Marine Biology Commons^™

Evaluation Of Possible Reproductively Mediated Character Displacement In The Crayfishes, Orconectes Rusticus And O. Sanbornii, Mark J. Butler Iv

Biological Sciences Faculty Publications

Orconectes rusticus is replacing several species of crayfishes in north-central and northeastern North America, including O. sanbornii in Ohio. Recent evidence suggests that the species replacements may be driven by asymmetrical reproductive success favoring O. rusticus. Nonetheless, some sympatric associations appear locally persistent. Because crayfish demonstrate size assortative mating and there is a disparity in the sizes of the species, further divergence in the sizes of the species in sympatry could enhance reproductive isolation, ultimately providing a mechanism for character displacement. To test this hypothesis the size differentials between crayfish collected from allopatric and sympatric populations in east-central Ohio …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Comparison Of An Improved Plankton Sampler To The Standard Conical Plankton Net, Ronald S. Schmidt

OES Theses and Dissertations

A comparison of field and tank tests between the standard conical plankton net and an improved version of a plankton sampler is presented. The improved sampler was shown to filter larger quantities of water than the standard net without having the filtration efficiency reduced below 85%. The improved sampler was also shown to capture an increased number of plankton per volume sampled, as a result of eliminating increased avoidance activity by zooplankton. It was not shown that. the improved sampler capture either larger maximum sizes of zooplankton or additional species.

The Distribution Of Ceratia Over The Mid-Atlantic Bight, Paul V. Zimba

Biological Sciences Theses & Dissertations

The distribution and concentration of Ceratium species, between Cape Hatteras, North Carolina and Long Island, New York ls discussed in relation to specific physical factors and the development of a phytoplankton bloom. The progression of high Ceratium counts Is discussed for the Bight areas of New York, Delaware, and the Chesapeake Bay (April through June). The concentration of Ceratium species declined after June, with highest concentrations along the New York and Delaware coast-lines. Coastal regions (less than 12 km from shore) were associated with high concentrations of several species. Path and regression analysis were used to relate physical factors and …

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

Biological Sciences Theses & Dissertations

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

Microbial Manganese Reduction By Enrichment Cultures From Coastal Marine Sediments, David J. Burdige, Kenneth H. Nealson

OES Faculty Publications

Manganese reduction was catalyzed by enrichment cultures of anaerobic bacteria obtained from coastal marine sediments. In the absence of oxygen, these enrichment cultures reduced manganates when grown on either lactate, succinate, or acetate in both sulfate-free and sulfate-containing artificial seawaters. Sodium azide as well as oxygen completely inhibited microbial manganese reduction by these enrichment cultures, whereas molybdate had no effect on them. The addition of nitrate to the medium slightly decreased the rate of Mn²⁺ production by these enrichment cultures. These findings are consistent with the hypothesis that the manganese-reducing organisms in these enrichment cultures use manganates as terminal …

The Effects Of X-Irradiation On The Metamorphosis And Budding Of Aurelia Aurita, Michael John Prokopchak

OES Theses and Dissertations

With the aid of the Aurelia Metamorphosis Test System, the acute or subtle morphological and behavioral effects of irradiation on the Norfolk Aurelia aurita were described and the sensitivity to X-irradiation of those organisms receiving thyroxine and those not receiving thyroxine was compared. Levels of radiation were 0 (control), 5,000, 10,000, 15,000, 20,000 and 40,000 rads. Morphology of the ephyrae, statolith and rhopalia numbers were recorded using the light microscope, Developmental abnormalities of the scyphistomae and ephyrae were recorded with the scanning electron microscope and light microscope. Two major findings from this investigation were the absence of rhopalia and statoliths …

The Spatial And Temporal Distribution Of The Larvae Of Sympatric Pagurid Hermit Crabs (Decapoda, Anomura) In Virginian Estaurine And Coastal Waters, Philip Wesley Sadler

OES Theses and Dissertations

Thirteen stations were occupied at two - week intervals from May through September 1980 within the York River, lower Chesapeake Bay depths encompassing the entire water column.

Three species of pagurids were identified: Pagurus longicarpus, P. pollicaris, and P. annulipes. The larvae of P. annulipes had not been previously identified from Virginian waters. The shapes of the antennae of P. pollicaris and P. annulipes weredistinctive, allowing rapid identification of these larvae. The shapes of the uropods were found to be useful in distinguishingthe glaucothoe· of P. longicarpus from P. annulipes. The larvae of these species …

A Molecular Phylogeny Of The Grunts (Perciformes: Haemulidae) Inferred From Nuclear Rag1 Gene Sequences, Millicent D. Sanciangco

Biological Sciences Theses & Dissertations

Species and genera of Haemulidae have undergone various taxonomic revisions, however, there is no study that infers the phylogeny of the haemulid genera using morphological or molecular data. The purpose of this study was to use approximately 1386 base pairs of the nuclear Recombination Activation Gene-I (RAG1) from 35 haemulid species representing 13 genera, one species of the closely related Inermiidae, and two species of the outgroup Sparidae to infer an intrafamilial phylogeny of Haemulidae. This analysis is corroborated using approximately 650 base pairs of the mitochondrial Cytochrome Oxidase I (COI) gene and RAG I-COI combined gene analyses of27 haemulids, …

Timing Of The Blue Crab Fisheries Of Virginia And Its Application To Harvest Management, J. Dale Shively

OES Theses and Dissertations

The timing of a fishery is a quantitative expression of the composite behaviors of harvesters, markets, animals and climatic events. A quantitative description of the timing of the blue crab (Callinectes sapidus) fisheries of Virginia was established using the time density model of Mundy (1979). Blue crab catch statistics supplied by the National Marine Fisheries Service and the Virginia Marine Resource Commission were divided into two fisheries based on gear type; the summer and winter fisheries. Average performance curves were then constructed using average cumulative proportions of catch. Annual yield estimates were also made and timing in five …

Episodic Nutrient Supply To A Kelp Forest Ecosystem In Southern California, Richard C. Zimmerman, James N. Kremer

OES Faculty Publications

Temporal patterns of nutrient input into a Southern California kelp forest were measured using traditional hydrocast sampling coupled with high frequency temperature profiling. Patterns of nutrient input were related to growth rates of Macrocystis pyrifera located in an adjacent kelp forest. There were 2 distinct components to the pattern of nutrient availability. The long term, or seasonal, component was consistent with large-scale storm-induced mixing and horizontal advection during winter months. In addition, vertical motions of the thermocline, bringing nutrients into the kelp forest, occurred throughout the year with a frequency of about 2 per day and were strongest during the …

Changes In The Lower Chesapeake Bay Food-Chain In Presence Of The Sea Nettle Chrysaora-Quinquecirrha (Scyphomedusa), David Feigenbaum, Michael Kelly

OES Faculty Publications

The abundance of 4 levels of the lower Chesapeake Bay food chain (Chlorophyll a, herbivores, ctenophore Mnemiopsis leidyi, and Scyphomedusa Chrysaora quinquecirrha) were moni­tored twice weekly at 4 stations from May 10 through Sep 30, 1982 in the Lafayette and Elizabeth Rivers (Virginia). The herbivore standing stock, largely copepods, declined sharply in late May when M. Jeidyi appeared, but rebounded a month later when C. quinquecirrha medusae reduced the ctenophore population. Despite the additional presence of Aurelia aurita (Scyphomedusa) from Jul onward, herbivore abundance remained at moderate levels until the end of the study period. Phytoplankton abundance fluctuated …

Review Of Upwelling Off The Southeastern United States And Its Effect On Continental-Shelf Nutrient Concentrations And Primary Productivity, Larry P. Atkinson, James A. Yonder, Thomas N. Lee

CCPO Publications

Gulf Stream induced upwelling occurs along the length of the southeastern United States continental shelf break. Upwelling events are produced by northward propagating Gulf Streams frontal meanders and eddies and travel northwards with these features. Meanders and eddies occur throughout the year in a period band of 2-14 days; however, resultant upwellings can affect the shelf quite differently. During fall, winter, and spring, upwelling is restricted to the outer shelf by cross-shelf density distributions, but in the summer upwelled water may penetrate across as a subsurface intrusion if aided by upwelling-favorable winds. If water does penetrate across the shelf, it …

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 …

The Effects Of The Mud Snail Ilyanassa Obsoleta (Say) Upon The Benthic Community Of Broad Bay, Virginia, Wick Timothy Harlan

Biological Sciences Theses & Dissertations

The effects of the presence of the mud snail Ilyanassa obsoleta (Say) upon the benthic community of Broad Bay, Virginia were examined through artificial removal and exclusion of the snail and artificial increase of the snail population. The enclosure treatment exhibited a significantly higher number of macrofaunal individuals than the control. The control had a significantly higher number of meiofaunal individuals than either treatment. There were no significant differences for the chlorophyll a. The increase in macrofauna and corresponding decrease in meiofauna were probably due to cage effects and not snail densities. The presence of the fences can act as …

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 …

The Effects Of Dredged Materials On The Copeod, Acartia Tonsa, Renee Suzanne Crouch

Biological Sciences Theses & Dissertations

A study was conducted to determine the potential impact of open ocean disposal of sediments dredged from a highly industrialized seaport. Sediments from three potential dredge sites along the Southern Branch of the Elizabeth River, Hampton Roads, Virginia were evaluated for acute toxicity. The suspended particulate fractions of dredged materials were tested in a series of 96-hour, static bioassays using the calanoid copepod, Acartia tonsa Dana. Significant mortalities were observed for all three sites with the sediments from the most heavily industrialized site producing immediate and severe mortality. Analysis of results indicates that mortality was highly related to the volatile …

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 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 …

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 …

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 …