Oceanography Commons^™

Coastal Upwelling Off The Rias Bajas, Galicia, Northwest Spain I: Hydrographic Studies, J. O. Blanton, L. P. Atkinson, F. Fernandez De Castillejo, A. Lavin Montero

CCPO Publications

Coastal upwelling occurs off the Rias Bajas of Spain between April and October. Superimposed on large-scale upwelling is a mesoscale regime of enhanced upwelling induced by topographic influences. We show that the region surrounding Cape Finisterre has intensified topographically induced upwelling.

The rias have a relatively unobstructed connection with the open ocean. Upwelling of high nitrate water on the continental shelf by Ekman transport sets up pressure gradients at the mouth of the rias that induce upwelled water to flow into the rias. Deep water in the rias responds directly to cycles of upwelling and downwelling on the continental shelf.

Underwater Acoustic Wavefront Phase Fluctuations, George L. Vojtech Jr.

OES Theses and Dissertations

In conventional underwater acoustics sound propagation is generally modeled and applied as a coherent or incoherent process. This paper addresses a relatively new theory, that of a range driven increasingly incoherent ray propagation through a real ocean environment, Possible mechanisms are discussed and experimental data presented to reinforce the theory.

The Effect Of Polynuclear Aromatic Hydrocarbons On The Fecundity Of Acartia Tonsa (Calanoid Copepoda), Juanita Y. Grabarczyk

OES Theses and Dissertations

The concentrations of polynuclear aromatic hydrocarbons (PNAHs) were determined for several stations in the Elizabeth River. Thirteen PNAHs of the sixteen EPA priority pollutant PNAHs were present in the particulate fraction. The concentrations ranged from 10.0 ng/1 to 1000 ng/1. Ten of the sixteen EPA priority pollutant PNAH were present in the dissolved phase. Concentrations ranged from 2.0 ng/1 to 100 ng/1.

The environmental PNAHs concentrations were used to determine test concentrations. Bioassays were conducted to determine the effects of indigenous concentrations of seven predominant PNAHs (0.01 mg/1 to 2.4 mg/1 concentrations) on the fecundity of Acartia tonsa (calanoid Copepoda). …

The Effect Of Sea Nettle Abundance On The Food Chain Of The Lower Chesapeake Bay, Michael Glenn Kelly

OES Theses and Dissertations

The significance of sea nettle abundance on lower levels of the Chesapeake Bay food chain was examined in a field study and by the analysis of medusa gut contents. In the field study, the abundance of four levels of the food chain (Chlorophyll (a), copepods, the ctenophore Mnemiopsis leidyi, and the Schyphomedusa Chrysaora guinguecirrha) were monitored twice weekly at four stations from May 10 through September 30, 1982. The copepod standing stock declined sharply in late May when M. leidyi appeared, but rebounded a month later when C. guinguecirrha medusae reduced the ctenophore population. Despite the additional presence …

The Distribution Of Phytoplankton In Frontal Regions Of The Lower Chesapeake Bay, Richard V. Lacouture

OES Theses and Dissertations

The spatial and temporal distribution of phytoplankton was measured in relation to frontal areas located in the entrance to the Chesapeake Bay. Phytoplankton biomass, taxonomy, and several physical parameters were measured on fifteen sampling cruises between September,1981 and February, 1983.

Several statistical tests revealed that phytoplankton biomass did not accumulate at the fronts and that generally the distribution of phytoplankton biomass was homogenous across the frontal region. The cell count data indicated that the community structure of the phytoplankton assemblage was usually very similar on both sides of the front. The data which was concerned with temporal variations in the …

Adaptations Of Dolphin Vision To The Oceanic Environment, Andre Rivamonte

OES Theses and Dissertations

The objective of this study has been to develop an hypothesis explaining comparable aerial and underwater visual acuity of the bottlenose dolphin, Tursiops truncatus. This objective was accomplished by integrating the findings of other dolphin researchers working in the fields of comparative psychology, histology and ophthalmology. Their combined results enabled the formulation of a schematic dolphin eye. It is proposed that a dolphin lens, similar to the spherical lens of teleost fish with a rigid core of uniformly high refractive index and a margin of radially decreasing refractive index, could function as a bifocal lens and compensate for the eye's …

Simultaneous Functional Hermaphroditism In The Shrimp Hippolysmata Wurdemanni (Gibbes) (Decopoda: Caridea: Hippolytidae), Marie Hollister Bundy

OES Theses and Dissertations

The caridean shrimp Hippolysmata wurdemanni Gibbes was studied from a histological and a behavioral basis and was found to be a protandric hermaphrodite which later adopts simultaneous functional hermaphroditism. When the animal reaches a certain size, the androgenic gland degenerates, the male secondary sexual characteristics are lost, and vitellogenesis occurs in the anterior portion of the gonad. The animals do not lose the ability to function as males as evidenced by the presence of mature sperm in the gonad and the gonadal lumen of gravid shrimp, and the ability of both members of an isolated pair of shrimp to repeatedly …

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

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 …

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

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 …

Input And Distribution Of Sewage Derived Sedimentary Material Adjacent To Chesapeake-Elizabeth Sewage Outfall, Virginia Beach, Virginia, Robert Carroll Brown

OES Theses and Dissertations

The concentrations of coprostanol and hydrocarbons were measured in the effluent from the Chesapeake-Elizabeth sewage treatment plant and surface sediments from the area surrounding the effluent discharge site. Most of the coprostanol (>84%) and hydrocarbons (>91%) were associated with particulates in the effluent. Some of these particles were incorporated into the sedimentary column within the study area, while some may have escaped from the area.

The study area is found to be a dynamic area where changes in the percentage and distribution of fine-grained sediments occur over periods of months. The movement of fine-grained sediments is an important …

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 …

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.

A Pore Water/Solid Phase Diagenetic Model For Manganese In Marine Sediments, David J. Burdige, Joris M. Gieskes

OES Faculty Publications

A steady state diagenetic model is developed which accounts for changes in both the pore water and solid phase manganese profiles in marine sediments as a result of advection, diffusion, and redox reactions. The model is applied to observations on two cores in the E equatorial Atlantic in which pore water and solid phase manganese data are available. In situ reaction rates for manganese oxidation and reduction are estimated. The oxidation rates calculated here are in good agreement with rates measured in laboratory studies. In addition, the calculated manganese oxidation and reduction rates are compared with other estimated rates for …

Transport And Fate Of River Discharge On The Continental Shelf Of The Southeastern United States, J. O. Blanton, L. P. Atkinson

CCPO Publications

We have analyzed 8 years of wind and salinity data from a frontal zone in a region of the inner continental shelf off the southeastern United States. The changes in low‐salinity water stored in the frontal zone have been parameterized by analyzing the monthly rate of change in freshwater content. When the rate of change in freshwater content was negative, we interpreted this as a loss of low‐salinity water from the frontal zone. When this parameter was compared with seasonally averaged alongshore wind stress, the rate of loss was independent of the alongshore wind stress magnitude until threshold of about …

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

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 …

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.

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

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 …

Analysis Of Heavy Minerals In Arenaceous Lutites From The Northern Canada Basin, Arctic Ocean, Kim Zauderer

OES Theses and Dissertations

Heavy minerals from arenaceous lutites in three widely spaced cores from the northern Canada Basin were analyzed for the first time to determine the provenance of these sediments. The abundant minerals (sp. gr. == 2.70) in decreasing order for most samples were detrital carbonate, micas, clinoamphibole, clinopyroxene, garnet, epidote, tourmaline, and chlorite. The majority of pyroxene grains were etched. Sedimentary sources dominated and metamorphic and igneous sources were important but secondary. The northern Canada Arctic Archipelago and northern Greenland is proposed as the provenance for the heavy minerals in the arenaceous lutites for at least the past three million years. …

The Effects Of Kepone On The Estuarine Copepod Acartia Tonsa, Judith Marie Wilson

Biological Sciences Theses & Dissertations

Due to the contamination of a 113 km reach of the James River, Kepone poses a serious environmental threat to the Chesapeake Bay. The purpose of the study is to determine the acutely toxic and sublethal levels of kepone for the copepod Acartia tonsa, and to investigate what effects those levels may have on filtration rates.

Kepone was determined to be acutely toxic to A. tonsa, with a 96 hour LC50 of 4.96 ug/1. Dunaliella tertiolecta was selected as the food source for the grazing experiments. Kepone concentrations of 0.046 ug/1 significantly (0.05 level) reduced the flltering rate …

The Temporal And Spatial Distribution Of Hydrocarbons In Atmospheric Deposition From Stations Surrounding Lower Chesapeake Bay, David Benjamin Webber

OES Theses and Dissertations

Hydrocarbon concentrations were determined in bulk, wet, and dry deposition samples from urban and non-urban locations surrounding lower Chesapeake Bay. Mean hydrocarbon concentrations in bulk deposition samples were over three times greater at the urban station indicating a localized source. The major hydrocarbons present were n-alkanes, polycyclic aromatic hydrocarbons (PAH), and the unresolved complex mixture (UCM). The PAH and the UCM were an indication of significant anthropogenic inputs while the odd/even distribution of the n-alkanes was an indication of biogenic sources. These findings indicated seasonal trends of highest biogenic hydrocarbon inputs in the spring and summer months and highest anthropogenic …

A Laboratory Study Of Nongenetic Embryonic Adaptation To Salinity And Its Subsequent Effects Upon Larval Development Of The Grass Shrimp Palaemonetes Pugio Holthius, Paul Jay Anninos

OES Theses and Dissertations

Fertilized embryos of the grass shrimp Palamonetes pugio Holthuis (Decapoda; Caridea) were exposed to two levels of salinity [5 ppt (exposed) and 20 ppt (control)] during incubation to determine the extent to which embryonic adaptation influences subsequent larval development. Larval response to embryonic exposure was measured at three salinities (5 ppt, 10 ppt, and 20 ppt) as the fraction of larvae surviving to metamorphosis and the duration (in days) of larval development. The survival rate of larvae hatched from control, or non-adapted, embryos was significantly influenced by rearing salinity. The differences in survival of pre-adapted larvae (exposed group), however, were …

A Comparison Of Recruitment Strategies Among Brachyuran Crustacean Megalopae Of The York River, Lower Chesapeake Bay And Adjacent Shelf Waters, David Franklin Johnson

OES Theses and Dissertations

Twenty-one stations forming a transect of the Pamunkey River, York River, lower Chesapeake Bay and adjacent coastal waters were sampled from July through September 1980. The megalopa stages of 11 brachyuran species were sampled. Vertical and horizontal distributions are described for each species in relation to salinity and water column stratification. The megalopae are assigned to three apparent recruitment strategies: retained estuarine, expelled estuarine and retained coastal megalopae. the megalopa stages of estuarine adults, such as Hexapanopeus angustifrons, Neopanope sayi, Panopeus herbstii and Pinnotheres ostreum, are retained in estuarine epibenthic waters, while Rhithropanopeus harrisii are retained in slightly shallower …

A Capacitance Wavestaff And Measurements Of Wave Height Decay In The Surf Zone, David L. Timpy

OES Theses and Dissertations

A wavestaff system utilizing capacitance was developed to measure wave heights in the surf zone. Data were used to test the assumption that wave height decays linearly across the surf zone. The instrument system consisted of two wavestaffs and housing which contained the needed electronic circuits and a data recorder. Acceptable frequency response for waves of period greater than two seconds could not be obtained if sensor wires were greater than 0.35 mm in diameter. The size used was 0.35 mm.

An Evaluation Of Nutrient Sources To Onslow Bay, North Carolina, Larry P. Atkinson, Leonard J. Pietrafesa, Eileen E. Hofmann

CCPO Publications

Hydrographic and current meter data from Onslow Bay, North Carolina, were examined to determine the relative importance of various nutrient sources.

Upwelled Gulf Stream water is the major source of nutrients while rivers represent a minor, if not insignificant, source. In the summer during stratified conditions, the upwelled water penetrates across the shelf, but in the winter the upwelled water is restricted to the outer shelf. Nitrate flux across the 40 m isobath was calculated from continuous temperature and current records. Flux during the summer of 1976 was 2 μM m² sec^-1 which is considerably less than flux …

Water Wave Refraction With Non-Linear Theory, Im Sang Oh

OES Theses and Dissertations

Two different kinds of wave refraction models are formulated in the present study using Stokes' third order wave theory. One type of model is utilized in a parametric study employing several different topographies. Wave trajectories obtained from this model, when obtained by using first and third order wave theory with and without the consideration of energy dissipation, show considerable differences. These differences are examined in more detail for a bottom of constant slope: (1) An approximate 10% difference occurs between the refraction coefficients obtained using the first and the third order wave theory. (2) Considerably different ray trajectories are detected …

A Quantitative Description Of Migratory Behavior Of The Brown Shrimp (Penaeus Aztecus) With Applications In Fisheries Management, Anne Madolyn Babcock

OES Theses and Dissertations

A quantitative description of the migratory behavior of the brown shrimp, Penaeus aztecus, was established using the density approach. A theoretical time density was estimated by the proportion of catch and catch per boat hour NOAA-NMFS fisheries statistics collected in Pamlico Sound, the Neuse River, and Core Sound. A clear quantitative description of brown shrimp migratory timing is found in the time densities. The impact of various physical tactors on the progress of the fishery in time and space can be objectively evaluated by using the time density statistics as dependent variables in modeling efforts. The distributions also enable …