Physical Sciences and Mathematics Commons^™

Identification And Quantitation Of Volatile Amines In Chesapeake Bay Sediments, Neeraja Y. Krishna

Chemistry & Biochemistry Theses & Dissertations

Sediments from different parts of the Chesapeake Bay were analyzed to determine the presence of volatile amines. A HF-HCl extraction method was used to extract both exchangeable and fixed amines from the sediments and a purge-and-trap technique was used to concentrate the amines. Following derivatization with heptafluorobutyric anhydride (HFBA), the HFBA-amines were analyzed by gas chromatography with electron capture detection and with mass spectrometric detection. One primary amine, i-amylamine with a concentration ranging from 0. 78 nmoles/g dry weight to < 0.05 nmoles/g dry weight was found in a total of twenty seven samples collected on three different dates in 1993. Another primary amine, 2-methylbutylamine with a concentration ranging from 0.18 nmoles/g dry weight to < 0.05 nmoles/g dry weight was found in a total of twenty three samples collected on three different dates in 1993. A secondary amine, diethylamine was detected but could not be quantified in a total of seven samples collected in September 1993. The concentrations of these amines varied with location in the Bay, depth in the sediment, and time of year the sediments were collected. The origin of i-amylamine and 2-methylbutylamine might be from the biological decarboxylation of amino acids leucine and isoleucine, respectively. The origin of diethylamine is unknown.

Description, Distribution, And Abundance Of The Blue Crab, Callinectes Sapidus (Rathbun), Spawning Stock Of The Lower Chesapeake Bay, Patrick John Geer

OES Theses and Dissertations

The lower Chesapeake Bay spawning stock of the blue crab, Callinectes sapidus, (Rathbun), is examined for seven years (1986 - 1992) in an attempt to better understand stock behavior. Three methods of post-stratification are used to describe the distribution and movement of the population over time. The three methods, density strata, geographic zones, and depth strata, did well in explaining movements of the population, indicating a trend of increased concentration of blue crabs near the eastern Bay late in the spawning season - October. The data suggest a bimodal period of spawning and a trimodal period of abundance. The …

Effect Of Wind Changes During The Last Glacial Maximum On The Circulation In The Southern Ocean, John M. Klinck, David A. Smith

CCPO Publications

Present-day surface wind stress climatology is manipulated to simulate wind conditions during the last glacial maximum. These estimated wind fields force a one-layer, wind-driven numerical model of the southern ocean to determine if a change in the strength of the surface wind stress can shift the location of the Antarctic Polar Front, which is part of the Antarctic Circumpolar Current. A change in the forcing by a factor of 0.5-2.0 results in a change in the speed of the flow by an identical factor with no change in position. However, if the present-day wind climatology is shifted meridionally there is …

Data Report : Hypoxia In The James River, 1992, G. M. Sisson, A. Y. Kuo, Bruce Neilson, Nancy C. Wilson

Reports

As part of the hypoxia program of the Virginia Chesapeake Bay Initiatives, the Department of Physical Sciences of the Virginia Institute of Marine Science (VIMS) conducted a series of measurements around the mouth of the James River estuary. The measurements were made in the summer of 1992. Two types of measurements were conducted: measurements at moored stations and measurements by slackwater surveys. The former collected data for investigation of dissolved oxygen (DO) variation, and associated physical parameters, in an intratidal time scale, as well as for studying the vertical distributions of the measured parameters. The latter collected data for spatial …

Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, With A Discussion Of Apparent Geographic Changes In Population Dynamics, Luiz R. Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones

OES Faculty Publications

Atlantic croaker, Micropogonias undulatus, collected from commercial catches in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 (n=1,967) were aged from transverse otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7, annuli are formed once a year during the period April-May. Otolith age readings were precise: >99% agreement within and between readers. Observed lengths-at-age were highly variable and growth rate decreased after the first year. Despite the high variability in sizes-at-age, observed lengths for ages 1-7 fit the von Bertalanffy growth model (r2=0.99; n=753) well. …

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1992 : A Report To The Virginia Department Of Environmental Quality, Kevin Curling, Rodney Jackson, Bruce Neilson

Reports

The Chesapeake Bay Water Quality Monitoring Program (WQMP) has three main objectives: (1) characterization of water quality conditions, (2) detection of temporal trends in water q1llality, and (3) crr.ation of a data base that furthers our understanding of the proceses that control water quality in the Chesapeake Bay system. The purpose of this report is to characterize water quality conditions in the Virginia portion of Chesapeake Bay during the 1992 water year, which runs from October 1991 through September 1992. These monitoring efforts have been conducted with funding from the US Environmental Protection Agency and the Commonwealth of Virginia.

The Biogeochemistry Of Iodine In Seawater, Lingsu Zhang

OES Theses and Dissertations

Iodate and iodide are the two major species of iodine in seawater. In comparison to iodate, iodide is thermodynamically unstable in oxic seawater. The conversion (or reduction) of iodate to iodide may be mediated via biological activities. Since biological activities vary with the season, the conversion of iodate to iodide may also vary seasonally. The conversion (or oxidation) of iodide to iodate is thermodynamically feasible, but the mechanism is poorly known. Hydrogen peroxide, which is ubiquitous in surface seawater, may oxidize iodide to iodate.

Water samples were collected in the middle and lower Chesapeake Bay in different seasons between 1990 …

Production And Decomposition Of Hydrogen Peroxide By Marine Phytoplankton, Dong-Beom Kim

OES Theses and Dissertations

H₂0₂ in seawater has complicated sources and sinks. The relative importance of biological regulation of H₂0₂ compared to other processes is not well understood. In addition, environmental factors affecting the biological regulation of H202 are largely unknown. Marine phytoplankton was examined for the kinetics of the production and decomposition of H₂0₂ in the dark. Effects of varying environmental factors such as light, temperature, salinity, nutrients, amino acids, trace metals and growth phase, were examined. H₂0₂ was determined with the scopoletin-fluorescence decay method.

Five out of 11 species produced …

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1991 : A Report To The Virginia Water Control Board, Kevin Curling, Bruce Neilson

Reports

The purpose of this report is to characterize water quality conditions during the 1991 water year, October 1990 through September 1991. Most information is provided in graphical format and only data for the Virginia portion of Chesapeake Bay is included. No interpretation is included, since data analysis is the stated purpose of several other reports. This report and companion data reports provide to both scientists and managers ready access to a portion of the data. It is possible, for example, to quickly examine seasonal patterns, compare conditions at two stations, or see if surface and bottom conditions differ significantly. Trends, …

Data Base Development For Characterizing Contaminated Sediments In The Chesapeake Bay Region, Gary F. Anderson, Caroline Brouwer-Riel, Maynard M. Nichols

Reports

This project is one component of the U.S. Geological Survey's National Coastal Geology Program directed to polluted sediments. Its long-term aim is to develop a comprehensive database on estuarine contaminated sediments that provides a summary of information and a digital reference source of detailed and readily accessible data. It focuses on Chesapeake Bay because there is a wealth of data on bottom sediments and sedimentary contaminants. However, this data is fragmented, uncollated and dispersed in many papers, books, reports, files and documents, often local sources, outside the mainstream of national consideration and scientific knowledge. Without an organized body of data, …

The Biogeochemistry Of Hydrogen Sulfide In The Open Ocean, Joël Radford-Knoery

OES Theses and Dissertations

Hydrogen sulfide is a poorly quantified component of the global sulfur cycle. In seawater, its dissolved species (dissolved sulfide) can react with trace metals to form dissolved complexes and insoluble compounds. Therefore, the study of dissolved° sulfide in the open ocean can yield a better understanding of the biogeochemical cycles of sulfur and trace metals.

The biogeochemical cycling of dissolved sulfide was examined using specially developed sampling and analytical methods. In the western North Atlantic and central Equatorial Pacific Oceans, total dissolved sulfide concentrations ranged from /L; they were highest, in the mixed layer and decreased with depth. The depth …

Paleobathymetric Interpretation Of Pleistocene Sediments In The South Padre Island Area, Northwestern Gulf Of Mexico, Using Benthic Foraminiferal Morphology, Karen Ianthe Kruebbe-Belwood

OES Theses and Dissertations

This study tested the validity of using intraspecific variation in benthic foraminifera as a means for determining Pleistocene paleobathymetry. Canonical variate analysis was used as a means for determining visually undetectable but statistically significant differences in the morphology of selected species. Two species, Cassidulina subglobosa and Uvigerina peregrina, were collected from Pleistocene well cuttings from the northwest Gulf of Mexico. The canonical analysis involved comparing the intraspecific variation of these Pleistocene species to their counterparts occurring in the modern Gulf of Mexico, where intraspecific variation was previously analyzed and found to be sufficient to allow detection of bathymetric differences …

Modeling Nutrient And Plankton Processes In The California Coastal Transition Zone, John Roland Moisan

OES Theses and Dissertations

Two time- and space-dependent, physical-bio-optical models have been developed for the California Coastal Transition Zone (CTZ) region with the overall objective of understanding and quantifying the processes th at contribute to the spatial and temporal development of nutrient and plankton distributions in the CTZ. The first of these models considers only time- and vertical processes at specific locations in the CTZ. The model food web components include: silicate, nitrate, ammonium, two phytoplankton size fractions, copepods, doliolids, euphausiids and a detritus pool. The wavelength dependent attenuation of the subsurface irradiance field, due to sea water, phytoplankton pigment concentrations and dissolved organic …

Methanesulfonic Acid In Coastal Antarctic Snow Related To Sea‐Ice Extent, K. A. Welch, Paul Andrew Mayewski, S. I. Whitlow

Earth Science Faculty Scholarship

Proxy records of biogenic sulfur gas obtained from ice cores suggest that variability in marine biogenic sulfur emissions may reflect changes in climate [Saigne and Legrand, 1987; Legrand et al., 1988, Legrand et al., 1991; Anderson and Charlson, 1991]. Increased sea‐ice extent has previously been proposed as one cause of relatively high methanesulfonic acid (MSA) in glacial‐age ice core samples [Gibson et al., 1990]. We have analyzed MSA, one of the oxidation products of the biogenic sulfur gas dimethylsulfide [Hatakeyama et al., 1985], from snowpit samples recovered from a coastal site in Southern Victoria Land, Antarctica. Time series of MSA …

Carbon, Nitrogen, And Phosphorus Leaching Rates From Spartina Alterniflora Salt Marshes, R. Eugene Turner

Faculty Publications

Annual carbon, nitrogen, and phosphorus leachate rates from live Spartina alterniflora Loisel in a Louisiana (USA) salt marsh were estimated to be 200, 14, and 3 g m-2, respectively, and to peak in summer and higher salinit~es. Leachate losses of P, N and C are equivalent to a turnover of live plant tissues of 10, 17 and 49 d, respectively, when submerged, and 148, 250 and 721 d, respectively, when unsubmerged. Plant leachate losses during marsh submergence and non-submergence are nearly equal because release rates are 15x greater during submergence. Nitrogen and carbon concentrations relative to phosphorus are proportionately 4x …

A Comparison Of Gulf Stream Sea Surface Height Fields Derived From Geosat Altimeter Data And Those Derived From Sea Surface Temperature Data, Tal Ezer, George L. Mellor, Dong-Shan Ko, Ziv Sirkes

CCPO Publications

Two types of satellite data, Geosat altimeter data and sea surface temperature data (SST), are compared and evaluated for their usefulness in assimilation into a numerical model of the Gulf Stream region. Synoptic sea surface height (SSH) fields are derived from the SST data in the following way: first three-dimensional temperature and salinity analysis fields are obtained through the Optimum Thermal Interpolation System (OTIS), and then SSH fields are calculated using a primitive equation, free-surface, numerical model running in a diagnostic mode. The aforementioned SSH fields are compared with SSH fields obtained from the Geosat altimeter data. Use of Geosat …

Molecular Diffusion Coefficients For Polycyclic Aromatic Hydrocarbons In Air And Water, Kurt E. Gustafson

Dissertations, Theses, and Masters Projects

No abstract provided.

Market Interactions And Competition Between Public And Private Oyster Production And Supplies From Other States, Ya-Ke Hsu

Dissertations, Theses, and Masters Projects

Oyster production in Virginia has declined dramatically in the past ten years, causing Virginia oyster processors to rely increasingly on oyster supplies from other regions. In response to the industry problems, the Virginia Marine Resources Commission (VMRC) developed and began implementing an Oyster Fishery Management Plan (OFMP) in 1985. Primarily, the plan seeks to increase Virginia oyster production from both public and leased grounds. A large increase in production could significantly affect the oyster market. There is thus a need to understand the Virginia oyster market, which derives raw material supplies primarily from public and leased-grounds production and from other …

Boundary Layer Structure In Homogeneous Tidal Flows: A Theoretical And Numerical Study, Jian Shen

Dissertations, Theses, and Masters Projects

No abstract provided.

The Dynamics Of An Oligohaline, Macrofaunal, Fouling Community, Michelle Lynne Thompson Neubauer

Dissertations, Theses, and Masters Projects

No abstract provided.

Seasonal Relationships Between Phytoplankton Composition, Abundance, And Primary Productivity In Three Tidal Rivers Of The Lower Chesapeake Bay, Harold G. Marshall, Kneeland K. Nesius

Biological Sciences Faculty Publications

The seasonal abundance and successional patterns of phytoplankton, including autotrophic picoplankton, are compared to spring, summer, and fall primary production maxima that occurred in three tidal rivers. The tidal freshwaters were dominated by diatoms, chlorophytes, and cyanobacteria during a late spring through early fall period of maximum growth. In contrast, downstream assemblages were dominated by estuarine diatoms, dinoflagellates, and cryptomonads which developed spring pulses and a protracted summer-fall maximum. Autotrophic picoplankton produced a major summer pulse at all river stations with reduced abundance during other seasons. The mean annual productivity rates for the tidal James, Rappahannock, and York rivers were …

Changes In The Sea-Ice Brine Community During The Spring-Summer Transition, Mcmurdo Sound, Antarctica .2. Phagotrophic Protists, Diane K. Stoecker, Kurt R. Buck, Mary Putt

OES Faculty Publications

The land-fast sea-ice brine contains a diverse phagotrophic protist assemblage consisting of < 5 mum heterotrophic flagellates, Cryothecomonas spp., heterotrophic dinoflagellates, and heterotrophic and mixotrophic ciliates. Fine-scale horizontal spatial variability is a feature of this assemblage; samples taken within 1 m of each other can be dominated by different heterotrophic protists. Many of the larger heterotrophic protists found in the brine are also found in the water column. The photosynthetic ciliate Mesodinium rubrum is also common. In mid to late austral spring, the heterotrophic assemblage accounts for ca 10% of the total protist biomass in the brine and is dominated by Cryothecomonas spp. This flagellate …

A Reproductive-Resting Stage In An Harpacticoid Copepod, And The Significance Of Genetically Based Differences Among Populations, D. J. Lonsdale, P. Weissman, Fred C. Dobbs

OES Faculty Publications

Dormancy is an important life-history strategy which allows copepods to increase their fitness by delaying growth and reproduction until harsh environmental conditions have ameliorated. For marine species, the primary strategies identified to date include the production of dormant eggs by shallow-water species, and copepodite overwintering in deep-water species. Herein, we describe a third strategy in which fertilized adult females enter a “reproductive-resting” stage during the late fall that allows them to overwinter and provide a first source of spring naupliar recruitment. This strategy has been observed in the estuarine copepod Coullana canadensis, but may also occur in other species. …

Sediment Processes Monitoring Data Report For Calendar Year 1989, Cheol Mo, Bruce Neilson, Richard L. Wetzel

Reports

Pairs of particle interceptor traps were deployed at three depths - 3, 6, and 9 meters with deployment intervals typically lasting about two weeks. At times of deployment and retrieval, profiles of water temperature, salinity and dissolved oxygen content were made and water samples were collected at trap depths. Bottom sediments also were collected and a sub-sample of the surficial sediments taken. Water samples, bottom sediments, and the materials collected in the traps were returned to the Virginia Institute of Marine Sciences for analysis. The data collected during both 1988 and 1989 are presented in the appendices. Both 1988 and …

Chesapeake Bay Wave Climate : Thimble Shoal Light Wave Station, Report And Summary Of Wave Observations, October 8, 1990 Through August 22, 1991 And Chesapeake Light Tower - Vims Star Gage Test Measurements And Evaluation, July, August, October 1991, John D. Boon, D. A. Hepworth, K. D. Suh, F. H. Farmer

Reports

This report also presents a description of a directional wave gaging system, known as a "Star" gage, that is designed for long-term, low-maintenance operation both within and immediately outside the Chesapeake Bay entrance area. This development was prompted by our dependence to date on the single-point, PUV-type directional wave gage described below. While ideally suited for short-term investigative studies at different sites, the PUV directional wave gage requires field service visits at monthly intervals to maintain adequate performance and uninterrupted operation. A prototype Star gage system was constructed and field tested to evaluate its potential use as a long-term and …

Life History, Population Dynamics And Yield-Per-Recruit Modeling Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Area, Luiz R. Barbieri

Dissertations, Theses, and Masters Projects

Otoliths, scales, dorsal spines, and pectoral fin rays, of Atlantic croaker, Micropogonias undulatus, were compared for legibility of presumed annuli and precision in repeated readings, to determine the best structure for ageing. Marks on transverse otolith sections were easiest to read and showed the best agreement between readings. Fish collected in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 were then aged using otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7 annuli are formed once a year during the period April-May. Otolith age readings were …

A Model Study Of Hydrodynamic And Water Quality Characteristics Of The Rappahannock Estuary, Virginia, Kyeong Park

Dissertations, Theses, and Masters Projects

A laterally integrated, two-dimensional, real-time model, consisting of linked hydrodynamic and water quality models, is developed and applied to the Rappahannock Estuary, Virginia. The hydrodynamic model, based on the principles of conservation of volume, momentum and mass, predicts surface elevation, current velocity and salinity. The water quality model, based on the conservation of mass alone, predicts eight parameters; dissolved oxygen (DO), chlorophyll 'a', carbonaceous biochemical oxygen demand (CBOD), organic nitrogen, ammonia nitrogen, nitrite-nitrate nitrogen, organic phosphorus and inorganic phosphorus. The model equations were solved using a two time level, finite difference scheme. The hydrodynamic model was calibrated and verified using …

Amorphometric And Meristic Study Of The Halfbeak, Hyporhamphus Unifasciatus (Teleostei: Hemiramphidae) From The Western Atlantic, With The Description Of A New Species, Heidi M. Banford

Dissertations, Theses, and Masters Projects

No abstract provided.

Dynamics Of Fish Assemblages Associated With An Offshore Artificial Reef In The Southern Mid-Atlantic Bight, Aaron J. Adams

Dissertations, Theses, and Masters Projects

No abstract provided.

Gill Surface Area In Relation To Growth Rates And Maximum Size In Sharks, David Noboru Hata

Dissertations, Theses, and Masters Projects

The most commonly used equation to describe size at age in fishes is the von Bertalanffy equation (VBE), which assumes that growth rate is based on the balance of anabolic and catabolic processes: dW/dt = HW&\sp{lcub}\rm d{rcub}&-kW&\sp{lcub}\rm m{rcub}&. Anabolism, HW&\sp{lcub}\rm d{rcub}&, is considered proportional to gill surface area (A = rW&\sp{lcub}\rm d{rcub}&), and a "generalized" VBE (GVBE) has been previously determined: L&\sb{lcub}\rm t{rcub}& = L&\sb\infty&(1-exp(-KD(t-t&\sb{lcub}\rm O{rcub})))\sp{lcub}\rm 1/D{rcub}&, where D = b-bd and b is from W = qL&\sp{lcub}\rm b{rcub}&. The growth rate may be rewritten in terms of gill area, A, as dW/dt = kA/(A&\sb\infty&/W&\sb\infty\sp{lcub}\rm m{rcub}&)-kW&\sp{lcub}\rm m{rcub}&. Gill areas were …