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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
Effects Of Periodic Environmental Hypoxia On Predator Utilization Of Macrobenthic Infauna, Janet A. Nestlerode
Effects Of Periodic Environmental Hypoxia On Predator Utilization Of Macrobenthic Infauna, Janet A. Nestlerode
Dissertations, Theses, and Masters Projects
Hypoxia and anoxia have significant deleterious ecological effects on living resources throughout many estuarine and marine ecosystems worldwide. Brief periods of low oxygen facilitate transfer of benthic production to higher trophic levels as many benthic infaunal species have shallower sediment depth distributions during hypoxic events. A baited time-lapse camera equipped with a water quality datalogger was used to document in situ exploitation of oxygen-stressed benthic invertebrate prey organisms by mobile fish and crustacean predators during alternating normoxia-hypoxia cycles in the York River. Based on photographic and diver observations, this hypoxiainduced benthic-pelagic transfer of production is more likely to occur when …
Growth Dynamics Of A York River Estuary Heterotrophic Dinoflagellate Grazing Katodinium Rotundatum, Angela Denise Smith
Growth Dynamics Of A York River Estuary Heterotrophic Dinoflagellate Grazing Katodinium Rotundatum, Angela Denise Smith
Dissertations, Theses, and Masters Projects
No abstract provided.
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
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
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.
Age, Growth, And Reproductive Biology Of Blackcheek Tonguefish, Symphurus Plagiusa (Cynoglossidae: Pleuronectiformes), In Chesapeake Bay, Virginia, Mark Richard Terwilliger
Age, Growth, And Reproductive Biology Of Blackcheek Tonguefish, Symphurus Plagiusa (Cynoglossidae: Pleuronectiformes), In Chesapeake Bay, Virginia, Mark Richard Terwilliger
Dissertations, Theses, and Masters Projects
No abstract provided.
The Development Of Affinity Maturation In Rainbow Trout Oncorhynchus Mykiss, Ing Wei Khor
The Development Of Affinity Maturation In Rainbow Trout Oncorhynchus Mykiss, Ing Wei Khor
Dissertations, Theses, and Masters Projects
No abstract provided.
Lipid Class Composition Of Oysters, Crassostrea Virginica, Exposed To Sediment-Associated Pahs, Tong Li
Lipid Class Composition Of Oysters, Crassostrea Virginica, Exposed To Sediment-Associated Pahs, Tong Li
Dissertations, Theses, and Masters Projects
No abstract provided.
Autoecology Of Paraprionospio Pinnata (Polychaeta: Spionide) Along An Estuarine Gradient, Elizabeth K. Hinchey
Autoecology Of Paraprionospio Pinnata (Polychaeta: Spionide) Along An Estuarine Gradient, Elizabeth K. Hinchey
Dissertations, Theses, and Masters Projects
No abstract provided.
Potential For Population Regulation Of The Zebra Mussel, Dreissena Polymorpha, In The Hudson River, Larry C. Boles
Potential For Population Regulation Of The Zebra Mussel, Dreissena Polymorpha, In The Hudson River, Larry C. Boles
Dissertations, Theses, and Masters Projects
No abstract provided.
Breeding Ecology, Success, And Population Management Of The Piping Plover (Charadrius Melodus) At Chincoteague National Wildlife Refuge, Virginia, Robert Richard Cross
Breeding Ecology, Success, And Population Management Of The Piping Plover (Charadrius Melodus) At Chincoteague National Wildlife Refuge, Virginia, Robert Richard Cross
Dissertations, Theses, and Masters Projects
No abstract provided.
The Role Of Epibenthic Predators In Structuring Marine Soft-Bottom Communities Along An Estuarine Gradient, Rochelle D. Seitz
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. …
Field And Laboratory Evidence Of Pheromone Mediated Mating Behavior In The Blue Crab, Callinectes Sapidus, Donald S. Gibbs
Field And Laboratory Evidence Of Pheromone Mediated Mating Behavior In The Blue Crab, Callinectes Sapidus, Donald S. Gibbs
Dissertations, Theses, and Masters Projects
No abstract provided.
The Influence Of Location, Seagrass Species And Water Depth On The Settlement And Distribution Of Early Stage Blue Crabs, Renee A. Pardieck
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.
Demersal Predator Exposure To Toxic Organic Contaminants: Direct Effects Of Macrofauna In Trophic Transfer, Patrick Winfield Lay
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 …
Expression Of The Xenobiotic Transporter P-Glycoprotein In The Mummichog (Fundulus Heteroclitus), Peter S. Cooper
Expression Of The Xenobiotic Transporter P-Glycoprotein In The Mummichog (Fundulus Heteroclitus), Peter S. Cooper
Dissertations, Theses, and Masters Projects
The mammalian mdr1 P-glycoprotein (Pgp) has been implicated in xenobiotic resistance of drug-resistant cell lines and tumors, and may function in excretion or exclusion of toxic xenobiotics at several sites within the body. Pgp gene family members are expressed in excretory epithelia of several aquatic taxa and may contribute to the survival of pollution-tolerant aquatic animals in contaminated environments. For this reason the expression of Pgp family members was investigated in the livers and liver tumors of creosote-resistant mummichog (Fundulus heteroclitus) inhabiting a creosote-contaminated site (Atlantic Wood) in the Elizabeth River, Virginia. Expression of members of the Pgp gene family …
Contributions To The Life History Of Juvenile Blueback Herring (Alosa Aestivalis): Phototactic Behavior And Population Dynamics, Douglas A. Dixon
Contributions To The Life History Of Juvenile Blueback Herring (Alosa Aestivalis): Phototactic Behavior And Population Dynamics, Douglas A. Dixon
Dissertations, Theses, and Masters Projects
This research investigated the relationship between juvenile abundance indexes (JAIs) for anadromous blueback herring (Alosa aestivalis) and abiotic factors (river flow and temperature) during the spawning and nursery period in the tidal freshwater areas of James, Pamunkey, Mattaponi, and Rappahannock Rivers in Virginia. Accomplishing this objective required the evaluation of the JAI methodology, specifically the effect of phototactic behavior on diel changes in the surface availability to the pushnet sampling gear, and obtaining population dynamics information (hatch dates, growth, natural mortality) during early life history from otolith microstructure of samples collected in 1991 and 1992. Mean catch-per-unit effort (CPUE) at …
Habitat Complexity As A Determinant Of Juvenile Blue Crab Survival, Jessica L. Schulman
Habitat Complexity As A Determinant Of Juvenile Blue Crab Survival, Jessica L. Schulman
Dissertations, Theses, and Masters Projects
No abstract provided.
Perkinsus Marinus Extracellular Proteases: Modulation Of Production By Environmental Factors And Effects On The Host Defense Parameters Of The Eastern Oyster Crassostrea Virginica, Kathleen A. Garreis
Perkinsus Marinus Extracellular Proteases: Modulation Of Production By Environmental Factors And Effects On The Host Defense Parameters Of The Eastern Oyster Crassostrea Virginica, Kathleen A. Garreis
Dissertations, Theses, and Masters Projects
No abstract provided.