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The Growth And Feeding Behavior Of Juvenile Spot, Leiostomus Xanthurus Lacepede, In The Nursery Region Of The James River, Virginia, John Thomas Mccambridge Jr. Jul 1983

The Growth And Feeding Behavior Of Juvenile Spot, Leiostomus Xanthurus Lacepede, In The Nursery Region Of The James River, Virginia, John Thomas Mccambridge Jr.

OES Theses and Dissertations

The in situ growth and feeding behavior of juvenile spot, Leiostomus xanthurus Lacepede, was investigated for populations in the nursery area of the James River, Virginia. Growth of juvenile spot was found to be fairly rapid (11.34 mm/month, standard length) during their first summer in the nursery grounds, but it levelled off in the autumn. The mean size of spot after the first year was calculated to be 195 mm total length. The weight-length relationship was log W = -5.018 + 3.246(log L), where W = wet weight in grams and L = standard length in millimeters.

Juvenile spot appeared …


The Effect Of Crowding On Growth Of The Cichlid Fish, Oreochromis Mossambicus, Bonnie A. Barrows Jul 1983

The Effect Of Crowding On Growth Of The Cichlid Fish, Oreochromis Mossambicus, Bonnie A. Barrows

OES Theses and Dissertations

It has been reported that the Java tilapia, Oreochromis mossambicus, displays hypersensitivity to a substance it produces when biomass levels in a flow-through culture system exceed 20 g/1, resulting in reduced growth and high mortality. Experiments on the growth of this species in small tanks were conducted in order to determine whether O. mossambicus produces a growth-inhibiting compound under crowded conditions. This species was successfully maintained at biomass levels of 38 g/1 and 57 g/1 with a total mortality of only 4.5%.

The Java tilapia can grow rapidly in small aquaria, as indicated by the data taken during Experiment …


The Effects Of Amphetamine And Ethanol On Habituation Of Exploratory Responses Of Rats In Novel And Familiar Environments, Kuen-Teng Kao Jul 1983

The Effects Of Amphetamine And Ethanol On Habituation Of Exploratory Responses Of Rats In Novel And Familiar Environments, Kuen-Teng Kao

Psychology Theses & Dissertations

To study the relationship between level of arousal and rate of habituation in rats, the current research manipulated arousal level using sedatives (ethanol 200 and 600 mg/kg) and stimulants(d-amphetamine 0.6 and 2.4 mg/kg). Furthermore, in order to investigate the possible contributions of differences in familiarity of the subjects with the test environment in producing discrepant reports about arousal-habituation relationships, half of the rats were tested in a completely novel cage without saline- pre-injection, while the other half were repeatedly given salinepreinjections and exposures to the test cage. Habituation was measured mainly as rate of change of responding level; i.e. slope …


A Model Of The Population Dynamics Of The Blue Crab In Chesapeake Bay, Betty Springer Hester Jul 1983

A Model Of The Population Dynamics Of The Blue Crab In Chesapeake Bay, Betty Springer Hester

OES Theses and Dissertations

This study has particular application to the blue crab fisheries in Chesapeake Bay, an economically important industry whose successful management has been hindered by relatively poor understanding of the population dynamics. Recent biological studies have indicated a systematic spawning behavior which seems designed for ejection of larvae seaward from the bay entrance where they spend their pre-metamorphosis stages in the neuston. A physical mechanism for retention of the larvae in sufficient proximity to the bay entrance for their return at the proper time which involves the action of wind stress in shallow waters is proposed. Since the supply of blue …


The Relationship Of Size Class Distribution To Migratory Behavior In Brown Shrimp (Penaeus Aztecus) In Pamlico Sound, North Carolina, Mario A. Paula Jul 1983

The Relationship Of Size Class Distribution To Migratory Behavior In Brown Shrimp (Penaeus Aztecus) In Pamlico Sound, North Carolina, Mario A. Paula

OES Theses and Dissertations

The potential of migratory timing information for dynamic yield estimation in the North Carolina brown shrimp fishery has been shown. The present research investigates the influence of size class distribution on the quantitative characterization of migratory timing in the brown shrimp. Catch and nominal effort data were stratified into count size ranges and the time density model of Mundy (1979) was specified for each stratum. The recruitment patterns of the shrimp into the fishery was also investigated.

The stratification of time densities by size class has shown a definite pattern in the migratory behavior of the brown shrimp. It appears …


Determination Of Erythrocyte Zinc Concentrations Using Zeeman Effect Atomic Absorption Spectroscopy, Tanya Maranda Lewis Jul 1983

Determination Of Erythrocyte Zinc Concentrations Using Zeeman Effect Atomic Absorption Spectroscopy, Tanya Maranda Lewis

Chemistry & Biochemistry Theses & Dissertations

The purpose of this research project was to develop assay procedures for determination of zinc in erythrocytes. Three methodologies were developed. The methods were evaluated on the basis of within-run and between-run precision. The most reproducible method, the 213.856 nm flame methodology, was used to determine red blood cell zinc concentrations in more than 200 samples obtained from the Neonatal Intensive care Unit at the Children's Hospital of the King's Daughters.

This study demonstrated that erythrocyte zinc levels in premature infants were similar to those of healthy adults. A linear relation between plasma and red blood cell zinc concentrations was …


Homing And Ecology In The Southern Flying Squirrel, Glaucomys Volans In Southeastern Virginia, Sherrie Lynn Sawyer Jul 1983

Homing And Ecology In The Southern Flying Squirrel, Glaucomys Volans In Southeastern Virginia, Sherrie Lynn Sawyer

Biological Sciences Theses & Dissertations

The purpose of this study was to determine whether homing occurred in the southern flying squirrel, Glauaomys volans, and if so, the greatest homing distance. Information on the squirrel's ecology, reproductive biology and use of artificial nest boxes was also obtained. The study was conducted from November 1978 through March 1981, using nest boxes placed in a deciduous forest in southeastern Virginia.

For the homing experiments, twenty squirrels were released a total of 29 times along three lines at distances of 250 m to 1.6 km from the homesites. Squirrels were found to home successfully up to 1,000 m.

The …


An Analysis Of The Correlation Between Nurses' Attitudes Toward Death And Their Presence With The Dying Patient, Uvonna Weeks Daniels May 1983

An Analysis Of The Correlation Between Nurses' Attitudes Toward Death And Their Presence With The Dying Patient, Uvonna Weeks Daniels

Ellmer School of Nursing Theses & Dissertations

The correlation between the nurses' attitudes toward death, as determined by the Questionnaire for Understanding the Dying Person and His Family, and the nurses' presence with a dying patient at the time of death was analyzed. The subjects were 31 registered nurses employed by eight acute care hospitals in Southeastern Virginia. The nurses were grouped into categories of flexible, moderate, and rigid attitudes toward death, relative to their scores on the questionnaire. Other variables of the nurses' age, sex, religion, strength of religious beliefs, entry level education, highest education level, years of experience, death of family members or friends, attitudes …


The Effect Of A Cardiac Education Program On The Knowledge, Stress, And State Anxiety Levels Of First Time Post Myocardial Infarction Patients In A Post Coronary Care Unit, Jeanine L. Johns May 1983

The Effect Of A Cardiac Education Program On The Knowledge, Stress, And State Anxiety Levels Of First Time Post Myocardial Infarction Patients In A Post Coronary Care Unit, Jeanine L. Johns

Ellmer School of Nursing Theses & Dissertations

The effect of a cardiac education program in terms of changes in knowledge, state anxiety and stress were examined for persons suffering a myocardial infarction for the first time. In addition, the relationship between stress and trait anxiety and changes in knowledge and state anxiety were examined. A sample of 20 patients were selected from two medium sized hospitals in Southeastern Virginia. Statistically significant differences at the .01 level were found between the means of the pretest and posttest scores of the experimental group for knowledge and state anxiety using the t test for dependent groups. The same test showed …


Registered Nurses' Ability To Discriminate Similar Human Need Fulfillment Alterations Specific To Chronic Obstructive Pulmonary Disease And To Diabetes Mellitus, Kathleen Bowen Waite May 1983

Registered Nurses' Ability To Discriminate Similar Human Need Fulfillment Alterations Specific To Chronic Obstructive Pulmonary Disease And To Diabetes Mellitus, Kathleen Bowen Waite

Ellmer School of Nursing Theses & Dissertations

The problem for this research study was to ascertain if registered nurses of varying educational backgrounds and experience discriminated similar human needs as being altered by specific pathologic states. The two pathologic states studied were chronic obstructive pulmonary disease and diabetes mellitus, chosen for their high prevalence in the population. A population sample of 55 registered nurses practicing on medical units in five hospital settings were surveyed. Data for this study were collected using the Human Needs Assessment Scales developed for this study. It was determined that registered nurses in this study did discriminate similar human need fulfillment alterations specific …


Investigation Of The Substrate Binding Site Of Nad Glycohydrolase In Human Seminal Plasma, Sau C. Cheung Apr 1983

Investigation Of The Substrate Binding Site Of Nad Glycohydrolase In Human Seminal Plasma, Sau C. Cheung

Chemistry & Biochemistry Theses & Dissertations

Nicotinamide adenine dinucleotide glycohydrolase (NADase) (E.C. 3.2.2.5) from human seminal plasma (HSP) was partially purified through a multistep purification procedure, including affinity chromatography on Amicon Red Matrex Gel A. The NADase activity was assayed by a fluorometric method with nicotinamide 1,N6 -ethenoadenine dinucleotide as the substrate. The enzymatic cleavage of etheno-NAD by NADase was accompanied by an eight-fold increase in fluorescence. This large increase in fluorescence provided a sensitive way to follow the rate of etheno-NAD hydrolysis.

NADase was found to be less specific for the purine moiety of NAD, since etheno-NAD was accepted as a substrate. The enzyme …


An Evaluation Of Small Rodents In Four Dismal Swamp Plant Communities, F. Elizabeth Breidling, Frank P. Day Jr., Robert K. Rose Apr 1983

An Evaluation Of Small Rodents In Four Dismal Swamp Plant Communities, F. Elizabeth Breidling, Frank P. Day Jr., Robert K. Rose

Biological Sciences Faculty Publications

Diversity and density of small rodents in the Dismal Swamp are believed to be low. Reasons for this may be excessive predation, heavy interspecific pressure from large rodents, lack of suitable habitat, low food availability or flooding.

Rodent populations were evaluated using live-traps and pitfall traps in four different Dismal Swamp plant communities. Habitat was compared on the basis of phytomass studies previously reported. Flood levels were recorded during live-trapping sessions. Mast from trees was collected in modified mast collectors, and fed to Peromyscus leucopus in the laboratory.

Only two small rodent species were captured: Ochrotomys nuttalli and Peromyscus leucopus …


A Quantitative Study Of The Aquatic Macroinvertebrates In An Irregularly Flooded Salt Marsh, Smith Island, Virginia, Leon L. Robert Jr. Apr 1983

A Quantitative Study Of The Aquatic Macroinvertebrates In An Irregularly Flooded Salt Marsh, Smith Island, Virginia, Leon L. Robert Jr.

Biological Sciences Theses & Dissertations

Little is known about the aquatic macroinvertebrate community structure in coastal salt marshes. This study investigated the aquatic macroinvertebrate community structure in a coastal Virginia salt marsh. Sixteen samples were taken weekly from two different sites on Smith Island, Virginia, from April to mid-October 1982. Bimonthly samples were taken during the months March and November due to low density of organisms and reduced growth rates at these times.

A total of 46 taxa were collected with 17 occurring regularly, indicating a relatively diverse fauna. Wide fluctuations in the physical parameters were observed; however, temporal changes in the macroinvertebrate community cannot …


Polychlorinated Biphenyl Levels In The Ocean Scallop (Placopecten Magellanicus) Gmelin From The Philadelphia Sewage Sludge Disposal Site, Guy Jeffrey Hall Apr 1983

Polychlorinated Biphenyl Levels In The Ocean Scallop (Placopecten Magellanicus) Gmelin From The Philadelphia Sewage Sludge Disposal Site, Guy Jeffrey Hall

OES Theses and Dissertations

Ocean Scallops (Placopecten magellanicus) were sampled from stations in and around the Philadelphia Disposal Site. Each sample was dissected and aliquots of adductor muscle and reproductive tissue were chemically extracted for Polychlorinated Biphenyls (PCBs). A perchlorinated procedure outlined by Diosady et al., 1972, Aromour, 1973 and Crist et al., 1977 was employed to increase detection levels and simplify quantitation of PCBs. PCB levels were reported in dry weight and lipid weight of both adductor muscle and reproductive tissue. Findings indicated residual levels or PCB/lipid weight increased as lipid levels decreased in both tissue types. Levels detected in all adductor muscle …


Immediate Effects Of A Storm On Coastal Infauna, Fred C. Dobbs, Joseph M. Vozarik Jan 1983

Immediate Effects Of A Storm On Coastal Infauna, Fred C. Dobbs, Joseph M. Vozarik

OES Faculty Publications

Effects of storms on benthic infaunal communities have thus far been inferred rather than documented; especially lacking are studies examining immediate effects. To this end, the water column and 2 subtidal benthic sites were sampled before and after Storm David in September 1979. There were large post-storm increases in the numbers of infaunal species and individuals in the water column, presumably due to turbulent benthic boundary conditions. At the benthic stations, there were no pre vs. post-storm differences in the density of infauna; however, the number of species decreased at 1 station. There were storm-associated changes in the rank order …


Monitoring Defecation Activity Of Infaunal Deposit Feeders, Fred C. Dobbs Jan 1983

Monitoring Defecation Activity Of Infaunal Deposit Feeders, Fred C. Dobbs

OES Faculty Publications

An inexpensive, reliable thermistor device capable of monitoring infaunal foraging activity was built and used in the laboratory to examine effects of temperature on sediment reworking by the maldanld polychaete Clymenella torquata. The worm defecated at least once per hour 55.0 % (12.0 "C) to 88.2 % (5.5 "C) of the time. Defecation rate was linearly and positively related to temperature. Estimated volume of sediment ejected per defecation (0.015 ml) did not change with temperature. Results are compared with previous reworking studies of C. torquata.


Climatology Of The Southeastern United States Continental Shelf Waters, Larry P. Atkinson, Thomas N. Lee, Jackson O. Blanton, William S. Chandler Jan 1983

Climatology Of The Southeastern United States Continental Shelf Waters, Larry P. Atkinson, Thomas N. Lee, Jackson O. Blanton, William S. Chandler

CCPO Publications

Data from 2872 hydrographic stations have been used to determine the oceanographie climatology of the southeastern United States continental shelf waters. The data were sorted by each degree of latitude and by depth into three zones (0–20 m, 21–40 m, 41–60 m). Inner shelf water temperatures were similar to adjacent land air temperatures, while outer shelf temperatures were moderated by the Gulf Stream. Minimum and maximum water temperatures occurred in Georgia and South Carolina inner shelf water. Bottom temperatures were unusually low off Florida in the summer probably because of shelf break upwelling. Surface salinity was lowest adjacent to the …


Low-Frequency Current And Temperature Variability From Gulf Stream Frontal Eddies And Atmospheric Forcing Along The Southeast U.S. Outer Continental Shelf, Thomas N. Lee, Larry P. Atkinson Jan 1983

Low-Frequency Current And Temperature Variability From Gulf Stream Frontal Eddies And Atmospheric Forcing Along The Southeast U.S. Outer Continental Shelf, Thomas N. Lee, Larry P. Atkinson

CCPO Publications

Low‐frequency current and temperature time series from the outer shelf between Cape Canaveral, Florida, and Cape Romain, South Carolina, are compared with shipboard hydrographic data, satellite VHRR, coastal and buoy winds, and coastal sea level during the period from February to June 1980. Low‐frequency current and temperature variability along the shelf break was primarily produced by cyclonic, cold core Gulf Stream frontal eddies. These disturbances traveled to the north at speeds of 50 to 70 cm s−1 with periods of 5 to 9 days throughout the experiment and produced cold cyclonic perturbations of the northward mean flow and temperature …


Cape Romain And The Charleston Bump: Historical And Recent Hydrographic Observations, J.J. Singer, L. P. Atkinson, J. O. Blanton, J. A. Yoder Jan 1983

Cape Romain And The Charleston Bump: Historical And Recent Hydrographic Observations, J.J. Singer, L. P. Atkinson, J. O. Blanton, J. A. Yoder

CCPO Publications

A review and analysis of historical and new hydrographic data are presented for the Charleston Bump region. An area of doming isotherms is identified primarily between 31.5° and 34.5°N and the 200 and 400 m isobaths. The highest incidences of doming are found off Long Bay (86%), Cape Fear (38%), and Cape Romain (25%). Evidence suggests that low salinity shelf water collects in the doming area off Long Bay in July and that seasonal fluctuations in the depth of the main thermocline layer in this area are linked to Gulf Stream transport and local winds. At times there is a …


Phytoplankton Studies Within The Virginia Barrier Islands. Iii. Phytoplankton Composition In A Saline Pond On Smith Island, Harold G. Marshall Jan 1983

Phytoplankton Studies Within The Virginia Barrier Islands. Iii. Phytoplankton Composition In A Saline Pond On Smith Island, Harold G. Marshall

Biological Sciences Faculty Publications

The phytoplankton that characterized the Smith Island pond was diverse, with several species of diatoms, dinoflagellates and blue-green algae dominant throughout the year. A total of 146 spp. were noted, predominantly composed of ultra and nanoplankters, that includes representatives from coastal waters. The island ponds are considered eutrophic habitats whose composition is influenced by overwash conditions and in turn introduce populations to surrounding pools and water channels.


Protein Contributions Of The Male Accessory Organs To The Composition Of Human Seminal Plasma As Determined By High Resolution Two-Dimensional Electrophoresis, Edward E. Gaunt Jan 1983

Protein Contributions Of The Male Accessory Organs To The Composition Of Human Seminal Plasma As Determined By High Resolution Two-Dimensional Electrophoresis, Edward E. Gaunt

Theses and Dissertations in Biomedical Sciences

Human Seminal Plasma was evaluated using a High Resolution Two-Dimensional Electrophoresis technique adapted by this laboratory. Seminal plasma from healthy volunteers with recently proven fertility were characterized using this technique to establish "normal" protein distribution patterns in the two-dimensional polyacrylamide gel slab. In addition, time studies were performed on selected specimens to determine the effects of liquefaction on seminal plasma protein composition within the first several hours after collection. Split ejaculates were collected for identification and elaboration of accessory organ components in the whole seminal plasma specimen. A more direct approach to accessory organ component analysis involved electrophoresis of semen …


Effects Of Aperiodic Noise On Serial Reaction: A Study Of The Range And Consistency Of Individual Differences With Repeated Measures, Stephen Victor Strunk Oct 1982

Effects Of Aperiodic Noise On Serial Reaction: A Study Of The Range And Consistency Of Individual Differences With Repeated Measures, Stephen Victor Strunk

Psychology Theses & Dissertations

The range and consistency of individual differences in response to two exposures of aperiodic-intermittent noise were examined. A computerized 5-choice serial reaction task was used to measure the number of correct responses and mean reaction times for each of 30 subjects during the two exposures to quiet and noise. The results indicate that (1) noise presented even for short durations can have adverse effects on performance; (2) individuals do perform consistently in terms of accuracy across exposures to noise; and (3) a wide range of performance changes can be expected from subjects performing a task under noise. Implications for the …


The Effects Of Dredged Material (Suspended Solid Phase) On The Hatching Success Of Spot Eggs (Leiostomus Xanturus), Meryl A. Masters Oct 1982

The Effects Of Dredged Material (Suspended Solid Phase) On The Hatching Success Of Spot Eggs (Leiostomus Xanturus), Meryl A. Masters

OES Theses and Dissertations

A 24-hour static bioassay was performed with the suspended solid phase of bottom sediment from a highly industrialized river utilizing eggs of the spot, Leiostomus xanthurus. Hatching success was measured at four concentrations of elutriates prepared from sediment obtained from the confluence of the eastern and southern branches of the Elizabeth River adjacent to the Norfolk Shipbuilding and Drydock in Norfolk, Virginia. Test results indicated no significant effect on hatching success at any of the four test concentrations.


The Effects Of Salinity On Growth And Survival Of The Blue Tilapia Oreochromis Aureus (Steindachner) (Pisces Cichlidae), Maylon Lowell White Jr. Oct 1982

The Effects Of Salinity On Growth And Survival Of The Blue Tilapia Oreochromis Aureus (Steindachner) (Pisces Cichlidae), Maylon Lowell White Jr.

OES Theses and Dissertations

The growth rate of the blue tilapia, Oreochromis aureus, was measured in fresh water, 15 ‰ salinity, and 30 ‰ salinity. The fish were given a hormone-treated feed to sex-reverse the females. Acclimations were achieved by raising the salinity only 5 ‰ per day. A biofilter and frequent water changes were used to maintain water quality in each 40 1 system. Synthetic sea salts were used to achieve desired salinity. The fish were grown for 87 days at 27°-30° C.

So significant difference in growth rate occurred among the three treatments. Salinity did not influence mortalities. All fish appeared to …


Some Effects Of The Polychaete Nereis Succinea Frey And Leukart 1847 On The Distribution Of Copper Cadmium And Zinc In Sediments And Water, Gabriela Kitzig August Oct 1982

Some Effects Of The Polychaete Nereis Succinea Frey And Leukart 1847 On The Distribution Of Copper Cadmium And Zinc In Sediments And Water, Gabriela Kitzig August

OES Theses and Dissertations

Two laboratory experiments, each lasting 216 hours, were conducted in order to determine the effects of a burrowing polychaete, Nereis succinea Frey and Leukart, 1847, on the distribution of copper, cadmium, and zinc in sediments and water in environmentally controlled microcosms. Dissolved metal concentrations in microcosms containing worms (experimental) decreased more rapidly than in microcosms without worms (controls). From 72 hours to 216 hours, suspended metal concentrations in experimental microcosms increased while concentrations in controls remained relatively constant. Sediment cadmium concentrations in experimental microcosms increased more over time than in controls. Polychaetes accumulated significant amounts of all three metals. These …


The Effects Of Varying Fresh Water Discharge On Dispersion In An Estuarine Hydraulic Model Of The Lafayette River, Norfolk, Virginia, Michael J. Jugan Oct 1982

The Effects Of Varying Fresh Water Discharge On Dispersion In An Estuarine Hydraulic Model Of The Lafayette River, Norfolk, Virginia, Michael J. Jugan

OES Theses and Dissertations

Three experimental tests were conducted in the Lafayette River branch of the Chesapeake Bay Hydraulic Model, each successive test with an increase in the amount of fresh water discharged into the head of the river. This was done to study the response from varying river discharge on mixing parameters including the longitudinal dispersion coefficient (E).

The model generated a tide of constant range and period. Batch releases of Rhodamine WT dye were made in the model and sampled throughout the river for ten tidal cycles. Samples were taken simultaneously at selected high and low water slack.

The calculation of the …


Environmental Influence On The Migratory Behavior Of The Brown Shrimp In Pamlico Sound North Carolina, Michael Andrew Matylewich Oct 1982

Environmental Influence On The Migratory Behavior Of The Brown Shrimp In Pamlico Sound North Carolina, Michael Andrew Matylewich

OES Theses and Dissertations

Environmental conditions in the nursery areas during times of development affect the migratory behavior of the brown shrimp (Penaeus aztecus) by influencing growth and natural mortality. A linearized logistic model and a multiple linear model are used to relate environmental factors (week number, water temperature, salinity, air temperature, precipitation, net heating degree days, river discharge) to the cumulative proportion of catch and catch-per-unit-effort, respectively. Multiple regression analysis yielded equations containing the week number, the water temperature and an interaction term as the independent variables. Predictions of total annual yield and total annual catch-per-unit-effort are made using the migratory …


Morphological Variation Of The Foraminifer Elphidium Excavatum (Terquem) On Crumps Bank And Willoughby Bank, Chesapeake Bay, Virginia, Pamela Kay Painter Oct 1982

Morphological Variation Of The Foraminifer Elphidium Excavatum (Terquem) On Crumps Bank And Willoughby Bank, Chesapeake Bay, Virginia, Pamela Kay Painter

OES Theses and Dissertations

Six variants of the highly variable foraminiferal species, Elphidium excavatum (Terquem) were recognized in the Crumps Bank and Willoughby Bank areas of the southern Chesapeake Bay. Measurements of the size of the test, the number of chambers, the number of umbilical bosses, and the number and average length of the sutural bridges on the last formed chamber, and opaqueness or translucence of the test were made on 30 specimens from each of 36 stations selected for differences in environmental parameters. The measurements were statistically analyzed by discriminant analysis to test the hypothesis that the variants are distinct morphotypes and to …


The Marine Geochemistry Of Selenium, Kazufumi Takayanagi Oct 1982

The Marine Geochemistry Of Selenium, Kazufumi Takayanagi

OES Theses and Dissertations

A fluorometric method for the determination of Se (IV) and total selenium in natural waters has been developed and optimized. The detection limit is about 20 pM for both analyses using a one liter sample. The precisions were about 2 % at 338 pM for Se (IV) and at 234 pM for total selenium.

The concentrations of both total selenium and Se (IV) decreased with increasing salinity in the surface waters of the James River and southern Chesapeake Bay. While total selenium seemed to exhibit conservative behavior at salinities above 0.36 ('o)/oo, Se (IV) was apparently removed during estuarine mixing. …


Factors Effecting Phytoplankton Assemblages In The Lafayette River Estuary, Laurie Ann Kalenak Oct 1982

Factors Effecting Phytoplankton Assemblages In The Lafayette River Estuary, Laurie Ann Kalenak

OES Theses and Dissertations

Chemical and physical parameters were measured with phytoplankton species composition and abundance in the Lafayette River from August to October 1981. Stations located in four distinct areas of the river were statistically analyzed to determine data relationships. Environmental factors considered as potentially influencing the presence and numbers of phytoplankton were salinity, temperature, Secchi depth, tidal phase, orthophosphate, combined nitrates and nitrites, ammonia, and reactive silicates.

The River mouth had higher salinity and nutrient values, with lower temperatures than the other river sections. Diatoms were the dominant cells in this section of the River. At mid-river, salinity and nutrient concentrations decreased, …