J. This study 735 1974 Manahawkin, N.J. This study Spartina alterniflora 508 1969 Long Island, N.Y. Udell et al. short form 590 1972 Great Bay, N.J. Good 558 1973 Maryland and Virginia Keefe and Boynton 592 1974 Great Bay, N.J. Squiers and Good 548 1977 Great Egg Harbor, N.J. Good 574 1973 Manahawkin, N.J. This study 444 1974 Manahawkin, N.J. This study Spartina alterniflora 300 1965 Cape May, N.J. Good all forms 1332 1969 Virginia Wass and Wright 427-558 1973 Maryland and Virginia Keefe and Boynton 362-573 1976 Virginia Mendelssohn and Marcellus Spartina patens 993 1919 Long Island, N.Y. Harper 805 1969 Virginia Wass and Wright 550 1972 Great Bay, N.J. Good 463 1972 Great Bay, N.J. Nadeau 618 1973 Manahawkin, N.J. This study 535 1974 Manahawkin, N.J. This study Distichlis spicata 360 1969 Virginia Wass and Wright 670 1972 Great Bay, N.J. Good 359 1972 Connecticut Steever 644 1973 Manahawkin, N.J. This study 613 1974 Manahawkin, N.J. This study 1974); Valiela and Teal 1974; Woodhouse et al. 1974; Gallagher 1975). Good (1972) reported that salinity stress may be a factor in decreased aboveground production of short form S. aZternifZora. The highest production values (SAT) were associated with the smallest fluctuation in soil salinity while the lowest production values (SAS) were associated with the largest fluctuation in soil salinity. Steever et al. (1976) found a high statistically significant corre- lation between tidal amplitude and streamside production estimates at sites along Long Island Sound. It is thought that tidal action may increase S. alter- niftora aboveground production along creek banks by either keeping soil salinity at a uniform level, increasing input of nutrients to creek bank soils, or re- moving toxic materials and metabolic wastes. 2.15 Information lacking during the first year of this study was aboveground produc- tion of the woody composite shrubs Iva frutescens and Baccharis halimifolia which grow along the lagoon dikes in the Popular Point area as well as through- out the Manahawkin marsh on margins of mosquito control ditches. These shrubs are estimated to occupy about 5% of the marsh. Table 7 shows the standing crop for these shrubs as well as the minor associates growing under them. Although there is considerable variation in the values for Iva, the average biomass for the two shrubs is comparable. Shrub production is similar to values for SAT. Production figures for the major communities are multiplied by the area covered by each species in the study area in Table 8. Of the 551 hectares, S. alterniflora short form has the greatest coverage, followed by S. patens, Iva and Baccharis shrubs, S. alterniflora tall form, and D. spicata. Despite having the lowest peak standing crop per unit area, SAS forms the bulk of the total marsh annual aboveground production. SAT, while having the highest peak stand- ing crop per unit area, covers only a small portion of the Manahawkin marsh area and thus contributes only a small portion of the total marsh annual aboveground production. Caloric and percent crude protein values for SAS stations 19, 20 and 21 are presented in Table 9. Caloric content of aboveground material remained nearly constant throughout the growing season, averaging 4.4 kcal.g-1. Similar results were obtained for SAS by Squiers and Good (1974) at Great Bay, New Jersey (4.5 kcal-g-1). Percent crude protein levels decreased throughout the growing season from 9.55% on 5 June 1974 to 4.81% on 23 October 1974 with a secondary peak on 18 September 1974. A similar pattern was reported by Squiers and Good (1974) for SAS. Protein levels decreased from 10.25% to 5.88% during the growing season. Squiers and Good (1974) felt that this pattern of early growing season accumulation of protein (of which nitrogen is a constituent) was of ecological significance. If nitrogen is limiting during the peak of the growing season, early spring accumulation of nitrogen could help offset possible shortages. BELOWGROUND PRODUCTION Methods Belowground productivity studies were conducted in 1974-75 at 17 permanent sampling stations described previously (Figure 2). Net primary production for belowground parts was determined by difference in biomass (Dahlman and Kucera 1965). Techniques were devised and equipment constructed for this aspect of the marsh plant productivity study. A pipe, 2.65 cm. x 100 cm. was driven into the marsh, filled with water, capped, aerated (to break the vacuum) and extracted with a modified sleeve (4 handles welded onto a sleeve slightly larger than the pipe). Cores, thus obtained, were divided in half lengthwise, and into segments horizontally to provide data in profile. Cores were divided into 5 cm segments for the upper 20 cm and into 10 cm segments between 20 and 50 cm core depth. One half of the core was dried untreated and the other half was washed over a 1 mm sieve in the laboratory with both halves dried for three days in a forced- draft oven at 550c. The washing procedure involved pulling apart the mat of roots and rhizomes and washing them repeatedly over a white enamel pan until no 2.16 Table 7. Standing crop of the current year's growth for the shrubs, Iva frutescens, Baccharis halimifolia, and minor associates. Total dry wt. (live Dry wt. Live wt. material Date Marsh shrub (g.m-) Associates (g.m-2) (g.m-2) 8/21/74 Baccharis halimifolia 858 Spartina patens 76 934 if If 775 " " 190 1,002 Pluchea purpurascens 37 10/2/74 Iva frutescens 1,017 Mixed grasses 324 1,341 it "763 " 192 955 "I " 474 72 546 951 " 319 1,270 Mean 806 1,008 further release of trapped soil particles was apparent. Because core material below 30 cm contained substantially more decomposition intermediates and was characterized by generally more variable composition, the material between 30-50 cm depth was collected and processed, but not included in production calculations. Samples were collected at approximately 1 month intervals between April 1974 and September 1975 and approximately bimonthly intervals between September 1975 and April 1976. Belowground biomass was analyzed with respect to biomass change within the upper 30 cm of each vegetation type as a whole and also to the 0-10, 0-20, 10-20, and 20-30 cm segments. The maximum differences in biomass is the net primary production for the belowground portion. Turnover is the ratio of net primary production to peak biomass. Samples from the undisturbed SAS grouping of stations 19, 20, and 21 were analyzed calorimetrically and for crude protein. Samples were grouped by collection date. Belowground samples were analyzed to a depth of 20 cm. All analyses were run in duplicate on dry, ground plant matter. Calorimetric determinations, ash content, and crude protein were determined as for the above- ground material. 2.17 Table 8. Production in kg on an area basis (aboveground, belowground, and total) for the five major community types at Manahawkin. Total area Annual production (kg) (ha) Aboveground* Belowground# Total S. alterniflora short form 320 16.0 x 105 96.0 x 105 112.0 x 105 S. patens 140 8.1 x 105 38.6 x 105 46.7 x 105 S. alterniflora 5 5 tall form 9 0.7 x 10 3.0 x 10 3.7 x 105 D. spciata 9 0.6 x 105 2.5 x 105 3.1 x 105 Iva frutescens and Baccharis halimifolia 73 5.8 x 10 5.8 x 105 Total 551t 31.2 x 105 140.1 x 105 171.3 x 105 * Aboveground production figures are the average of 1973 and 1974 figures except Iva and Baccharis which are from 1974 only. # Belowground production figures are from 1974-1975. t (for 90.7% of marsh area; remainder is other species and open water) For interpretative purposes both the SAS and S. patens stations were sub- divided into two groups. SAS stations 19, 20, and 21 represent that vegetation type in an undisturbed state and serve as a control or basis for comparison with stations 2, 4, 7, 9 and 14 which represent conditions ranging from un- disturbed to transitional (stations 7 and 9 at Popular Point). For S. patens the disturbed Popular Point stations 6 and 8 were separated from the remaining stations 1, 3, and 10 which served as a standard. Results and Discussion -2 Table 10 presents values for belowground biomass (kg-m- ) of the vegetation types studied. Both SAS and S. patens stations are divided into two groups, one representing stations in undisturbed areas and the other representing stations in disturbed areas. Although 50 cm cores divided into seven segments were col- lected for all communities, the discussions are concerned with the first 30 cm taken as a whole. This was done since it was felt that most of the living 2.18 Table 9. Energy content (kcal-g- ) and percent crude protein for aboveground portions of SAS at stations 19, 20, and 21 from 5 June 1974 to 23 October 1974. Energy content Crude protein Date (kcal.g-1) (%) 5 June 1974 4.3 9.55 1 July 1974 8.31 15 July 1974 4.5 7.85 31 July 1974 4.4 5.97 19 August 1974 4.4 6.25 18 September 1974 4.4 6.99 23 October 1974 4.4 4.81 component occurred in this layer, a judgment which is supported by other workers (Gallagher 1974; Woodhouse et al. 1974). Data broken down into separate seg- ment components can be found in Appendix B. While initial attempts were made to separate the belowground component into living and nonliving categories, results were unsuccessful so that estimates of living biomass were obtained by analysis of annual change in biomass. The validity of the change in biomass method of measuring belowground net primary production has been challenged on a few points. The most obvious shortcoming is that dry weight changes are a result of three major concurrent processes: increases resulting from growthl decreases resulting from decomposition and consumption; and transient net increases or decreases resulting from trans- location in response to seasonal demands or environmental stresses (Smith 1976). This can be examined in more detail using data obtained from the undisturbed SAS sites. Table 10 shows an increase in belowground biomass from January to April. It is felt that this increase which occurs before peak aboveground bio- mass (Table 4) is primarily a function of growth. There appears to be a drop in belowground biomass in late spring and early summer which may be due to trans- location of materials from the roots to the developing shoots. Belowground biomass remains constant throughout the summer and early autumn before showing a slight increase in October. This October peak may be the result of trans- location of material from the shoots to the roots after peak aboveground biomass has been reached (Table 10). From October to January there is a decrease in belowground biomass which may be due to decomposition of root material during late autumn and winter. Smith (1976) continued sampling at these sites for the remainder of 1975 and found that the same general pattern of season belowground biomass changes occurred although there were changes in the actual biomass quantity as well as shifts in the occurrence of certain biomass peaks. 2.19 Table 10. Seasonal changes in belowground biomass for the major vegetation types at Manahawkin during 1974-1975. SAS SAS S. patens S. patens SAT D. spicata Date (19,20,21)* (2,4,7,9,14)# (1.3,10)* (6. 8)# (5.12.15.22) (18) April 1974 10.53 May 1974 9.59 8.19 6.06 June 1974 10.39 8.76 6.79 8.50 7.35 11.03 July 1974 11.10 11.73 11.49 7.82 5.17 8.89 August 1974 11.09 13.18 9.87 8.24 9.74 10.08 September 1974 11.09 11.27 6.98 7.56 October 1974 11.73 10.12 7.13 November 1974 11.07 10.97 8.19 December 1974 11.27 9.15 7.85 7.27 8.10 January 1975 9.97 12.04 February 1975 7.22 7.29 10.22 March 1975 11.46 9.39 6.53 April 1975 12.37 10.29 6.77 8.25 Mean 11.07 11.20 9.57 6.33 7.38 8.21 * Undisturbed sites # Disturbed sites Belowground biomass changes at other sites, followed somewhat different patterns (Table 10). At disturbed SAS stations, the greatest increase in below- ground biomass occurred concurrently with aboveground growth reaching a peak in August. Belowground biomass generally declined after the peak throughout the autumn, winter, and early spring reaching levels similar to the previous spring. A similar pattern was observed for both disturbed and undisturbed S. patens sites with belowground biomass showing a low point at the beginning of the growing season and a peak in the summer. The peak was delayed approximately a month at the disturbed site. At the SAT sites, there was a sharp drop in belowground biomass in July followed by a sharp increase to an August peak. Biomass dropped sharply in late September and remained fairly constant for the remainder of the study period. The sharp decline in belowground biomass in July might be the result of rapid transfer of materials to the shoot for flower production (Squiers and Good 1974). Translocation appears to be quickly reversed in August since the increase in belowground biomass is unlikely to be the result of root growth at this time (Stuckey 1941). Belowground biomass of D. spicata increased from a low point in late winter to a peak in August. Biomass dropped sharply in September followed by a slight increase in November. Biomass then decreased through February. Table 11 shows the dates of greatest biomass differences, the peak biomass, belowground production, and the turnover rate for the top 30 cm of belowground material for all communities in this study. Percent turnover for the top 30 cm varied from 19.41 for SAS to 39.14 for D. spicata. These represent the extremes in years for complete replacement (turnover as discussed by Dahlman and Kucera (1965)) as 5.15 and 2.55 respectively. These turnover rates may well define those habits which are thought to be responsible for different growth response of genetically indistinguishable growth forms of S. aZterniflora (Shea et al. 1975). A comparison of the two groupings of SAS indicates a shorter turnover for the disturbed stands. The two stand groupings of S. patens have quite similar turnover rates. Turnover for D. spicata appears to be more similar to SAT than any other community. Belowground production varied from 2.25 kg.m-2 for S. patens disturbed sites to 3.59 kg.m-2 for SAS disturbed sites. There appears to be no correlation be- tween belowground production and maximum biomass or turnover rate. Only a few studies to date have dealt with belowground production of salt marsh plants. Valiela et al. (1976) working in Massachusetts marshe~ estimated belowground productivity of Spartina aZternifZora to be 3.5 kg-m- and 2.5 kg.m-2 for S. patens. Woodhouse et al. (1974) found belowground productivity of S. aZternifZora in North Carolina to range from 1.79 to 2.22 kg-m-2. These values are comparable to those obtained in this study. de la Cruz and Hackney (1977) found belowground productivity for Juncus roemerianus in Mississippi to be 1.36 kg-m-2, a value slightly lower than found in this study. Stroud (1976) estimated belowground ~roduction to be 0.46 kg.m-2 for short form S. alter- niflora and 0.50 kg.m-3 for tall form. These values are much lower than other reported results. 2.21 Table 11. Maximum biomass, belowground production, and turnover rates for the major vegetation types at Manahawkin during 1974-1975. Maximum Belowground Vegetation type Period of greatest biomass production Turnover rate difference (kg.m-2) (kg.m-2) (%)(Years) SAS undisturbed 28 Jan-30 April* 12.37 2.40 19.41 5.15 SAS disturbed 16 May-8 August* 13.18 3.59 27.21 3.67 S. patens undisturbed 8 May-29 July* 11.49 3.27 28.50 3.51 S. patens disturbed 8 May-26 August* 8.24 2.25 27.32 3.66 SAT 5 June*-15 July 8.50 3.33 39.14 2.55 D. spicata 12 August*-3 Feb 10.08 2.78 27.63 3.62 * Date of greatest biomass Net annual above and belowground production values as well as below to aboveground rations are presented in Table 12. If we assume that the method of determining net production of the belowground component is accurate, the net total production per year for the marsh plants as a unit ranges from 2.71 kg.m-2 to 3.97 kg-m-2. With the exception of SAS disturbed, net annual belowground pro- duction is about 5 times greater than aboveground production. Valiela et al. (1976) obtained similar root to shoot ratios: 8.3 for S. alterniflora and 4.0 for S. patens. Woodhouse et al. (1974) found root:shoot ratios for S. alter- niflora greater than 3:1. Waisel (1972) noted that halophytes generally have a higher root to shoot ratio than glycophytes. Table 8 presents total (above and belowground) production values for each community type multiplied by the area covered by each species in the study area. SAS not only covers the largest area (320 hectares) but is also the most impor- tant producer both above and belowground giving a value which comprises about two-thirds of the total production. Consequently, any change in the production by SAS will have great impact on the total production for this and similar marsh types. Caloric content of belowground material down to 20 cm from the undisturbed SAS sites is found in Table 13. For the entire depth, calcric content ranged from 4,621-4,919 (mean = 4,761) cal.g ash-free dry weight during the study period. Caloric values were lowest during the summer, the period of greatest aboveground growth. Caloric content also increased with depth from 4,556 cal.g-1 in the 0.5 cm depth to 4,943 cal.g-1 in the 15-20 cm depth. Caloric values of belowground material were also higher (; 300 than aboveground material (Table 9). Stroud (1976) found mean caloric content of two communities of short form S. altern- flora to be 3,819 and 3,969 cal.g-1. These values, however, were not on an ash- free basis. If one assumes the ash content of belowground material to be 12.0% (the average ash content of belowground material in the present study), the caloric values on an ash-free dry weight basis are 4,340 and 4,510 cal.g-1. Stroud also found belowground caloric values to be lowest in the summer and that belowground material had a higher caloric content than aboveground material. 2.22 Table 12. Net annual production (kg.m ) in 1974-1975 for the below and above- ground components of six communities and ratio of below to aboveground. Vegetation type Aboveground Belowground Total Root:shoot (Station) (kg.m-2) (kg.m-2) (kg.m-2) ratio SAS (19, 20, 21)* 0.52 2.40 2.92 5.24:1 SAS (2, 4, 7, 9, 14)#11 0.36 3.59 3.59 10.15:1 S. patens (1, 3, 10)1 0.59 3.27 3.86 5.58:1 S. patens (6, 8)2 0.46 2.25 2.71 5.71:1 SAT (5, 12, 15, 22) 0.64 3.33 3.97 4.53:1 D. spicata (18) 0.62 2.78 3.40 4.50:1 * undisturbed stations # disturbed stations de La Cruz and Hackney (1977) reported for J. roemarianus belowground material a mean caloric count of 5,020 cal-g ash-free dry wt-l for the first 20 cm. These investigators also reported that caloric content increased with root depth (although not statistically significant) and that belowground material had a greater caloric value compared to aboveground material. Table 14 presents crude protein levels of SAS undisturbed site belowground material. Percent crude protein ranged from 4.56 to 5.86% (mean = 5.22) on an ash-free dry weight basis. After the first 10 cm there is an increase in per- cent crude protein with depth. Percent crude protein levels of belowground material are generally higher than for aboveground material (Table 9). Smith (1976) analyzed SAS belowground material at Mud Cove for crude pro- tein, crude fat, crude fiber, and nitrogen free extract. It was found that the percentage of crude protein and crude fat remained fairly constant throughout the year at approximately 7% and 1% respectively. Percent crude fiber varied from 32-45% and percent nitrogen free extract from 47-65%. Yearly changes in percent crude fiber and nitrogen free extracts were found to be inversely related. Decreases in percent crude fiber (an indication of the breakdown of structural carbohydrate) were accompanied by increases in percent nitrogen free extract (an indication of an increase in storage carbohydrate) and vice versa. Standing crop of crude protein, crude fiber, and nitrogen free extract were found to be a direct function of belowground dry matter biomass. 2.23 Table 13. Caloric values (ash-free) and percent ash for S. alterniflora, short form, belowground material by depth at stations 19, 20,and 21 during 1974- 1975. 0-5cm 5-10 cm 10-15 cm 15-20 cm 0-20 cm Date (cal.g-1)(% ash)(calg-1l)(% ash)(cal.g-l)(% ash)(cal-g-1)(% ash)(cal.g-1) 6/5/74 4,631 8.4 4,707 13.4 4,990 13.4 5,349 14.3 4,919 7/1/74 4,500 11.5 4,597 12.8 4,766 13.8 5,153 12.1 4,754 7/31/74 4,390 10.8 4,512 15.5 4,745 15.5 4,860 13.7 4,627 8/19/74 4,552 9.0 4,696 12.0 4,917 11.7 4,340 12.0 4,626 9/18/74 4,459 8.2 4,613 11.0 4,617 12.1 4,794 10.3 4,621 10/23/74 4,557 10.0 4,773 13.0 4,896 13.9 4,981 14.0 4,802 11/27/74 4,683 8.9 4,821 12.5 5,008 14.5 4,952 10.4 4,866 12/30/74 4,609 10.4 4,764 12.2 4,875 12.3 4,917 10.4 4,791 1/28/75 4,501 8.3 4,696 10.6 4,749 12.1 4,957 12.0 4,725 3/5/75 4,661 10.2 4,714 13.7 4,974 15.1 4,989 13.7 4,835 3/30/75 4,577 9.9 4,733 13.2 4,833 13.9 5,079 13.5 4,805 Mean 4,556 4,693 4,852 4,943 4,761 PHENOLOGICAL STUDIES Methods The fates of individual stems after the growing season were studied in the five main sites, Spartina alterniflora short (PSAS) and medium (PSAM) forms at Popular Point and S. alterniflora short (SAS), medium (SAM), and tall (SAT) forms at Mud Cove. These were studied by setting decimeter square quadrats out of each site and selecting individual plants from these. The plants were mea- sured for stem thickness, height of leaf blade from the marsh surface, length of the leaf blade, and leaf blade thickness near the stem. Notes were also kept on color of the leaf and its condition; living or dead, wet or dry. Measurements were taken from 14 October 1975 to 13 January 1976. A similar study was conducted at the same sites in 1976 to determine the fate of individual stems during the growing season. Results from this study could then be combined with the results of the previous study to give a long- term phenological pattern. The same measurements and observations were taken in this study as in the previous study. Measurements were taken three times in June and once each in July, August, September, and October. 2.24 Table 14. Percent (%) crude protein for S. alterniflora, short form belowground material at stations 19, 20,and 21 during 1974-1975. Crude protein (%) Belowground segment (cm) Date 0-5 5-10 10-15 15-20 0-20 5 June 1974 4.17 4.51 4.69 5.60 4.74 1 July 1974 4.24 3.99 4.79 5.22 4.56 15 July 1974 4.45 4.51 5.22 6.57 5.19 31 July 1974 4.38 4.47 5.54 6.54 5.23 19 Aug 1974 4.30 4.17 4.96 5.60 4.75 18 Sept 1974 4.64 4.70 5.54 5.97 5.21 23 Oct 1974 4.69 4.95 6.12 7.12 5.72 27 Nov 1974 4.27 3.83 4.88 5.81 4.70 30 Dec 1974 5.48 5.27 5.95 6.18 5.72 28 Jan 1975 5.11 5.05 5.16 6.98 5.58 5 Mar 1975 5.66 5.07 6.27 6.44 5.86 10 Mar 1975 4.95 4.86 5.75 6.02 5.40 Mean 4.70 4.62 5.41 6.17 5.22 Results and Discussion While phenological records were kept, in general, at the five study sites during the 1976 growing season, detailed records were obtained at four sites from a limited number of plants: PSAS (2 plants), PSAM (2 plants), SAM ( 1 plant), and SAT (1 plant). Since the plants measured at each site were typical for that site, results obtained can be applied to the particular study site in general. The assignment of S. alterniflora into short, medium, or tall form is sub- jective, therefore the height of plants of a certain assigned height form may vary from one area to another. This is shown in Table 15 where the maximum height of each measured plant at each site is listed. Short form S. alternifZora from Popular Point is taller than Mud Cove SAS while PSAM is taller than Mud Cove SAM. These results along with general observations revealed that there was little difference in plant height between the SAM and SAT study sites. These study sites, however, were chosen during the 1975 growing season when there was an obvious height difference in plants from the SAM and SAT sites. Apparently, changing environmental and/or site conditions between 1975 and 1976 caused plants at the SAT site to become more like SAM plants in terms of height. However, differences between plants from the SAM and SAT sites did not allow combining results from each site. 2.25 Table 15. Maximum leaf lengths obtained during the 1976 growing season at Popular Point and Mud Cove. Study site Plant no. Maximum height Average height (cm) (cm) PSAS 1 36 2 27 SAS 325 P SAM 1 58 2 42 50 SAM 1 39 SAT 1 42 Two patterns of leaf placement were observed. At sites PSAS, SAS, and SAM, the nodes were compressed resulting in leaves which originated quite close to one another at or very near the marsh surface. At sites PSAM and SAT, leaves originated from nodes which were approximately I cm apart from one another. It was noted that during the 1976 growing season, the greatest flooding occurred at both SAT and SAM sites. It is not known, however, if there is a connection between flooding pattern and leaf arrangement on the culm. Leaf lengths and condition of the plants studied are listed in Table 16. Plants at all sites were found to follow the same pattern. An individual leaf will grow to some maximum length. This maximum length within a given site is small at the beginning of the growing season and then increases during the pe- riod of maximum growth. At the end of the growing season (September-October), the maximum length of developing leaves begins to decrease (Table 16). As new leaves originate and develop, chlorosis of older full grown leaves develops at the leaf blade tip and progresses toward the plant stem. This is followed by necrosis (death) of the leaf blade originating at the tip and progressing toward the stem. As necrosis of the leaf blade progresses, the blade begins to curl adaxially. When the leaf blade completely dies, it loses its rigidity and lays on the surface of the marsh. Once the leaf reaches the wet marsh surface, decomposition of the blade begins while it is still attached to the plant stem. Eventually the leaf blade will break off of the plant at the sheath. As seen in Table 16, this pattern of leaf growth, dieback, and decay occurred throughout the late spring, summer, and early fall. The presence of dead, decomposing leaves still attached to the plant stem as early as 4 June 1976 indicates that this pattern probably occurs from the beginning of the growing season. This dieback and decay pattern during the growing season is of importance when considering net aboveground primary production. As shown by Bradbury and 2.26 Table 16. Leaf lengths and leaf condition of plants from 4 June 1976 to 10 October 1976 at Popular Point and from 20 July 1976 to 10 October 1976 at Mud Cove. Date of observation 6/14/76 6/16/76 6/20/76 7/20/76 8/17/76 9/14/76 10/10/76 Study site (Leaf length (cm) in order of oldest to youngest leaf) PSAS plant #1 8.5* 9.0* 9.0* 9.0* # # # # 7.0* 7.0* 7.0* # # # # 12.0 14.0* 14.0* # # # # 19.0 23.0 23.0 # # # # 21.0 29.0 28.0 28.5* 17.0* 17.0* 25.5 29.0 30.0 30.1* 28.0* 28.5* 29.0* 25.0 33.5 32.0 32.0 32.0* 14.0 35.2 36.0 34.5 34.5* 29.7 36.5 36.5 36.5 18.7 t + t PSAS plant #2 5.0* 5.0* 5.0* # # # # 13.0 16.0 16.0* # # # # 17.0 22.0 21.0 21.0 14.0* # # 16.0 20.0 26.0 26.8 20.5* 17.5* 18.0* 7.0 15.0 20.0 27.0 26.0* 27.0* 27.0* 8.0 25.9 27.5 27.5 27.5* 15.9 25.5 25.2 25.5 24.9 24.5 24.5 17.5 20.0 20.0 14.0 14.8 6.5 PSAM plant #1 11.0* # # # # # # 20.0 21.5* 21.0* # # # # 27.0 28.0 12.0* # # # # 17.0 29.5 27.0 28.5* # # # 20.5 28.0 34.9 35.5* # # 8.0 21.0 41.2 41.5 41.5* 13.0* 8.0 45.7 45.5 45.5 33.5* 43.4 43.7 44.0* 17.0* 45.5 46.2 46.0 44.0 30.8 46.2 45.2 48.5 48.0 48.0 48.0 41.0 47.0 47.5 20.0 38.5 38.0 29.5 29.0 * Leaf blade completely dead # Leaf blade no longer attached to plant t Central portion of stem broken off 2.27 Table 16. Continued. Date of observation 6/4/76 6/16/76 6/20/76 7/20/76 8/17/76 9/14/76 10/10/76 Study site (Leaf length (cm) in order of oldest to youngest leaf) PSAM plant #2 6.5* 4.0* # # ## 21.5 23.0 # # # # 32.5 35.5 33.0 # # # 21.0 32.0 31.8 32.0 31.5* 32.5* 19.0 31.8 32.0 32.5 29.0* 25.8 30.5 30.5 30.5* 14.1 32.7 32.6 32.5* 29.9 35.5 34.5 15.0 36.0 37.0 24.0 32.0 18.5 SAM plant #1 33.0* 34.0* # # 38.0 37.0* 29.0* # 24.0 24.5 24.0* 24.0* 38.5 39.0 38.5 38.0* 28.0 39.1 39.0 38.5 33. 0 32.0 24.5 25.7 15.0 SAT plant #1 20.0* # # # 26.0 27.0* # # 27.0 28.0 27.5* 28.0* 28.0 28.0 28.0 28.5* 19.5 33.0 34.0 33.5 19.0 34.0 34.0 28.0 27.0 * Leaf blade completely dead # Leaf blade no longer attached to plant Hofstra (1976), Kirby and Gosselink (1976), and Turner (1976) determination of aboveground primary production without taking into consideration vegetation death and disappearance can lead to significant underestimation of primary pro- duction. Table 17 presents the percentage of leaf losses during the growing season of plants at study sites PSAS and PSAM as well as percentages obtained from other researchers. The values obtained in this study are quite similar to those from other studies. While biomass losses due to vegetation death and disappearance during the growing season were not determined, it is apparent from this study that such losses should be taken into consideration in order to more accurately determine net aboveground primary production of salt marsh grasses. At the end of the growing season, new leaf development stops, but the same dieback and decay pattern occurs throughout the fall and by early December there is only dead brown tissue present. For the first 3 months after the end of the growing season the major causes of plant breakdown were rotting (from being 2.28 Table 17. Comparison of percent leaf loss of Spartina alterniflora during the growing season for several salt marsh studies. Marsh location % Leaf loss Author New Jersey This study PSAS 27.3 PSAM 31.5 Canada Tall 23.3 Hatcher and Mann 1975 Medium 27.1 Short 35.1 North Carolina Marsh average 19.3 Williams and Murdock 1972 Georgia Streamside 22.4 Odum and Fanning 1973 Medium and low marsh 8.9 Average all studies 21.6 constantly wet) and wind breakage. Wind breaks off the brittle tips of the higher leaves which are infrequently wetted by tidal water. This breakage is usually only 1 to 15 cm of the higher leaves and represents less than one per- cent of the total plant. Rotting of the lower leaves is responsible for the loss of 20% to 40% of the plant. In addition to leaf decay, the culm of the plant also begins to decay near the marsh surface by early December. By January and February many of the culms have rotted through. At the sites where there is heavy to moderate tidal flooding (SAT, SAM, PSAM), much of this material is washed from the marsh. Thus most of the plant material (60-80%) is not broken or decayed from off the plants while they are still standing, rather than most of the plant is removed as a whole. At the less flooded sites (SAS, PSAS) , decaying plant material tends to remain on the marsh surface. There are also differences in the breakdown of the different height forms of Spartina alterniflora which are caused by the placement of the leaves rela- tive to the marsh surface. Since it is the lower leaves which are rotted off while the plant is still standing, those height forms which have leaves near the base of the stem (SAS, SAM, PSAS) will lose a greater biomass before the stem is broken off. As the taller forms (SAT, PSAM) have their larger leaves up higher, these forms will tend to lose less material before the stem breaks. 2.29 DECOMPOSITION OF END OF THE SEASON PLANT MATERIAL Methods The in situ decomposition of Spartina alterniflora and Spartina patens was conducted at 10 stations during 1975-1976. The stations, shown on Figure 3, were established in two general areas, Mud Cove and Popular Point. Table 18 lists the 10 stations, their location, and type of plant material used. Study sites 1-6 were considered major stations while study sites 7-10 were considered minor stations. Study sites 1-8 used aboveground material while study sites 9- 10 used below ground material. Table 18. Study sites, locations, and vegetation used for the decomposition of end of season material study. Study sites and vegetation used Designation Popular Point 1. Spartina aZterniflora (short) (1) PSAS 2. " " (medium) (2) PSAM Mud Cove 3. Spartina alterniflora (short) (3) SAS 4. " " (medium) (4) SAM 5. " " (tall) (5) SAT 6. Spartina patens (6) S. patens 7. Spartina alterniftora (short) (7) SAS (placed belowground) 8. Spartina alternifZora (tall) (8) SAT (placed in ditch) 9. S. alterniflora (short) (9) SAS belowground material washed and placed on surface 10. S. alterniflora (short) (10) SAS belowground material cut in half and replaced belowground Plant material, consisting of aboveground standing dead culms (marsh cores for sites 9 and 10), was collected on 28 October 1975 and returned to the labo- ratory. Aboveground material was air dried with belowground material washed free from mud and debris before being air dried. 2.30 The decomposition of plant material was determined by the use of plastic net litter bags in the form of tubes approximately 50 cm long by 15 cm diameter filled with 100 g of air dried aboveground plant material. This arrangement al- lowed for a mesh size of 5 mm. Approximately 30-40 g of belowground material was used for sites 9 and 10. The bags were set out on 2 November 1975 and collections were made at 4 week intervals between 2 December 1975 and 10 October 1976. Three bags were retrieved on each sample date at study sites 1-5, two bags at study site 6, and one bag at study sites 7-10. After the bags were collected they were returned to the lab, washed of mud, air dried, and weighed. Weight loss was interpreted as the field decomposition rate. Ash content was measured in a Temco model F-1635 muffle furnace. Percent fat was determined by petroleum ether extraction for 3 hours in a Goldfisch Fat Extractor (Assoc. Offic. Agr. Chem. 1965). Crude fiber was determined ac- cording to the method in Cusmano and Scotton (1951). Percent Kjeldahl nitrogen of decomposition samples was determined using a modification of the macro- Kjeldahl method described by Skoog and West (1969) to a semimicro method. Per- cent crude protein was determined by multiplying Kjeldahl nitrogen content by 6.25 (Assoc. Offic. Agr. Chem. 1965). Results and Discussion PERCENT DECOMPOSITION - Percent weight loss of decomposition bags versus time (2 November 1975-10 October 1976) at all stations is listed in Table 19 and graphed on Figures 4-12. Linear regression analysis and calculation of correla- tion coefficients of percent weight loss of decomposition bags vs. time (2 No- vember 1975-10 October 1976) are presented in Table 20. Of the six major study sites, four - (1)PSAS, (2)PSAM, (4)SAM, and (5)SAT - had a very high positive linear correlation (r>.950) between percent weight loss and time. For study site (3)SAS this correlation was high (r=.918), but low (r=.584) for study site (6)S. patens. The linear correlation between percent weight loss and time at the minor study sites was high for (8)Sat (r=.953) and moderate for (7)SAS (r=.821) and (9)SAS (r=.776). The "very high" or "high" correlation coefficients found in six of the nine study sites indicate that a constant (linear) decompositional rate is statisti- cally significant. The results from this study differ with results obtained by other workers (Odum et al. 1973; Kirby and Gosselink 1976). Most decomposition curves for aboveground plant material of salt marsh species have three more or less distinct sections with differing slopes; an initial steep slope (high decomposition rate) section representing the rapid loss of soluble compounds; a second section with a more moderate slope (moderate decomposition rate) repre- senting the microbial breakdown of moderately labile compounds and the mechanical reduction of material by larger organisms such as amphipods; and a final gradual slope state (low decomposition rate) representing the slow breakdown of resistant material (Odum et al. 1973). To determine if a three step decomposition rate pattern existed in this study (despite strong statistical evidence for a constant decomposition rate) a calculation of the percent weight loss increment of decomposition bags for each sampling date at all study sites was made (Table 21). The percent weight loss increment was determined by subtracting the percent weight loss of decomposi- tion bags at a study site on a given sampling date from the percent weight loss at that study site on previous sampling date. A negative increment value would indicate that the percent weight loss of a sample was greater on the earlier 2.31 Table 19. Percent weight loss (+ 1 SD) for decomposition samples at all Popular Point and Mud Cove study sites from 2 December 1975 to 10 October 1976. Date (1) PSAS (2) PSAM (3) SAS (4) SAM (5) SAT (6)S. patens (7)SAS (8)SAT (9)SAS 12-2-75 14.4+ 4.0 11.6+8.1 23.6+ 6.8 7.8+10.4 14.7+6.0 21.3+10.1 11.3 6.0 - 12-30-75 15.6+11.0 18.7+2.0 27.5+ 6.7 28.6+ 4.8 17.2+1.0 24.7+ 5.6 14.6 12.9 2.8 1-26-76 30.6+ 2.5 29.2+6.2 32.1+ 5.1 29.4+11.4 20.6+5.1 13.7+ 0.6 - 15.8 17.2 2-23-76 27.2+ 2.2 18.2+6.2 36.5+ 9.2 39.8+ 5.5 21.9+7.8 11.6+ 2.7 4.2 24.9 2.9 3-25-76 35.3+ 7.4 24.7+4.9 33.9+ 0.3 41.8+ 0.5 23.9+9.3 23.3+ 2.3 8.9 23.8 12.0 4-26-76 34.3+ 3.7 36.9+3.1 27.3+ 1.9 43.3+ 8.8 30.8+6.5 26.0+15.6 18.3 21.3 1.1 5-20-76 43.0+ 3.4 56.9+3.1 42.1+ 5.3 53.8+ 9.3 39.8+3.0 36.2+18.0 21.2 48.6 10.2 6-23-76 48.0+11.0 50.2+5.6 39.8+ 6.8 55.1+ 7.5 47.7+3.2 26.6+ 9.1 29.4 46.5 7.9 7-20-76 51.3+ 1.8 63.7+4.7 46.7+11.5 74.7+ 3.1 58.7+8.4 12.7+ 0.1 26.0 - 11.2 8-17-76 59.0+10.2 79.1+1.9 53.6+ 7.8 89.7+ 3.5 65.5+5.5 23.1+ 1.1 - 71.9 38.1 9-14-76 55.9 77.2+2.6 72.1+15.6 82.6+ 6.4 69.4+4.6 36.7+15.1 - - 32.1 10-10-76 56.3+ 9.7 81.0+0.2 70.0+ 0.7 91.9+ 1.4 76.3 28.0 - - 44.0 ao - so - (1)PSAS 60 20- 0 11-2 12-2 12-31 1-26 2-23 3-26 4-26 5-20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 4. % wt. loss vs. time for (1)PSAS. Vertical lines = I SD. 100 - o80- (2)PSAM B 60- 40- 20 - 11-2 12-2 12-31 1-26 2-23 3-26 4-26 5-20 6-23 7-20 B-17 9-14 10-10 Sampling Date Fig. 5. o wt. loss vs. time for (2)PSAM. Vertical lines = 1 SD. 100- 80- 1(3)SAS 60- 40- 20- 11-2 12-2 12-31 1-26 2-23 3-26 4-26 5-20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 6. % wt. loss vs. time for (3)SAS. Vertical lines = 1 SD. 2.33 100. 80 (4)SAM JO60 40 20 11-2 12.2 12-31 1-26 2-23 3-26 4-26 5.20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 7. % wt. loss vs. time for (4)SAM. Vertical lines = 1 SD. 100 80~ (5) SAT -60 C40- 20 11-2 12-2 12-31 1.26 2-22 3-26 4-26 5-20 6-23 7-20 8-17 9.14 10-10 Sampling Date Fig. 8. % wt. loss vs. time for (5)SAT. Vertical lines = 1 SD. 00 8O (6)S. patens -60 040 20 11-2 12-2 12-31 1-26 2-22 3-26 4-26 5-20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 9. ?% wt. loss vs. time for (6)S. patens. Vertical lines = 1 SD. 2.34 100 - 80 - (7) SAS 60 - - c 40 - 20 - 11-2 12-2 12-31 1-26 2-23 3-26 4-26 5-20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 10. % wt. loss vs. time for (7)SAS. 100 e 80o - (8) SAT 60 - 0 20 - 11-2 12-2 12-31 1-26 2-23 3-26 4-26 5-20 6-23 7-20 8-17 9-14 10-10 Sampling Date Fig. 11. % wt. loss vs. time for (8)SAT. 100 - 80 - (9)SAS 60- - 11-2 12-2 12-31 1-26 2 23 3-26 4-26 5-20 6-23 7-20 8-17 9-4I 10-10 Sampling Date Fig. 12. % wt. loss vs. time for (9)SAS. 2.35 Table 20. Linear regression line equations and correlation coefficients (r) for percent weight loss of decomposition samples for the study period 2 November 1975 to 10 October 1976 at Popular Point and Mud Cove. Linear regression Correlation Study site line equation coefficient (r) (1)PSAS y = 8.86 + 4.56x .967 (2)PSAM y = 0.71 + 6.90x .971 (3)SAS y = 11.62 + 4.54x .918 (4)SAM y = 4.46 + 7.41x .979 (5)SAT y = 0.94 + 6.08x .983 (6)S. patens y = 12.66 + 1.53x .584 (7)SAS y = 2.97 + 2.55x .821 (8)SAT y = -3.00 + 6.52x .953 (9)SAS y = -4.98 + 3.11x .766 sampling date and would be an indication of the error involved in the method used to determine decompositional weight losses. Of the six major study sites, the greatest percent weight loss increment occurred in the first sampling date at three sites ((3)SAS, (5)SAT, and (6)S. patens) (Table 21). This large percent weight loss could be attributed to the loss of highly soluble materials in the plant tissue (the initial step in the three step pattern). A decrease in the percent weight loss increment in the latter stages of this study appears to occur at four of the six major study sites ((1)PSAS, (2)PSAM, (3)SAS, and (6)S. patens) (Table 21). This could be attributed to the slow breakdown of remaining resistant material (the last step in the three step pattern). While individual steps of the three step decompo- sition rate pattern exist at some study sites, only site (3)SAS appears to fit the three step decomposition pattern described by Odum et al. (1973). The minor study sites, (7) SAS and (8)SAT appear to fit a linear decomposition pattern while (9)SAS appears to follow neither pattern. It should be noted that site (9)SAS is a study of root material decomposition and may not fit patterns ob- served for aboveground material. Differences between results of this study and that of other workers appear to be related to several factors. First, the condition of the plant material used plays a major role. The use of live, fresh cut material will result in a large initial percent weight loss due to leaching of soluble materials (as discussed in the decomposition study of live "harvested" aboveground material section). The plant material used in the present study was harvested on 28 October 1975, a time when much of the soluble component of the plant had either been translocated to the roots or already been leached from the plant. Thus, initial percent weight losses due to leaching of such components would be small. It appears, therefore, that initial percent weight losses are strongly influenced by the soluble component content of the plant tissue. It was also 2.36 Table 21. Percent weight loss increments of decomposition samples at all Popular Point and Mud Cove study sites for the period 2 December 1975 to 10 October 1976. Study site 12/2 12/31 1/26 2/23 3/26 4/26 5/20 6/23 7/20 8/17 9/14 10/10 (1)PSAS 14.4 1.2 15.0 -3.4* 8.1 -1.0 8.7 5.0 3.3 7.7 -3.1 0.4 (2)PSAM 11.6 7.1 10.5 -11.0 6.5 12.2 20.0 -6.7 13.5 15.4 -1.9 3.8 (3)SAS 23.6 3.9 4.6 4.4 -2.6 -6.6 14.8 -2.3 5.9 6.9 18.5 -2.1 (4)SAM 7.8 20.8 0.8 10.4 2.0 1.5 10.5- 1.3 19.6 15.0 -7.1 9.3 (5)SAT 14.7 2.5 3.4 1.3 2.0 6.9 9.0 7.9 11.0 6.8 3.9 6.9 (6)S. patens 21.3 3.4 -11.0 -2.1 11.7 2.7 10.2 -9.6 -13.9 10.4 13.6 -8.7 (7)SAS 11.3 3.3 -10.4 4.7 9.4 2.9 8.2 -3.4 (8)SAT 6.0 6.9 2.9 9.1 -1.1 -2.5 25.5 -0.3 35.4 (9)SAS 2.8 14.4 -14.3 9.1 -10.9 9.1 -2.3 3.3 16.9 -3.0 * A negative value indicates that the percent weight loss was lower than the percent weight loss on the previous sampling date at that site. noted that the percent weight loss increment decreased toward the end of the study period at four of the six, major study sites. This trend indicates it is likely that the rate of decomposition does decrease in the later stages due to an increasing percentage of more refractory material. If this study could have been extended for a longer period of time, the decrease in the decomposition rate could have been more apparent. A decrease in the decomposition rate was not observed at any of the minor study sites, however, sampling at both (7)SAS and (8)SAT were completed earlier than at the major study sites and study site (9)SAS involving root material. While temperature did not appear to strongly influence decomposition in this study, other workers (Kirby and Gosselink 1976; Waits 1967) felt that temperature strongly influenced decomposition rates. Higher summer temperatures increased the rate of decomposition in those studies. A general pattern of decomposition of aboveground plant material at Mana- hawkin can be described under these special conditions. Because of the initial condition of the plant material used, percent weight losses due to leaching of soluble material are 'kept to a minimum. The only notable exception to this is at study site (3)SAS where the initial percent weight loss was quite high. Be- cause initial percent weight losses are not extremely high, decomposition rates are more or less constant from the start (representing the second step of the three step pattern). While this rate is constant at a particular site, rates vary from site to site depending upon the environmental conditions at each site and, to some extent, on the nature of the plant material itself. Results from this study indicate that, in general, the rate of decomposition is affected by moisture content and exposure to air. The highest decomposition rates are shown by (2)PSAM and (4)SAM, both intermediate height forms of Spar- tina alterniftora. These sites appear to have the best balance of exposure to air and moisture content (primarily due to flooding). Sites with less exposure to air due to more flooding ((5)SAT and (8)SAT, tall height forms of S. alter- niflora) have slightly lower decomposition rates. It was noted that decomposi- tion bags at these sites tended to be covered by mud and silt. This most likely created anaerobic conditions in some parts of the decomposition bags which may have slightly slowed down the decomposition process. This seems to indicate that aerobic decomposers are more efficient or plentiful than anaerobic decomposers. Sites with longer air exposure time (thus allowing for the drying out of the material) such as (1)PSAS and (3)SAS have even lower decomposition rates. The anaerobic site, (7)SAS, has a low decomposition rate. At some point the rate of decomposition decreases because of a relative increase in the amount of refrac- tory material left in the sample. This occurrence is most likely a function of the original decomposition rate, controlled by environmental conditions at that site, and the nature of the decomposing material itself. It appears that this stage was just beginning at most of the major study sites at the end of the study period. This stage was not evident at some of the major study sites and all of the minor study sites; thus correlation coefficients for linear decomposition rates remained quite high. If this study was longer, it is likely that a leveling off of the decomposition would have been evident, changing the decomposition process from a one step (linear) pattern to a two step pattern or even a three step pattern at site (3)SAS. The only exception to this general description is study site (6)S. patens which has a fluctuating pat- tern of percent weight loss with time. This site pattern could possibly be due to differences in washing the samples free from mud on the different sampling 2.38 dates. Study (9)SAS measured percent weight loss of root material placed on the marsh surface. Percent weight loss was low and fluctuated from the start of the study to 20 July 1976 followed by a sharp increase in percent weight loss for the remainder of the study period. Reasons for this pattern are not evident. Another factor which plays a role in the decomposition process is that of small organisms such as amphipods, snails, and crabs which accelerate the frag- mentation of plant material into smaller particles so they can be flushed out of litter bags by tidal action (Odum et al. 1973). While this factor was not investigated in the study, it was noted that small organisms (primarily amphi- pods and the snail Melamrpus) were found at study sites (1)PSAS, (2)PSAM, (3)SAS, (4)SAM, and (5)SAT. Such organisms at study sites (4)SAM, (2)PSAM, and (5)SAT no doubt help contribute to the high decomposition rates found at those sites. Anaerobic conditions at study site (8)SAT most likely limited association with these organisms, but apparently had little effect on the decomposition rate. While amphipods and Melacpus were found at sites (1)PSAS and (3)SAS, reduced flooding conditions resulted in lower decomposition rates. Sites with little flooding and/or anaerobic conditions ((6)S. patens, (7)SAS, (9)SAS) which had few associated small organisms, had the lowest decomposition rates. Because of differences in the mesh size of decomposition bags used, duration of the experiments, and environmental conditions, direct comparisons of decompo- sition rates obtained by other workers must be made with caution (Williams and Murdoch 1972). Burkholder and Bornside (1957) reported a z90% weight loss of S. alterniflora put in a shallow stream in Georgia after 300 days. At site (8)SAT in this study there was a 72.1% weight loss after approximately 300 days. Burkholder and Bornside, however, used wooden crates rather than decomposition bags. Odum and de la Cruz (1967) reported a 42% weight loss after 300 days for S. alterniflora placed at a stream side in Georgia. At a comparable site in this study ((5)SAT), there was a 65.5% weight loss after approximately 300 days. The mesh size of the decomposition bags used by Odum and de la Cruz was 2.5 cm compared to 5.0 cm in this study. Kirby and Gosselink (1976) working in Louisiana, found decomposition losses of 78% for short form S. alterniflora and 89% for tall form S. alterniflora after 11 months and 95% for tall form S. alter- niflora placed in a stream after 10 months. Results from comparable stations in this study were 72.1%, 69.4% and 71.9% respectively. Mesh size of decomposi- tion bags in the Kirby and Gosselink study was 2 mm. Seneca et al. (1976) working in North Carolina, found decomposition to be related to the leaf:stem ratio. S. alterniflora short form had the highest leaf:stem ratio and also the highest weight loss (-93% after 11 months) followed by S. alterniflora medium (-90% after 11 months) and S. alterniflora tall (~72% after 11 months). With the exception of S. alterniflora short, similar results were obtained in this study (70%, 91.9%, and 76.3% respectively). Seneca et al. (1976) also reported that litter bags placed in creeks had slightly slower decomposition rates when compared to litter bags containing the same type of material which were placed on the marsh surface. This agrees with the results from this study, but differs from that of Kirby and Gosselink (1976). In addition to differences in the decomposition bags used, environmental factors in these studies, such as tidal amplitude, varied greatly (from -50 cm in Louisiana to 1.8 m in Georgia). PERCENT ASH - Percent ash analysis for all samples in this study is presented in Table 22. At four of the six major study sites, there is a sharp decrease in 2.39 percent ash between the 2 November 1975 (initial plant material) and 3 December 1975 samples. It is thought that the high initial percent ash content of three of these sites ((l)PSAS, (4)PSAM, (6)S. patens) was in part a result of mud covering the plant material that was not completely removed. True percent ash content is probably close to that found at the other sites (9-13%). Minimum percent ash values occur between 3 December 1975 and 26 January 1976 at all of the major sites. It is felt that leaching of the mineral content of the plant material accounts for this minimum. All major sites show a general increase in percent ash from this minimum until 23 June 1976. Percent ash content at study sites (2)PSAM, (3)SAS, and (5)SAT then decreases until 17 August 1976; then in- creases for the remainder of the study period. At study site (I)PSAS, percent ash increases until 17 August 1976 then decreases for the rest of the study period, while at study site (6)S. patens, percent ash increases to 20 July 1976 * ~then shows a slight general decrease for the rest of the study period. Percent ash at study site (4)SAM shows a general increase until 14 September 1976 and then rises quite sharply on 10 October 1976. The high percent ash in this sample can be attributed to mud which was in the sample. The samples collected at this site on that sample date had undergone a large amount of decomposition (91.9% weight loss of the original sample) and was in small fragments. Treatment needed to effectively remove all mud trapped in the sample would have broken down the sample to a point where it would all be washed out of the decomposition bag. Table 22 presents data for the two minor sites at Mud Cove involving aboveground material. At study site (7)SAS there is a sharp drop in percent ash content from 2 November 1975 to 3 December 1975. The high initial ash content is most likely due to mud that was not completely washed off the plant material. Percent ash increased until 23 June 1976, then decreased on 20 July 1976. At study site (8)SAT there is a fluctuation in ash content (between 6 and 10%) throughout the entire study period. Table 22 shows percent ash values for the two minor sites at Mud Cove using belowground (root) material. Percent ash content is generally higher at these sites compared to aboveground material sites. At both (9)SAS and (10)SAS there is a general increase in percent ash to a maximum on 23 June 1976 followed by a decrease until 17 August 1976 with a subsequent increase for the remainder of the study. At a majority of the study sites there is, in general, an increase in per- cent ash content from a minimum in December or January to a maximum on 23 June 1976. This increase seems logical since mud tends to become incorporated with the plant material in the decomposition bags with time. This in turn requires a more vigorous washing of the decomposition bags to remove such mud. With increasing time, however, decomposition material becomes more "fragile" and has been broken down to a point where excessive and vigorous washing removes such material as well as mud from the bags. In order to prevent excessive material loss, decomposition bags must be washed less vigorously resulting in an increase in mud (ash) in the sample. The sharp decrease in percent ash content found at many sites from 23 June 1976 to 17 August 1976 is somewhat difficult to explain. One possible explanation is the method by which decomposition bags were pro- cessed. Decomposition bags collected from 3 December 1975 to 23 June 1976 were processed by one worker while all bags collected since 20 July 1976 were pro- cessed by the present graduate assistant on this study. A more vigorous washing of decomposition bags collected on 20 July 1976 and 17 August 1976 to remove mud would result in lower percent ash values. PERCENT CRUDE FAT - Table 23 presents crude fat values for all sites. Because of the backlog of samples, analysis at most study sites was made only to 2.40 Table 22. Percent ash content (1 1 SD) of samples at all study sites from 2 November 1975 to 10 October 1976. (6) S. Date (1)PSAS (2)PSAM (3)SAS (4)SAM (5)SAT .atens (7)SAS (8)SAT (9)SAS (10)SAS 11-2-75 20.07 11.91 17.88 13.45 9.07 18.99 17.88 9.07 12-2-75 8.11+ .38 10.69+2.03 6.71+1.37 9.11+ .47 9.13+ .55 5.52+ .56 6.24 5.94 17.63 12-30-75 6.39+ .66 7.97+ .35 6.36+ .28 11.11+ .77 8.02+2.01 3.70+ .98 5.46 9.05 11.21 15.65 1-26-76 6.56+1.15 8.06+2.68 5.94+1.29 10.04+3.46 7.29+ .59 6.44+ .50 9.75 10.33 2-23-76 11.55+1.29 12.39+ .51 7.66+1.21 11.16+ .50 8.97+1.56 7.88+ .13 8.89 6.78 12.00 22.32 3-25-76 9.61+1.15 9.07+2.39 8.39+ .72 9.70+1.06 8.44+ .69 6.27+ .23 9.66 8.17 14.46 13.00 4-26-76 9.19+ .08 9.93+ .69 10.59+1.05 13.94+2.11 8.52+1.23 5.94+ .32 10.17 9.67 15.99 13.79 5-20-76 9.02+1.70 8.56+1.38 9.04+1.54 12.96+2.49 9.02+1.28 5.21+ .99 11.28 7.76 17.57 20.47 6-23-76 11.55+1.06 11.69+3.65 12.49+1.23 18.36+6.76 11.43+ .38 7.08+ .35 12.23 10.79 24.14 39.91 7-20-76 13.87+3.38 8.76+2.58 8.66+2.80 14.23+3.53 8.68+2.23 8.21+ .75 8.39 20.42 18.59 8-17-76 15.60+2.84 5.70+1.05 6.90+1.59 19.10+3.04 6.64+ .63 5.39+ .90 7.33 15.30 13.20 9-14-76 12.52 8.11+4.33 6.80+1.51 13.33+2.18 9.72+ .92 7.23+1.91 14.62 24.90 10-10-76 10.95+1.89 12.87+3.29 8.41+3.05 33.23+3.38 11.41 6.57 17.20 23 June 1976. Of the six major study sites, all but (6)S. patens follow the same general pattern. For the first 20-24 weeks, percent crude fat at these sites in general remained fairly constant. Percent crude fat values at these sites ranged from z2.1% for (3)SAS to zl.5% for (5)SAT. After this period, percent crude fat values decrease reaching 1.07% at (3)SAS and 0.63% at (5) SAT by the end of the study. Except for a 26 January 1976 peak, percent crude fat values at (6)S. patens fluctuated between 0.74-1.25%. All of the minor study sites followed the same general pattern, but this pattern was shifted over an 8 week period between the four sites. All sites showed an increase in percent crude fat to a maximum between 2 December 1975 - 26 January 1976, fell to a minimum between 30 December 1976 - 24 March 1976, increased to a secondary maxi- mum between 25 March 1976 - 26 April 1976, and decreased. It is not known why all minor sites followed this pattern and why this pattern was followed. Percent crude fat was generally higher at sites (7)SAS and (8)SAT (1.20-3.11%) which used aboveground material than at sites (9)SAS and (10)SAS (0.29-2.30%) which used belowground material. Odum and de la Cruz (1967) reported a decrease in fat from :4% to >1% in decomposing S. aZterniflora. Teal (1962) working in the laboratory with finely ground inoculated Spartina material collected in midwinter found a gradual decrease in percent fat from z2.5% to zO.6% in 16 weeks. PERCENT CRUDE FIBER - The percent crude fiber of all samples that have been analyzed is presented in Table 24. Because of a backlog of samples, only samples to 23 February 1976 were analyzed. For this period the percent crude fiber of all decomposition samples (except (9)SAS (10)SAS) show, in most cases, an increase with time. Since crude fiber is a measure of materials (e.g. lignins and cellulose) which are more resistant to microbial decomposition, an increase in the percent crude fiber can be explained due to a differential decomposition rate between the crude fiber and noncrude fiber components of plant material. Percent crude fiber increased between z8%-21% at these sites from Z35-42% to 48-57% during a 16 week period. At sites (9)SAS and (10)SAS, using root and rhizome material, percent crude fiber remained fairly constant. Extreme caution must be used in applying the results obtained for crude fiber beyond the time period studied. It is not known whether percent crude fiber will continue to increase, level off, or decrease through time. Odum and de la Cruz (1967) noted for Spartina an increase in percent crude fiber followed by a decrease then another increase. Teal (1962) using finely ground inoculated Spartina in the laboratory, found a decrease in percent fiber from -35% to z8% in 16 weeks. PERCENT NITROGEN AND PERCENT CRUDE PROTEIN - Because of the backlog of samples to be processed, it was felt that analysis of samples from a single study site for the entire study period would be of more value than analysis of samples from all study sites on a single sampling date. Using this approach, all samplesi from study sites (3)SAS, (4)SAM, (5)SAT, and (6)S. patens were processed; results are presented in Table 25. Since crude protein is determined by multiplying Kjeldahl nitrogen content by 6.25 (Assoc. Offic. Agr. Chem. 1965), only nitrogen data will be discussed. Percent nitrogen levels at site (3)SAS followed a similar pattern as that of site (5)SAT. After a slight initial drop during the first four week period, percent nitrogen levels remained more or less constant for 20 weeks followed by an increase in percent nitrogen for the remainder of the study. Final percent nitrogen was greater than initial percent nitrogen content at site (3)SAS (0.83% vs. 1.27%) but not at site (5)SAT (1.45% vs. 1.35%). 2.42 Table 23. Percent (%) crude fat ash-free dry weight of samples at all study sites. (6) S. Date (1)PSAS (2)PSAM (3)SAS (4)SAM (5)SAT patens (7)SAS (8)SAT (9)SAS (10)SAS 11-2-75 1.71 1.82 1.61 1.73 1.20 1.37 1.61 1.20 12-2-75 1.86 1.67 2.15 1.96 1.53 0.94 2.52 1.50 1.13 12-30-75 1.47 2.31 2.13 2.55 1.56 1.02 1.58 2.76 0.29 2.05 1-26-76 2.23 1.84 2.11 1.71 1.55 1.65 3.11 2.30 2-23-76 1.82 1.83 2.00 1.77 1.52 0.85 1.98 1.81 1.24 0.95 3-25-76 2.02 1.87 2.12 1.76 1.57 1.19 1.76 1.75 0.89 1.38 4-26-76 1.96 1.85 2.09 1.66 1.30 1.25 2.23 2.87 1.32 0.92 5-20-76 1.79 1.35 1.75 1.29 1.30 1.19 1.83 1.60 0.76 0.99 6-23-76 1.75 1.61 1.72 1.13 0.85 0.99 1.85 1.27 0.83 1.28 7-20-76 1.53 1.14 0.84 0.88 8-17-76 1.51 0.75 1.05 0.76 9-14-76 1.45 1.04 0.74 10-10-76 1.07 0.63 1.00 Table 24. Percent (%) crude fiber ash-free dry weight of samples at all study sites from 2 November 1975 to 23 February 1976. Study sites 11/2/75 12/2/75 12/30/75 1/26/76 2/23/76 (1)PSAS 34.40 43.81 54.45 50.41 48.35 (2)PSAM 36.92 44.45 48.50 51.24 51.72 (3)SAS 34.74 44.07 47.22 51.30 55.70 (4)SAM 41.97 48.88 46.65 50.33 50.45 (5)SAT 35.68 47.18 47.35 50.16 54.72 (6)S. patens 42.85 49.37 53.90 51.68 57.05 (7)SAS 34.74 45.43 53.64 55.17 (8)SAT 35.68 44.81 46.47 52.46 42.10 (9)SAS 53.90 55.27 49.88 (10)SAS 35.33 38.62 36.92 At site (4)SAM there was also an initial decrease in percent nitrogen during the first 4 week period (1.23% to 0.93%). Percent nitrogen, however, increased immediately and continued to do so for the remainder of the study reaching a final value of 2.94%. As with site (3)SAS, the final percent nitrogen level was greater than the initial value although (4)SAM values at the later stages of the study were about two times higher than (3)SAS levels. Percent nitrogen values at site (6)S. patens showed no initial drop and fluctuated between 0.56% and 0.71% throughout the entire study period. Percent nitrogen at this site in general were the lowest of all the study sites ana- lyzed. The nitrogen and crude protein pattern observed at sites (3)SAS, (4)SAM, and (5)SAT is similar to that found by other workers using litterbags (Odum and de la Cruz 1967; Odum et al. 1973) or finely ground inoculated Spartina in the laboratory (Teal 1962; Gosselink and Kirby 1971). Work by Seneca et al. (1976) showed an increase in percent crude protein in all height forms of S. alterni- flora at the end of a 13 month study period, but the monthly pattern observed fluctuated and differed between sites. The pattern did not follow that de- scribed by Odum et al. (1973). The initial drop in percent nitrogen and protein has been attributed to a rapid breakdown of these components with the subsequent rise due to the en- richment of the plant material (detritus) by bacterial and fungal colonization as well as the loss of carbohydrate from the material (Odum et al. 1973). DECOMPOSITION STUDY OF LIVE (HARVESTED) ABOVEGROUND MATERIAL Methods A study of the decomposition of aboveground material at different stages of the growing season was conducted during the summer and fall of 1976. The 2.44 Table 25. Percent Kjeldahl nitrogen ash-free dry wt (� 1 SD) and percent crude protein ash-free dry weight (+ I SD) of samples at study sites (3)SAS, (4)SAM, (5)SAT, and (6) S. patens at Mud Cove from 2 November 19775 to 10 October 1976. Sample (3)SAS (4)SAM (5)SAT (6). patens date %C.F.* %K.N.# %C.P. %K,.N. %G.P. %K.N. %C.P. %K.N. 11-2-75 5.11 0.83 7.68 1.23 9.06 1.45 3.39 0.56 12-3-75 4.12+ .27 0.66+.05 5.97+ .30 0.96+.07 4,22+.76 O.68+.12 3.59+.22 O.58+.04 12-31-75 4.64+ .41 0.75+.07 6.49+ .31 1.04+.31 3.86+.43 0.63+.07 3.66+.06 0.59+.01 1-26-76 4.29+ .64 0.69+.10 7.07+ .64 1.13�.10 4.l1+.39 0.66+.07 3.50+.ll 0.57+.Ol 2-23-76 4.82+ .22 0.78+.04 7.76+ .38 1.25+.06 3.78+.53 0.62+.08 4.03+.Ol 0.65+.00 3-25-76 4.34+ .34 0.70+.07 7.09+ .34 1.14�.06 4.25+.47 0.68+.08 3.77+.14 0.61+.02 4-26-76 4.88*+ .11 0.78+.02 8.01+1.54 1.26+.25 4.53+.60 O.73�.10 3.55+.16 0.57+.03 5-20-76 5.23+ .42 0.84+.07 8.21+ .83 1.31+.13 4.87+.39 0.78+.06 3.69+.17 0.59+.03 6-23-76 5.42+1.00 0.87+.16 10.03+2.07 1.60+.33 4.69+.03 0.75+.01 4.02+.21 0.65+.03 7-20-76 5.44+ .69 0.87+.il 12.57+1.09 2.01+.18 6.19+.74 l.01+.11 4.39+.54 0.71+.08 8-17-76 6.87+ .42 1.10+.06 15.65+ .23 2.51+.04 7.13+.38 1.15+.07 3.77+.42 0.61+.08 9-14-76 7.36+ .51 1.18+.08 13.52+1.43 2.16+.23 7.21+.59 1.16+.09 4.29+.37 0.69+.06 10-10-76 7.89+ .64 1.27+.11 18.33+ .53 2.94+.06 8.52 1.35 4.16 0.66 * C.P. =crude protein # K.N. mKjeldahl nitrogen study sites selected were the same five major sites used in the 1975-76 Decomposition Study. The sites were (l)PSAS, (2)PSAM, (3)SAS, (4)SAI4, and (5)SAT. This was done so that results from this experiment could be directly compared to the 1975-1976 study. Live aboveground material was collected at each site on 4 June 1976. This material was returned to the laboratory where it was air dried, bagged in nylon netting, weighed, and returned to the field on 16 June 1976. Six decomposition bags were set out at each site. These bags were collected on 23 June 1976 (one bag at each site), 20 July 1976 (two bags), 17 August 1976 (two bags), and 14 September 1976 (one bag). A second collection of live material was made on 20 July 1976 and returned to the laboratory where it was processed as the first collection. Four decomposition bags for each site were returned to the sites on 17 August 1976. Two bags at each site were re- trieved on 14 September 1976 and two more on 10 October 1976. A third collec- tion of live material was made on 17 August 1976, processed in the laboratory, and returned to the sites on 14 September 1976 (two bags at each site). These bags were collected on 10 October 1976. Bags retrieved were washed of mud, air dried, and weighed. Weight loss through time was determined as the field decomposition rate. Results and Discussion 'Table 26 presents the weight loss of the live harvested decomposition bags at all sites for the entire study period. In looking at the first fresh clipped collection (material clipped 4 June 1976, set out 16 June 1976), the following patterns are noted. First, all sites showed a very high percent weight loss within one week. The percent weight loss was about the same for all sample sites (gzt35%). After this high initial decomposition rate, the rate decreased at all sites but to varying degrees. Sites PSAM and SAT had the highest percent weight loss (-80-85%) after 13 weeks (17 August 1976), while sites SAM, PSAS, and SAS had a lower percent weight loss (1:65%) after 13 weeks. These results differ greatly from those obtained in the 1975-76 decomposi- tion study in two major ways: (1) Percent weight loss through time in this study was not a linear relationship as it was in the 1975-76 study and (2) the rates of decomposition were much greater than in the 1975-76 study. Such differences can possibly be explained due to the type of material used in this study compared to the 1975-76 study. The initial material used in the 1975-76 study was standing dead material. Such material would contain very little soluble material such as sugars which would be lost rapidly in the first month of a decomposition study. Fresh clipped material (such as that used in this study) would have large amounts of soluble materials and could account for the large percent weight loss in the first week of a decomposition study. After this rapid ini- tial loss, the breakdown of more resistant material would occur at a slower rate. This could account for the rapid, non-linear decomposition rate of fresh clipped material. Squires and Good (1974) reported that percent crude fiber of S. alterniflora increases during the growing season. Therefore, fresh material clipped in June has a lower percentage of crude fiber (high % crude fiber slows decomposition) than material clipped in November. This, too, could help account for the higher decomposition rate in this study compared to the 1975-76 study. In looking at all three collection series, several trends are seen. At highly and moderately flooded sites (PSAM, SAM, SAT), the initial percent weight loss decreased with each succeeding live harvested collection series. It is thought than an increase in percent crude fiber and/or decrease in soluble com- ponents in the plant tissues during the growing season are factors influencing 2.46 Table 26. Percent weight loss (+ 1 SD) of live harvested decomposition bags at Popular Point and Mud Cove. Except where noted bags were set in the field on 16 June 1976. Study site Date of collection 6/23/76 7/20/76 8/17/76 9/14/76 10/10/76 (I)PSAS 35.3 39.2+3.2 59.6+2.2 61.9 13.7+2.1* 32.7+1.9* 24.1+1.7# (2)PSAM 34.7 71.5+1.3 84.2+0.7 184.8 57.9+1.1* 66.7+0.2* -- 34.97T (3)SAS 42.3+8.1 57.1+6.5 69.4 18.0+1.7* 56.6+6.0* 36.1+2.6# (4)SAM 32.5 50.8+0.4 66.1+2.6 80.7 35.4+2.8* 60.5+3.0* 43.8+5.5# (5)SAT 79.3+0.3 84.8+1.0 58.7+0.2* 68.0+0.4* 50.0+0.71# Bags set in field 8/17/76 # Bags set in field 9/14/76 the decrease in initial percent weight loss of live harvested material collected throughout the growing season. Initial percent weight losses at all these sites for all three collection series, however, were greater than the initial percent weight losses obtained at those sites in the 1975-76 Decomposition Study. At less flooded sites (SAS, PSAS), the initial percent weight loss of mate- rial in the third collection series was lower than the first collection series, but was about twice as great as that of the second live harvested collection series. It is not known why such a pattern would exist. Possible differences in flooding patterns at the less flooded sites at different times during the study period may effect initial percent weight losses. The decomposition pattern for live harvested material at all sites appears to fit a three step pattern as described by Odum et al. (1973) rather than a linear pattern found in the 1975-76 Decomposition Study. Decomposition of live harvested material is quite rapid when compared to the 1975-76 Decomposition Study. Percent weight losses of live harvested material from the first collec- tion series after 13 weeks (16 June 1976-14 September 1976) were nearly identical to percent weight losses of 1975-1976 Decomposition Study material after 48 weeks. It is felt that the difference in the soluble component and crude fiber content of the initial plant material used in the two studies ac- counts, to a large extent, such differences. 2.47 STUDY OF BELOWGROUND MATERIAL DECOMPOSITION Methods An attempt was made to measure the in situ decomposition of belowground (root and rhizome) material at two sites, SAS and S. patens (sites (3)SAS and (6)S. patens of the 1975-76 Decomposition Study). On 9 June 1976, 12 below- ground cores were taken to a depth of 30 cm at each site. Each core was cut in half lengthwise and weighed on a solution balance in the field. One core half was tagged and placed in a nylon mesh bag and returned to the core hole. The other core half was returned to the laboratory where all core halves were washed over a screen of 0.5 mm mesh to separate root material from mud. These roots were then air dried and weighed. At 4 week intervals between 23 June 1976 and 21 November 1976, 2 core halves from each site were removed from the marsh and returned to the laboratory where they were processed as the initial core halves. Based on the assumption that root and rhizome material is evenly distrib- uted throughout the two core halves, the dry root-rhizome weight (hereafter termed dry root weight) of the core half left in the core at the start of the study could be estimated using the following equation: dry root weight - core half returned 'dry weight to laboratory core half left in core hole wet weight entire wet weight entire core half (root x core half (root and mud) returned and mud) left in L to laboratory -core hole Core halves subsequently collected were processed and actual dry root weights were determined. Losses in dry root weight between calculated initial estimates and actual values when collected were considered as decompositional weight losses. Results and Discussion Estimated initial dry root weights for core halves left in the field as well as actual dry root weights for core halves collected from 23 June 1976 to 21 November 1976 are found in Table 27. This table also presents the difference in actual-initial dry root weights. As seen in Table 27, actual dry root weights for samples collected between 23 June 1976 and 14 September 1976 were greater than estimated initial dry root weights (with one exception). It ap- pears that root growth rather than root decomposition was taking place in both short form Spa~rtina alternif'lora and S. patens. It also appears that root bio- mass at both sites increased from 23 June 1976 through 14 September 1976. The large increase in actual dry root weight compared to initial weight for the 23 June 1976 and one of the 14 September 1976 SAS cores is probably due to mud that was not washed from the cores during processing. 2.48 Table 27. Estimated initial dry root weight, actual dry root weight, and actu- al-initial dry root weight difference for belowground samples collected from 23 June 1976 to 21 November 1976 at Mud Cove. Estimated Difference in initial Actual dry dry root wt. Sample site Collection date dry root wt. root wt. (actual-initial) (g) (g) (g) SAS 23 June 76 31.3 53.3 +22.0* SAS (a) 20 July 76 31.7 (b) 32.0 S. patens (a) 26.8 (b) 23.4 SAS (a) 17 August 76 34.9 32.9 - 2.0# (b) 36.8 39.7 + 2.9 S. patens (a) 23.3 26.8 + 3.5 (b) 28.3 32.0 + 3.7 SAS (a) 14 September 76 31.7 52.2 +20.5 (b) 29.9 37.0 + 7.1 S. patens (a) 23.6 29.8 + 6.2 (b) 24.5 35.0 +10.5 SAS (a) 10 October 76 31.0 39.0 + 8.0 (b) 34.4 34.1 - 0.3 S. patens (a) 24.2 22.8 - 1.4 (b) 29.1 23.6 - 5.5 SAS 21 November 76 32.2 33.1 + 0.9 * Positive value indicates increase in root biomass # Negative value indicates decomposition of root material It appears that the increase in root biomass in the cores was not due to root growth into the cores from outside surrounding root material as this was not visibly noticed during core collection. It was also noticed that limited shoot regrowth occurred on some but not all of the cores left in the field. On the 10 October 1976 collection there was a decrease in actual dry root weight compared to estimated initial weights for both S. patens and one SAS core sample. It appears that for at least S. patens there is some decomposition of root material. It is less apparent for SAS as one core sample gained weight and one lost weight, however, there was an overall decrease in dry root weight com- pared to September. The SAS core collected on 21 November 1976 showed a slight increase in dry root weight compared to the initial, but this increase was less than increases from previous sample dates. This seems to indicate that some belowground decomposition of SAS root material is taking place. The pattern of belowground biomass changes observed in this experiment is quite similar to that found in the belowground production study (Table 10). Belowground biomass at all S. patens and the disturbed SAS sites increased during the growing season to a maximum in August or September followed by a decrease in belowground biomass. Coring and bagging of belowground material during the late spring apparently has little or no effect on normally occurring 2.49 biomass changes during the growing season. Belowground biomass dynamics, there- fore, are quite stable and can respond to such stress quite readily. CONCLUSIONS Primary production in the Manahawkin marshes is derived from both the aquatic and terrestrial systems; both lower plants (algae) in the water and on the marsh surface as well as higher plants in the water and on the marsh. This study has been involved with the primary production resulting from the vascular plants of the marsh. The fate of the resulting biomass has also been followed through the decompositional process utilizing phenological studies as the link between production and decomposition. Furthermore, all phases of the produc- tion/decomposition process have been related to environmental parameters present. In the 1974 progress report of this study (Good and Smith 1974) comparisons of aboveground production to other areas were made. Later, belowground produc- tion information was obtained and comparisons with similar vegetation data were also made. A comparison of above and belowground production showed that below- ground production was about 5 times greater than aboveground. Values for total production that are available in the literature are often in the form of energy units. Therefore conversion of the biomass figures for SAS (the most abundant vegetation type of this study) to the same energy units allows for comparison. This is done by multiplying the caloric value per gram times the annual production (g.m-2) which gives kcal.m-2. Using values of 4.4 kcal.g-1 (aboveground) and 4.7 kcal.g-1 (belowground) for energy equivalents on an ash-free dry weight basis, the 500 g.m-2 (aboveground) and 3,000 g.m-2 (be- lowground) production estimates yield an energy value for SAS of approximately 16,000 kcal.m-2 which represents annual net primary production. Therefore, 320 ha covered by SAS at Manahawkin would thus have an annual net production of 5.12x109 kcal. This 16,000 kcal.m-2 value for SAS would fall into the 10-25 thousand kcal.m-2.y-1 range given by Odum (1971) for this type of system although down- ward adjustment must be made since his figures are for gross production. If we assume that net primary production is 60% of the gross primary production, the net primary production for Odum's range would be 6-15 thousand kcal.m-2.y-l; with SAS at the top of this range. Odum (1971) gives net primary production values of 15,200 kcal.m-2 for alfalfa and 13,000 for a mature rain forest; values which represent some of the highest presented. It therefore appears that the value of 16,000 kcal.m-2 is a good starting figure which can be used for net primary production of the SAS marsh types until further refinements can be made. Chemical analyses performed in this investigation and related studies (Smith 1976) revealed that standing crops of crude fiber, nitrogen free extract, crude fat (aboveground material only), and crude protein (belowground material only) were a function of dry matter biomass. Accumulation of crude protein (containing nitrogen) in aboveground material during the beginning of the growing season was thought to be a storage mechanism for nitrogen which is potentially limiting later in the growing season. Since this early season accumulation of nitrogen is not evident for the belowground component and since crude protein standing crop is directly related to belowground biomass, it appears that nitrogen is not as limiting as it is in the aboveground component. Woodhouse et 2.50 al. (1974) and Valiela et al. (1976) showed that application of nitrogen im- proved the aboveground production, but had little impact on the root-rhizome system. Woodhouse et al. (1974) felt that nitrogen and other nutrients such as phosphorus limited aboveground production because they are tied up in the large amount of belowground biomass. There is a possibility that with the compact nature of the root-rhizome system of SAS, space for root growth is limiting rather than nutrients. If indeed this form of S. alterniflora is limited by nitrogen and phos- phorus it may very well serve to remove these nutrients from the tidal waters. There are reports of freshwater marshes acting to improve dissolved oxygen as well as lowering nutrient levels (Grant and Patrick 1970) although a study of wetlands in Chesapeake Bay showed that the marshes were not functioning in this manner (Bender and Correll 1974). The general findings for North Carolina (Woodhouse et al. 1974) are that the marshes may be important in the recycling of nutrients that might otherwise occur as pollutants in the estuary. Woodhouse et al. (1974) feel that using marshes for removal of excessive nutrients in- creases growth of Spartina which would provide an increased supply of food en- ergy and nutrients to the detritus food chain rather than to other energy path- ways. That portion of the net primary production which is unharvested at the end of the growing season represents a large percentage of the yearly production (estimated for this study at 90%). While a majority of the study sites had the same general decomposition pattern, only those sites with similar environmental regimes had similar decomposition rates. In addition, the type of plant mate- rial in question may have an effect on the decomposition rate. Based on the litterbag studies, SAS loses approximately 4.5% of the origi- nal material per month during the first year of decomposition. SAT loses about 6.0% per month while S. patens loses about 1.5% per month during the first year of decomposition. Using 1975 aboveground production values of 444 g.m-2 for SAS, 735 g.m-2 for SAT and 535 for S. patens, approximately 20 g.m-2-month-1 (SAS), 44 g-m-2.month-1 (SAT) and 8 g'm-2-month-l (S. patens) of plant material enters the detrital food chain. These values, however, do not account for all vascular plant material which enters the detrital food chain. Material lost during the growing season should also be included. It was shown for S. alterniflora in the phenological study section of this report that some aboveground plant material dies during the growing season and undergoes decomposition. The rate of decomposition of this material is much greater than material which undergoes decomposition at the end of the growing season. While biomass losses were not directly measured, it was estimated that about 10% of net aboveground production is lost in this manner. Using the previously stated production figures and a 5 month growing season (May-September) approximately 9 g.m-2-month-1 (SAS) and 15 g.m-2.month-1 (SAT) are contributed during the growing season. The amount contributed by S. patens was not determined but would be quite small. It was shown in this study that end of the season material doesn't decom- pose entirely in 1 year. Therefore, contributions to the detrital food chain made by this older material must be considered. It was shown in this study that 2.51 there appears to be a fairly large decrease in the decomposition rate of plant material by the end of the first year of decomposition at many of the major study sites. Also, it is this older material which becomes incorporated into the marsh itself. Once incorporated into the marsh, the amount of plant mate- rial which becomes part of the detrital food chain, is quite small. With these two factors taken into account, the contribution made by this older decaying plant material to the detrital food chain would be small. While SAS contributes less than half the amount of plant material than does SAT to the detrital food chain on a meter square basis, the large coverage of SAS (320 ha) and small coverage of SAT (9 ha) make SAS the most important source of detritus in the Manahawkin marshes. S. patens, an abundant type (140 ha) represents a vast store of plant material in a temporarily nonusable form for the detrital food chain. It has a higher average production than the short form of S. alterniflora and it loses very little material over the year. Thus there is an accumulation of material espececially in the S. patens sites which only slowly and partially decomposes, becoming available to consumers. Chemical analysis of decomposition material revealed that for nearly all study sites percent crude fat decreased and percent crude protein increased by' the end of the study period. Percent crude fiber analysis of early samples showed an increase with time. The increase in percent crude protein was attributed to colonization of the plant material by bacteria and fungi. Odum and de la Cruz (1967) and Odum et al. (1973) have stated that it is the micro- bial enrichment of detritus which makes it a good food source for consumers; better than the grass tissue that forms the base of most detritus. The Barnstable (Massachusetts) intertidal marsh with its high flooding frequency has been shown to have an average rate of vertical accretion of 1.83 cm.year-i (Redfield 1972). This accretion is due to input of sediment from the flooding tide as well as any net accumulation of organic matter (from primary production of vascular plants). In the high marsh at Barnstable (vegetated by S. alterniflora short form and S. patens) the increase in ele- vation has been at a rate which exceeded the general rise in sea level during the several thousand years of its existence; exceeding it by 15.2 cm in 103 years (Redfield 1972). Since the opportunity for sediment input is reduced in the less frequently flooded high marsh, the contribution from incompletely decomposed plant material may be significant. Specifically, Redfield's find- ings at Barnstable should be considered in interpreting the low rate of decom- position for S. patens and its role in marsh accretion at Manahawkin. In interpreting the results for S. aZterniflora short form, the contribution by the belowground biomass (Table 10) in marsh accretion should be considered as balancing out the greater rate of decomposition for the aboveground material of S. alternifZora compared to S. patens. Since the Manahawkin marshes have probably existed for a similar period of time as the Barnstable marshes (Daddario 1961) and the marsh sediments are partially plant material in origin, a fine balance must exist, (now and in the past) among production, decomposition, detrital export, accumulation, and incorporation. For the marsh to remain stable these processes must also be in balance with tide levels and on a long term basis, sea level. Figure 13 is a model of these dynamic processes for a salt marsh plant community like Spar- tina alterniflora. The status of the marsh is then dependent on the rates of these processes. 2.52 Solar Input Standing Dying [ Sen~~V~ Dead Shoot A bP or Lit ter vo Leaching ed edmenta tion > U -ed ot no Particulate Dissolved n dn L Da S/IMaterial RhzMatter I R an Fig. 13. A model of the dynamic processes of a Spartina a~ternif~oraeP A oo T marshentatioi co) Boxe r c o gu rc ot Particulate eac / n o dn Fragmen a Dead Stem Bases, Roots and Dying Stem Bases, Senescence Rh i zornes I (Deat Roots and Rhizomes Fig. 13. A model of the dynamic processes of a Spartina alternifora salt marsh community. Boxes represent components of the system with diamonds re- presenting processes occurring within the system. Arrows show the possible in- puts, exports, and transfers which can occur. (Modified from Gallagher 1977). 2.53 REFERENCES CITED Association of Official Agricultural Chemists. 1965. Official methods of analysis. Assoc. Offic. Agr. Chem., Washington, D.C. 957 p. Bender, M. E. and D. L. Correll. 1974. 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L. 1974. Sampling macro-organic matter profiles in salt marsh plant root zones. Soil Sci. Soc. Am. Proc. 38: 154-155. . 1975. Effect of an ammonium nitrate pulse on the growth and elemental composition of natural stands of Spartina aZterniflora and Juncus roemarianus. Am. J. Bot. 62: 644-648. 1978. Decomposition processes: Summary and recommendations, p. 145-151. In R. E. Good, D. F. Whigham, and R. L. Simpson (eds.) Fresh- water wetlands: Ecological processes and management potential. Academic Press, N. Y. Good, R. E. 1965. Salt marsh vegetation, Cape May, New Jersey. Bull. N. J. Acad. Sci. 10: 1-11. . 1972. Salt marsh production and salinity. Bull. Ecol. Soc. Am. 53: 22. (abstract) -. 1977. An environmental assessment of the proposed reconstruction of State Route 152 (Somers Point-Longport) Atlantic County, New Jersey. A report submitted to E. Lionel Pavlo Engineering. Center for Coastal and Environmental Studies. Rutgers Univ., New Brunswick, N. J. 49 p. 2.55 and K. Smith. 1974. 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Primary production in a Louisiana Gulf Coast Spartina aZternifZlora marsh. Ecology 57: 1052-1059. Mendelssohn, I. A. and K. L. Marcellus. 1976. Angiosperm production of three Virginia marshes in various salinity and soil nutrient regimes. Chesapeake Sci. 17: 15-23. Milner, C. and R. E. Hughes. 1968. Methods for the measurement of the primary production of grasslands. IBP Handbook No. 6. Blackwell Sci. Publ. Oxford. 70 p. Nadeau, R. J. 1972. Primary production and export of plant materials in the salt marsh ecosystem. Ph.D. dissertation, Rutgers University. 175 p. Odum, E. P. 1961. The role of tidal marshes in estuarine production. The Conservationist 15: 12-15. . 1971. Fundamentals of Ecology. W. B. Saunders Co., Philadelphia. 574 p. and A. A. de la Cruz. 1967. Particulate organic detritus in a Georgia salt marsh-estuarine ecosystem, p. 383-388. In H. Lauff (ed.) Estuaries. AAAS, Washington, D. C. and M. E. Fanning. 1973. Comparison of the productivity of Spar- tina alterniflora and Spartina cynosuroides in Georgia coastal marshes. Bull. Ga. Acad. Sci. 31: 1-12. , J. C. Zieman, and E. J. Heald. 1973. The importance of vascular plant detritus, p. 91-114. In R. H. Chabreck (ed.) Proceedings of the coastal marsh and estuary management symposium. LSU Div. Continuing Education, Baton Rouge. 2.56 Parr Instrument Company. 1968. Oxygen bomb calorimetry and combustion methods. Technical Manual No. 130. Parr Inst. Co., Moline, Ill. 56 p. Redfield, A. C. 1972. Development of a New England salt marsh. Ecol. Monogr. 42: 201-237. Reed, A. and G. Moisan. 1971. The Spartina tidal marshes of the St. Lawrence estuary and their importance to tidal birds. Le Naturaliste Canadien 98: 905-922. Reiners, W. A. and N. M. Reiners. 1972. Comparison of oxygen-bomb combustion with standard ignition techniques for determining total ash. Ecology 53: 132-136. Seneca, E. D., L. M. Stroud, D. Blum, and G. R. Noggle. 1976. An analysis of the effects of the Brunswick Nuclear Power Plant on the productivity of Spartina alternifZora (smooth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden Creek marshes, Brunswick County, North Carolina, 1975-1976. Third Annual Report to Carolina Power and Light Company, Raleigh, N. C. 335 p. Shea, M. L., R. S. Warren, and W. A. Niering. 1975. Biochemical and trans- plantation studies of the growth form of Spartina aZterniflora on Connecticut salt marshes. Ecology 56: 461-466. Skoog, D. A. and D. M. West. 1969. Fundamentals of analytical chemistry. Holt, Rinehart, and Winston, Inc., N. Y. 835 p. Smith, K. K. 1976. Production ecology and dynamics of belowground material in a Spartina alterniflora salt marsh. M. S. thesis, Rutgers University. 83 p. Squires, E. R. and R. E. Good. 1974. Seasonal changes in the productivity, caloric content, and chemical composition of a population of salt-marsh cordgrass (Spartina alterniflora). Chesapeake Sci. 15: 63-71. Steever, E. Z. 1972. Productivity and vegetation studies of a tidal salt marsh in Stonington, Connecticut: Cottrell marsh. M. A. thesis, Connecticut College. 56 p. , R. S. Warren, and W. A. Niering. 1976. Tidal energy subsidy and standing crop production of Spartina alterniflora. Estuarine Coastal Mar. Sci. 4: 473-478. Stroud, L. M. 1976. Net primary production of belowground material and carbohydrate patterns of two height forms of Spartina aZterniflora in two North Carolina marshes. Ph.D. dissertation, North Carolina State University. 140 p. Stuckey, I. H. 1941. Seasonal growth of grass roots. Am. J. Bot. 28: 486-491. Sullivan, M. J. and F. C. Daiber. 1974. Response in production of cordgrass, Spartina alterniflora, to inorganic nitrogen and phosphorus fertilizers. Chesapeake Sci. 15: 121-124. 2.57 Teal, J. M. 1962. Energy flow in the salt marsh ecosystem of Georgia. Ecology 43: 614-624. Turner, R. E. 1976. Geographic variations in salt marsh macrophyte production: A review. Contrib. Mar. Sci. 20: 47-68. Udell, A. F., J. Zardusky, and T. E. Doheney. 1969. Productivity and nutrient values of plants growing in the salt marshes of the Town of Hempstead, Long Island. Bull. Torrey Bot. Club 96: 42-51. United States Department of Commerce. 1973, 1974, 1975, 1976. Climatological Data. Annual Summary. New Jersey National Oceanic and Atmospheric Admin- istration. Environmental Data Service. Vols. 78-81. 1976. High and low water predictions, east coast of North and South America including Greenland. 290 p. Valiela, I. and J. M. Teal. 1974. Nutrient limitation in salt marsh vegetation, p. 547-563. In R. J. Reimold and W. H. Queen (eds.) Ecology of halophytes. Academic Press, N. Y. _ _ ___, , and N. Y. Persson. 1976. Production and dynamics of experimentally enriched salt marsh vegetation. Limnol. Oceanogr. 21: 245- 252. Waisel, Y. 1972. Biology of halophytes. Academic Press, N. Y. 359 p. Waits, E. D. 1967. Net primary productivity of an irregularly-flooded North Carolina salt marsh. Ph.D. dissertation, N. Carolina State University. 124 p. Wass, M. S. and T. D. Wright. 1969. Coastal wetlands of Virginia Interim Rept. to the Governor and General Assembly. Va. Inst. Mar. Sci. Special Report in Appl. Mar. Sci. and Oceanogr. Engr. 10. 154 p. Williams, R. B. and M. B. Murdoch. 1972. Compartmental analysis of the pro- duction of Juncus roemerianus in a North Carolina salt marsh. Chesapeake Sci. 13: 69-79. Woodhouse, W. W., E. D. Seneca, and S. W. Broome. 1974. Propagation of Spar- tina aZternifZora for substrate stabilization and salt marsh development. U. S. Army Corps of Engineers, Coastal Engineering Research Center, Fort Belvior, Va. Technical Memorandum No. 46. 155 p. 2.58 APPENDIX A Tables and Figures from the June 1974 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity LIST OF FIGURES Figure Page 2a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina alterniflora - short form Station 2, 1973 . . 2.70 2b Aboveground litter standing crop (g.m-2). Spartina aZ- terniflora - short form Station 2, 1973 . . . . . . . .... 2.70 3a Aboveground standing crop and ash-free dry weight standing crop (g'm-2). Spartina alterniflora - short form Sta- tion 4, 1973 . . . . . . . . . . . . . . . . . . . . . . . . . 2.70 3b Aboveground litter standing crop (g.m-2). Spartina aZterni- flora - short form Station 4, 1973 . . . . . . . . . . .... 2.70 4a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina alternifZora - short form Station 7, 1973 . . . . . . . . . . . . . . . . . . . . . . . . . . 2.70 4b Aboveground litter standing crop (g.m-2). Spartina alter- niflora - short form Station 7, 1973 . . . . . . . . . . . . . 2.70 5a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina alterniflora - short form Station 9, 1973 . . . . . . . . . . . . . . . . . . . . . 2.71 5b Aboveground litter standing crop (g.m-2). Spartina aZter- niflora - short form Station 9, 1973 . . . . . . . . . .... 2.71 6a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina aZternifZora - short form Sta- tion 11, 1973 ........................ 2.71 6b Aboveground litter standing crop (g.m-2). Spartina alter- niflora - short form Station 11, 1973 . . . . . . . . . . 2.71 7a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina aZterniflora - short form Sta- tion 14, 1973 .................2.71 7b Aboveground litter standing crop (g.m-2). Spartina alter- niflora - short form Station 14, 1973 . . . . . . . . .... 2.71 8a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina patens Station 1, 1973 . . . . . ... 2.72 8b Aboveground litter standing crop (g.m-2). Spartina patens Station 1, 1973 ....................... 2.72 9a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina patens Station 3, 1973 . . . . . ... 2.72 9b Aboveground litter standing crop (g.m-2). Spartina patens Station 3, 1973 ....................... 2.72 10a Aboveground standing crop and ash-free dry weight standing crop (g-m-2). Spartina patens Station 6, 1973 . . . . . . . . 2.72 10b Aboveground litter standing crop (g-m-2). Spartina patens Station 6, 1973 . . . . . . . . . . . . . . . . . . 2.72 lla Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina patens Station 8, 1973 . . . . . ... 2.73 2.59 Figure Page llb Aboveground litter standing crop (g.m-2). Spartina patens Station 8, 1973 . . . . . . . . . . . . . . . . . 2.73 12a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina patens Station 10, 1973 ....... 2.73 12b Aboveground litter standing crop (g.m-2). Spartina patens Station 10, 1973 . . . . . . . . . . . . . . .. 2.73 13a Aboveground standing crop and ash-free dry weight standing crop (g'm-2). Spartina patens Station 13, 1973 . . . . . . . 2.73 13b Aboveground litter standing crop (g.m-2). Spartina patens Station 13, 1973 . . . . . . . . . . . . . . . . . . . . . . 2.73 14a Aboveground standing crop ash-free dry weight standing crop (g.m-2). Spartina patens Station 16, 1973 ....... 2.74 14b Aboveground litter standing crop (g.m-2). Spartina patens Station 16, 1973 . . . . . . . . . . . . . . . . . 2.74 15a Aboveground standing crop ash-free dry weight standing crop (g.m-2). Spartina aZterniflora tall form Station 5, 1973 . . 2.74 15b Aboveground litter standing crop (g' m-2). ' Spartina a- ternifZora tall form Station 5, 1973 . . . . . . . . .... 2.74 16a Aboveground standing crop ash-free dry weight standing crop (g.m-2). Spartina alternif7ora tall form Station 12, 1973 . . . . . . . . . . . . . . . . . . . . . . . . 2.74 16b Aboveground litter standing crop (g.m-2). Spartina aZter- nifZora tall form Station 12, 1973 . . . . . . . . . .... 2.74 17a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Spartina aZterniflora tall form Station 15, 1973 . . . . . . . . . . . . . . . . . . . . . . . . . . 2.75 17b Aboveground litter standing crop (gm-2). Spartina aZterni- flora tall form Station 15, 1973 . . . . . . . . . . . . 2.75 18a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). DistichZis spicata and Juncus gerardi .2.75 18b Aboveground litter standing crop (g.m-2). DistichZis spicata and Juncus gerardi Station 17, 1973 . . . . . . . . . 2.75 19a Aboveground standing crop and ash-free dry weight standing crop (g.m-2). Distichlis spicata Station 18, 1973 . . . . . . . . . . . . . . . . . . . 2.75 19b Aboveground litter standing crop (g.m-2). DistichZis spicata Station 18, 1973 .................. 2.75 20a Salinity and precipitation values for Stations 2 and 4 (Spartina aZterniflora short form) from August through December 1973 . . . . . . . . . . . . . . . 2.78 20b Salinity and precipitation values for Stations 2 and 4 (Spartina aZterniflora short form) from January through May 1974 . . . . . . . . . . . . . . . . . 2.78 21a Salinity and precipitation values for Stations 7 and 9 (Spartina alterniflora short form) from August through December 1973 .................... 2.78 21b Salinity and precipitation values for Stations 7 and 9 (Spartina aZternifLora short form) from January through May 1974 ...................... 2.78 22a Salinity and precipitation values for Stations 11 and 14 (Spartina alternifZora short form) from August through December 1973 . . . . . . . . . . . . . . . . . . 2.79 2.60 Figure Page 22b Salinity and precipitation values for Stations 11 and 14 (Spartina altterniflora short form) from January through May 1974 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.79 23a Salinity and precipitation values for Stations 1, 3, 6, and 8 (Spartina patens) from August through December 1973 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.79 23b Salinity and precipitation values for Stations 1, 3, 6, and 8 (Spartina patens) from January through May 1974 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.79 24a Salinity and precipitation values for Stations 10, 13, and 16 (Spartina patens) from August through December 1973 ........................ 2.80 24b Salinity and precipitation values for Stations 10, 13, and 16 (Spartina patens) from January through May 1974 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.80 25a Salinity and precipitation values for Stations 5, 12, and 15 (Spartina alternifZora tall form) from August through December 1973 . . . . . . . . . . . . . . . . . 2.80 25b Salinity and precipitation values for Stations 5, 12, and 15 (Spartina alterniflora tall form) from January through May 1974 ............... 2.81 26a Salinity and precipitation values for Station 17 (Distichlis spicata with Juncus gerardi) and Station 18 (D. spicata) from August through December 1973 . . . . . . . . . . . . . . . . . . . . . . . . 2.81 26b Salinity and precipitation values for Station 17 (Distichlis spicata with Juncus gerardi) and Sta- tion 18 (D. spicata) from January through May 1974 . . . . . . 2.81 2.61 LIST OF TABLES Table Page _ ~~~~~~~~~~~~~~~~~~Page 2 Mean dry weight - one standard deviation (g.m-2) of live and litter for Spartina alterniflora short form (SAS) for stations 2, 4, 7, 9, 11, and 14 throughout the 1973 growing season ... . ............... . . . . . . 2.65 3 Mean dry weight - one standard deviation (g'm-2) of live and litter for Spartina patens for stations 1, 3, 6, 8, 10, 13, 16 throughout the 1973 growing season . . . . . . . . 2.66 4 Mean dry weight - one standard deviation (g.m-2) of Spartina alternifiora tall (SAT) for stations 5, 12, and 15 throughout the 1973 growing season . . . . . . . . . . 2.67 5 Mean dry weight - one standard deviation (g.m-2) of live and litter for Distichlis-Juncus for stations 17 and 18 throughout the 1973 growing season . . . . . . . . . . . . 2.68 6 Mean seasonal dry weight (g. m-2) for all stations by species throughout the 1973 growing season . . . . . . . . . . 2.69 7 Peak live standing crop, peak litter standing crop, dates of peak live and litter standing crops and ratios of live to dead on those dates . . . . . . . . . . . . . . . . . 2.76 8 Change in litter standing crop (g.m-2) for the five com- munities . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.77 2.63 Table 2. Mean dry weight - one standard deviation (g-m-2) of live and litter for Spartina alterniflora short form (SAS) for stations 2, 4, 7, 9, 11, and 14 throughout the 1973 growing season. Month Station no. 2 4 7 9 11 14 Live Litter Live Litter Live Litter Live Litter Live Litter Live Litter 7A 380-60 184-53 389-40 142-39 405-86 265-38 7B 393-89 146-56 8A 306�126 168-144 8B 547-60 159-26 9A 669�33 944-11 484-13 213-28 633-231 513-44 442-146 535-243 734-42 243-5 9B 360-80 673-45 353-25 165-19 10A 473-117 395-5 295 381 422-32 467-13 O1B 348-11 574-100 232-36 364-134 234-0 689-4 273-4 494-11 349-30 434-98 369-83 353-117 11A 188�6 823-110 A First to fifteenth of month B Sixteenth to end of month Table 3. Mean dry weight - one standard deviation (g.m-2) of live and litter for Spartina patens for stations 1, 3, 6, 8, 10, 13, 16 throughout the 1973 growing season. Month Station no. 1 3 6 8 10 13 16 Live Litter Live Litter Live Litter Live Litter Live Litter Live Litter Live Litter 7A 344-62 525-111 7B 440-118 525�0 390-81 902-134 458-66 1275�183 498+36 927�68 691-42 665-42 8A 558-3 763-4 8B 613-15 612-40 680-10 505-0 631�13 632-121 694-64 743-33 380-16 488-74 9A 684-11 308-26 519-202 1183-174 746-0 844-112 9B 601-144 545-63 428-140 1528-139 425-35 688-180 548-247 464-93 559-64 887-111 365-124 529-66 A First to fifteenth of month B Sixteenth to end of month Table 4. Mean dry weight - one standard deviation (g.m-2) of Spartina aZternifZora tall (SAT) for stations 5, 12, and 15 throughout the 1973 growing season. Month Station no. 5 12 15 Live Litter Live Litter Live Litter 8A 639+85 306+119 8B 1098+255 609-109 739-82 270-49 9A 9B 10A 368-45 327-23 10B 666-208 624-4 322-22 405-73 477-18 360-30 11A 358-108 771-146 491-47 256-2 A First to fifteenth of month B Sixteenth to end of month Table 5. Mean dry weight + one standard deviation (g.m-2) of live and litter for Distichlis and Distichlis-Juncus for stations 17 and 18 throughout the 1973 growing season. Month Station no. 17 18 Live Live Distichlis Juncus Litter Live Litter 8A 189-59 325-120 278-49 8B 364-102 150-28 557-211 644-77 937-113 9A 9B 1OA 235 - 57 636+69 565-60 561-86 A First to fifteenth of month B Sixteenth to end of month 2.68 Table 6. Mean seasonal dry weight (g'm 2) for all stations by species throughout the 1973 growing season. S. aSterniflora S. patens S. alterniflora D. spicata D. spicata-Juncus short tall Month Live Litter Live Litter Live Litter Live Litter Live Litter 7A 391 197 (344) (525) 7B (393) (146) 495 859 8A (306) (168) (558) (763) 639 306 515 278 8B 515 178 600 596 919 440 644 937 514 557 9A 592 490 650 778 9B 356 419 488 774 lOA 396 414 365 327 565 561 235 636 10lOB 300 485 488 463 11llA (188) (823) 425 514 Parentheses indicate that figure represents one station. A. First to fifteenth of month B. Sixteenth to end of month 1200 - 1200 - 1200 Fig. 2 a. Spartina alterniflora-short form Fig. 2 b, Spartina alterniflora-short forr Station 2, 1973 Station 2, 1973 1000 - 1000- 800 - 800 - 600 - 600 400- 400 Standing Crop 200 - ____ Ash-free Standing Crop 200 - NE o 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 1200 N 1200 - 1200-E 120- Fig. 3 b. Spartina alterniflora-short form Spartina alterniflora-short form Station 4, 1973 o o Station 4, 1973 0 00- 800- - [. c 600 - , 600 - *0 -. - 400- -- 400 - n 200 - Standing Crop 0 a ---- ---Ash-free Standing Crop 200 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 1200 - 1200 - Fig. 4 a. Spartina alterniflora-short form Fig. 4 b. Spartina alterniflora short form Station 7, 1973 Station 7, 1973 1000 - 1000 - 800- 800 - 600 - 600- 400- Y, 400 - 200 - Standing Crop 200- Ash-free Standing Crop 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/ 1 11/1 Date Date Figs. 2 a, 3 a, and 4 a. Aboveground standing crop Figs. 2 b, 3 b, and 4 b. Aboveground litter standing and ash-free dry weight standing crop (g m-2). crop (g-m-2). 2.70 1200 - 1200 - Fig. 5 b. Spartina alterniflora- short form Fig. 5 a. Spartina alterniflora short form Station 9, 1973 Station 9, 1973 1000 800- 800- 600 - 600 - 400 - 400 - 200 - Standing Crop 200- Ash-free Standing Crop E 7/1 8/1 9/1 1011 1111 7/1 8/1 9/1 10/1 11/1 a 1200 - 1200 - c 1200 - E 1200- Fig. 6 b. Spartina alterniflora-short form Fig. 6 a. Spartina alterniflora-short form c ' Station 11, 1973 v Station 11, 1973 r 00 0 1000 - , lo00 - � -, 800 800- 400- 400 - Standing Crop N 200 - Ash-free Standing Crop , 200 - xo 0: 7/1 8/l 9/1 10/1 11/1 7/1 8/1 9/1 101 1 11/1 1200 - 1200 - �, 1200 - 1200- Spartina alterniflora-short form Spartina alterniflora-short form Fig. Station 14, 1973 Fig. 7 a. Station 14, 1973 1000 - 1000- 800 - 800- 600- 600 - 400- . 400- 200 Standing Crop 200 - Ash-free Standing Crop 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 Date Date Figs. 5 a, 6 a, and 7 a. Aboveground standing crop Figs. 5 b, 6 b, and 7 b. Aboveground litter standing and ash-free dry weight standing crop (g'm-2). crop (g9m-2). 2.71 1200 - 1200 - Spartina patens Fig. 8 a. Station 1, 1973 Station 1, 1973 1000 - 1000 - 800- 800- 600- 600- 400 - 400 - Standing Crop 200 - ---- Ash-free Standing Crop 200- E o 7/I 8/1 9/1 10/1 11/I 7/1 8/1 9/1 10/1 11 /1 - 1200 120 Spartina patens a SPartina patens 19. 9 a. Station 3, 1973 ' Fig. 9 b Station 3, 1973 o0 100-00 . C OO 600 400 - 400 TP ---- ~~~ Standing Crop 200- Ash-free Standing Crop 200 3 11 8/I 9/I 10D/- 111 7/1 8/1 9/1 10/ 11 /1 1800 1200 - Spartina patens 10~Fig. 10 a. Station 6, 1973 1600 1400. .600~~~~~ ~1200 - 600 - 1000. Spartina patens Station 6, 1973 Fig. 10 b. 20- - Standing Crop B00 Ash-free Standing Crop 7/1 8/1 9/l 10/l 11/l 7/1 8/1 9/1 10/1 11/1 Date Date Figs. a, 9 a and 10 a. Aboveground standing crop Figs. 8 , 9 b, and 10 b. Aboveground litter standing and ash-free dry weight standing crop (gm-2). crop (gm-). 2.72 1200 .Spartina Patens 1200 p Fig. II a. __ __I_ _ _ Station 8, 1973 Fig. 11 b. Spartina patens Station 8, 1973 1000 looo L 800 800- 600- 600- 400 400- Standing Crop 200 - - -Ash-free Standing Crop 200 - N 7/1 8/1 9/1 10/1 11/1 711 811 9 ll 10/t II1 0 1200- N 1200 - ~,m~~~~ ~Spartina patens . Spartina patens Fig. 12 a. Station 10, 1973 Fig. 12 b. Station 10, 1973 1000- 2 1000 o 00- 800 a L 6o6 00 - O 400- 400 0. 0 Standing Crop ' 200- - - Ash-free Standing Crop > 200 a~~~~~~~~~ 711 8/1 9/1 10ll 11/1 711 8/1 9/1 loll 11/ 0 1200 - Sanptes1200 - Spartina patens Fig. 13 a. Spartina patens Station 13, 1973 Fig. 13 b. Station 13, 1973 1000 - 1000 - 800 - 800o - 600 -.600 - 400- 400- Standing Crop 200 - Ash-free Standing Crop 200- 7/1 811 911 10/I 11/1 7/1 8/1 9/1 10/1 11/ Date Date Figs. 11 a, 12 a, and 13 a. Aboveground standing Figs. 11 b, 12 b, and 13 b. Aboveground litter crop and ash-free dry weight standing crop (g.m2). standing crop (g.mn2). 2.73 1200 - 1200 - Fig. 14 a. Spartina patens Spartina patens 10004- Station 16, 1973 1000- Station 16, 1973 800 - Standing Crop 800 - Ash-free Standing Crop 600- 600- 400- 400- 200- 200- NE 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 1200- -- 1200- Fig. 15 b. Spartina alterniflora tall form U, m l Station 5, 1973 c 1000- 1000- 800- 800- - Fig. 15 a. 600- Spartina alterniflora tall form N 600- ci Station 5, 1973 ; 400- g 400- , 200 - Standing Crop 200 - Ash-free Standing Crop i i i -I 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 0 q 1200 - FgISa SpartLna alterniflora tall form 1200 - F. 16-Station 12, 1973 Fig. 16 b Spartina alterniflora tall form Station 12, 1973 1000 - 1000 - 800- 800oo- 600- N 600 400- O 400 Standing Crop 200 - Ash-free Standing Crop 200 - 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 Date Date Figs. 14 a, 15 a, and 16 a. Aboveground standing Figs. 14 b, 15 b, and 16 b. Aboveground standing crop and ash-free dry weight standing crop (g'm-2). crop (g m-2). 2.74 1200 1200 - Fig. 17 a. Spartina alterniflora tall form Fig. 17 b. Spartina alterniflora tall form Station 15, 1973 Station 15, 1973 1000 1000 - 800 800- 600 Ir 600- 400 -- 400- Standing Crop 200 Ash-free Standing Crop 200 - NE 2 2200- 7/1 8/l 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/ 1 1200 F Distichlis spicata & Juncus gerardi 1200 r0a ~ ~ ~ ~ ~ ad Distichlis spicata & Juncus gerardi - - - Standing Crop Station 17, 1973 O 1000 Distichlis spicata 000 - :o - Standing Crop 18 b ~09. Ash Free Standing Crop P Fig. 18 b. c, 800- eJuncus gerardi 800 Standing Crop , 600 X X- Ash Free Standing Crop . 600- , 600- 0 Fig. 18 a. 400 m 400- 400 - : N 200 200 - f L I I I I _ 1 1 1 -n 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/11 0/1 11/ 0 4 1200 - 1200 - Fig. 19 a. Station 18, 1973 1000 - 1000 - 800- 800- ~~~~~600 - }=~600 - ~ Fig. 19 b. Distichlis spicata 400 400 - Station 18, 1973 Standing Crop 200 - - Ash-free Standing Crop 200 - 7/1 8/1 9/1 10/1 11/1 7/1 8/1 9/1 10/1 11/1 Date Date Figs. 17 a, 18 a, and 19 a. Aboveground standing Figs. 17 b, 18 b, and 19 b. Aboveground litter crop and ash-free dry weight standing crop (g-m ). standing crop (g-m2). 2.75 Table 7. Peak live standing crop, peak litter standing crop, dates of peak live and litter standing crops, and ratios of live to dead on those dates. Peak live Date of P'eak litter Date of standing peak live Ratio standing peak litter Ratio crop (gm2 standing live/ $rop (g.m2 standing Live/ Vegetation type Station i S x) crop dead - S x) crop Dead Spartina alternifZora 2 669+33 9/7/73 0.71 944-11 9/7/73 0.71 short form 4 484-13 9/7/73 2.27 364+134 10/20/73 0.64 7 633-231 9/5/73 1.23 689-4 10/17/73 0.33 9 442+146 9/5/73 0.83 676+45 9/26/73 0.53 11 735-42 9/5/73 3.03 467+13 10/10/73 0.90 14 483+49 8/27/73 2.47 353-117 10/27/73 1.05 Spartina patens 1 613+15 8/31/73 1.00 612-+40 8/31/73 1.00 3 684-11 9/12/73 2.22 505+0 8/31/73 1.35 6 519+202 9/4/73 0.44 1,528+139 9/19/73 0.28 8 746�0 9/4/73 0.88 927168 7/16/73 0.53 10 691+42 8/17/73 1.04 665+42 8/17/73 1.04 13 694-65 8/24/73 0.93 887-111 9/29/73 0.63 16 380-16 8/27/73 0.78 529-66 9/29/73 0.69 Spartina alterniflora 5 1,098�255 8/24/73 1.80 771�146 10/31/73 0.46 tall form 12 739+82 8/20/73 2.74 405�76 10/31/73 0.80 15 639�85 8/6/73 2.09 360-30 10/17/73 1.33 DistichZis spicata 17 514-77 8/7/73 and 1.85 and Juncus gerardi 8/27/73 0.92 557+210 8/27/73 0.92 + + DistichlZis spicata 18 644-77 8/20/73 0.69 937-113 8/20/73 0.69 Table 8. Change in litter standing crop (g.m2) for the five communities. D. S. spicata SAS patens SAT D. spicata with Juncus Change in litter +264 -82 +42 +376 279 between harvest 1 & harvest 2 Change in litter +21 -8 +40 between harvest 2 & harvest 3 Change in litter +45 between harvest 3 & harvest 4 Total change +330 -90 +82 +376 279 2.77 411.6 -10.0 -100 Station 2 Station 2 60 Station 4 --- - -- 60- Station 4 ------ 50 -50 - -6.0 E - 60 30 / ' A ' ' �0 - Fig. 20 a. Salinity and precipitation values for Statons Fig. 20 b. Salinity and precipitation values for Stations through Sep December 1973. through May 194. Months Months Fig. 20 a. Salinity and precipitation values for Stations Fig. 20 b. Salinity and precipitation values for Stations 16- 10-10.0 60- Station 7 60- Station 7 -- Station 9 ----- Station 9 --- 8.0 -80 a,40-6.0 40- -6.0 0- . s - E J J 30:0- 10 - IO-2, , Aug Sep Oct Nov Dec Jan Feb Mar Apr May Months Months Fig. 21 a. Salinity and precipitation values for Stations Fig. 21 b. Salinity and precipitation values for Stations 7 and 9 (Spatlna alternifltora short form) from August 7 and 9 (Spart'ina aZterniflora short form) from January through December 1973. through May 1974. 2.78 105.21 Station 11 84.75 ,116 Station 14 ------- - Io10.0 Station 11 10.0 Station 14 60- :7 i 60- 10 1 41 E 60_l 60 i 0 E ark30 * C 30- Cl) (V U (V 20- * '* "X toi > �20- 0-20 - 20 Aug Sep Oct Nov Dec Jan Feb Mar Aug May Months Months Fig. 22 a. Salinity and precipitation values for Stations Fig. 22 b. Salinity and precipitation values for Stations 11 and 14 (Spartina alternifZora short form) from August 11 and 14 (Spartina alterniflora short form) from January through December 1973. through May 1974. 11.6 Station 1 Station 3 --100 -10.0 Station 6 ------ Station 1 60- Station 8--- 60- Station 3--- Station 6 ------ Station 8 -*- 5- 1-8.0 - 8.0 , 40 -6.0E 40- -6.0 E i 430 - 1 i I l I -.0 > \ ii 4- 6E 4 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Months Months Fig. 23 a. Salinity and precipitation values for Stations Fig. 23 b. Salinity and precipitation values for Stations 1, 3, 6, and 8 (Spartina patens) from August through Decem- 1, 3, 6, and 8 (Spartina patens) from January through May ber 1973. 1974. 2.79 11.6 Station 10 721 . Station 13 ------- [ ;' Station 16 -- 100 - 0 Station 10 60 60- Station 13 -------- Station 16--- -8.0 -8.0 50- : 50- c40 - :40- \ 6.0 E 30 - 1, o0 I 0 I0 - Aug Sep i Aug Sep Oct Nov Dec Jan Feb Mar Apr May Months Months Fig. 24 a. Salinity and precipitation values for Stations Fig. 24 b. Salinity and precipitation values for Stations 10, 13, and 16 (Spartina patens) from August through Decem- 10, 13, and 16 (Spartina patens) from January through May ber 1973. 1974. 227.9 [9/71 104.5 104.2 [9/121 11,6 139.8 L Station 5 10.0 Station 12 -----10 60K l l Station 15 --- - 8.0 oS~ "i , ;1 ',I ' 7 Ce I/ 20o -2.0 Aug Sep Oct Nov Dec Months Fig. 25 a. Salinity and precipitation values for Stations 5, 12, and 15 (Spartina aZternifZora tall form) from August through December 1973. 2. 80 81.5 103.17 11.6 Station 5 - 10.0 - 10.0 oI Station 12 ------- Station 17 - Station 15 --- 0- Station 18 SOL8.0 9 -8.0 50'r- so- 40'- E 40 - 6.0 E X 30 /- . 30- : , u';, / 00 : .E t:) /,,/ i~-4.004.0 c 20- - 20- -- 2.0 '.O 10- I -0 Jan Feb Mar Apr May Aug Sep Oct Nov Dec Months Months Fig. 25 b. Salinity and precipitation values for Stations Fig. 26 a. Salinity and precipitation values for Station 5, 12, and 15 (Spartina aZterniflora tall form) from January 17 (DistichZis spicata with Juncus gerardi) and Station 18 through May 1974. (D. spicata) from August through December 1973. - 10.0 60- Station 17 Station 18 ------ -8.0 50 - 4.0 O 20- 0 Jan Feb Mar ug May Jan Feb Mar Aug May Months Fig. 26 b. Salinity and precipitation values for Station 17 (Distichlis spicata with Juncus gerardi) and Station 18 (D. sricata) from January through May 1974. 2.81 APPENDIX B Tables and Figures from the June 1975 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity LIST OF FIGURES Figure Page 2 Seasonal change in above and belowground biomass (kg-m-2) for SAS at stations 19, 20, and 21 . . . . . . . . . . . . . . 2.94 3 Seasonal change in caloric content (kcal-g ash-free dry wt-1l) of four belowground segments of SAS for stations 19, 20, and 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.94 4 Seasonal change in above and belowground biomass (kg.m-2) for SAS at stations 2, 4, 7, 9, and 14 . . . . . . . . . . . . . . 2.94 5 Seasonal change in above and belowground biomass (kg.m-2) for S. patens at stations 1, 3, and 10 . . . . . . . . . . . . . . 2.99 6 Seasonal change in above and belowground biomass (kg-mn2) for S. patens at stations 6, and 8 . . . . . . . . . . . . . . . . 2.99 7 Seasonal change in above and belowground biomass (kg-m-2) for SAT stations 5, 12, 15, and 22 . . . . . . . . . . . . . . . . 2.99 8 Seasonal change in above and belowground biomass (kg-m-2) for Distichlis spicata station 18 . . . . . . . . . . . . . . . . 2.99 2.83 LIST OF TABLES Table Page 1 List of vascular species occurring in the Manahawkin marshes . . . . . . . . . . . . . . . . . . . . . 2.87 4 Individual salinity values (0/oo) for each station, with mean values for each vegetation type and monthly precipitation, during 1974-1975 . . . . . . . . . . . . . . . . . . . . . . 2.88 6 Dry weight (g-m-2) of Spartina alterniflora short form from Mud Cove stations 19, 20, and 21 for aboveground and washed belowground material. Each data point is based on six sam- ples from the 1974-1975 period . . . . . . . . . . . . . . . 2.91 9 Dry weight (g.m-2) of Spartina aZternifZora short form from stations 2, 4, 7, 9, and 14 for aboveground and washed below- ground material during the period 1974-1975 . . . . . . . . . 2.93 10 Dry weight (g-m-2) of Spartina patens from stations 1, 3, and 10 for aboveground and washed belowground material. Each data point is based on six samples from the 1974-1975 period . . . . . . . . . . . . . . . . . . . . . . . . . . 2.95 11 Dry weight (g.m-2) of Spartina patens from Popular Point sta- tions 6 and 8 for aboveground and washed belowground mate- rial. Each data point is based on four samples from the period 1974-1975 . . . . . . . . . . . . . . . . . . . . 2.96 12 Dry weight (g.m-2) of Spartina alterniflora tall form from stations 5, 12, 15 and 22 for aboveground and washed below- ground material during the 1974-1975 period . . . . . . . . . 2.97 13 Dry weight (g-m-2) of DistichZis spicata from Mud Cove station 18 for aboveground and washed belowground material. Each data point is based on two samples from the period 1974-1975 . . . . . . . . . . . . . . . . . . . . . . . . . 2.98 14 Seasonal change in belowground biomass and turnover rate of S. alternijora, short form, stations 19, 20 and 21 and S. alternifora, short form, stations 2, 4, 7, 9 and 14 . . . . 2.100 15 Seasonal change in belowground biomass and turnover rate of S. patens, stations 1, 3, 10 and S. patens, stations 6 and 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.101 16 Seasonal change in belowground biomass and turnover rate of SAT stations 5, 12, 15, and 22 and D. spicata, station 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.102 2.85 Table 1. List of vascular species occurring in the Manahawkin marshes* Chenopodiaceae Gramineae AtripZex patula var. hastata Spartina alternifZora Saiecornia europaea Spartina patens Suaeda zinearis# Spartina cynosuroides Compositae DistichZis spicata Iva frutescens# Phragmites communis Aster tenufjoZius Panicwn virgatum SoZidago sempervirens# Juncaceae Pluchea purpurascens Juncus gerardi Baccharis haZimifolia# Onagraceae Cirsium vulgare # Oenothera biennis# Cyperaceae Phytolaccaceae Scirpus otneyi -Phytolacca americana# Scirpus robustus Typhaceae Scirpus americanus Typha angustifoZia Nomenclature following Fernald (1950). Found on spoilbank or fill areas at Popular Point. 2.87 Table 4. Individual salinity values (o/oo) for each station, with mean values for each vegetation type and monthly precipitation, during 1974-1975. Vegetation Station types no. 6/5 6/11 6/17 6/25 7/1 7/8 7/15 7/22 7/29 S. patens 1 11.9 16.5 35.4 19.0 13.6 18.2 23.8 13.4 24.3 3 17.4 25.8 34.7 10.1 18.1 20.8 22.2 22.7 30.7 6 3.0 2.2 4.7 5.7 4.5 4.6 6.3 5.4 11.5 8 18.8 27.7 32.8 20.8 19.6 22.7 22.1 25.4 30.6 10 19.8 23.2 38.6 24.7 24.3 26.3 40.6 44.1 Mean 14.2 19.1 29.2 16.1 15.2 18.1 20.1 22.3 28.3 SAS 2 17.2 26.9 43.2 14.3 21.8 20.8 27.9 20.7 33.0 4 30.0 73.4 95.5 18.2 17.5 41.9 41.5 22.1 47.6 7 13.4 33.1 52.9 19.4 18.2 31.3 16.9 52.2 57.8 9 28.2 37.5 37.1 21.6 20.6 28.8 40.7 32.5 36.2 11 23.3 39.8 42.4 24.1 21.3 31.0 41.0 30.9 53.7 14 47.3 50.4 81.3 42.8 28.7 90.2 191.7 25.8 113.4 19 27.4 39.4 37.7 20 24.2 54.5 31.7 46.6 21 70.5 58.9 46.3 Mean 26.6 43.5 58.7 23.4 19.0 40.7 56.9 54.9 52.5 SAT 5 21.4 25.1 100.9 33.4 35.9 59.8 114.1 151.0 122.0 12 27.7 27.8 29.5 22.9 27.3 28.1 27.5 27.4 32.7 15 21.1 31.3 34.9 20.6 23.0 12.0 27.2 26.5 30.3 Mean 23.4 28.1 55.1 25.7 28.7 33.3 56.3 68.3 61.7 D. spicata 18 21.7 13.8 31.8 18.0 23.3 58.7 22.7 27.4 29.7 Precipitation (cm) 1974-1975 8.18 3.96 1973-1974 16.28 9.73 2.88 Table 4. Continued. Vegetation Station types no. 8/5 8/14 8/25 9/9 10/2 10/20 11/6 11/27 S. patens 1 36.1 13.9 14.0 10.4 14.2 19.0 14.3 15.2 3 37.3 16.3 19.6 12.5 20.6 18.4 12.1 21.8 6 12.2 3.9 4.1 2.1 2.9 2.7 3.0 3.3 8 35.1 22.0 21.3 16.9 23.7 23.4 14.2 26.5 10 50.7 22.5 20.7 16.4 21.4 20.0, 13.0 26.7 Mean 34.3 78.6 15.9 11.7 16.6 16.7 11.3 18.7 SAS 2 38.6 23.1 20.9 15.5 25.8 14.3 22.9 24.8 4 60.3 25.2 20.5 16.2 41.0 26.9 17.1 19.7 7 45.3 28.9 7.6 5.8 10.4 9.1 8.3 15.0 9 50.7 22.5 20.7 22.1 29.7 27.9 22.2 30.6 11 52.0 28.6 25.3 19.6 30.5 24.8 27.2 25.8 14 68.8 36.2 27.2 24.5 55.2 37.0 40.2 42.6 19 56.8 26.3 23.8 19.5 27.7 24.9 27.3 27.8 20 69.3 32.2 25.6 24.2 35.1 33.1 26.9 28.7 21 83.3 42.7 21.2 19.7 35.9 25.5 37.0 32.6 Mean 58.3 29.5 21.4 18.6 32.3 24.9 25.5 27.5 SAT 5 140.4 25.5 31.1 14.3 43.1 42.2 29.5 34.7 12 28.2 31.2 21.8 19.3 26.2 23.5 13.2 15 40.7 17.7 24.1 18.7 25.2 20.8 20.0 19.3 Mean 69.8 24.8 25.6 17.6 31.5 28.8 20.9 27.0 D. spicata 18 31.5 23.6 21.8 23.4 34.5 32.8 27.6 24.6 Precipitation (cm) 1974-1975 20.57 9.50 4.37 3.43 1973-1974 5.33 13.72 6.30 3.43 2.89 Table 4. Continued. Vegetation Station types no. 12/30 1/28 3/5 4/21 S. patens 1 18.6 8.3 18.2 19.5 3 19.4 7.3 9.1 16.1 6 6.9 1.9 1.2 2.1 8 21.0 10.4 10.0 15.7 10 25.0 6.0 16.4 13.1 Mean 18.2 6.8 11.0 13.3 SAS 2 18.3 11.5 15.9 18.2 4 21.3 9.3. 15.2 20.5 7 13.4 5.0 3.9 10.6 9 19.5 9.8 21.5 24.7 11 21.4 14.1 24.1 31.0 14 25.2 20.0 23.1 26.4 19 20.9 15.0 23.5 29.0 20 27.4 18.0 36.1 27.9 21 27.7 11.8 26.5 29.1 Mean 21.7 12.7 21.1 24.1 SAT 5 25.6 13.1 12 22.9 16.6 20.3 27.7 15 20.7 14.8 24.2 Mean 23.0 14.9 22.3 27.7 D. spicata 18 25.7 12.0 22.2 Precipitation (cm) 1974-1975 10.67 13.72 10.41 1973-1974 14.99 10.41 11.43 5.84 2.90 Table 6. Dry weight (g.m-2) of Spartina aZternifZora short form from Mud Cove stations 19, 20, and 21 for aboveground and washed belowground material. Each data point is based on six samples from the 1974-1975 period. Sample 5 Jun 1 Jul 15 Jul 31 Jul 19 Aug 18 Sep 28 Oct Aboveground material Live 312 395 459 440 361 357 295 +37* +146 +211 +107 +105 +114 +51 Litter 691 646 540 695 566 499 616 +157 +139 +75 +221 +140 +100 +82 Belowground material Segment 1 (0-5cm) 2,210 2,335 2,310 2,275 2,489 2,285 2,730 +191 +800 +316 +389 +331 +424 +215 2 (5-10cm) 2,609 2,351 2,455 2,558 2,459 2,738 2,621 +412 +451 +259 +233 +413 +614 +296 3 (10-15cm) 1,974 2,071 2,154 2,164 2,034 2,099 2,101 +364 +546 +432 +521 +226 +218 +353 4 (15-20cm) 1,225 1,765 1,255 1,517 1,526 1,699 1,947 +233 +198 +652 +384 +248 +351 +679 5 (20-30cm) 2,367 2,511 2,528 2,587 2,577 2,269 2,687 +255 +330 +532 +715 +498 +445 +467 6 (30-40cm) 2,116 1,961 1,905 2,995 2,283 2,663 2,534 +472 +236 +987 +829 +476 +224 +526 7 (40-50cm) 2,394 1,529 1,796 2,268 1,337 1,641 2,148 +193 +350 +1,012 +877 +408 +1,072 +820 Table 6. Continued. Sample 27 Nov 30 Dec 28 Jan 5 Mar 30 Mar 30 Apr Aboveground Live Litter Belowground Segment 1 (0-5cm) 2,359 2,559 2,319 2,102 2,593 2,760 +433 +368 +305 +606 +494 +357 2 (5-10cm) 2,408 2,633 2,451 2,448 2,539 2,742 +411 +481 +269 +125 +394 +285 3 (10-15cm) 2,263 2,067 1,672 1,871 1,943 2,043 +365 +414 +147 +321 +125 +244 4 (15-20cm) 1,654 1,607 1,361 1,732 1,762 1,878 +530 +381 +165 +368 +397 +409 5 (20-30cm) 2,388 2,400 2,167 2,068 2,636 2,949 +187 +229 +527 +467 +333 +406 6 (30-40cm) 2,017 2,110 1,989 2,015 2,457 2,613 +520 +533 +528 +696 +930 +35'3 7 (40-50cm) 1,782 2,051 1,191 1,041 1,751 1,608 +667 +887 +265 +170 +491 +851 * This value equals 1 SD. Table 9. Dry weight (g.m-2) of Spartina aZternifZora short form from stations 2, 4, 7, 9, and 14 for aboveground and washed belowground material during the period 1974-1975. Sample 8 Apr 16 May 3 Jul 8 Aug 9 Sep 27 Nov 28 Jan 21 Apr. Aboveground material Live 145 320 353 256 +80* +108 +111 +39 Litter 735 473 535 335 +199 +153 +165 +182 Belowground material Segment 1 (0-5cm) 2,518 2,271 2,244 2,462 2,215 1,848 2,226 2,190 +621 +667 +710 +870 +1,001 +711 +871 +580 2 (5-10cm) 2,534 2,460 2,550 3,175 2,933 2,464 2,545 2,541 +348 +537 +493 +605 +607 +624 +540 +405 3 (10-15cm) 2,009 1,884 2,342 2,589 2,244 2,294 2,441 1,961 +508 +653 +459 +876 +200 +479 +321 +559 4 (15-20cm) 1,510 1,739 1,826 2,151 1,617 2,074 1,979 1,678 +399 +580 +522 +702 +289 +475 +667 +821 5 (20-30cm) 1,963 1,236 2,767 2,799 2,256 2,289 2,847 1,916 +515 +534 +1,017 +1,268 +807 +593 +841 +1,218 6 (30-40cm) 2,052 1,507 1,936 1,977 1,823 1,273 2,077 1,701 +1,445 +956 +641 +938 +608 +805 +819 +1,237 7 (40-50cm) 1,350 1,268 2,120 1,438 1,848 947 1,918 1,181 +586 +465 +1,170 +689 +703 +713 +729 +1,074 No. of samples Aboveground 10 12 11 10 Belowground 10 10 12 11 9 10 10 10 * This value equals 1 SD. ABOVEGROUND f~~i-~: Live and litter Live 11i-~;~ i iLive and Litter i A s 0 Live BELOWGROUND 0 - Live 12 T BELOWGROUND � 12- -T g, !/'tIiI ' 20-30 cmT -1 ;1O T I -. I 0 T r r i/i g 10�� ~~~ ~~~~~~~~~~~a IvA . -30cm 0 I 0 115-20 L- 52cm1\\ 8��i r T 15-2Dcm I 10-15 cm -L 6�� 1 I~~~~~~~~~~~~~~~~~T -1 1- c 5-10 cm 4. 5-10cm I T j ! 1 - .! T f 2.-111-i I Jij1 0-5 cm 2 I 1 0-5c-. 0 . . . . 0 J A S O N 0 J F M A M M J J A Months Months Fig. 2. Seasonal changes in above and belowground Fig. 4.. Seasonal change in above and belowground biomass (kg-m2) for SAS at Stations 19, 20, and 21. biomass for SAS at stations 2, 4, 7, 9, and 14. Ver- Vertical lines equal I SD. tical lines equal 1 SD. 0 0-5 cm l 5-10 cm 5.5-,� 10-15 cm .15-20 cm >, 5.0 - ~4.5- - ~ /0,~ 4.0-� 0~~~~~~~~~~~~~~~~~~~~ A S ~~0 N-. 0 Months Fig. 3. Seasonal change in caloric content (kcal-g ash-free dry wt-1) for four belowground segments of SAS for stations 19, 20, and 21. 2.94 Table 10. Dry weight (g.m-2) of Spartina patens from stations 1, 3 and 10 for aboveground and washed belowground material. Each data point is based on six samples from the 1974-1975 period. 8 May 11 Jun 29 Jul 26 Aug 30 Oct 30 Dec 5 Mar Aboveground material Live 372 587 424 85 +80* +54 +77 +24 Litter 705 651 720 979 +232 +276 +270 +634 Belowground material Segment 1 (0-5cm) 1,827 2,174 2,842 2,718 2,591 2,142 2,448 +539 +384 +724 +695 +990 +631 +334 2 (5-10cm) 1,751 1,671 2,500 2,056 2,133 1,857 1,889 +405 +523 +170 +632 +689 +438 +384 3 (10-15cm) 1,511 1,665 2,192 1,617 1,834 1,624 1,633 +456 +438 +534 +191 +658 +262 +169 4 (15-20cm) 1,416 1,477 2,138 1,533 1,327 1,315 1,239 +207 +566 +1,067 +413 +508 +285 +333 5 (20-30cm) 1,683 1,773 1,814 1,941 2,239 2,215 2,176 +419 +921 +334 +657 +700 +952 +904 6 (30-40cm) 1,393 1,569 1,785 1,404 1,772 1,578 1,787 +660 +981 +381 +286 +197 +595 +1,180 7 (40-50cm) 1,402 1,477 1,827 1,812 1,384 1,490 1,640 +352 +722 +514 +826 +582 +698 +639 * This value equals 1 SD. Table 11. Dry weight (g.m-2) of Spartina patens from Popular Point stations 6 and 8 for aboveground and washed belowground material. Each data point is based on four samples from the period 1974-1975. Sample 8 May 11 Jun 29 Jul 26 Aug 30 Oct 30 Dec 5 Mar Aboveground material Live 301 399 391 134 +105* +46 +105 +43 Litter 1,039 947 1,137 868 +215 +158 +605 +735 Belowground material Segment 1 (0-5cm) 998 1,221 1,932 2,077 1,415 1,907 1,384 +114 +133 +621 +1,086 +402 +1,010 +427 2 (5-10cm) 1,200 1,223 1,495 1,490 1,642 1,651 1,198 +360 +374 +425 +842 +441 +716 +323 3 (10-15cm) 1,089 1,116 1,402 1,458 1,225 1,411 1,159 +144 +381 +190 +442 +332 +709 +213 4 (15-20cm) 1,058 1,094 1,277 1,286 958 1,123 1,141 +166 +453 +232 +330 +294 +456 +213 5 (20-30cm) 1,710 2,135 1,718 1,925 1,891 1,753 1,646 +487 +897 +638 +395 +355 +785 +153 6 (30-40cm) 1,067 1,130 1,072 1,474 1,227 1,114 1,085 +82 +347 +382 +354 +639 +411 +304 7 (40-50cm) 1,187 901 713 1,162 505 1,298 1,042 +339 +142 +323 +310 +218 +507 +114 * This value equals 1 SD. Table 12. Dry weight (g.m-2) of Spartina aZternifZora tall form from stations 5, 12, 15 and 22 for aboveground and washed belowground material during the 1974-1975 period. Sample 5 Jun 15 Jul 12 Aug 26 Sep 4 Dec 3 Feb 30 Apr Aboveground material Live 80*# 468+189#t 547+165# 735+110 575+125 638+56 Litter 3,388*# 567+706# 658+480# 209+50 268+263 380+268 Belowground material Segment 1 (0-5cm) 1,409 643 1,560 1,320 961 666 842 +392 +299 +619 +711 +372 +432 +318 2 (5-10cm) 1,778 969 1,710 1,558 1,330 1,295 1,583 +370 +411 +795 +490 +947 +755 +653 3 (10-15cm) 1,642 1,116 2,108 1,449 1,652 1,841 1,424 +320 +630 +855 +565 +858 +980 +655 4 (15-20cm) 985 1,232 1,805 1,304 1,357 1,576 951 +131 +670 +924 +706 +630 +991 +480 5 (20-30cm) 2,688 1,214 2,561 1,366 1,965 1,843 1,966 +797 +446 +1,240 +773 +969 +784 +1,562 6 (30-40cm) 3,152 874 2,072 1,363 1,645 1,483 1,465 +1,279 +660 +1,157 +1,103 +1,035 +755 +902 7 (40-50cm) 2,312 697 2,267 1,739 1,842 1,667 1,509 +1,430 +432 +1,552 +1,195 +542 +1,090 +947 No. of samples Aboveground 2 6 6 6 Belowground 2 6 6 6 5 6 6 * Based on one sample This includes samples from SAT area undergoing change resulting from altered drainage pattern. t This value equals 1 SD. Table 13. Dry weight (g-m-2) of Distichlis spicata from Mud Cove station 18 for aboveground and washed belowground material. Each data point is based on two samples from the period 1974-1975. Sample 5 Jun 15 Jul 12 Aug 26 Sep 6 Nov 4 Dec 3 Feb 30 Apr Aboveground material Live 204 482 613 538 +102* +7 +3 +68 Litter 994 813 520 211 +59 +97 +17 +97 Belowground material Segment 1 (0-5cm) 133 1,637 1,900 1,180 1,806 1,270 541 922 +317 +86 +602 +205 +226 +680 +38 +74 2 (5-10cm) 1,291 1,803 2 ,145 1,474 2,534 1,696 1,078 1,463 +897 +1,002 +45 +1,118 +532 +183 +144 +400 3 (10-15cm) 1,719 1,221 1,438 1,626 1,229 1,212 1,477 1,343 +160 +528 +99 +138 +132 +311 +349 +231 4 (15-20cm) 1,990 1,492 1,678 1,166 1,150 985 1,449 1,157 +330 +522 +967 +445 +221 +289 +61 +467 5 (20-30cm) 2,215 2,740 2,915 2,113 1,472 2,935 2,747 3,372 +253 +128 +1,185 +69 +544 +240 +109 +211 6 (30-40cm) 2,276 1,991 1,597 1,769 1,169 2,348 2,163 2,276 +110 +58 +813 +775 +263 +501 +179 +112 7 (40-50cm) 1,954 962 2,253 1,823 956 1,680 2,330 1,877 +224 +596 +208 +314 +199 +985 +131 +330 * This value equals 1 SD. ABOVEGROUND rr T , ABOVEGROUND li------i _ ! Live and Litter Live and Litter E M J J A S 0 N t t a 12 BELOWGROUND , ,ive 0 M J J A S 0 N 3 lo/ T . T T/ I t, W BELOWGROUND /o 20-30cm 6 TT ~ ~ ~~~~~~~~~~~T T 5-20cm T T 1. / rT i 5-'1Ocm l' . '.T/-4. 0-5cm 2T '. 2 0-5cm 0 0 M J A S O N D F J MA S 0 N b F M Months Months Fig. 5. Seasonal change in above and belowground Fig. 6. Seasonal change in above and belowground biomass (kg-m-2) for S. patens at stations 1, 3, and biomass (kg.m-2) for S. patens at stations 6 and 8. 10. Vertical lines equal 1 SD. Vertical lines equal I SD. ABOVEGROUND ABOVEGROUND 1 T Live and Litter Live and Litter *Live ,i Live ON o0 - A S 0 J J A S O E BELOWGROUND o BELOWGROUND T . r 10 I -. 10 082 20- [ / / T 1 5-3Ocmi tI 1_0 ,_ Ocm 1/i\2 4 : :- : : :- r : !'�0-5cmI11 cmTi l J J A S O N D J I M A M 2 r 5-10cm ~2-- 0-5cm 1~-Scm J J A S 0 N D J F M A M J Months Months Fig. 7. Seasonal change in above and belowground Fig. 8. Seasonal change in above and belowground biomass (kg-m-2) for SAT stations 5, 12, 15, and 22. biomass (kg.m-2) for Distich7is spicata station 18. Vertical lines equal 1 SD. Vertical lines equal I SD. 2.99 Table 14. Seasonal change in belowground biomass and turnover rate of S. alter- nifZora, short form, stations 19, 20, and 21 and S. aZternifZora, short form, stations 2, 4, 7, 9, and 14. Segment Period of greatest Maximum Increment Turnover rate (cm) difference biomass (g.m-2) () (Years) (g. m2) S. aZternifora short form, stations 19; 20 and 21: 0-10 5 March-30 April* 5,502 952 17.30 5.78 0-20 23 October -28 January 9,399 1,596 16.98 5.89 0-30 28 January-30 April* 12,372 2,402 19.41 5.15 10-20 23 October*-28 January 4,048 1,015 25.07 3.99 20-30 5 March-30 April* 2,949 882 29.91 3.34 S. alterniftora short form, stations 2, 4, 7, 9, 14: 0-10 8 August*-27 November 5,637 1,325 23.51 4.25 0-20 16 May-8 August* 10,377 2,023 19.49 5.13 0-30 16 May-8 August* 13,176 3,585 27.21 3.67 10-20 8 April-8 August* 4,740 1,221 25.76 3.88 20-30 28 January*-21 April 2,847 931 32.70 3.06 * Date of greatest biomass. 2.100 Table 15. Seasonal change in belowground biomass and turnover rate of S. patens, stations 1, 3, and 10 and S. patens, stations 6 and 8. Segment Period of greatest Maximum Increment Turnover rate (cm) difference biomass (g.m-2) (%) (Years) (g.m-2) S. patens, stations 1, 3 and 10: 0-10 8 May-29 July* 5,342 1,764 33.02 3.03 0-20 8 May-29 July* 9,672 3,143 32.49 3.08 0-30 8 May-29 July* 11,486 3,274 28.50 3.51 10-20 29 July*-5 March 4,330 1,458 33.67 2.97 20-30 8 May-30 October* 2,239 556 24.83 4.03 S. patens, stations 6 and 8: 0-10 8 May-26 August* 3,567 1,438 40.31 2.48 0-20 8 May-26 August* 6,311 2,035 32.25 3.10 0-30 8 May-26 August* 8,236 2,250 27.32 3.66 10-30 8 May-26 August* 2,744 597 21.76 4.60 20-30 11 June*-March 5 2,135 489 22.90 4.37 Date of greatest biomass 2.101 Table 16. Seasonal change in belowground biomass and turnover rate of SAT stations 5, 12, 15, and 22 and D. spicata, station 18. Segment Period of greatest Maximum Increment Turnover rate (cm) difference biomass (g-m-2) (%) (Years) (g-m-2) S. aZternifjora tall form, stations 5, 12, 15, 22: 0-10 15 July-12 August 3,270 1,658 50.70 1.97 0-20 15 July-12 August* 7,183 3,223 44.87 2.23 0-30 5 June*-15 July 8,502 3,328 39.14 2.55 10-20 3 February*-30 April 3,417 1,042 30.49 3.28 20-30 5 June*-15 July 2,688 1,474 54.84 1.82 DistichZis spicata, station 18: 0-10 6 November*-3 February 4,340 2,721 62.69 1.59 0-20 12 August*-3 February 7,161 2,616 36.53 2.74 0-30 12 August*-3 February 10,076 2,784 27.63 3.62 10-20 12 August -4 December 3,116 919 29.49 3.39 20-30 6 November-30 April* 3,372 1,900 56.35 1.77 * Date of greatest biomass. 2.102 APPENDIX C Tables and Figures from the July 1976 Estuarine Evaluation Study Annual Report: Marsh Plant Productivity Decomposition LIST OF FIGURES Eilure_ Page 2 Precipitation and mud salinity at 0 and 10 cm depths for site (1)PSAS from September 1975 . . . ........... 2.105 3 Precipitation and mud salinity at 0 and 10 cm depths for site (2)PSAM from September 1975 . . . ........... 2.105 4 Precipitation and mud salinity at 0 and 10 cm depths for site (3)SAS from September 1975 . . . ........... 2.105 5 Precipitation and mud salinity at 0 and 10 cm depths for site (4)SAM from September 1975 . . . ........... 2.105 6 Precipitation and mud salinity at 0 and 10 cm depths for site (5)SAT from September 1975 . . . ........... 2.105 2.103 Site 1 (PSAS) Site 2 (PSAM) 10-- -- 0-- -60 Saliniy60 C u0re Salinity Curves Salinity Curves --50 � 0 cm depths --50 8-- * 0 cm depths 8-- o 10 cm depths E 10 cm depths E U - 40 6E-- Er-6 ~-- --20 --230 o( ~~~~2-- --lo / II --20 --I0 O N D J F M SO N O F M Months Months Site 3 (SAS) Site 4 (SAM) 10-- --60 10-- --60 Salinity Curves Salinity Curves 0 cm depths --50 * 0 cm depths -50 8-- o 10 cm depths 8-- 10cm depths E --40 Z 40E 6-- 6-- 4-- C 4-- --20 c --20 '- 4- t \ 2 I rir 4 20 2-- iT--10 2-- O --10 S O N D J F M S O N D J F M Months Months Site 5 (SAT) 10-- --60 Salinity Curves 8-- * 0 cm depths o 10 cm depths --40 --30 ( IT 4-- --20 2--- 2-- I T Tl T 10 S O N D J F M Months Figs. 2-6. Precipitation and mud salinity at 0 and 10 cm depths for sites (I)PSAS, (2)PSAM, (3)SAS, (4)SAM, and (5)SAT from September 1975. 2.105 3. MARSH PRODUCTIVITY: SUBMERGED SALT POND VEGETATION Dennis Slate1 SUMMARY Data collected from 24 permanent salt ponds (nine of which supported Ruppia growth) for the period 15 March to I November 1976 have been analyzed statistic- ally. A step-wise discriminant procedure was employed to delineate which physi- cal and chemical parameters measured may be used to predict the presence or absence of submerged vascular vegetation in these salt ponds. Three parameters, depth, salinity, and surface area predicted accurately 21 of 24 attempts. Two replicate one half square meter (m2/2) biomass samples were collected from a total of 26 Ruppia ponds. Mean peak standing crop biomass estimates ranged from 0.04 - 79.66 g dry wt/m2; least significant interval (lsi) = 4.8; grand mean (X) =30.2 g dry wt/m2. BACKGROUND Permanent salt ponds and their associated flora and fauna are an integral component of the salt marsh ecosystem. Ponds provide resting and feeding sites for waterfowl, as well as other avian species. Algal blooms frequently occur in many ponds which may in turn provide food and cover for invertebrates, especially amphipods. Some permanent ponds support higher vascular plant life, whereas others do not. Since the dynamics of permanent salt ponds are not well under- stood, information derived from this study will assist in drafting guidelines for future salt pond management. OBJECTIVES The primary objective of this project are: 1) To determine why some salt ponds produce submerged vascular sperma- tophytes and others do not, based on certain physical, chemical, or environmental parameters. 2) To estimate the standing crop biomass of submerged vascular plants in permanent salt ponds. PROCEDURE In March 1975, eight salt ponds were selected at each of three different locations that lie on a transect approximately parallel to Oyster Point Creek 1The author is associated with Cook College, Rutgers University. This re- port was prepared for the N.J. Division of Fish, Came, and Shellfisheries with funds provided in part by the Federal Aid to Wildlife (Pittman-Robertson) Act for Project W-53-R-2, "Wetlands Ecology," during the period 15 August 1975 to 31 May 1976. 3.1 and perpendicular to the uplands and Little Egg Harbor. Such a design allows for a check on any environmental or production gradients that may exist. The surface area of individual ponds was determined with the use of a Gurley table, alidade, compass, and steel tape. Depths were randomly taken within each pond. The apparatus consisted of a rule with an attached flattened base to pre- vent it from penetrating the soft bottom sediments. A marked stake delineating the initial depth was permanently driven into each pond. On subsequent sampling trips, the change in depth was taken from this mark to obtain estimates of mean depth. Water samples were collected from each pond. From these samples, the salinity, pH, and dissolved oxygen concentration were determined. 1) Salinity - The Harvey method was employed. This involves a silver nitrate (AgNO3) titration, with potassium chromate (K2CrO4) as an indi- cator of end point. 2) pH - The pH for each pond was determined in the field on a Photovolt 126A pH meter. 3) Dissolved oxygen - Water samples were collected in BOD bottles. Manga- nous sulfate (MnSO4) and an alkali-azide (NaOH-NaN3) reagent were added and then samples were acidified with concentrated sulfuric acid (H2SO4). Samples (200 ml) were titrated in the field with sodium thiosulfate (Na2S203). Soluble starch indicator was used. Other analyses were performed to determine nitrate concentrations (NO3) and turbidity. Spectrophotometric methods were employed; however, experimental variation due to low turbidity and nitrate concentrations was too high to justify continuing these tests. Water temperature was obtained by suspending a stem Cel- sius thermometer at middepth in each pond. Sediment samples were collected from each of the 24 ponds. These are still in the process of being analyzed for sediment texture, organic content, and ca- tion exchange. Two replicate (m2/7) samples were collected biweekly from the nine ponds supporting Ruppia growth to monitor for the occurrence of peak biomass. Twelve transects were sampled in the interim such that the proportion of ponds supporting Ruppia to those which did not could be determined (Figure 1 and Table 1). All those ponds found that supported Ruppia were added to the nine in the original sample. At peak biomass, two replicate (m2/2) samples were collected from a total of 26 ponds (9 from the original sample and 15 supplementary ponds). The larger sample size provided for a more precise estimate of peak standing crop biomass of Ruppia. Wet weights and dry weights were obtained for all plant sam- ples. In March 1976, a slightly modified sampling regime was implemented. A total of 30 ponds (15 Ruppia producers and 15 non-producers) were sampled on a weekly basis to obtain estimates of salinity, mean depth, and water temperature. The surface area of new ponds has been determined. These data will be used to test the predictability of the parameters mentioned (i.e., can they be used to pre- dict the presence of Ruppia in a given pond). Triplicate (m2/2) Ruppia samples were collectedbiweekly and returned to the lab for analysis. 3.2 yst~~~~~~~~~~~~~~ioeer Fiue chmti f apln taset Table 1. Relative proportion of Ruppia ponds (Life~~~~~~~~~~~l) to non-Ruppia ponds (Life=or Pt 0) f~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Oys logther saPligtascs ~~~~~~~~~~~~~~~~~~~~~~~~~~LITE 13G0 Fiur 16 S c e a i 1fsmpigtascs L 9 32 TOA 127 32 1702 23. FINDINGS Since some ponds produced Ruppia maritima and others did not, ponds included in each group were treated as two separate populations. The simple statistics for these populations are presented in Table 2 (salinity in parts per thousand, temperature in degrees Celsius, oxygen in mg/l, depth in inches, surface area in square feet). As a first approximation, these data was subjected to discrimi- nant analysis to ascertain the predictability of these parameters. Table 3 clearly indicates their predictive value, with 23 of 24 ponds properly classified. Table 2. Simple statistics for Life=0 (Ruppia absent) and Life=l (Ruppia present) populations. Standard Variable n Mean deviation For Life=O: Salinity 135 22.2 �/oo 2.7 Temperature 120 25.4 �C 1.2 Dissolved oxygen 120 6.2 mg/l 1.2 Depth 135 9.1 in. 2.0 pH 45 7.7 0.4 Surface area 15 1,910.5 ft2 5,284.4 For Life=l: Salinity 81 17.2 �/oo 3.7 Temperature 72 24.9 �C 0.9 Dissolved oxygen 72 7.7 mg/l 1.2 Depth 81 12.7 in. 1.5 pH 27 7.8 0.3 Surface area 9 3,111.8 ft2 2,291.9 Table 3. Classification of salt ponds from the discriminant analysis. Life classification: 0 1 Life: 0 14 1 1 0 9 Data were then analyzed by a stepwise discriminant procedure to determine which of these six parameters were best suited to discriminate between the two populations of ponds. Depth, salinity, and surface area were all significant at a = 0.05. Twenty-one of 24 ponds were correctly classified with these three parameters. Ponds with lower salinities tend to support Ruppia growth. This may reflect the inability of Ruppia to tolerate higher salinities for long periods of time. A salinity-temperature interaction is also possible. 3.4 Ruppia is present consistently in the deeper ponds. Salinity is generally lower in the larger and deeper ponds. Larger ponds offer greater surface area for the interception of rainfall. Since larger ponds are generally deeper, the salt concentration remains diluted. Only under extreme evaporative conditions or frequent tidal inundation would the salinities of the larger ponds approxi- mate those of small ponds. Under laboratory conditions, it should be possible to test the effects of various salinity levels on Ruppia to determine its toler- ance limits. Peak biomass occurred between the last week of July and early August (Figure 2). With the addition of 15 supplementary ponds, two replicate (m2/2) samples were collected from a total of 26 ponds. Biomass estimates ranged from 0.04 - 79.66 g dry wt/m2 with a grand mean (X) of 30.2 g dry wt/m2 and a least significant interval of 9.6 (Table 4). Pond 3 Pond 9 Pond 20 5- E Pond 6 Pond 13 Pond 21 Er. 5- Pond 8 Pond 15 Pond 24 E (5- J J A S o J J A 0 J J A S 0 Month Figure 2. Peak biomass occurred between the last week of July and early August. Monthly means were generated by pooling the four one seventh meter squared samples collected within each month (i.e., two replicates were collected bi- weekly). Sampling began in March 1976. Ruppia growth was observed on 31 March 1976 approximately one month earlier than 1975. The unreasonably warm spring suggests that temperature has a pronounced effect on the initiation of Ru~pia growth. Salinity, pH, and mean depth were sampled weekly. Triplicate (mZ/2) plant sam- ples were collected biweekly since early May. 3.5 Table 4. Mean peak biomass estimates generated from two replicates collected from each permanent salt pond. Pond Number Xi ranked Pond Number X- ranked (g dry wt/m2) (g Wry wt/m2) 13 79.66 21 2.30 301 66.08 207 1.20 206 58.18 20 .60 24 33.80 212 .58 6 30.20 200 .52 9 27.04 204 .46 15 22.98 208 .32 201 15.82 215 .26 210 12.62 203 .04 209 11.78 214 .04 8 11.72 202* 0.00 211 8.70 205* 0.00 3 7.68 213* 0.00 MS = 21.82 lsi = 9.6 * Ruppia was present in these ponds; however, growth was either sparse or clumped such that no stems occurred in the two (m2/2) samples. A triplicate sampling regime has been employed this year. 3.6