Oceanography and Atmospheric Sciences and Meteorology Commons^™

Molting In The Mature Female Blue Crab, Callinectes Sapidus, Rathbun, Kirk J. Havens

OES Theses and Dissertations

The present study examines the hypothesis that mature female blue crabs, Callinectes sapidus, do not have a terminal anecdysis. Induced molting via eyestalk ablation, size frequency distributions and gonad and limb regeneration indices from field collected animals are used as indicators of potential post maturity molts.

Eyestalk ablation of mature females resulted in ecdysis approximately 51 days after ablation, indicating a physiological ability if mature females to complete ecdysis. Analysis of size frequency distributions indicates two distinct shifts from smaller to larger females, one in early spring and a second in early fall. While migration of larger females into …

Sulfide In Shelf/Slope Waters Of The Western Atlantic, Christian F. Krahforst

OES Theses and Dissertations

Sulfide in the surface ocean has been recently considered as a source of hydrogen sulfide gas in the marine boundary layer. This "oxic" sulfide may also be important as a ligand in trace metal complexation. In the absence of actual data, the existence of sulfide in the ocean mixed layer remains speculative. The purpose of this study was to develop a sensitive technique (having picomolar detection limits) for the determination of sulfide in seawater, and to investigate the distribution of sulfide in the surface ocean.

In order to assess the abundance and distribution of sulfide in surface waters, samples were …

Sediment Budgets And Shoreline Dynamics Cape Henry, Virginia, Marcia R. Berman

OES Theses and Dissertations

Analysis of 1183 beach profiles from Cape Henry, Virginia indicated that the recession-erosion ''rule" established by the Army Corps of Engineers underestimates the short-term response of the shoreline to changes in sediment volume.

Correlation between bi-weekly backshore volume change and the change in high water line (HWL) position was stronger (0.67 < r < 0.88) than correlation between bi-weekly total volume change and the change in mean low water (MLW) shoreline position (0.33 < r < 0.52). The short-term change in position of MLW is influenced by minor features such as bars. The position of the HWL is controlled by volume change at the backshore.

Correlation between change in HWL and MLW shoreline positions improved from r = 0.01 tor·= 0.67 for intervals of two weeks to two years, respectively. This suggests parallel-shore retreat only may be operable for greater than two-year periods.

Phytoplankton Dynamics In The Very Low Salinity Region Of The James River Estuary, Virginia, U.S.A., Changho Moon

OES Theses and Dissertations

During summer and autumn discharge from the James River estuary, Virginia, was less than 120 _m³sec^-1. There was a peak phytoplankton biomass in the very low salinity region (defined as the location where surface salinity measured less than 0.5$ 0/00) and this peak represented five to ten times greater biomass than adjacent waters. The peak biomass occurred independent of the tidal state and the location of nutrient inputs. It disappeared during winter and spring, and nutrient limitation was not responsible for the low phytoplankton biomass, indicating there were physical, not chemical controlling factors.

The peak biomass …

Analysis Of Phytoplankton And Particle Variability At A Warm Core Ring/Shelf Break Front Using Flow Cytometry, Kimberly G. Davis

OES Theses and Dissertations

Particle variability at a Gulf Stream warm core ring/ shelf break front on 09 Nay 1985 was analyzed. Single particle measurements of fluorescence, perpendicular light scatter, and volume were made using a FACS Analyzer flow cytometer. Advantages and disadvantages of at-sea use of the instrument are described. To evaluate the flow cytometry data, individual particle data were compared with bulk phytoplankton and particle measurements. Abundance and size distributions of fluorescent and non-fluorescent particles indicated a convergence zone at the front while upwelling was likely within the ring perimeter. Variability in fluorescence (approximating chlorophyll A) and cell biovolume exposed regions of …

Processes Which Create And Destroy Stratification In The South Atlantic Bight During Gabex Ii, Rebecca Lynn Lovingood

OES Theses and Dissertations

The stratification present on the South Atlantic Bight (SAB) during the summertime is influenced by creative forces, namely surface heating, precipitation, fresh water runoff and advection of Gulf Stream water, and destructive forces, these being wind, bottom currents, tides, evaporation and cooling. During the summer of 1981 the Georgia Bight Experiment II (GABEX II) was conducted to evaluate the Gulf Stream intrusions on the shelf dynamics. Calculations using potential energy as an indicator of stratification showed that the mixing forces were strong enough to destroy the stratification if the advection of buoyancy is ignored. During this period, however, the potential …

Growth Potential Of Young Black Sea Bass, Centropristis Striata, In Artificial Environments, Joung Won Kim

OES Theses and Dissertations

The growth potential of the commercially important marine finfish, black sea bass (Centropristis striata), was examined for aquaculture under controlled conditions. The effect of food and body weight on growth was evaluated using juveniles and young black sea bass cultured with a natural diet and a commercial diet at various feeding levels.

Growth was affected by type of food, food consumption rate, and fish body weight. For fish having positive weight gain, absolute growth rate (gram/day) increased exponentially as food consumption rate (percent of body weight per day) and/or body weight increased. Instantaneous growth rate (percent of body weight per …

Cross-Shore Sediment Transport In Relation To Waves And Currents In A Groin Compartment, Hyo Jin Kang

OES Theses and Dissertations

In nearshore areas waves are generally irregular, and the irregular wave-induced currents have different peak velocities (magnitude asymmetry) and durations (duration asymmetry) between forward and backward motions. These asymmetries may produce a net cross-shore sediment transport in one direction. The sediment transport mostly occurs as bedload where the waves are non-breaking.

Sediment transport on a sloping bed is also affected by gravity, and accordingly the Shields parameter should be re-evaluated for a grain on a sloping bed. It was also found that the affect of a steady current that interacts nonlinearly with the waves was important for the cross-shore sediment …

The Geochemistry Of Selenium And Sulfur In A Coastal Salt Marsh, David Jay Velinsky

OES Theses and Dissertations

Investigation of the various chemical forms of selenium and sulfur in sediments and pore waters can provide information about various oxidation/reduction processes. Five cores were obtained from the Great Marsh, from April 1985 to June 1986. Sampling times coincided with the seasonal redox cycle known to occur within the marsh system. Sediments were analyzed for various selenium and sulfur phases.

Iron monosulfides and elemental sulfur both display large seasonal changes in concentration and distribution with depth, indicating a coupling with redox conditions. In contrast, the depth distribution of greigite did not show appreciable changes with season. Pyrite underwent large concentration …

Laminar Viscous Effects On Longitudinal Dispersion In Tidal Froude Models, Larry H. White

OES Theses and Dissertations

A laboratory investigation was designed to test the ability of a tidal Froude model operated according to the minimum Reynolds number criterion of 1400 to simulate the longitudinal dispersion of its turbulent, laboratory prototype in the absence of depth distortion and density stratification. To examine the model's performance, comparative tracer-dye dispersion tests were conducted in the model and in the prototype to determine spatial and temporal longitudinal dye distributions. Froude similitude of cross-sectional mean tide heights and current velocities was achieved. The minimum Reynolds number criterion did not guarantee turbulent flow throughout all tidal stages, prolonged periods of laminar flow …

A Comparison Of Potential Fishing Methods Associated With Fish Aggregating Devices Off The Northeast Coast Of Puerto Rico, Alan M. Friedlander

OES Theses and Dissertations

Six fish aggregating devices (FADs) were deployed in June and monitored through December 1986. Emphasis was placed on trolling, live-bait handlining and longlining.

There was a significant difference (x2 = 7.815, pCoryphaena hippurus) which made up 64.2% of the catch.

Handlining at night around inshore buoys for one boat yielded 82.7 kg per trip. Pelagic fish comprised 83.9% of the catch, with the majority (81.4%) being kingfish (Scomberomorous cavalla). Catch rates were 50% higher and the species diversity much greater on the FADs versus control during experimental nightfishing, but the difference was not significant.

Longlining resulted in 3.4 …

A Simple Numerical Model For The Study Of Baroclinic Estuarine Shelf Interactions, Thomas J. Berger

OES Theses and Dissertations

A one and a half layer nonlinear f-plane numerical model was used to study estuarine-shelf interactions. The single active layer covered a domain consisting of a 100 km long by 20 km wide channel discharging onto a 100 km wide by 300 km long shelf. Channel and "western” shelf boundaries were no-slip, "eastern" or oceanic boundary was free-slip and "northern" and "southern" shelf boundaries were open. The channel was forced with a constant inflow velocity spun up from 2 cm s^-1 to 27 cm s^-1over five days. The model initial conditions were a flat interface at …

Groin-Associated Rip Currents Measured Using A New Digital Current Meter, Dennis L. Lundberg

OES Theses and Dissertations

Rip currents have often been noted in physical model studies of groins and their effectiveness. Nevertheless, detailed field investigations of rip currents along a groin wall have not been heretofore conducted. A new digital current meter system was designed and built to study the groin-associated rip currents in a test groin compartment at Willoughby Spit, Norfolk, VA. Six ducted impeller current meters are controlled by a data acquisition system that utilizes an onboard microprocessor and solid state memory. The new system provides high quality data on horizontal water velocities associated with wave action. The velocities stored are time mean velocities …

Validation Of The Otolith Increment Aging Technique For Striped Bass, Morone Saxatilis, Larvae Reared Under Suboptimal Feeding Conditions, Cynthia Jones, Edward B. Brothers

OES Faculty Publications

Striped bass, Morone saxatilis, larvae were reared in the laboratory for 97 days to validate the otolith increment aging technique for this species. Otolith-increment deposition rates were determined under optimal laboratory conditions for growth and under three conditions of restricted feeding and using both light and scanning electron microscopy (SEM). Under optimal laboratory conditions. increments were deposited daily from the fourth day after hatching through the first 2 months of life and were discernible with the light microscope. For larvae reared under restricted feeding regimes and readings done with the light microscope, counts did not reflect true age. Counts …

Acceleration Of Nutrient Uptake By Phytoplankton In A Coastal Upwelling Ecosystem: A Modeling Analysis, Richard C. Zimmerman, James N. Kremer, Richard C. Dugdale

OES Faculty Publications

Studies of upwelling centers in the eastern Pacific suggest that maximum rates of nitrate uptake (light and nutrient saturated) increase, or shift-up, as newly upwelled water moves downstream. The rate of shift-up appears to be related to irradiance and the ambient concentration of limiting nutrient at the time of upwelling. A mathematical model was developed to evaluate effects of irradiance and initial nitrate concentration on temporal patterns of shift-up and subsequent time scales of nutrient utilization over a range of simulated upwelling conditions. When rates consistent with field studies were used, complete shift-up was possible only under certain conditions, and …

Shoreward Intrusion Of Upper Gulf Stream Water Onto The United States Southeastern Continental Shelf, Lie-Yauw Oey, Larry P. Atkinson, Jackson O. Blanton

CCPO Publications

In winter, cooling of the South Atlantic Bight continental shelf water results in higher density in the middle shelf region relative to the shelf-break region where the western flank of the Gulf Stream flows. Shoreward, estuarine-like intrusion of the upper Gulf Stream water in the presence of such a positive onshore density gradient is then possible through advective processes triggered either by the meander of the Stream or onshore Ekman transports by southward wind stresses. Repeated cross-shelf hydrographic transects were conducted from 10 January through 30 January 1986 to more closely study this intrusion process. These observations show many features …

The Relationship Of Upwelling To Mussel Production In The Rias On The Western Coast Of Spain, Jack O. Blanton, Kenneth R. Tenore, F. Castillejo, Larry P. Atkinson, Franklin B. Schwing, Amy Lavin

CCPO Publications

We have calculated an upwelling index for each month over a 17-year period (1969-1985) for a point off the western coast of Spain. We interpret April through September values of the index to indicate the flux of nitrate-rich water in the Spanish Rias. The index representing the 6-month upwelling series has been correlated with an index representing the conditions of mussels grown during that season on rafts in Ria de Arosa. Two seasons represent extreme upwelling conditions over the 17-year sampling period: 1977 when the upwelling index was the highest, and 1983 when it was the lowest. A comparison of …

Is Growth Of Eelgrass Nitrogen Limited? A Numerical Simulation Of The Effects Of Light And Nitrogen On The Growth Dynamics Of Zostera Marina, Richard C. Zimmerman, Robert D. Smith, Randall S. Alberte

OES Faculty Publications

A numerical model of nitrogen uptake and growth was developed for the temperate seagrass Zostera marina L. Goals were to evaluate the relative effects of light and nitrogen availability on nitrogen uptake and partitioning between leaf and root tissue, and to estimate nitrogen concentrations in the sedment and water column required to saturate growth. Steady-state predictions are quite robust with respect to a range of parameter values justified by available data The calculations indicated that roots are probably more important in overall nitrogen acquisition in most light and nitrogen environments encountered in situ, but may contribute less than 50 …

Mesoscale Hydrographic Variability In The Vicinity Of Points Conception And Arguello During April May 1983: The Opus 1983 Experiment, Larry P. Atkinson, Kenneth H. Brink, Russ E. Davis, Burton H. Jones, Theresa Paluszkiewicz, David W. Stuart

CCPO Publications

In April and May 1983, interdisciplinary oceanographic observations were made of upwelling events in the Point Conception area off southern California. The principal objective was to observe the structure and time dependence of the upwelling system. To accomplish this, two ships, two aircraft, moorings, drogues, and satellite imagery were all included in the observational effort. During the intensive measurement period three main upwelling events and two intervening relaxation or downwelling intervals were sampled during what was a period of overall longer-term sea surface warming. Surface temperatures during upwelling were as low as 10.5°C in the upwelling center between Point Arguello …

A Histological Investigation Of The Larval Mandibular Organ In The Mud Crab Rhithropanopeus Harrisii (Gould) (Crustacea Decapoda Xanthidae), Lore Lynn Hantske

OES Theses and Dissertations

Mandibular organs of the mud crab, Rhithropanopeus harrisii (Gould) were histologically located and followed throughout the larval cycle to determine their role in metamorphosis. Specimens from each day of the four larval stages and the megalopa stage were embedded in paraffin, sectioned at 8 μm, stained and observed under the microscope for the mandibular organs. The organs were located in the mandibular area of second, third and fourth stage larvae. The organs were probably present in the first stage zoeae and in the megalopa stage, although the

techniques of the study were not sensitive enough to observe them. The …

Disease Incidence Of Demersal Finfishes From The Southern And Western Branches Of The Elizabeth River, Virginia, Randal D. Owen

Biological Sciences Theses & Dissertations

Fishes from the industrialized environs of the Elizabeth River, Virginia were surveyed for external evidence of disease during June through October 1984. A highly significant (p < 0.001) incidence of disease was found in demersal fishes collected by otter trawl from a site in the industrially contaminated Southern Branch compared to a less contaminated Western Branch site. Cataracts, fin erosion and dermal lesions were the most commonly occurring anomalies in the Southern Branch finfish.

Static, solid-phase toxicity tests employing sediment collected from the Southern Branch site resulted in an immediate toxic stress in the spot, Leiostomus xanthurus, which resulted in 100% mortality within 24 hours, compared with no mortalities in control systems. Spot exposed to control, i.e., pollution free, and diluted Southern Branch sediments innoculated with the pathogenic bacterial species, Vibrio anguillarium, developed significant (p ≤ 0.020) cases of fin erosion at a mean total bacterial community density …

Patterns Of Diurnal Vertical Distribution And Dispersal-Recruitment Mechanisms Of Decapod Crustacean Larvae And Postlarvae In The Chesapeake Bay, Virginia And Adjacent Offshore Waters, Robert Copeland Maris

OES Theses and Dissertations

Larval dispersal and subsequent postlarval recruitment are extremely significant processes affecting the maintenance of ecologically and economically important populations of decapod crustaceans. Vertical positioning in the water column plays a major role in the particular strategies of retention or expulsion with immigration.

The present study was undertaken to investigate variations in vertical distribution according to temporal (diurnal), spatial (estuarine, transition, oceanic), ontogenetic (larval stages, postlarvae) and various environmental factors (especially light, temperature, salinity and tides). Also, effects of vertical positioning on dispersal-recruitment were examined.

Three stations were established for the present study: York River mouth (estuarine) (37°12'N, 76°16'W); Chesapeake Bay …

Storm Surge Predictions At Sewell's Point With Local Wind, Pressure, And Previous Surge As Surge Predictors In Chesapeake Bay, Joy Elaine Moses

OES Theses and Dissertations

The statistical model used to predict storm surge. which is defined as the difference between observed water level and predicted astronomical tide. at Sewell's Point. Virginia. for the last ten years relies on forecast surface air pressures interpolated over a large portion of the Atlantic Ocean. A variation on this method is developed which adds previous station surge and local wind and pressure terms with time leads up to 18 hours to the Pore prediction for surge. and develops surge prediction equations for three substations eight to 65 miles (13 to 105 km) from Sewell's Point. The Sewell's Point surge …

Tidal Circulation In Chesapeake Bay, Carl W. Fisher

OES Theses and Dissertations

This study is a comprehensive examination of the tidal circulation of Chesapeake Bay and its major tributaries. Tide and current data, which were observed in Chesapeake Bay by the National Ocean Service during the period from 1972 to 1983, are analyzed and used to construct charts that describe the tide and tidal current. Frictionally damped analytic models are used to: explain the tidal hydrodynamics of the observed tides, determine the location of the quasinodes and antinodes of the M₂ and K₁ tidal waves, explain the relationship of the tides and tidal currents, and determine if the tide in …

Sediment Processing And Selective Feeding By Pectinaria Koreni (Polychaeta: Pectinariidae), Fred C. Dobbs, Teresa A. Scholly

OES Faculty Publications

Pectinaria (Lagis) koreni (Malmgren) is an abundant, deposit-feeding, infaunal inhabitant of shallow-water marine environments in northern Europe. Laboratory experiments were performed to quantify the polychaete's sediment processing in 2 distinct sediments, 1 fine-grained and high in combustibles, the other coarse-grained and low in combustibles. Gut passage time and time to pseudodefecation were predictable only in coarse-grained sediment. In both sediments, reworking rate increased with worm size and over time, although temporal patterns differed in the 2 sediments. The ratio of pseudodefecated sediment to defecated sediment did not differ significantly over time in either sediment, but the ratio was greater in …

In Situ Growth And Chemical Composition Of The Giant Kelp, Macrocystis Pyrifera: Response To Temporal Changes In Ambient Nutrient Availability, Richard C. Zimmerman, James N. Kremer

OES Faculty Publications

Temporal variations in growth of the giant kelp Macrocystis pyrifera were examined in relation to ambient nutrient availability and chemical composition of mature blades, the primary site of nutrient and carbohydrate storage in M. pyrifera. The effect of nutrient availability on growth was well approximated by a Monod rectangular hyperbola, with growth saturating at ambient nitrate concentra- tions between 1 and 2 FM. M. pyrlfera was unable to generate nutrient reserves that would last beyond 30 d. Nitrogen reserves were stored as free amino acids, and generally constituted about 10 % of total tissue nitrogen. Total nitrogen content was …

Deep Flow Variability In Central Drake Passage, John M. Klinck, Eileen E. Hofmann

CCPO Publications

A rotary empirical orthogonal function analysis of the currents measured in central Drake Passage during DRAKE 79 shows that the deep (2500 m) flow has the same spatial and temporal structure as the flow at 500 m, suggesting that current variability in this region penetrates to the bottom. However, comparison of the time amplitude of the corresponding modes indicates that the variability of the 2500 m flow resulting from north to south shifts in the location of the Polar Front lags that at 500 m by one to three days. This implies that the Polar Front slopes to the east …

The Physics Of The Antarctic Circumpolar Current, Worth D. Nowlin, John M. Klinck

CCPO Publications

A region of transition of surface water characteristics from subantarctic to Antarctic and an associated eastward flowing Antarctic Circumpolar Current (ACC) have long been recognized to exist as a band around Antarctica. In this review we summarize the most important observational and theoretical findings of the past decade regarding the ACC, identify gaps in our knowledge, and recommend studies to address these. The nature of the meridional zonation of the ACC is only now being revealed. The ACC seems to exist as multiple narrow jets imbedded in, or associated with, density fronts (the Subantarctic and Polar fronts) which appear to …

Wind-Driven Upwelling In The Vicinity Of Cape Finisterre, Spain, Charles R. Mcclain, Shenn-Yu Chao, Larry P. Atkinson, Jack O. Blanton, Frederico De Castillejo

CCPO Publications

Observations and numerical simulations of upwelling along the Galician coast of Spain during April 1982 are presented. In situ measurements include shipboard determinations of hydrographic and biological parameters from a grid of stations covering the continental shelf from Cape Finisterre to Ria de Vigo, sea level data from Vigo and La Coruña, and wind stress estimates derived from the ship winds and from surface pressure charts. Sea surface temperature information and pigment concentration information have been obtained from a sequence of satellite images from the NOAA 7 advanced very high resolution radiometer and the Nimbus 7 coastal zone color scanner, …

Factors Regulating Settlement And Microhabitat Use By Spiny Lobsters Panulirus Argus, William F. Herrnkind, Mark J. Butler Iv

Biological Sciences Faculty Publications

Clumps of highly-branched red algae Laurencia spp. serve as important settling habitat for postlarval spiny lobsters Panulirus argus and as residence for early benthic-stage juveniles. Given choice between the 2 most abundant macrophytes in Florida Bay, Laurencia spp. and the seagrass Thalassia testudinum, postlarval and juvenile lobsters chose Laurencia spp. Postlarvae apparently use intricate algal architecture as a cue for settlement, whereas juveniles use both architecture and food abundance in selecting habitat. In tethering experiments, predation on juvenile lobsters was very high on open sand, much reduced in algal clumps and seagrass, and lowest in dense algal meadows. Predation …