Life Sciences Commons^™

Determination Of The Ecological Condition Of Benthic Communities Affected By Polycyclic Aromatic Hydrocarbons In The Elizabeth River, Chesapeake Bay, Usa, Adam M. Webb

Biological Sciences Theses & Dissertations

The Southern Branch of the Elizabeth River, a tributary of Chesapeake Bay, has historically been polluted with hydrocarbon based industrial by-products. My study compared benthic community condition from two locations in the Southern Branch: the subtidal region near Money Point, historically affected by pollution of polycyclic aromatic hydrocarbons (PAHs), to a subtidal region near Blows Creek on the opposite shore that is putatively designated as unimpacted by P AH contamination. Samples from both study sites in the Southern Branch were compared to the benthic community condition of samples from the same habitat type designations collected as part of the Chesapeake …

Interannual Variation Of Stratification In Lower Chesapeake Bay, Christopher S. Katzenmiller

OES Theses and Dissertations

Stratification in the water column can prove to be an important indicator to the state of the water column and ecosystem. The focus of this research is to evaluate trends in stratification in the Lower Chesapeake Bay. Detailed analysis was performed on a 14 year data set to study interannual variation in the region of study. Potential energy anomaly was used to quantify stratification. Potential energy anomaly is the amount of energy required to mix a water column. It is determined from the vertical density structure of density. Potential energy anomaly is the departure of potential energy from climate conditions. …

Summer Vertical Phytoplankton Distribution In The Lower Chesapeake Bay, Mollie Jill Weinstein

Biological Sciences Theses & Dissertations

Autotrophic picoplankton and phytoplankton composite samples were collected from the surface, pycnocline, and bottom water layers at three stations in the lower Chesapeake Bay between June and September 1993. Using light microscopy a total of 170 phytoplankton taxa were identified. Utilizing epifluorescent microscopy, the picoplankton taxa were distinguished by size, representing species with cells less than 2 microns. Diatoms were the dominant taxa during this period, with lesser representation by the other phytoplankton components. Within the picoplankton category, cyanobacteria were dominant. Statistical analyses of the data indicated the vertical composition and abundance of the phytoplankton was not significantly different over …

Zooplankton Community Dynamics In The Elizabeth River, Virginia, William C. Sharp

Biological Sciences Theses & Dissertations

Zooplankton community structure and dynamics were studied over a 12 month period in the Elizabeth River, an industrially polluted tidal river in the Chesapeake Bay estuarine system. An additional site in this estuary (Hampton Roads) was sampled for comparative purposes. Multivariate analysis indicated five distinct temporal groups occurred during the year, but there were no significant differences in spatial composition within the river. Maximum zooplankton concentrations were observed in July and lowest abundances were observed in February, March, and November. Copepods, especially Acartia species, were the most abundant components of the zooplankton community, comprising 67 to 93% of the total …

The Distribution And Occurrence Of Aerobic Heterotrophic Antimicrobic-Producing Bacteria Isolated From The Lower Chesapeake Bay, Linda Lea Gilmer

Biological Sciences Theses & Dissertations

Three different estuarine microenvironments in the lower Chesapeake Bay were investigated for the occurrence and geographical distribution of antimicrobic-producing bacteria. Samples were taken from the water column, fish skin, and algal surfaces. A total of 1472 bacterial isolates were assayed for antimicrobial activity against fungal, Gram-negative and Gram-positive bacterial test organisms. Of the total bacterial isolates assayed, 5. 2% were active antimicrobic producers. Algal surf aces were shown to have a higher incidence of antimicrobic-producing bacteria than the water column or fish skin. No antimicrobic activity was demonstrated by bacteria isolated from the flounder fish skin. The majority of the …

A Multivariate Characterization Of Assemblages Of Planktonic Mysids Decapods And Sergestids In The Chesapeake Bay Mouth Area, John Charles Seibel

Biological Sciences Theses & Dissertations

This study is the first to focus on the assemblages of the planktonic mysids, decapods, and sergestids found in the lower Chesapeake Bay. The assemblages of these organisms in the lower Chesapeake Bay and nearby shelf were characterized using three different statistical approaches, and the methods used were evaluated for their effectiveness at delineating ecologically meaningful assemblages. Three stations were sampled across the Chesapeake mouth and one offshore, with oblique and neuston net tows. Twenty-seven larval stages, representing at least 23 species, were found in sufficient numbers to be analyzed statistically. The statistical approaches were each based upon a different …

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 …

Age And Growth Of The Tautog, Tautoga Onitis (Pisces: Labridae), From Lower Chesapeake Bay And Coastal Waters Of Virginia, E. Brian Hostetter

Biological Sciences Theses & Dissertations

The tautog, Tautoga onitis (Pisces: Labridae), is rapidly gaining popularity in Virginia by anglers, spearfishermen and specialized commercial interests. In Virginia, tautog are seasonally abundant on hard bottom substrates in nearshore (ca. 2-10 m) habitats and inhabit offshore wrecks and reef areas (ca. 10-30 m) year round. Habitat restriction and slow growth of the species coupled with recent technological advances in marine electronics which simplify locating tautog populations by user groups may contribute to overexploitation of tautog within the region.

Tautog were collected over a two year period from the lower Chesapeake Bay and nearshore waters of the Atlantic Ocean …

A Biochemical And Genetic Analysis Of The American Shad Alosa Sapidissima Migrating Into The Chesapeake Bay, Edward Norbert Sismour

Biological Sciences Theses & Dissertations

Seven enzymes extracted from heart and liver tissues of American shad Alosa sapidissima captured during migrations into the Chesapeake Bay and Nansemond River were electrophoretically surveyed. Malate dehydrogenase and nonspecific esterase displayed polymorphic loci. The esterase polymorphism was used as a biochemical genetic marker to analyze the shad migration through the southern Chesapeake Bay. The genetic composition of the shad migration changed significantly over time indicating that this migration is probably composed of multiple, genetically divergent spawning populations. Results of this study are subject to differing interpretations. Observed temporal heterogeneity may result from separation of northern and James River stocks …

Seasonal Composition Of Zooplankton Of Lower Chesapeake Bay And Virginia Coastal Waters, Elizabeth W. Atkinson

Biological Sciences Theses & Dissertations

Abstract unavailable.