Research Projects

We aim to convert an existing autonomous instrument for phosphate monitoring into an instrument for urea monitoring and integrate the effort with ongoing research to understand, detect and mitigate HABs in Maryland. This will require equipping the existing instrument with a colorimeter/heater in the 520-530 nM range with a higher temperature (~85 degrees vs 50 degrees) capability; optimizing existing urea determination and standardization protocols for interfacing with our instrument; testing the instrument in the laboratory; deploying the instrument in the field; posting the urea data on web sites; and describing our results to colleagues, environmental managers, and the public.

The aim of the proposed initiative is to continue our characterization of the infectivity and pathogenicity of recently described Perkinsus species for eastern oysters, relative to that of P. marinus. Our lab and others have identified and characterized new Perkinsus species and strains that maybe present in the eastern oyster. We are currently using molecular probes we developed and validated, for the assessment of epizootics in oysters and clams in the Chesapeake Bay and the northeastern coast of USA. Once the distribution of these Perkinsus species is revealed, it is critical to determine if they are equally capable to produce a "Dermo"-like disease.

The goal of this project is to develop and test a new approach to examine the degree to which methods used for mitigation and remediation of wetland and estuarine sediments reduce the transfer of contaminants to the environment. We will compare and contrast three proposed mitigation strategies: capping, phytoremediation, and marsh restoration using contaminated sediments.

Objectives: This grant seeks to test the hypothesis that small inlets and creeks along Chesapeake Bay tributaries act as 'reactor vessels' for gelatinous zooplankton species that can control much of plankton dynamics and survival of early life stages of summer breeding fishes in the mesohaline region of the Chesapeake Bay system. If the hypothesis is correct, exchange between these reactor vessels and the mainstem tributaries may strongly influence, and under some circumstances may even control, upper trophic level dynamics in Chesapeake Bay tributaries.

The primary objective is to test the robustness of key assumptions that underlie current invasive species risk assessments (i.e., demography of native populations predicts demographic behavior of populations in non-native locations). By investigating multiple populations of two marine invaders, Gemma gemma and Rhithropanopeus harrisii in their native and non-native regions, and then comparing these results to those of our current research on the marine invader Littorina saxatilis, we will compile important demographic data that are now lacking. These data can then be used to model population dynamics of the marine invasion process more explicitly than is possible now and will generate important information to enhance biologically based risk assessments.

Oysters have long been critical to the ecology of the Chesapeake Bay and the base of a valuable fishery. Although they have declined dramatically over the last 20-30 years due to a combination of harvesting and disease, major efforts are presently underway in Maryland by the Department of Natural Resources and the Oyster Recovery Partnership to reestablish oyster populations. Maryland harvests averaged 2.5 million bushels (bu) during much of the 20th century, but decreased to 80 thousand bu by the 1993-94 season. Subsequent harvests climbed above 400 thousand bu as recently as 1998-99, but with projections for the 2002-03 season of 50 thousand bu, and possibly less the following year, populations are clearly not recovering as expected.

This proposal continues and expands a project begun in 2000 involving the testing of a variety of technologies for ballast water treatment aboard a vessel in Baltimore Harbor owned by the U S. Maritime Administration. The focus of the current proposal is on combination technologies, specifically UV irradiation and biocide dosing (in series) of ballast water during a ballasting operation, primary filtration (using a depth filter & separator) used in tandem with UV irradiation and primary filtration, UV irradiation and biocide dosing used together.

This project addresses one of the priorities established by Maryland Sea Grant: the health of our coastal ecosystems, or more specifically, a physical-biological link between oyster reefs and seagrass habitats. Our objectives are: (1) quantify the impact of oyster reefs and breakwaters on wave attenuation and water clarity using a combination of numerical modeling and field studies; (2) evaluate the potential for oyster reefs to create suitable seagrass habitats using these same approaches; (3) develop a model that can be used by managers to help guide their seagrass and oyster restoration efforts; (4) educate managers and citizens about the importance of oyster reefs in maintaining water quality and seagrass habitat.

The basic objective of our proposed work is to quantify the effectiveness of deoxygenation in removing ballast water organisms while reducing ballast tank corrosion and to provide the information required to evaluate the feasibility of Venturi Oxygen Stripping as a cost-effective ballast water treatment. Specifically we proposed to:

• Quantify levels of mortality for planktonic organisms found in Chesapeake Bay (zooplankton, phytoplankton, and microbes) after treatment with the Venturi Oxygen Stripping system a function of time after exposure to hypoxia.
• Quantify corrosion rate of carbon steel under deoxygenated conditions and establish corrosion mechanism.

A synthesis effort is proposed to examine relationships among benthic community composition and biogeochemical function, and identify "keystone" species having disproportionate effects on benthic biogeochemistry and benthic-water column interactions. The objectives are: (1) To examine the quality of faunal data sources, and to sort and arrange the data in terms of ecological relationships and likely biogeochemical interactions; (2) To examine the quality of related biogeochemical data and evaluate the extent of overlap (e.g.

Several concrete objectives will be met by capitalizing on the ground work achieved with previous Sea Grant funding. The two years of funding requested here will allow (1 ) estimation of recruitment distance distributions around focal reefs planted with disease-tolerant DEBY strain oysters, (2) quantification of rates of interbreeding between DEBY strain oysters and wild background oysters, informing an analysis of introgression of genetic factors contributing to disease tolerance, and (3) quantification of inbreeding in DEBY strain broodstock as well as an analysis of the inbreeding effects of standard hatchery amplification for supplementation.

Compare the growth, disease acquisition, mortality and potential reef structure creation of sterile triploid Crassostrea ariakensis and sterile tripoid C. virginica at four sites in the Chesapeake Bay.

Lipofuscin (LF)-based age determination of blue crabs will be used to measure the rate at which juvenile blue crabs grow and recruit into Chesapeake Bay peeler and hard crab fisheries during summer and fall months. We seek to develop a temperature-based growth model for juvenile blue crabs and apply this model to predict monthly fishery yield patterns.

QPX is an emerging disease affecting cultured M. mercenaria from Atlantic Canada to Virginia. A suite of quantitative immunoassays will be carried out in order to understand the basis of the clams' susceptibility to this protistan parasite. Parameters of host defense such as pathogen recognition, inhibition of replication, and killing of QPX organisms by circulating blood cells and serum molecules will be measured.

The overall objective is to measure quantitatively the spatial and temporal patterns of coastal invasions. We propose to establish a national baseline of data that measure invasion attributes by location (including geographic region or latitude), taxonomic group, source region, vector, and date of arrival.

Lack of detailed knowledge regarding the spatial extent and character of Chesapeake Bay oyster habitat greatly hinders our ability to assess and effectively manage the resource. Oyster restoration activities are presently applied piecemeal, and are not scaled to the true size of the habitat. Population assessments and models lack the most basic information concerning area habitat quality, and antecedent geological controls that appear to govern the natural oyster bed location, evolution, and survival. We propose to develop GIS integrated remote acoustic survey techniques that will allow a more realistic assessment and quantification of oyster habitat. Principal to this system will be newly advanced Acoustic Seabed Classification Systems (ASCS) technology.

The main objective of this study is to generate expressed sequence tags (EST) data from single-pass sequencing of clones from P. marinus exposed to conditions that have been demonstrated to increase parasite virulence, such as high temperature, salinity, and iron levels. We will construct normalized P. marinus cDNA libraries using cultures grown under diverse physical factors (high temperature, salinity, iron) and biological factors (presence of oyster serum). EST sequences will be generated using two approaches (i) clones directly sequenced from the cDNA libraries, and (ii) clones sequenced from subtracted cDNA libraries using P. marinus grown in standard culture medium.

The overall objective is to explore how sediment quality and associated biogeochemical processes change with seagrass bed development and spatial distribution. We will investigate how these interactions affect bed sustainability and potential for successful SAV restoration. The project will also expand ongoing efforts to improve environmental science education by involving school teachers directly into our research.

We will quantify mortality rates of different sized C. ariakensis when exposed to the dominant predators in the mesohaline region of estuaries in the mid-Atlantic region. In concurrent studies we will measure the mortality of similarly sized eastern oyster C. virginica exposed to the same predators. By statistically comparing rates of mortality between the two species exposed to the same predators under identical conditions we will ascertain if natural predators can control feral populations of C ariakensis to the same degree as they control eastern oyster populations. We will use these data to inform managers charged with evaluating the possible consequences of the proposed introduction of a non-native oyster.

To develop a simple and generic treatment for inducing sterility in farmed fish, that is based on altering the migration pattern of GnRH neurons during early development using gamma-aminobutyric acid (GABA). The hybrid striped bass will be the studied model. This goal includes the following objectives: I. Study the early development of the GnRH and GABA systems and of the gonads. II. Study the effect of GABA and agonists on the establishment and expression of the GnRH system. III. Study the effect of GABA and agonists, and of altered GnRH development patterns, on gonadal development, associated endocrine factors and growth rate. IV. Optimize and scale up a GABA-based treatment for the induction of sterility in hybrid striped bass and other farmed species.

(1) To test the hypothesis that winter mortality of blue crabs is related to winter severity; (2) To determine mechanism(s) of winter mortality with respect to interactive effects of cold temperature, low salinity, size class, and nutritional condition; and (3) To incorporate the survival and growth functions with the winter dredge survey into spatially explicit and stage-based models of Chesapeake blue crab stock dynamics to improve fishery targets.

Our studies will focus on the impact of ambient sound on tilapia (Tilapia aurea), an aquaculturally important finfish species in Maryland and a good model of general teleost hearing capabilities. This will be accomplished by evaluating a suite of integrated endpoints in response to specific acoustical stress exposures. These endpoints include alterations in growth, hearing capabilities as determined using neurophysiological techniques, microanatomical pathology as assessed by electron microscopy, and changes in whole organism stress assessed by alterations in serum stress hormones and susceptibility to opportunistic pathogens.

The goal of the proposed project is to assist blue crab stakeholders to move beyond current controversy and conflict toward deliberations on co-management of fishery.

Submersed aquatic macrophytes (SAY) are a critical component of the Chesapeake Bay estuary ecosystem and have been targeted for restoration under the Chesapeake 2000 Agreement (C2K) to achieve historic (1930's) SAV distributions. While SAV restoration projects are currently underway in all parts of the Chesapeake Bay ranging from the freshwater upper reaches to seawater in the lower reaches, little is still known about effective strategies that enhance restoration success of SAV. The proposed research program would evaluate the success of past restoration projects and assess the effectiveness of planting diverse SAV communities to enhance restoration success throughout the Chesapeake Bay.

1. Characterization of 2-40 chitinosomes, including protein complement, genetic regulatory sequences, protein interaction domains and operon organization. 2. Elucidation of the organization and environmental applications of chitinosomes and chitinase-containing extracellular structures (ES).