Spartina Alterniflora Marsh Research Articles

Annual cycle of gaseous sulfur emissions from a New England Spartina alterniflora marsh : Steudler, P.A. and B.J. Peterson, 1985. Atmos. Environ., 19(9):1411–1416

Annual cycle of gaseous sulfur emissions from a New England Spartina alterniflora marsh : Steudler, P.A. and B.J. Peterson, 1985. Atmos. Environ., 19(9):1411–1416

Meiofaunal Densities and Copepod Species Composition in a Louisiana, U.S.A., Estuary

Meiofaunal Densities and Copepod Species Composition in a Louisiana, U.S.A., Estuary

Annual cycle of gaseous sulfur emissions from a New England Spartina alterniflora marsh

A flow-through chamber was used to measure the net gaseous sulfur fluxes (emission minus uptake) to the atmosphere from an area of Spartina alterniflora in a New England salt marsh. The fluxes of hydrogen sulfide, dimethyl sulfide, carbonyl sulfide, carbon disulfide and dimethyl disulfide were measured monthly over a year to obtain the annual emission estimates. Peak releases of the various sulfur gases did not occur simultaneously but were measured from July through to October depending on the individual sulfur species. The total annual emission was estimated to be 5.8 g S m −2 y −1, with dimethyl sulfide (49% of the total) and hydrogen sulfide (35% of the total) the major components emitted. The emissions of the other sulfur gases were nearly 10-fold lower.

Environmental patchiness, litter decomposition and associated faunal patterns in a Spartina alterniflora marsh

Spartina alterniflora leaf litter bundles were placed in a North Carolina salt marsh to study the effects of environmental heterogeneity on decomposition and animal colonization. Sediment type (mud vs. sand), tidal inundation zone (near bay, mid-marsh and upper marsh) and Spartina growth form (tall vs. short) were studied. Tidal zone had the greatest effect on decomposition rate. The main effects of sediment type and growth form were not significant. All treatments affected animal distribution patterns in the leaf bundles. Nearly all common taxa were more common on mud than sand. Most taxa showed a strong association with one tidal zone. Half of the taxa were associated with one of the Spartina growth forms. Many interactions among the treatments were also significant. This study demonstrates the significance of environmental heterogeneity in a Spartina marsh both for litter decomposition and animal distributions.

Relationships of Soil, Plant, and Microbial Characteristics in Silt-Clay and Sand, Tall-Form Spartina alterniflora Marshes

The relationships between soil texture, plant growth, and anaerobic microbial activity in two tall-formSpartina alterniflora marshes on Sapelo Island, Georgia, were compared. The soil of one marsh was composed of typical silt-clay-sized particles; the soil of the other marsh consisted of >90% sand-sized particles. The two soils supported similar biomasses ofS. alterniflora, however, plants were taller and more robust in the silt-clay-soil than in the sand soil. Total microbial adenosine triphosphate concentrations in the silt-clay and sand soils averaged 5.71 and 1.64 μg per cm3, respectively. Seawater slurries of both soils exhibited potential for microbial sulfate reduction, methanogenesis, and glucose fermentation; rates for the processes averaged 2.03 and 0.33 nmol S-cm3 per h; 1.20 and 0.87 μmol CH4 per cm3 per h; and 0.04 and 0.12 per min (rate constant) for the sand and silt-clay soils, respectively.

Nitrate Reduction in Spartina Alterniflora Marsh Soil

AbstractThe transformation of nitrate (NO‐3) was investigated in flooded Louisiana Gulf Coast salt marsh soll. Nitrate formed in the aerobic zone of the soil is readily reduced in the deeper anoxic zone by dissimilatory and/or assimilatory processes. The experiments were conducted in soil cores 15 cm in diameter by 12 to 15 cm in depth. 15N‐labelled NO‐3 at 0.6 g N m−2 was administered in either a single injection into the floodwater or in repeated small injections below the sediment‐water interface. For the single application experiment, 14% of the 15N remained in the system; 4% NH+4‐N and 10% organic N. This implies dissimilatory reduction, with NO‐3 being reduced to NH+4 prior to formation of organic N. Fifty separate applications increased the recovery of 15N in the NH+4‐N and organic N pool to 52%. The latter procedure more nearly reproduces the low steady‐state concentration of NO‐3 observed in salt marsh soil; the increased recovery suggests that the internal inorganic‐N cycling in these soils may be more efficient than previously reported.

Energy Flow Through the Fiddler Crabs Uca pugnax and U. minax and the Marsh Periwinkle Littorina irrorata in a North Carolina Salt Marsh

Energy budgets were developed for populations of the fiddler crabs Uca pugnax and U. minax and the periwinkle Littorina irrorata in a Spartina alterniflora marsh in the Cape Fear River Estuary, North Carolina. Production, respiration and assimilation (kcal mr-2 year-), respectively, were: 51, 55 and 106 for U. pugnax; 13, 44 and 58 for U. minax, and 8, 94, and 101 for L. irrorata. Assimilation efficiencies were relatively low: 9% for U. pugnax, 8% for U. minax and 14% for L. irrorata. Net growth efficiencies (production/assimilation) were 48% for U. pugnax, 23% for U. minax and 7% for L. irrorata. Together, the three species consumed the equivalent of about one-third of the net production of the emergent marsh and assimilated about onetenth of that amount. INTRODUCTION Fiddler crabs of the genus Uca and the periwinkle Littorina irrorata are among the most conspicuous invertebrates inhabiting salt marshes along the Atlantic and Gulf coasts (Smalley, 1958; Teal, 1958; Odum and Smalley, 1959; Shanholtzer, 1973; Wolf et al., 1975; Alexander, 1976; Krebs, 1976; Stiven and Hunter, 1976). Their abundance alone suggests that they are important in the flow of energy through the marsh ecosystem. As part of an attempt to formulate an energy budget for the entire salt marsh ecosystem at Walden Creek, North Carolina, an energy budget was constructed for the dominant invertebrate residents, U. pugnax, U. minax and L. irrorata. Ecological energy transformations are described by

Tracer Analysis of Methanogenesis in Salt Marsh Soils

Differences in paths of carbon flow have been found in soils of the tall (TS) and short (SS) Spartina alterniflora marshes of Sapelo Island, Ga. Gaseous end products of [U-C]glucose metabolism were CO(2) and CH(4) in the SS region and primarily CO(2) in the TS region. Sulfate concentration did not demonstrably affect glucose catabolism or the distribution of end products in either zone. [U-C]acetate was converted to CO(2) and CH(4) in the SS soils and almost exclusively to CO(2) in the TS soils. Sulfate concentration did not affect acetate metabolism in the SS soils; however, a noticeable effect of sulfate dilution was seen in TS soils. Sulfate dilution in TS samples resulted in increased methane formation. Total glucose and acetate metabolism were similar in TS and SS soils despite differences in end products. A microbial community characterized by fermentative/sulfate-reducing processes has developed in TS soils as opposed to the fermentative/methanogenic/sulfate-reducing community found in SS soils.

Short- and long-term variation in a high marsh meiofauna community

The meiobenthos from a high Spartina alterniflora marsh was studied in North Inlet, South Carolina over a 22 month period to assess long- (seasonal, yearly) and short- (weekly, monthly) term variation in community structure. Nematodes composed a mean 73% of the meiofauna assemblage and copepods ranked second in abundance. Stenhelia (D.) bifidia, Schizopera knabeni, Microarthridion littorale and Enhydrosoma propinquum were the four dominant copepod species recorded from this site and each displayed seasonally distinct patterns of abundance and reproduction. Meiofaunal polychaetes, represented by Manayunkia aestuarina and juvenile Streblospio benedicti, were also seasonally important constituents of the community. Community structure parameters indicated that there was little similarity of the copepods assemblage within seasons or between years. These findings suggest that unpredictable events are important influences on meiofauna community structure and cause this system to fluctuate over the time scale of this study.

Zonation of meiobenthic copepods in a southeastern United States salt marsh

Studies in various regions of southeastern U.S. Spartina alterniflora marshes indicate distinct zonation patterns of the meiobenthic copepods. Transversing a water depth gradient from the subtidal at the bottom of a tidal creek to the high intertidal marsh, one species, Microarthridion littorale, occurs along the entire gradient. Other species are common along certain large portions of the gradient and still others are restricted to subhabitats. Potential reasons for the observed distribution patterns include water depth, tidal exposure, and presence or absence of both vegetation and macrofaunal disturbers/predators.

Food Sources of Estuarine Invertebrates Analyzed Using 13C/12C Ratios

The complex nature of, and importance of detritus consumption in, estuarine food webs make analysis of specific pathways of carbon in estuaries very difficult. We have evaluated the use of the natural abundances of the stable carbon isotopes in estuarine flora and fauna as a qualitative indicator of food sources in a Georgia salt marsh estuary. The salt marsh ecosystem is particularly amenable to this technique because of the wide span of distinctive 13C/12C ratios of the dominant plants °13C of ‐12 to ‐26%). Laboratory experiments showed negligible further fractionation of the characteristic °13C of marsh plants during microbial degradation of dead plant material, and during assimilation of ingested detritus by estuarine invertebrates. Invertebrates having a variety of feeding habits were collected in monospecific and mixed species stands of marsh plants. Marsh snails and insects had °13C values close to those of the associated vascular plants. Deposit—feeding crabs had isotope ratios biased away from the marsh plant °13C values, likely a result of feeding on benthic diatoms and out—of—stand foraging. Mud snails and filter—feeding bivalves showed 13C/12C ratios similar to those of benthic and pelagic algae. The °13C values of marsh fiddler crabs varied from ‐12 to ‐24% in various habitats having predominately C4 or C3 food source plants. Individuals collected from populations of 3 crab species in a Spartina alterniflora marsh had 13C/12C ratios with a standard deviation of only about 1% from the mean°13C. Stable carbon isotope ratio analysis appears to be a powerful tool in the evaluation of carbon pathways in estuarine food webs.

Methane release from soils of a Georgia salt marsh

A seasonal study of methane release from marsh soils to the atmosphere indicates that ebullition is a significant process varying both seasonally and spatially. Release rates are higher during summer months than winter months and ebullition is greatest in the short Spartina alterniflora marshes and least in the tall S. alterniflora marshes. The annual amounts of methane released in the short and tall marshes are 53.1 and 0.4 gm −3 which represents a loss of 8.8 and 0.002% of the net carbon fixation in the two respective marsh types. In vitro experimentation shows that methane production is sensitive to changes in temperature and addition of H 2 and CO 2.

Flax Pond ecosystem study: Exchanges of phosphorus between a salt marsh and the coastal waters of Long Island Sound

The exchanges of phosphorus between the Flax Pond, a tidal Spartina alterniflora marsh on the north shore of Long Island (USA) and Long Island Sound were measured over 18 months. Phosphate was exported from the marsh from May through December and imported during the remainder of the year. Organic phosphorus appears to be accumulated in all seasons, but the yearly phosphorus budget of the marsh is approximately balanced despite the accumulation of about 6 mm of sediment annually.

Primary Production in a Louisiana Golf Coast Spartina Alterniflora Marsh

Live and dead aboveground biomass of Spartina alterniflora Loisel in a Louisiana salt marsh was determined monthly over an annual cycle. Litterbags were used to determine loss rates of particulate vegetation from the marsh surface. Net aboveground primary production estimates ranged from 750 to 2,600 g m(—2) yr(—1), depending on how data were handled. Analysis of these results suggested that true net production was probably much closer to the highest estimate, than to the lowest.

Accumulation rate and turnover time of organic carbon in a salt marsh sediment1

Concentrations of organic carbon (excluding belowground plant material) decreased logarithmically with depth in the sediment of a Spartina alterniflora marsh near Drum Inlet, N.C. A similar decrease was measured in nearby areas of unvegetated dredge spoil and in dredge spoil planted with Spartina. Both spoil areas accumulated organic carhon, but the annual rate was higher where Spartina was present (range, 80.3–96.8 g C m−2). The organic carbon in the top 13 cm of the natural marsh sediment has a turnover time, based on this rate of accumulation, of 3.7 to 4.5 years.

Sedimentation rates in a Long Island marsh determined by 210Pb dating1

Mean rates of vertical accretion of from 0.47 to 0.63 cm yr−1 have been determined for the past century from two widely separated sites at Flax Pond, a Spartina alterniflora marsh on the north shore of Long Island. Sediments were dated from 210Pb activity. The rates are equivalent to deposition of 325 to 436 g of dry organic matter m−2 yr−1 or about 146 to 196 g of carbon m−2 yr−1 Although the two sites differed in salt peat thickness, the basal layer of the peat was deposited about 100 years ago at both.

Pollen and paleosalinity analyses from a Holocene tidal marsh sequence, Cape May County, New Jersey

Evaluation of sediment types, SPM paleosalinity values, and pollen spectra for the Dennis Creek Tidal Marsh indicates fluctuation of marsh environments related to rate of sea-level rise. The rise of sea level which initiated and accompanied the deposition was not constant, but rather changed throughout the period of time represented by the Dennis Creek sequence. Prior to about 3000 years ago rising sea level first affected the Dennis Creek area. Initially, an open water environment existed, followed by the development of a Spartina alterniflora marsh. A decrease in the rate of sea-level rise allowed a fresh-water environment to move out over the established marsh. A later increase in the rate of sea-level rise produced a marine transgression again establishing the marsh area. Areas immediately adjacent to major tributaries responded to the transgressions, and fluctuations therein, to a greater degree than those areas further away from major tributaries. Thus, isolated cores from a marsh system may not contain the complete record of all that has happened in the area. A major transgression of the sea occurred at around 1800 years B.P. This transgression is also indicated by changes in pollen spectra of sediments from Barnstable, Massachusetts. Thus, previously published curves for sea-level rise appear to show mean values, and do not reflect actural fluctuations. The evidence of man's colonization of the area is quite clear in the pollen record. The influx of the Compositae in the pollen spectra for the cores indicates the deforestation of the area, allowing these weed plants to become abundant. The high percentages of the Chenopodiaceae in core # 16 is the result of ditching of the marsh. The elucidation of the stratigraphy of Dennis Creek Tidal Marsh and the correlation of this stratigraphy with adjacent areas indicates that the methods utilized are, in fact, valid for this type of study. Pollen analysis can be utilized for the determination of local vegetation in conjuction with other methods. Also, the SPM paleosalinity techniques is valid within a single vertical sequence, where there has been no variation in the source area of the sediment. The salinity values obtained by this method may not be exact; however, the trends established are extremely valuable in the interpretation of paleoecology.