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VIMS Articles

1997

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Articles 1 - 21 of 21

Full-Text Articles in Life Sciences

Small-Scale Settlement Patterns Of The Oyster Crassostrea Virginica On A Constructed Intertidal Reef, Ik Bartol, Roger L. Mann Oct 1997

Small-Scale Settlement Patterns Of The Oyster Crassostrea Virginica On A Constructed Intertidal Reef, Ik Bartol, Roger L. Mann

VIMS Articles

The construction of three-dimensional, intertidal reefs resembling those widely present during colonial times in the Chesapeake Bay, but now absent due to years of overharvesting, may provide a more ecologically advantageous environment for oyster settlement and subsequent survival than present subtidal, two-dimensional habitats. We examined settlement processes on a constructed, 210 x 30 m intertidal reef composed of oyster shell. The reef was destructively and non-destructively sampled weekly throughout the summer and fall at tidal heights ranging from 30 cm above to 90 cm below mean low water (MLW) and at two substrate levels (reef surface and 10 cm below ...


The Postlarval Phase Of Bivalve Mollusks: A Review Of Functional Ecology And New Records Of Postlarval Drifting Of Chesapeake Bay Bivalves, P Baker, Roger L. Mann Sep 1997

The Postlarval Phase Of Bivalve Mollusks: A Review Of Functional Ecology And New Records Of Postlarval Drifting Of Chesapeake Bay Bivalves, P Baker, Roger L. Mann

VIMS Articles

Many bivalve mollusks have one or more separate post-metamorphic stages which are functionally distinct from the late juvenile or the adult. The benthic plantigrade and the planktonic postlarva are defined and reviewed here. The plantigrade is a developmentally obligatory stage in mast bivalves. Various anatomical or conchological features, depending on taxa, are intermediate between the veliger and the juvenile. The plantigrade is benthic but highly mobile, via the foot and byssus, relative to the adult, although in some highly mobile bivalves, the plantigrade is functionally similar to the adult. The plantigrade may enter the water column briefly, but not nearly ...


Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow Aug 1997

Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow

VIMS Articles

To identify the biochemical response of heterotrophic bacterioplankton to changing environmental conditions, seasonal and diel cycles of bacterial protein and DNA synthesis rates were estimated in temperate estuarine habitats from H-3-leucine (Leu) and H-3-thymidine (TdR) incorporation rates. Several short-term temperature manipulation experiments (5 to 35 degrees C) and 2 mesocosm experiments were performed to examine the effects of temperature and substrate supply on the ratio of Leu:TdR, respectively. The molar ratio of Leu to TdR varied about 5-fold (5.6 to 29.5) in the field and the values of the ratio were lower and more constant during high ...


Phenotypic Plasticity In The Foot Size Of An Intertidal Snail, Gc Trussell Jun 1997

Phenotypic Plasticity In The Foot Size Of An Intertidal Snail, Gc Trussell

VIMS Articles

The risk of dislodgment due to hydrodynamic forces on rocky intertidal shores is greater on wave-exposed than an protected shores, and this:is believed to represent an important selective force in intertidal communities. For intertidal snails, the probability of dislodgment by a given flow is determined, in part, by shell size and shape, and by the attachment strength of the foot. This study addressed two questions. First, do habitat-specific differences in traits that reduce the risk of dislodgment of an intertidal snail(Littorina obtusata) parallel differences in wave energies? To address this question, I measured variation in (1) shell size ...


Phenotypic Selection In An Intertidal Snail: Effects Of A Catastrophic Storm, G. Trussell May 1997

Phenotypic Selection In An Intertidal Snail: Effects Of A Catastrophic Storm, G. Trussell

VIMS Articles

Littorina obtusata exhibits clear morphological variation (e.g. shell height, shell length, and aperture area) among shores differentially exposed to wave energies. Selection imposed by the hydrodynamic environment is often invoked to explain the correlation between morphology and wave exposure in intertidal organisms, but rarely is this hypothesis tested. I examined the effects of a catastrophic storm on the shell length and relative shell height and aperture area of L. obtusata populations on 2 protected and 1 wave-exposed share in New England (USA) to test this hypothesis. Snails sampled after the storm had relatively squatter shells than those sampled before ...


Sensitivity Of Bottom Stress And Bottom Roughness Estimates To Density Stratification, Eckernforde Bay, Southern Baltic Sea, Carl T. Friedrichs, Ld Wright Mar 1997

Sensitivity Of Bottom Stress And Bottom Roughness Estimates To Density Stratification, Eckernforde Bay, Southern Baltic Sea, Carl T. Friedrichs, Ld Wright

VIMS Articles

Thermohaline density stratification may significantly alter the classic near-bottom logarithmic velocity profile in many weak to moderately energetic, partially mixed estuaries. Results from Eckernforde Bay suggest fits to log profiles which neglect thermohaline stratification may lead to overestimates of bottom stress and roughness of the order of 130 % and 600 %, respectively. Measurements of velocity obtained at four heights within 1 m of the seabed are input to theoretical models for velocity shear derived via dimensional arguments for the ''overlap'' layer. Previous investigators applying dimensional arguments to thermohaline stratification in estuaries have assumed buoyancy flux to be independent of height within ...


Investigating The Management Potential Of A Seagrass Model Through Sensitivity Analysis And Experiments, P Fong, Me Jacobson, Mc Mescher, D Lirman, Mc Harwell Feb 1997

Investigating The Management Potential Of A Seagrass Model Through Sensitivity Analysis And Experiments, P Fong, Me Jacobson, Mc Mescher, D Lirman, Mc Harwell

VIMS Articles

Loss of seagrass-dominated ecosystems worldwide has been attributed to anthropogenic modifications of watersheds; in response, proper management of these systems has become a priority. In this paper, sensitivity analysis and comparison of model predictions to field observations identified conditions under which a subtropical to tropical seagrass ecosystem model would be a useful management tool. Sensitivity analysis indicated that under low-nutrient conditions, physical factors such as temperature, light, and salinity controlled model predictions of seagrass and epiphyte biomass, but that when nutrients were abundant (5 mu mol/L sediment pore water P; 10 mu mol/L water column P) control shifted ...


Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator Jan 1997

Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator

VIMS Articles

A modified mE medium (mEI) containing the chromogenic substrate indoxyl-beta-D-glucoside to detect beta-D-glucosidase activity was evaluated with respect to specificity and recovery of enterococci from environmental eaters. Extending incubation from 24 to 48 h improved enterococci recovery but 77% of the colonies classified as non-target were confirmed as enterococci. Randomly chosen enterococcal isolates from sewage, exposed in microcosms containing 0.22 mu m membrane filtered fresh or estuarine water, exhibited differences in persistence as a function of exposure treatment. Decreasing the concentration of or eliminating indoxyl-beta-D-glucoside from mE did not significantly affect recovery of purified isolates.


Introduction To The Proceedings Of The Symposium Fish Larvae And Systematics: Ontogeny And Relationships, Jm Leis, Je Olney, M Okiyama Jan 1997

Introduction To The Proceedings Of The Symposium Fish Larvae And Systematics: Ontogeny And Relationships, Jm Leis, Je Olney, M Okiyama

VIMS Articles

The International Larval Fish Conference was held in Sydney, Australia (26- 30 June 1995) as part of the 19th Annual Meeting of the Early Life History Section of the American Fisheries Society. At the conference, we convened a symposium ("Fish Larvae and Systematics: Ontogeny and Relationships") that was intended to stimulate the application of ontogenetic data to solve problems in fish systematics. The brief we gave the contributors to the symposium was this: "The theme of this symposium will be the use of information gained from egg and larval ontogeny in solving problems in systematics and phylogeny. Thus, we are ...


Genetic Divergence And Loss Of Diversity In Two Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck, 1819), Sandra G. Blake, Norman J. Blake, Michael Oesterling, John Graves Jan 1997

Genetic Divergence And Loss Of Diversity In Two Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck, 1819), Sandra G. Blake, Norman J. Blake, Michael Oesterling, John Graves

VIMS Articles

Researchers at the Virginia Institute of Marine Science (VIMS) have been maintaining a small-scale bay scallop (Argopecten irradians) culturing operation since the late 1960s. The cultured Line was originally established with broodstock collected from the coasts of Virginia and North Carolina, but it has since been augmented with a ''grab bag'' of introductions from other source populations. A large bay scallop-culturing operation was reportedly founded in China in the early 1980s, with 26 individuals provided by the VIMS researchers. The degree of genetic divergence between these two populations since the founding of the Chinese operation is unknown, as are the ...


Settlement Site Selection By Oyster Larvae, Crassostrea Virginica: Evidence For Geotaxis, Patrick Baker Jan 1997

Settlement Site Selection By Oyster Larvae, Crassostrea Virginica: Evidence For Geotaxis, Patrick Baker

VIMS Articles

Settlement of larval oysters, Crassostrea virginica, with respect to upper and lower surfaces of natural substrates, was studied in the field and in the laboratory. Enclosures were used to retain pediveligers of Crassostrea under controlled field conditions: until they settled. About 62% of these larvae settled onto rough (outer) surfaces of natural oyster shell substrate; this closely marched the proportion of substrate oriented with the rough surface downward. In the laboratory, about 83% of larvae settled onto the lower surfaces of similar shell substrates, in the absence of light, regardless of how the shell substrate was positioned. Both field and ...


Potential For Population Regulation Of The Zebra Mussel By Finfish And The Blue Crab In North American Estuaries, Larry C. Boles, Rom Lipcius Jan 1997

Potential For Population Regulation Of The Zebra Mussel By Finfish And The Blue Crab In North American Estuaries, Larry C. Boles, Rom Lipcius

VIMS Articles

We conducted a series of descriptive and manipulative experiments aimed at quantifying the abundance, natural mortality, and effectiveness of predators in controlling the zebra mussel, Dreissena polymorpha, in the Hudson River Estuary. First, we measured distribution, abundance, and mortality rates of a zebra mussel population in the middle portion of the Hudson River Estuary, NY. Rocks were collected along a depth gradient in the field and sampled for the density and size structure of the resident mussels over the growth season. Next, we either allowed access (controls) or denied access (predator exclusion) to predators in field experiments with rocks harboring ...


Evidence That Qpx (Quahog Parasite Unknown) Is Not Present In Hatchery-Produced Hard Clam Seed, Susan E. Ford, Roxanna Smolowitz, Lisa M. Ragone Calvo, Rd Barber, John N. Kraueter Jan 1997

Evidence That Qpx (Quahog Parasite Unknown) Is Not Present In Hatchery-Produced Hard Clam Seed, Susan E. Ford, Roxanna Smolowitz, Lisa M. Ragone Calvo, Rd Barber, John N. Kraueter

VIMS Articles

A protistan parasite known as QPX (Quahog Parasite Unknown) has been recently associated with disease and mortality of adult hard clams, Mercenaria mercenaria, from Canada to Virginia. There is concern that the organism may be transported in hatchery-reared seed. Tissue sections of 2,203 seed clams (<1-20 mm) from 13 different hatcheries in six states, collected from 1995 to 1997 and examined by pathologists in three laboratories, failed to show QPX or QPX-like organisms. Further, QPX was not detected in a total of 756 hatchery-produced clams examined during their first year of field growout. From this, we conclude that hatchery-produced seed clams are an unlikely source of QPX organisms.


Yield-Per-Recruit Analysis And Management Strategies For Atlantic Croaker, Micropogonias Undulatus, In The Middle Atlantic Bight, Luiz R. Barbieri, Mark E. Chittenden, Cynthia M. Jones Jan 1997

Yield-Per-Recruit Analysis And Management Strategies For Atlantic Croaker, Micropogonias Undulatus, In The Middle Atlantic Bight, Luiz R. Barbieri, Mark E. Chittenden, Cynthia M. Jones

VIMS Articles

The effect of different fishing mortality (F) and natural mortality (M), and age at first capture (t(c)) on yield-per-recruit of Atlantic croaker, Micropogonias undulatus, in the lower Chesapeake Bay and North Carolina were evaluated with the Beverton-Holt model. Independent of the level of M (0.20-0.35) or F (0.01-2.0) used in simulations, yield-per-recruit values for Chesapeake Bay were consistently higher at t(c) = 1 and decreased continuously with increases in t(c) (2-5). Although maximum yield per-recruit always occurred at the maximum level off (F=2.0), marginal increases in yield beyond F = 0.50-0.75 ...


Isotopic Compositions Of Lipid Biomarker Compounds In Estuarine Plants And Surface Sediments, Elizabeth A. Canuel, Katherine H. Freeman, Stuart G. Wakeham Jan 1997

Isotopic Compositions Of Lipid Biomarker Compounds In Estuarine Plants And Surface Sediments, Elizabeth A. Canuel, Katherine H. Freeman, Stuart G. Wakeham

VIMS Articles

We examined the isotopic compositions of fatty acids, sterols, and hydrocarbons isolated from three coastal macrophytes (Zostera marina, Spartina alterniflora, and Juncus roemerianus) in order to investigate the relative contribution of these vascular plants as sources of organic matter in coastal sediments such as Cape Lookout Eight, North Carolina. On average, lipid biomarker compounds extracted from the plants were depleted in C-13 by 3-5 parts per thousand relative to delta(13)C total organic carbon (TOC). However, individual compounds within each lipid class varied by up to 5.6 parts per thousand. Trends in the isotopic compositions of lipids were ...


Predator And Shelter-Size Effects On Coral Reef Fish And Spiny Lobster Prey, Db Eggleston, Rom Lipcius, Jj Grover Jan 1997

Predator And Shelter-Size Effects On Coral Reef Fish And Spiny Lobster Prey, Db Eggleston, Rom Lipcius, Jj Grover

VIMS Articles

Population dynamics of coral reef fishes and spiny lobster appear to be determined by variable recruitment interacting with post-settlement processes, particularly predation. The risk of predation may be modified by the scaling between prey and shelter size, which enhances the protective capacity of a reef. We experimentally tested these predictions by manipulating densities of predatory Nassau grouper Epinephelus striatus on 8 artificial patch reefs of 2 sizes (small, large) in a large seagrass bed near Lee Stocking Island, Bahamas. We initially censused patch reefs for 7 mo, after which we randomly selected equivalent numbers of small and large reefs to ...


Cannibalism, Refugia And The Molting Blue Crab, Ch Ryer, J Vanmontfrans, Ke Moody Jan 1997

Cannibalism, Refugia And The Molting Blue Crab, Ch Ryer, J Vanmontfrans, Ke Moody

VIMS Articles

In this study, we examined how habitat and tidal stage influence predation upon molting blue crabs Callinectes sapidus. On 3 separate occasions we monitored the survival of tethered soft crabs in each of 2 different-sized marsh creeks and 2 seagrass sites, during both low and high tides. On one of these occasions, we also tethered hard crabs. Survival was much lower for soft crabs than for hard crabs, indicating that crabs may be particularly vulnerable when they molt. In both seagrass and marsh creeks, there was a tidal influence upon soft crab survival, with greater survival during low tides. There ...


Development Of A Process-Based Nitrogen Mass Balance Model For A Virginia (Usa) Spartina Alterniflora Salt Marsh: Implications For Net Din Flux, Iris C. Anderson, Cr Tobias, Bb Neikirk, Rl Wetzel Jan 1997

Development Of A Process-Based Nitrogen Mass Balance Model For A Virginia (Usa) Spartina Alterniflora Salt Marsh: Implications For Net Din Flux, Iris C. Anderson, Cr Tobias, Bb Neikirk, Rl Wetzel

VIMS Articles

Primary production is nitrogen limited in most salt marshes with the possible exception of those impacted by high anthropogenic inputs of nitrogen. It is hypothesized that mature salt marshes which receive only small inputs of 'new' nitrogen from the atmosphere, surface water runoff, groundwater, tidal creek, and nitrogen-fixation will have a conservative nitrogen cycle. We have developed a process-based N mass balance model for a short-term Spartina alterniflora marsh in Virginia, USA. Data for the model included rates of gross mineralization, nitrification, denitrification, nitrogen fixation, above- and belowground macrophyte production, and benthic microalgal production. The annual balance between sources (mineralization ...


Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal Jan 1997

Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal

VIMS Articles

In the present study we describe a protein-free, chemically defined culture medium, designated JL-ODRP-3, which supports the propagation of Perkinsus marinus, a parasite of the eastern oyster, Crassotrea virginica. P. marinus adapted rapidly to the defined medium and the growth rate of the protozoan increased significantly following a few subcultures. Two isolates of P. marinus, one from the Chesapeake Bay (Virginia) and the other from the Gulf of Mexico (Texas) were cultured for at least ten passes. The doubling times far the isolates from Virginia and Texas, in Jog phase, were 18 +/- 1.2 and 28.6 +/- 3.2 hours ...


Larvae Of Gillellus Jacksoni, G-Uranidea (Dactyloscopidae), Stathmonotus Stahli Tekla, And S-Hemphilli (Chaenopsidae), With Comments On The Use Of Early Life History Characters For Elucidating Relationships Within The Blennioidei, Mr Cavalluzzi Jan 1997

Larvae Of Gillellus Jacksoni, G-Uranidea (Dactyloscopidae), Stathmonotus Stahli Tekla, And S-Hemphilli (Chaenopsidae), With Comments On The Use Of Early Life History Characters For Elucidating Relationships Within The Blennioidei, Mr Cavalluzzi

VIMS Articles

Larvae of the families Dactyloscopidae (Gillellus jacksoni, G. uranidea) and Chaenopsidae (Stathmonotus stahli tekla, S. hemphilli) are described from specimens collected in Ambergris Gay, Belize. Larvae are characterized by precocious development of fins and sensory canals, and little pigmentation overall, with the majority of pigmentation occurring ventrally. Pigment distributions in larvae are summarized for the six blennioid families. There are no unifying pigment characters among blennioid larvae. Larvae possess the six shared specialized characters or character complexes (as described in adults) currently used to hypothesize the monophyly of the Blennioidei, and thus, provide no new phylogenetic information.


Disease Processes Of The Parasite Perkinsus Marinus In Eastern Oyster Crassostrea Virginica: Minimum Dose For Infection Initiation, And Interaction Of Temperature, Salinity And Infective Cell Dose, Fle Chu, Ak Volety Jan 1997

Disease Processes Of The Parasite Perkinsus Marinus In Eastern Oyster Crassostrea Virginica: Minimum Dose For Infection Initiation, And Interaction Of Temperature, Salinity And Infective Cell Dose, Fle Chu, Ak Volety

VIMS Articles

Experiments were conducted to: (1) test the response of oysters to different doses of the oyster parasite Perkinsus marinus and to 2 stages, meronts or prezoosporangia; and (2) investigate the synergistic effects of temperature, salinity and infective cell concentration on P. marinus infection in oysters. A dose-dependent response of P. marinus infection was found in oysters inoculated with 0, 10, 10(2), 10(4), and 10(5) meronts or prezoosporangia per oyster and maintained at 22 to 25 degrees C and 14 to 21 ppt for 8 to 12 wk. The minimum dose required to infect oysters was 10(2 ...