Life Sciences Commons^™

Utilization And Turnover Of Labile Dissolved Organic Matter By Bacterial Heterotrophs In Eastern North Pacific Surface Waters, J Cherrier, Je Bauer, Erm Druffel

VIMS Articles

Seawater incubation experiments were conducted in June and October 1992 to examine bacterial utilization of labile dissolved organic matter (DOM) in open ocean surface waters of the eastern North Pacific. Natural plankton extract-DOM (PE-DOM) and selected model compounds were added to seawater samples to evaluate bacterial utilization and respiration rates relative to bacterial carbon production rates for the various amendments. PE-DOM always stimulated bacterial production and DOM utilization, and the primary nitrogen source supporting this bacterial production was dissolved organic nitrogen (DON). Utilization of DON during exponential growth was balanced by the production of ammonium for samples amended with PE-DOM. …

Non-Structural Carbohydrate Reserves Of Eelgrass Zostera Marina, Mk Burke, Wc Dennison, Ka Moore

VIMS Articles

The high minimum Light requirement of eelgrass Zostera marina L. suggests that this species has difficulty in maintaining a positive carbon balance except under high light conditions. The carbon balance of Z. marina can be studied by following seasonal changes in non-structural carbohydrate (NSC) reserves, however, little is known about the seasonal variation in NSC reserves in seagrasses or the influence of shading on NSC reserve content and distribution. Seasonal changes in eelgrass NSC reserves were measured in a shallow coastal lagoon, Chincoteague Bay, Maryland/Virginia, USA, near the southern edge of this species' distributional range. Concentrations of sugar varied seasonally …

Seasonal Variability Of Particulate Organic Radiocarbon In The Northeast Pacific Ocean, Ellen R.M. Druffel, James E. Bauer, Peter M. Williams, Shelia Griffin, David Wolgast

VIMS Articles

We present Delta(14)C measurements of particulate organic carbon (POC) collected on four cruises at our time series site (station M) in the northeast Pacific Ocean. We observe a large gradient with depth in the suspended POC Delta(14)C values (124-160 parts per thousand). These profiles display lower Delta(14)C values (by 20-30 parts per thousand) in samples between 2500 m and the bottom during June 1992 and July 1993 than those during February and October 1992. Values of Delta(14)C in sinking POC from deep-moored sediment trap collections suggest a semiannual trend that displays lower overall Delta(14)C in material collected during periods of …

Effects Of Sand-Mining On Benthic Communities And Resource Value : Thimble Shoal, Lower Chesapeake Bay, Linda C. Schaffner, Michele A. Horvath, Carl H. Hobbs Iii

Reports

In August 1990 the City of Hampton placed approximately 276,000 cubic yards of sand from a designated borrow site on Thimble Shoal onto Buck:roe Beach for beach restoration. The Buck:roe reserve identified by Kimball et al. (1989) contains large quantities of beach quality material and is located less then 2.5 km offshore of Buck:roe Beach. In early 1989 a small section (330 m by 240 m) located in 5 m of water was delineated and permitted for dredging. This project represents the first instance of permitted, sand-mining activities for beach nourishment in the lower bay. Although the impacts of the …

Integrative Analysis Of Ecosystem Processes In The Littoral Zone Of Lower Chesapeake Bay: A Modeling Study Of The Goodwin Islands National Estuarine Research Reserve, Christopher P. Buzzelli

Dissertations, Theses, and Masters Projects

Approximately 40% of the bottom of Chesapeake Bay is less than 2.0 m in depth and many of these broad shoal environments are bordered by wetlands. The vegetated and nonvegetated subtidal and intertidal environment is a dynamic mosaic of highly productive estuarine habitats linked by the exchange of waterborne materials. This study developed simulation models of primary production and material exchange for four littoral zone habitats of the Goodwin Islands National Estuarine Research Reserve (NERR) in lower Chesapeake Bay. Field studies were conducted to determine the sediment biogeochemical and biomass characteristics of sandy shoal, seagrass, silt-mud, and marsh habitats. Ecological …

The Role Of Microbial Food Webs In Benthic-Pelagic Coupling In Freshwater And Marine Ecosystems, Adele J. Pile

Dissertations, Theses, and Masters Projects

A majority of carbon in freshwater and marine ecosystems is in the form of ultraplankton, heterotrophic and autotrophic plankton &<&5 &\mu&m including heterotrophic bacteria, Prochlorococcus, cyanobacteria, and autotrophic eucaryotes. However, ultraplankton and subsequently microbial food webs have yet to be incorporated into models of benthic-pelagic coupling despite the preponderance of macroinvertebrates with the capacity to feed on ultraplankton. I have examined the role of microbial food webs in benthic-pelagic coupling in three ecosystems: Lake Baikal, Siberia, Russia; Gulf of Maine, Northwest Atlantic Ocean; and Conch Reef, Florida Keys, USA. Using sponges as a model organism and in situ measurements, I have quantified (1) suspension feeding on ultraplankton and (2) release of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) resulting in direct evidence that benthic macroinvertebrates do occupy the level of primary consumer within the microbial food web. Dual-beam flow cytometry was employed to quantified sponge suspension feeding on five types of ultraplankton: heterotrophic bacteria, Synechococcus-type cyanobacteria, autotrophic picoplankton &<&3 &\mu&m, autotrophic eucaryotes 3-10 &\mu&m, and in marine ecosystems Prochlorococcus. Grazing by the freshwater sponges Baikalospongia intermedia and B. bacilliferia and the boreal marine sponge, Mycale lingua, was unselective for all types of ultraplankton with efficiencies ranging from 63-99%. This is the first time that grazing on Synechococcus-type cyanobacteria and Prochlorococcus by macroinvertebrates has been quantified in freshwater and marine ecosystems. Conversely, the coral reef sponges Ircinia felix and I. strobilina release significant amounts of DIN and DIP as a result of grazing on procaryotic plankton. Using a general model for organism-mediated fluxes, it is conservatively estimated that through active suspension feeding sponges in Lake Baikal retain 1.97 g C day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& and M. lingua retains 29 mg C day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& while at Conch Reef sponges released 204 &\mu&mol DIN day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}& and 48 &\mu&mol DIP day&\sp{lcub}-1{rcub}& m&\sp{lcub}-2{rcub}&. A majority of the carbon retained at all three locations was from procaryotic cell types suggesting that ultraplankton are an important overlooked component of benthic-pelagic coupling.

Autoecology Of Paraprionospio Pinnata (Polychaeta: Spionide) Along An Estuarine Gradient, Elizabeth K. Hinchey

Dissertations, Theses, and Masters Projects

No abstract provided.

Phosphorous Limitation And Trophic Status In Limestone Quarry Lakes, Dade County, Fl, Isaac Peter Chase

HCNSO Student Theses and Dissertations

While limestone quarry lakes have existed in South Florida for many years, only recently have they received serious scrutiny. A thorough understanding of the trophic dynamics of these lakes has yet to be achieved. Questions have arisen as to the value of these lakes for such purposes as water reclamation, conservation, and recreational use. The purpose of this study was twofold, 1) to investigate the trophic processes within these lakes with special regard to phosphorus limitation, and 2) to help provide a better understanding of the linmology of these lakes, specifically through the quantification and identification of the invertebrate life …

Diet And Seasonal Feeding Habits Of The Yellow Stingray, Urolophus Jamaicensis, T. Patrick Quinn

HCNSO Student Theses and Dissertations

Urolophus jamaicensis, the yellow stingray, is a common elasmobranch found on and around the coral reefs off Florida's southeastern coast. Its diet consists of polychaetes, crustaceans, nemerteans, sipunculids, nematodes, and chaetognaths with polychaetes and crustaceans comprising almost 67% of the stomach contents by volume. There does not appear to be any diet preference between the male and females stingrays. The seasonal changes in diet preference are limited to an increase in the proportion of polychaetes found in the stomach during spring when compared to fall.

Regulation Of Beta-Glucosidase In Marine Bacteria, Dennis Stetter

HCNSO Student Theses and Dissertations

The following is a study of the regulation of production of a catabolic enzyme, beta-glucosidase, by isolated strains of marine bacteria. Catabolic enzymes transform organic matter to monosaccharides which are utilized as an energy source for growth by bacteria. The bacterial strains were isolated from the Gulf Stream off the coast of Florida, as well as from particulate matter collected from waters adjacent to the Florida coast.

The first section describes the preparation of a liquid medium using sterile saltwater supplemented with inorganic nutrients and a carbohydrate component. This medium allowed growth of marine bacteria under carbohydrate-limiting conditions. A solid …

Subadult Loggerhead Sea Turtle (Caretta Caretta) Behavior In St. Mary's Entrance Channel, Georgia, United States, David A. Nelson

Dissertations, Theses, and Masters Projects

A study of channel utilization and behavior of subadult loggerhead turtles was conducted in the St. Mary's River entrance channel area, Georgia. A total of 38 loggerheads were captured by trawling and instrumented with radio and depth sensitive sonic tags from April to November 1993. Turtles were monitored for 6 to 36 hours continuously for approximately 30 days in the spring (13), summer (13), and fall (14). On a daily basis turtles generally confined their diving activity to one location for one to twelve hours in 10 to 20 m water depths then moved 1 to 5 kilometers to a …

The Role Of Epibenthic Predators In Structuring Marine Soft-Bottom Communities Along An Estuarine Gradient, Rochelle D. Seitz

Dissertations, Theses, and Masters Projects

A unifying theory of community regulation in soft-bottom systems remains elusive, despite extensive field studies on factors controlling community structure. Here, I have (1) reviewed models of community regulation, (2) examined the role of predation in controlling benthic diversity along a salinity gradient, (3) examined effects of predation upon an abundant bivalve, Macoma balthica, and (4) revised a model of community regulation in an estuarine soft-bottom system. The Menge and Sutherland (MS) "consumer stress model" posits that consumers feed ineffectively in harsh environments, and the importance of physical disturbance, competition and predation varies with recruitment, environmental conditions, and trophic position. …

Utilization Of Seagrass Habitat By The Blue Crab, Callinectes Sapidus Rathbun, In Chesapeake Bay: A Review, Robert J. Orth, Jacques Van Montfrans, Romuald N. Lipcius, Karen S. Metcalf

VIMS Books and Book Chapters

Seagrasses are generally presumed to provide important habitats for numerous species of vertebrates and invertebrates, serving as a nursery, structure for attachment, or foraging area. However, few species appear directly dependent on seagrass, one notable exception being the bay scallop, Argopecten irradians Lamarck. Research in Chesapeake Bay on the abundant, and commercially exploitable blue crab, Callinectes sapidus Rathbun, over the last decade, focused on the relevance of seagrass habitat for the overall population. Our research has demonstrated: I. higher densities of juvenile blue crabs in seagrass habitats compared to adjacent marsh and unvegetated areas, 2. seagrasses to be an important …

Patterns Of Phytoplankton Abundance And Nutrient Concentration In The York River Estuary, Virginia: 1984-1994, Yongsik Sin, Richard L. Wetzel

Reports

No abstract provided.

Development And Lipid Composition Of The Harpacticoid Copepod Nitocra Spinipes Reared On Different Diets, Gregory M. Weiss, George B. Mcmanus, H. Rodger Harvey

OES Faculty Publications

We reared the harpacticoid copepod Nitocra spinipes on diets of bacteria, a diatom, or a macroalga, evaluating survivorship and growth in short-term (≤ 1 generation) experiments. Lipid content of the copepods and their diets was measured and used as an index of nutrition. Although growth, survivorship and lipid content of N. spinipes were significantly greater when fed the diatom, which had the highest lipid content of the 3 diets, the copepod was able to develop from egg to adult when fed a lipid- poor bacterial diet. Furthermore, this species was able to go through developmental molts without the addition of …

Faunal Diversity Among Avian Parasite Assemblages: The Interaction Of History, Ecology, And Biogeography In Marine Systems, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Systematics and parasite biodiversity provide power and predictability in broad studies of history, ecology and biogeography in marine systems. Parasitic helminths are elegant markers of contemporary and historical ecological relationships, geographic distribution and host-phylogeny. Complex life cycles of helminths are strongly correlated with intricate food-webs. Dependence on a series of intermediate, paratenic, and definitive hosts indicates that each parasite species represents an array of organisms within a community and tracks broadly and predictably across many trophic levels. Host and geographic ranges of parasites are historically constrained by genealogical and ecological associations, and these determinents interact resulting in characteristic parasite community …

The Influence Of Location, Seagrass Species And Water Depth On The Settlement And Distribution Of Early Stage Blue Crabs, Renee A. Pardieck

Dissertations, Theses, and Masters Projects

No abstract provided.

Effect Of Light/Dark Transition On Carbon Translocation In Eelgrass Zostera Marina Seedlings, Richard C. Zimmerman, Randall S. Alberte

OES Faculty Publications

Carbon translocation in the marine macrophyte Zostera marina L. (eelgrass) was investigated to elucidate the impact of light/dark transitions on sucrose partitioning between roots and shoots. After exposure of leaves to C-14-bicarbonate, the level of C-14-labelled photoassimilates increased monotonically in both leaves and fully aerobic roots of plants maintained in the light. Accumulation of C-14 in roots and leaves ceased abruptly when plants were transferred to darkness that induced root anaerobiosis even though C-14 levels remained high in the dark-exposed leaves. Thus, translocation of C-14 photoassimilates from shoots to roots was inhibited when roots became anoxic. Anoxia induced by light …

Demersal Predator Exposure To Toxic Organic Contaminants: Direct Effects Of Macrofauna In Trophic Transfer, Patrick Winfield Lay

Dissertations, Theses, and Masters Projects

The bioaccumulation and metabolism of organic contaminants (PAH, PCB) by three estuarine polychaetes, Nereis succinea (Frey and Leuckart 1847), Paraprionospio pinnata (Ehlers 1901) and Polydora ligni (Webster 1879), and by the fish predator, spot (Leiostomus xanthurus Lacepede 1802), were examined in laboratory experiments. Variations in trophic transfer of these contaminants resulting from differences in prey and contaminant type were also investigated. Toxicokinetic modeling reveals that metabolism of organic contaminants by invertebrate species result in variations in uptake, metabolism and elimination rate constants. Incorporation of prey metabolism potential in kinetic models increases the latter's predictability of biota-sediment accumulation factors (BSAFs), or …

Habitat Complexity As A Determinant Of Juvenile Blue Crab Survival, Jessica L. Schulman

Dissertations, Theses, and Masters Projects

No abstract provided.

Food-Limited Growth And Condition Index In The Eastern Oyster, Crassostrea Virginica (Gmelin, 1791), And The Bay Scallop, Argopecten Irradians Irradians (Lamarck, 1819), Michael A. Rice, Robert B. Rheault Jr.

Michael A Rice

The growth response of the eastern oyster, Crassostrea virginica, and the bay scallop, Argopecten irradians irradians, to varying degrees of food limitation was evaluated. Under conditions of low current speed, dense assemblages of shellfish can rapidly deplete ambient food concentrations, resulting in measurable effects on growth and condition index. A flume study demonstrated significant growth and condition index responses to resource competition after reductions as small as 27% in relatively high ambient food concentrations (—4.6 u.g/1 chlorophyll). Growth rates and condition index are linearly correlated with the average chlorophyll ration consumed. A field study demonstrated similar growth responses when the …

A Survey Of Disease In The Oyster Crassostrea Virginica (Gmelin, 1791) In Rhode Island Coastal Estuaries, Retno Andamari, Michael A. Rice, Paul P. Yevich

Michael A Rice

The presence of potential pathogens and lesions in American oysters, Crassostrea virginica (Gmelin, 1791), from coastal estuaries in Rhode Island was studied. Oysters were collected by hand or tongs from three stations in the Pawcatuck River, two stations in Narrow River, three stations in Charlestown Pond, and three stations in Green Hill Pond, during July/August 1991, November 1991, March 1992, and May 1992. Oysters were processed for histologic examination and determination of condition index. MSX, Haplosporidium nelsoni (Haskin, Stauber et Mackin, 1966), was detected in four of 480 oysters (0.8%); Sphenophyra sp., 15 of 480 (3.1%); Bucephalus sp. 16of 480 …