Research Projects

This project examines the meaning of restoration in the Chesapeake Bay by exploring the human relationships with the Bay that have been threatened or disrupted by industrial and commercial development. Utilizing the concept of "place," it will provide framework for understanding restoration in cultural and psychological, as well as biological and economic terms. The project will elicit contemporary visions of restoration through focus groups comprised of Bay area residents, workers, users, activists, and policy makers, and will investigate historical and literary accounts of the Bay to place contemporary views in a broader context.

Collect fry or fingerlings from five different strains of striped bass and rear to a suitable size for tank culture. Compare between and among production performance of the different strains for 24 months in a recirculating and flow-through system. Track performance on a monthly basis of each separate strain and family. Compare growth, survival, FCR, and dress-out percentages of the five strains and families in the different systems. Determine the fastest growing, best adapted strain for between-family selection potential.

To identify genetic differences among geographically separate C. virginica populations. To correlate genetic differences or markers among those populations with differences in disease susceptibility or resistance.

We plan to apply the methodologies developed from our current NMFS-funded project for mtDNA markers, DNA fingerprinting, RNA probes and PCR technologies to quantify low-levels of Perkinsus marinus infections in order to fully describe the etiology of this oyster disease. Our progress in working with genetic markers of P. marinus has: Developed a sensitive PCR-based diagnostic assay for detecting P. marinus infections ; Identified an extrachromosomal relic plastid-genome in P. marinus that is indicative of this species' close affinity to dinoflagellates and a photosynthetic ancestor; Described two ribosomal RNA genes that have been used in a phylogenetic reconstruction of the ancestral lineages of P. marinus ; Quantified tissue-specific P.

To implement the most successful of several recent wind-wave computer models (currently being tested in a limited region of upper Chesapeake Bay) for the entire Bay; to gather a suite of wind and wave observations in northern Chesapeake Bay during different seasons and at different locations, both for the intrinsic value of the wave data and for comparison to and calibration of the model(s); to generate a model data base of general wave climatology and predicted responses to specific events; to develop a graphically oriented data base front end for other interested scientists and managers, in order to allow them to explore the surface wave climate of the northern Bay without having to implement or run the wave model.

The overall objective of the proposed research is to understand the endocrine mechanism regulating the onset of puberty in fish, using striped bass as a model, with a view towards developing techniques for accelerating or inhibiting puberty in farmed fish. This objective will be obtained through the following steps: study the ontogeny of the brain-pituitary gonadal (BPG) function prior to and throughout puberty study the ontogeny of the responsiveness of BPG axis to exogenous hormones induction of advanced (precocious) complete gametogenesis leading to spawning of good-quality eggs.

To develop radioimmunoassays (RIAS) for the measurement of the striped and white bass major reproductive hormones, the gonadotropins (GtH-I&II). To enable monitoring GtH levels in striped and white bass broodfish exposed to environmental or hormonal manipulations. To use a novel recombinant DNA approach for expressing immunoactive GtHs and for developing RIAs for fish gonadotropins.

We propose to examine how dissolved oxygen concentrations and the spatial patterning of dissolved oxygen, water temperature and predation and prey abundances interact to affect the consumption, growth, production and recruitment of important fishes in the Chesapeake Bay. Research will focus on key piscivores (striped bass, bluefish, weakfish) and planktivores (Atlantic menhaden, bay anchovy). Spatially-explicit models will be used to compare patterns of growth and consumption relative to changes in habitat structure, prey abundances and spatial heterogeneity in the environment. Model simulations will address specific management questions dealing with the interrelationships of fish production and water quality.

Funds are requested to develop and implement advanced chemical process modeling and control techniques on two activated sludge wastewater treatment facilities. In the first phase of the project, it is proposed to complete this prototype development at the Patuxent facility in Crofton, MD, i.e., a model will be extended to the full range of normal process conditions, and an improved control strategy will be evaluated. The improvements in effluent product quality and reductions in operating costs will be measured. In the second phase, it is proposed to apply the same modeling tool to a quality control problem at the Maryland City facility in Laurel, MD. The outcome will be a monitoring procedure that should improve effluent quality. These improvements will be measured.

The objective of this program is to assess the extent and degree that metals impact the picoplankton in Chesapeake Bay and selected tributaries. This objective includes isolation and cloning of the gene encoding metallothionein (MY) from representative marine cyanobacteria (Synechococcus spp.). The cloned genes will be used as probes to examine variations in transcription rates in natural populations isolated from the lower Bay, Elizabeth River and James River. The goal of this program is to apply the newest molecular biological techniques to the problem of determining how metal stress impacts the Chesapeake Bay ecosystem.

Specific objectives will be to map the usage patterns of Dimilin in the northeast Chesapeake Bay catchment area, and monitor Dimilin run-off at two field sites. Bioassay results from two crustacean species at these field sites will be compared with bioassay data from a (Dimilin-free) reference site. End points from these and laboratory bioassays will characterize the role of food in Dimilin bioavailability and will form the basis of hazard assessment for this compound's specific mode of action. Chemical application, run-off and toxicity data will be combined as a model risk assessment for non-point source pesticide run-off.

The objectives of this project are to develop scientifically-based risk assessment methods applicable to the testing of transgenic marine organisms in the open marine environment, appraise the need to adopt new or improved regulations based on new risk assessment methods, and estimate the costs that research institutions and industry will have to bear to meet these new or improved regulations.

This project will determine the susceptibility of the Chesapeake Bay to the invasion of exotic species released daily in huge volumes of commercial ballast water. We propose: to determine the viability of life history stages of exotic species released into the bay from ballast tanks of cargo vessels; to measure the interactive influence of environmental salinity and temperature on the survivorship and growth of organisms collected from ballast water; to estimate the likelihood that exotic propagules, released into Chesapeake Bay can survive under the environmental conditions of the Bay at the time of deballasting; and to test whether introductions of non-native species are occurring at areas of high commercial maritime activity.

To look for changes in heterotrophic bacterioplankton production, biomass and C cycling in the Patuxent River as point source N loadings to the river decline. To examine the limitations on pelagic bacterial production. To use the information collected from this research project in conjunction with other studies of C and nutrient cycling the Patuxent to work toward a C budget for the Patuxent. We will extend our baseline studies of N & P cycling in the river through the current period of sharp reduction of N inputs. In addition to determining changes in bulk water characteristics, we will specifically examine the relative importance of planktonic heterotrophs, relative to autotrophs, in the uptake and regeneration of N & P as a function of season and site in the river.

The main objective is to test the hypothesis that pollutant stress may predispose aquatic organisms to infectious diseases or accelerate the progression of the disease. The host-parasite system proposed is Crassostrea virginica - Perkinsus marinus; the environmental toxicants under study will include a lower MW polycyclic aromatic hydrocarbon (naphthalene) and tributyltin. An attempt will be made to associate pollutant-induced changes in disease progression to changes in cell-mediated immune function.

To use microcosm studies to measure the availability, the rate of uptake, trophic transfer, and the toxicity of toxic trace elements released from contaminated sediments to representative benthic species.

The objective of the proposed research is to use ocean color data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) to determine the distribution of chlorophyll in the Chesapeake Bay and adjacent coastal waters. This work will concentrate on the development of Case 2 pigment algorithms for estuarine and coastal waters, development of a long-term climatology for the Bay, and integration of satellite, aircraft, and shipboard data into a geographic information system (GIS) for geographic data base development, graphical display, and spatial modeling using UNIX ARC/INFO.

To synthesize available contaminants data and use simulation modeling techniques to integrate existing information and explore processes that control exposure, transfer, and accumulation of contaminants in biota in Baltimore Harbor. Also, to explore how the dynamics of the carbon flow in Baltimore Harbor affects the cycling of toxic organic contaminants in the water column biota and their eventual, delivery to the sediments.

1. Test biomagnification of Cu and Cd by microbial biofilms. Test set of Crassostrea virginica and C. gigas on biofilms exposed to Cu and Cd. Test toxicity of Cu ancl Cd for C. virginica and C. gigas.

This project will: assess historical changes in the Blackwater River watershed on Maryland's Eastern shore for the period from 1850 to the present by creating a GIS data base of these changes; create a process based, spatially explicit ecological economic simulation model to help explain these historical changes; and project future changes under various management and climate scenarios using the model.

To examine the behavioral repertoire of the introduced quagga mussel to determine if some advantage can be taken of this knowledge to avoid fouling of industrial water delivery systems. The objectives in Year 1 are to refine culture protocols for the rearing of quagga mussel larvae. Study swimming behavior of quagga mussel larvae in relation to gravity, temperature, salinity, and dissolved oxygen. The objectives in Year 2 are to complete study of swimming behavior. Study settlement behavior of quagga mussel pediveligers in relation to light and substrate orientation.

The general goal of this program is to develop new chemical models for pharmaceutical and agrochemical agents from marine natural products. To accomplish this, we propose to collect, extract and screen marine macro- and microorganisms in a battery of pharmacological and agrochemical screens. Active constituents of the extracts will be isolated and their structures identified.

We will investigate temperature/salinity tolerance for larvae of the freshwater bivalve mollusc Dreissena polymorpha using a temperature/salinity matrix which encompasses the northern Chesapeake Bay during the spawning season. Results of survival and growth observations will be entered in a stepwise multiple regression equation which will be used to generate predictive response surfaces relating growth and survival to salinity/temperature combinations. Investigations will also be made into the contributions made by individual electrolytes to salinity stress in Dreissena larvae. A comprehensive study will also be made of the sodium regulatory mechanism in Dreissena larvae.

The objective of the proposed study is to test the hypothesis that planktonic and benthic trophic dynamics and benthic-pelagic coupling control the speciation, transport, bioavailability, bioaccumulation and toxic effects for synthetic organic contaminants in Chesapeake Bay. We propose to develop a numerical simulation model of the key ecological processes: to integrate data collected by various investigators in the Bay region; to test hypothesis about interactions between trophic dynamics and contaminant fate/effects; and to provide information needed for Ecological Risk Assessment.

To use microcosm studies to measure the availability and the rate of uptake of toxic trace elements released from contaminated sediments, by natural estuarine communities and the effect of these compounds on the lower trophic levels.