Life Sciences Commons^™

Changes In Caloric Content As A Result Of Sub-Lethal Stress In Neanthes Virens (Sars), Phyllis J. Friello

Biological Sciences Theses & Dissertations

Neanthes virens were subjected to a toxicity test with 1.8, 3.4, 6.7 and 11.0 mg/1 Cd²⁺. Worms were withdrawn on Days 1, 4, 7, 10 and 14 from each of five replicate tanks and their caloric content determined by bomb calorimetry. Analyses of variance and covariance showed no significant differences in worm caloric content with withdrawal day or cadmium concentration.

In a second experimental series, a sediment toxicity test with Neanthes virens was conducted in contaminated sediments from two sites, as well as reference sediments from a control site. Caloric content of the worms was measured by bomb …

The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell

OES Theses and Dissertations

Recruitment processes are important information for the management of commercially and recreationally exploited marine species. Recruitment processes of the Chesapeake Bay's most important commercial and recreational species, the blue crab, are unknown, due in part to the lack of knowledge of the processes directly preceeding recruitment.

The present study was undertaken to investigate and explain the movement and developmental patterns of blue crab larvae while offshore. Interannual and intraseasonal variations of these patterns were also examined.

Sampling occurred from May to November during 1982 and 1983. Larvae were collected at three depths (neuston layer (upper 10 cm), one meter and …

Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth

OES Theses and Dissertations

The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.

Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …

Behavioral Determination Of A Geomagnetic Senstivity In The Atlantic Bottlenose Dolphin, Tursiops Truncatus (Cetacea, Onotoceti), Alene A. Minchew

Master's Theses

No abstract provided.

Population Variation In The Mitochondrial-Dna Of Two Marine Organisms: The Hard Shell Clam Mercenaria Spp. And The Killifish, Fundulus Heteroclitus, Bonnie Lynn Brown

OES Theses and Dissertations

The two major topics are covered in this dissertation: the integration of molecular genetic tools with applied aquacultural research and short-term evolutionary dynamics. The first study investigated the extent of geographic differentiation of native clam stocks along the U.S. east and Gulf coasts. Clam mitochondrial DNA (mtDNA) demonstrated size polymorphism (16.5-19.0 kb) and restriction site heteroplasmy. Size heteroplasmic individuals occurred at a frequencies of 0-89% in clam populations. Restriction site heteroplasmy occurred in 12% of the 317 individuals assayed. Results of the study indicated that although harbouring a wealth of genetic variation, clams from northern regions were similar and lacked …

Aspects Of Volume Regulation In Two Estuarine Invertebrates: Glycera Dibranchiata (Annelida) And Modiolus Demissus (Mollusca), Ana Marie Beardsley

Dissertations, Theses, and Masters Projects

No abstract provided.

Recruitment And Growth Of Juvenile Crassostrea Virginica (Gmelin) In Relation To Tidal Zonation, George Curtis Roegner

Dissertations, Theses, and Masters Projects

No abstract provided.

The Influence Of Salinity On The Swimming Behavior Of Larval Crassostrea Virginica (Gmelin), Kevin J. Mccarthy

Dissertations, Theses, and Masters Projects

No abstract provided.

Pcb Congener Analysis With Hall Electrolytic Conductivity Detection, Robert D. Edstrom

Dissertations, Theses, and Masters Projects

This work reports the development of an analytical methodology for the analysis of PCB congeners based on integrating relative retention data provided by other researchers. The retention data were transposed into a multiple retention marker system which provided good precision in the calculation of relative retention indices for PCB congener analysis. Analytical run times for the developed methodology were approximately one hour using a commercially available GC capillary column. A Tracor Model 700A Hall Electrolytic Conductivity Detector (HECD) was employed in the GC detection of Aroclor standards and environmental samples. Responses by the HECD provided good sensitivity and were reasonably …

Heterotrophic Bacterial Production: Relationships To Biological And Abiological Factors In Estuarine Environments, Eric Thor Koepfler

Dissertations, Theses, and Masters Projects

Section 1. Ecotoxicological effects of creosote contamination on benthic bacterial communities in the Elizabeth River, Virginia were investigated using both structural and functional microbial parameters. Results indicated that cell specific and total heterotrophic bacterial production parameters were depressed in a dose dependent manner with increasing sediment PAH concentrations. Toxicity effects upon production were modified by temporal trends associated with temperature as well as spatial sediment characteristics. of the parameters employed, the tritiated thymidine production assay was found to be the most sensitive for detection of ecotoxicological effects. Section 2. Bacterial abundance and production were examined during a destratification event in …

Nitrogen And Phosphorus Cycling Strategies In Two Tidal Freshwater Macrophytes, Peltandra Virginica And Spartina Cynosuroides, Paul Milton. Booth Jr

Dissertations, Theses, and Masters Projects

Monotypic stands of the macrophytes Peltandra virginica and Spartina cynosuroides, which shared a common boundary, were studied at Sweethall Marsh, a tidal freshwater marsh located on the Pamunkey River within the Chesapeake Bay estuarine system, Virginia. Compartmental models indicate that both Peltandra and Spartina take up, internally cycle, and release to the environment, significant levels of nitrogen and phosphorus. Models also suggest that Peltandra and Spartina and their associated sediment compartments are capable of regulating nitrogen and phosphorus fluxes through their uptake and storage capacity. Nitrogen use efficiency was significantly higher in the shoots and roots of Spartina compared to …

The Influence Of Tributyltin On Various Aspects Of Activation And Reactive Oxygen Formation In Oyster Toadfish (Opsanus Tau) Macrophages, Charles D. Rice

Dissertations, Theses, and Masters Projects

The effects of tributyltin (TBT) on phorbol myristate acetate (PMA)- and calcium ionophore (A23187)-stimulated peritoneal macrophages from oyster toadfish (Opsanus tau) were evaluated in a luminol-dependent chemiluminescence (CL) assay. PMA-stimulated CL responses were increased by in vitro exposure to 50 ug/L TBT, but depressed to baseline values by 500 ug/L TBT. A23187-stimulated CL increased with 5 ug/L and 50 ug/L TBT, and depressed by 500 ug/L TBT. Responses stimulated by synergistic doses of PMA and A23187 were increased by 50 ug/L TBT and depressed by 500 ug/L TBT. Enhanced PMA- and A23187-stimulated CL following TBT exposure returned to baseline values …

Effect Of Nitrogen And Phosphorus Enrichment On Lipid And Fatty Acid Composition Of Estuarine Microplankton, Jia Chen

Dissertations, Theses, and Masters Projects

No abstract provided.

Virginia's Pelagic Recreational Fishery: Biological, Socioeconomic And Fishery Components, Eleanor A. Bochenek

Dissertations, Theses, and Masters Projects

Catch, effort, fleet size and boat owner expenditure data were collected on Virginia's recreational marlin/tuna fishery for the 1983-1985 seasons. Logbooks, dockside interviews and a telephone survey were evaluated to determine which method was the most efficient and effective for collecting and estimating catch and effort for Virginia's pelagic recreational fishery. In 1984, logbooks were used to collect catch and effort data and fishing effort was estimated using Bochenek's method. Very few fishermen returned their logbooks and as a result this data is probably less reliable than the data collected in other years. Due to the poor return of logbooks, …

Uptake Kinetics And Toxicity Of Diazinon In The American Oyster, Crassostrea Virginica Gmelin, Ruth L. Williams

Dissertations, Theses, and Masters Projects

Several aspects of effects of the organophosphate pesticide diazinon on the American oyster Crassostrea virginica Gmelin were investigated. Uptake of diazinon directly from water was compared with uptake of diazinon sorbed to either fine sediment or algae; the primary route of assimilation seems to be from the water. Concentrations of diazinon between 0.91 and 2.03 mg/L inhibit shell growth during 96 hours of exposure; there is a sharp threshold of effect for this response which is probably an indirect one caused by lack of food during shell closure. Acetylcholinesterase inhibition is significant in oyster heart tissue at concentrations of approximately …