Biennially, Maryland Sea Grant issues a request for research proposals. Following are the current research projects supported by Maryland Sea Grant for February 1, 2009 to January 31, 2011 in these areas of concentration:
- Ecosystem Health and Function
- Coastal Resources
- Coastal Communities and Economic Opportunities
- Coastal & New Technologies (extended from 2005-2007)
- Water Quality (extended from 2005-2007)
- Aquatic Invasive Species (extended from 2005-2007)
- Oyster Disease Research (extended from 2005-2007)
Ecosystem Health and Function
Managing Prescribed Burns To Restore Tidal Marshes
Prescribed burns in the sustainable conservation and restoration of tidal marshes (R/EH-8)
PIs: Brian Needleman, Raymond R. Weil, University of Maryland College Park
Land managers in the Chesapeake Bay region use prescribed burns to stimulate plant growth in area marshes. This research project aims to improve understanding of how burns affect plant growth, with respect to variables such as nutrient availability, soil temperatures, and light. The researchers will conduct the project within a long-term prescribed burn study administered by the U.S. Fish and Wildlife Service at the Blackwater National Wildlife Refuge. They plan to measure how ash deposition and canopy removal influence plant growth prescribed burns. These data will provide insight for land managers on optimal burn frequency and strategies for how best to incorporate prescribed burns into marsh restoration efforts.
Controlling Algae Blooms to Promote Chesapeake Bay Restoration
Cyanobacterial Blooms: A Roadblock to Estuarine Restoration? (R/EH-9)
PIs : Diane Stoecker, Jeffrey C. Cornwell - University of Maryland Center for Environmental Science Horn Point Laboratory
Despite efforts to reduce algae-fueling phosphorus and nitrogen, blooms of blue-green algae, or cyanobacteria, occur in a number of tidal freshwater tributaries of the Chesapeake Bay. In this study, the researchers will explore what conditions promote the growth, persistence, and demise of the cyanobacteria Microcystis in the upper Sassafras River. Their specific objectives include: 1) examining the role of external nutrient loading on blooms, 2) the role of “internal” sources of nutrients in maintaining the bloom (e.g., sediment nutrient regeneration and pH-mediated phosphate release), and 3) the role of nutrient depletion and increasing salinity on of the breakdown of the bloom. While most studies occur after a bloom is evident, this study will examine the factors that trigger blooms, with the hope of targeting ways to avoid them.
Modeling Chincoteague Bay’s Response to Nitrogen Inputs and Climate Change
Forecasting the Response of Delmarva Lagoons to Changing Landuse and Climate: Alternative Stable States and Recovery Trajectories (R/P-59a)
PIs: Lora Harris, Walter Boynton, Chesapeake Biological Laboratory University of Maryland Center for Environmental Science, Mark Brush, Virginia Institute of Marine Science
Improving water quality, reducing algae blooms, and restoring underwater grasses in Chincoteague Bay and other lagoons on the Delmarva peninsula will require an understanding of how these systems respond to nitrogen inputs. This study will create an ecosystem model to explore the response of Chincoteague Bay to watershed nitrogen loading. Existing models that simulate the dynamics of eelgrass, benthic microalgae, phytoplankton, and macroalgae will be linked to show patterns under various nitrogen loading scenarios. The researchers will pay special attention to nitrogen cycling, feedbacks on light attenuation, and sedimentation processes mediated by underwater grasses. They hope a combined modeling and experimental approach will improve capacity to quantify the potential for non-linear recovery trajectories by considering nitrogen retention and cycling among sediments and primary producers.
Restoring Streams to Reduce Nitrogen Pollution
Investigation of stream restoration as a means of reducing nitrogen pollution from rapidly urbanizing coastal watersheds of Chesapeake Bay (R/EH-7)
PIs: Sujay Kaushal, Keith Eshleman, Robert Hilderbrand, Margaret Palmer University of Maryland Center for Environmental Science; Peter Groffman, Institute of Ecosystem Studies; Paul Mayer, US Environmental Protection Agency.
The Chesapeake Bay watershed encompasses one of the fastest growing regions of the United States. Rapid expansion of its urban centers has substantially increased nitrogen inputs to coastal waters, contributing to the overgrowth of algae (eutrophication), low oxygen (hypoxia), and harmful algal blooms. While nitrogen pollution from point and nonpoint sources have increased, the capacity of many suburban and urban streams to remove nitrogen has decreased.
This study will quantify the potential for stream restoration to improve nitrogen removal from rapidly urbanizing coastal watersheds, and identify which stream restoration features (e.g. armored pools and riffle sequences, oxbow ponds and riparian wetlands) work most effectively to remove nitrogen. Results will be integrated with a large restoration database containing information on the types, numbers, costs, and river miles of restoration projects to estimate how much nitrogen can be removed by stream restoration projects. These data will also help determine the most economical restoration strategies for nitrogen removal and estimate how many urban streams need to be restored to substantially reduce nitrogen loads to Chesapeake Bay and its tributaries.
Ecosystem-level Effects of Restoring Underwater Grasses
Quantifying ecological feedbacks and transition points for enhanced restoration of submerged aquatic vegetation (R/EH-6)
PIs: W. Michael Kemp, Laura Murray, University of Maryland Center for Environmental Science Horn Point Laboratory
Seagrass and other submerged aquatic vegetation (SAV) interact with their environment in a variety of ways. Many of these interactions create positive feedback loops whereby plant beds alter their local environment in ways that improve conditions for plant growth, especially water quality and sediment conditions. There is substantial evidence that seagrass beds amplify their own growth by increasing availability of light and nutrients, decreasing competition with algae, and decreasing exposure to toxins in the sediment.
Building on the work of two prior Maryland Sea Grant research projects, the objective of this project is to quantify and model ecological feedback effects in which underwater grass beds enhance water and sediment conditions across a range of scales to promote improved growth and survival of plants.
Using field sampling, GIS analysis, and simulation modeling, the researchers will investigate how different plant beds affect water quality and sediment conditions. This information will be used to examine how trends in bed size and density over time relate to variations in water quality and climate, and will better define what environmental conditions lead to abrupt changes in SAV density. Models will assist in developing effective SAV restoration strategies that capitalize on these positive feedback processes.
Understanding Harmful Algal Blooms (HABs)
Does cryptophyte abundance drive mixotrophic harmful algal blooms? K. veneficum as a model system (R/EH-5)
PIs: Allen R. Place, Jason E. Adolf, University of Maryland Biotechnology Institute Center of Marine Biotechnology (COMB)
Small algae called cryptophytes are a major component of the Chesapeake Bay phytoplankton community, yet their importance is poorly understood compared to other common phytoplankton such as diatoms and dinoflagellates. Cryptophytes can be an important nutrient source for mixotrophic algae — algae capable of getting energy from both photosynthesis and by consuming other organisms. Several mixotrophic algae species, including Karlodinium veneficum, have been blamed for Harmful Algal Blooms (HABs) in Chesapeake Bay, and many exhibit dramatic increases in growth rate (2-3 fold) when using cryptophytes as a food source.
The researchers on this project hypothesize that cryptophyte blooms drive blooms of other harmful algae. They suspect that monitoring cryptophyte abundance may improve our ability to predict HABs. Using field monitoring techniques they will observe the relationship in time and space between mixotrophic harmful algae (particularly K. veneficum) and cryptophytes in Chesapeake Bay. Then, using both these new and historical datasets, they will determine statistical relationships between the presence of cryptophytes and HABs.
Sea Nettles and the Bay’s Food Web
Reconstructing long-term patterns in sea nettle abundance and effects on the Chesapeake Bay food web (R/EH-4)
PI: Denise L. Breitburg, Smithsonian Environmental Research Center
Predicting potential benefits and unintended consequences of ecosystem restoration requires an understanding of history. As managers move towards a more holistic ecosystem-based approach to management, it becomes increasingly important to understand how dominant species and interactions within the Chesapeake Bay food web have changed over time.
This research project seeks to determine the pattern and magnitude of changes in abundance of sea nettles — dominant consumers of zooplankton — and to evaluate the effects of recent sea nettle decline on the Chesapeake Bay food web.
The researchers will reconstruct unpublished historical data on the abundance of sea nettles ( Chrysaora quinquecirrha) to learn how historical patterns in sea nettle abundance shaped the Bay’s food web. They will produce a publicly available electronic database that can be used as a foundation for future research and management efforts. The so-far unpublished data will provide a valuable understanding of how the structure and function of the Chesapeake Bay ecosystem has changed with respect to sea nettle abundance, and how abundance might change further under proposed Bay restoration actions.
Forecasting Rip Currents
Prediction of Rip Currents (R/EH-3) (extended from 2005-2007)
PI: Robert A. Dalrymple, Johns Hopkins University
Rip currents are the leading surf hazard for all beachgoers and account for the greatest percentage of ocean rescues by lifeguards each summer. As waves travel from deep to shallow water, they will break near the shoreline. When waves break strongly in some locations and weakly in others, this can cause circulation cells, which are seen as rip currents: narrow, fast–moving belts of water traveling offshore. By providing a simple theory–based methodology to predict the likelihood of these currents, people can be warned and lives saved.
This project aims to develop a simple method to predict rip currents based on theories, numerical modeling, and field observations. A system of cameras at Ocean City beaches monitors the water conditions to detect and observe rip currents as they form. This aspect of the project involves the cooperation and assistance of the Ocean City lifeguards to test the system and help gather data. Researchers completed a literature review that identified eleven different physical mechanisms involved in rip current formation. They have also developed a modeling approach to predict rip currents that relies on a system of equations known as Boussinesq wave models. Developed initially at the University of Delaware, the model is now up and running at Johns Hopkins University.
Preserving Submerged Aquatic Vegetation
Erosion, Suspended Solids and Submerged Aquatic Vegetation in the Little Choptank River (R/EH–2) (extended from 2005-2007)
PIs: Lawrence P. Sanford and Evamaria W. Koch, University of Maryland Center for Environmental Science Horn Point Laboratory; Jeffrey P. Halka, Department of Natural Resources Maryland Geological Survey
Once abundant in the Chesapeake Bay, submerged aquatic vegetation (SAV) provides protection and nursery habitat for a broad range of aquatic organisms, contributes to the oxygenation of the water, and prevents erosion and sedimentation. The Chesapeake 2000 Agreement, the strategic plan to achieve a vision for the future of the Chesapeake Bay, calls for the need to "characterize direct and indirect threats to SAV, including shoreline erosion and tidal resuspension, and develop and implement new best management practices and protection measures, as necessary." However, there are few data and only rudimentary models of these relationships. This project evaluates the extent of shoreline stabilization needed in order to protect adjacent SAV beds.
Specifically, this study investigates the relationship between waves, tides, shoreline erosion, nearshore turbidity, and SAV in a study of two sites in the lower Little Choptank River on Maryland's Eastern Shore. This project uses a combination of seasonal field surveys and modeling. Field surveys quantify the variation in time of hydrodynamic characteristics, shoreline erosion, sediment suspension, and SAV health. These data will then be used to expand and validate a model for the nearshore environment that links waves, shoreline erosion, total suspended solids, SAV, and light.
Understanding Blue Crab Recruitment
PIs: Elizabeth North, Michael R. Roman and William Boicourt, University of Maryland Center for Environmental Science Horn Point Laboratory
A symbolic icon of the region, the blue crab supports one of the largest inshore fisheries in the states of Delaware, Maryland, and Virginia. Sustainable management of this commercially and recreationally significant fishery depends on understanding the physical factors, such as freshwater flow, that affect the recruitment of crabs to Chesapeake and Delaware Bays. Information on recruitment variability will help managers make more informed decisions regarding the spawning stock size necessary to maintain sustainable blue crab harvest.
This project seeks to identify how physical and chemical conditions, such as freshwater flow, influence the transport of larval crabs (megalopae) into Chesapeake and Delaware estuaries. This information will be combined with monitoring data and numerical models to determine how differences in freshwater flow could affect patterns of blue crab recruitment from offshore to on–shore habitats. To date, one of two research cruises has been completed and modeling efforts are well underway. This study reflects a regional effort and combines the expertise of scientists in Maryland, Delaware, and Virginia, including the University of Maryland Center for Environmental Science, Old Dominion University in Norfolk, Virginia, and the University of Delaware.
Probing the Role of Genetic Diversity on the Resiliency of Striped Bass Populations
Intrapopulation Biodiversity, and Recruitment Pathways for Chesapeake Striped Bass (R/FISH-98 a)
PIs: Thomas Miller, Chesapeake Biological Laboratory University of Maryland Center for Environmental Science, Allen Place - Center of Marine Biotechnology, UMBI
Back from the brink after a fishing moratorium, striped bass tell a dramatic success story of species recovery. The researchers involved in this study believe the striped bass’ success relied on the diversity in age structure within the population. They think that biodiversity within populations is an overlooked, but central, factor in promoting population resiliency. To this end, using striped bass as a model, the researchers will employ traditional fisheries science approaches combined with state-of-the-art chemical analyses and molecular genetics to quantify the role of diversity in population resilience among spawning females and their offspring. As stress on living resources in the Chesapeake Bay and other coastal ecosystems increases, understanding how such intra-population variability contributes to sustainability and resiliency will prove key.
Insights on a Bay Icon: Understanding Blue Crab Life Processes
Large-scale blue crab recruitment limitation in upper Chesapeake Bay nurseries: Dispersal and post-settlement processes (R/FISH-99)
PIs: Eric Johnson, Denise L. Breitburg, Smithsonian Institute, Environmental Research Center
The persistent decline in the Chesapeake blue crab population correlates with reductions in spawning females and, as a result, limited numbers of juveniles. Variation in blue crab abundance throughout the Bay reflects differences in the number of juveniles that move into nursery habitats as well as processes affecting survival and growth once there. In this study, the researchers aim to develop a mechanistic understanding of blue crab recruitment, focusing on juvenile dispersal to nursery grounds in Maryland’s sub-estuaries and their survival and growth once there. The researchers will use field sampling and spatial modeling to gather information that can inform fishery managers’ efforts to restore blue crab stocks.
Understanding the Connection between Fish Habitats in Maryland’s Coastal Bays and Near Shore Ocean
Connectivity of Fish Nursery Habitats between Maryland’s Coastal Bays and Near Shore Ocean Environment (R/P-60)
PI: David Secor, University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory
Understanding how fish use interconnected ocean and coastal bay habitats may play an important role in managing fisheries. This study will rank relative nursery habitat values across estuarine (coastal bay), inlet, and nearshore ocean areas based upon the abundance of fish species. Using trawl surveys and food web analysis, the researchers will examine the level of connectivity between areas of nursery habitat. This study will help highlight the potential repercussions of mounting environmental stresses (e.g., shoreline development, beach nourishment, sea level rise, shoreline loss and modification, and dredging) on the ecological function of coastal bay and nearshore ocean nursery habitats.
Understanding Larval Transport of Offshore Fish into Chesapeake and Delaware Bays
Dynamics of ichthyoplankton ingress from the coastal ocean into Chesapeake and Delaware Bays: comparing spatiotemporal concordance and transport mechanisms (R/CR-4)
PIs: Elizabeth North and William Boicourt, University of Maryland Center for Environmental Science, Horn Point Laboratory; Timothy Targett and Richard Garvine, University of Delaware College of Marine Studies; Edward Houde, University of Maryland Center for Environmental Science Chesapeake Biological Laboratory; John Olney and John Brubaker, Virginia Institute of Marine Science
Fish that spawn offshore and then move as larvae to estuarine nursery areas — including Atlantic menhaden, Atlantic croaker, and American eel — support important components of commercial and recreational fisheries in the Chesapeake and Delaware Bays. But the mechanisms that control their influx into these systems are poorly understood. To address this issue, the Delaware, Maryland, and Virginia Sea Grant programs are coordinating research efforts to identify patterns in the timing and abundance of fish larvae (ichthyoplankton) that enter into Chesapeake and Delaware Bays from offshore waters.
Using a combination of sampling, research cruises, observing system data, and numerical models, the researchers seek to develop a clearer picture of processes influencing larval influx into each estuary for selected species (menhaden, croaker, and eel). Mechanisms supporting larval dispersion may differ between Chesapeake and Delaware Bays according to different physical conditions. The researchers will investigate these differences in an effort to understand coastwide population fluctuations in these fishes.
Genetic Diversity and Underwater Grasses
The role of genetic diversity in restoration success for Vallisneria americana in the Chesapeake Bay (R/CR-3)
PIs: Katharina Engelhardt, University of Maryland Center for Environmental Science Appalachian Laboratory; Maille Neel, University of Maryland College Park
The far-reaching consequences of the decline in submerged aquatic vegetation (SAV) in Chesapeake Bay have focused attention on restoration. Genetic diversity may enhance restoration success and long-term health of this important Bay resource.
This research project investigates the influence of genetic diversity on ecosystem function and restoration success for the SAV species Vallisneria americana. The researchers focus on V. americana because it was once a dominant species in the Chesapeake Bay and it may serve as a model species to understand the consequences of genetic diversity and SAV-community structure on restoration success in similar species in the Chesapeake Bay and beyond.
The researchers will evaluate patterns of genetic diversity in natural, restored, and cultured populations of Vallisneria americana; quantify relationships between genetic diversity, ecological characteristics, and restoration success; and culture and develop a genetically diverse supply of SAV propagules.
Fishing Impacts on Blue Crab Economics
Development of bioeconomic models for blue crabs in the Chesapeake Bay (R/CR–2) (extended from 2005-2007)
PIs: Thomas J. Miller and David B. Bunnell, University of Maryland Center for Environmental Science Chesapeake Biological Laboratory
Although now showing signs of stabilizing, since 1996 Chesapeake Bay blue crab populations have followed a downward trajectory that has reduced total landings and monetary value for commercial crabbers. Managers have recently instituted regulations to reduce fishing effort to protect the smaller spawning population, resulting in further economic hardship for the crabbers. This study focuses on the development of models that can reconcile biological and economic viewpoints by determining management strategies that maximize economic return while ensuring sustainable exploitation rates.
Specifically, the models developed as the result of this effort will reveal how changes in fishing effort influences the spawning potential, yield, revenue, and profit of the blue crab. Through a series of steps, these models will also define sustainable levels of fishing mortality that maximize the economic return for commercial crabbers and maximize annual profits by determining the optimal number of pots to fish. Model output can also help determine how many pots should be allocated to the soft–shell peeler and hard–shell fishery each week, for a given license type. So far, the study has found that exploitation fractions of soft–shell crab greater than 0.45 are not sustainable. But a three–fold increase in soft–shell harvest (from 10–30 percent) resulted in an $8.6 million increase in revenue (30 percent) for the fishery. Preliminary model results have also found that as the percent of the female harvest decrease, sustainable exploitation fractions increase, but will only lead to a marginal increase (1.4 percent) in revenue.
Water Quality Effects on White Perch
PI: David H. Secor, University of Maryland Center for Environmental Science Chesapeake Biological Laboratory
Living resources of the Chesapeake Bay experience effects caused by ecosystem–level changes in water quality. But since water quality parameters, such as temperature and dissolved oxygen, often interact in nonlinear ways, the effects of these changes on fish production, for example, are hard to measure. This project aims to enhance current bioenergetic models for the white perch, a dominant player in the Chesapeake Bay fish community, to provide information about how future changes in water quality might affect fish populations.
Specifically, this project will use laboratory experiments to test the interdependent effects of temperature, salinity, and dissolved oxygen on growth, food consumption, metabolism, and excretion rates (bioenergetics) for white perch juveniles. These observations will determine the parameters for a bioenergetic model, similar in structure to a model that the researcher has already developed for sturgeon. Mesocosm trials, that simulate real–life conditions as closely as possible, will help test the model. The researcher also plans to use 17 years of available water quality data to map and analyze past effects of water quality on the production of white perch and evaluate possible production scenarios with future changes in temperature and dissolved oxygen.
Coastal Communities and Economic Opportunities
Tools for Land Use Planning
Developing a decision support system for the Delmarva Peninsula – a tool to integrate alternative growth scenarios and environmental impact assessments into local land use planning (R/CE-2)
PIs: Glenn Moglen, University of Maryland Department of Civil and Environmental Engineering; Claire Jantz, Shippensburg University; Jim Reilly, Maryland Department of Planning
Since 2001, the Delmarva Peninsula has been one of the fastest growing regions within the Chesapeake Bay watershed. Such growth, if poorly planned, can lead to forest conversion and fragmentation, water quality degradation, loss of aquatic habitat, and other social and environmental impacts.
This project will provide local governments in the Delmarva Peninsula with an easy-to-use, free, web-enabled Decision Support System (DSS) that will allow managers to visualize where future growth could occur under various scenarios; to estimate water quality, stream flow, and biodiversity implications of each of these scenarios; and to develop and test alternative land development scenarios that meet local growth and water quality goals. The objective of this project is to enable local planners to use these tools to inform discussion regarding revisions to land use plans and zoning ordinances.
The researchers will model future development patterns for the Delmarva Peninsula using two models – GAMe and SLEUTH. GAMe is a growth model, which takes regional forecasts and assigns them to smaller, municipal-scale units. SLEUTH takes the municipal-scale trend and alternative growth forecasts (numbers) produced by GAMe and produces GIS maps detailing where growth is likely to occur in each locale. The resulting GIS maps will be embedded into GISHydro, a web-enabled GIS application, to evaluate the impacts of different land use change scenarios on water quality and stream biodiversity.
Helping Communities Confront Change
Visioning for sustaining rural communities on Maryland's eastern shore (R/CE–1) (extended from 2005-2007)
PIs: Wayne H. Bell and Wendy G. Miller, Washington College; Philip G. Favero, University of Maryland College Park
As coastal Maryland faces unprecedented population growth and development in the 21st century, rural coastal communities are confronting powerful social, political, and economic drivers, many of which are threatening the integrity of their working landscapes, eroding their sense of place, and degrading the quality of their environment. This project aims to help communities participate in visioning their future and understand how these forces of change can provide opportunities rather than threats for sustainable development.
Specifically, researchers will develop a CD–ROM and internet–based "Sustainability Tool Kit" of information on leadership methods and user–friendly Geographic Information System (GIS) resources to enable community visioning exercises. They will also provide hands–on educational opportunities through internships for Washington College undergraduate students. Researchers assembled information about forces for change at three levels of scale: unincorporated municipality (Jonestown, Caroline County), incorporated municipality (Chestertown, Kent County), and countywide (Caroline and Talbot Counties) and are assisting each of these entities with a visioning exercise to develop proactive rather than reactive responses to change. Among other milestones, the project has already seen the completion of seven "growth summit" meetings involving county commissioners and elected officials from municipalities in Caroline County, resulting in the development of a strategic plan: "Caroline County – The Quintessential Rural Place."
Development of a New Wetland Monitoring Tool
Hyperspectral Reflectance of Freshwater Tidal Emergent Macrophytes as a Remote Sensing Tool for Assessing Wetland Nitrogen Status (R/CT-02) (extended from 2005-2007)
PIs: David R. Tilley and Andrew Baldwin, University of Maryland College Park
This study adapts models for relating plant reflectance indices to wetland ammonia concentrations to field-scale canopy reflectance measurements of freshwater tidal marsh plant communities. The researchers will design, build, and test a boat-borne platform for rapidly collecting canopy hyperspectral reflectance of marshes, which can be used to quantify marsh nitrogen status. The researchers will then demonstrate the technology to state agencies for consideration as a wetland monitoring tool.
How Do “Buried Streams” Affect Nitrogen Inputs to the Bay?
Investigating impacts of headwater stream burial during development on downstream nutrient export to Chesapeake Bay (R/WS-1a)
PIs: Andrew Elmore, University of Maryland Center for Environmental Science Appalachian Laboratory, Sujay Kaushal, University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory
Coastal development threatens the ecological services, such as habitat, shading, and nutrient uptake provided by headwater streams particularly as streams are “buried” (paved over stream channels, streams in culverts, and stormwater drains). Using field studies, mapping, and modeling, this project will investigate three questions related to buried streams and their impact on the Chesapeake Bay: 1) Where are the headwater streams in Maryland? 2) What is the present extent of stream burial as a function of urban land use change? 3) What is the effect of stream burial on ecosystem functions and nitrogen export to coastal receiving waters? Results from the study should help managers prioritize locations for stream conservation and restoration efforts.
Resolving Nutrient–Brown Tide Connections
Tracking the source of nutrients fueling brown tide blooms in Maryland (R/WQ–3) (extended from 2005-2007)
PIs: Patricia M. Glibert and Louis A. Codispoti, University Of Maryland Center For Environmental Science Horn Point Laboratory
Blooms of brown tide, Aureococcus anophagefferens, have occurred in the Coastal Bays and lower Chesapeake Bay for at least a decade. These blooms have significant impacts on the ecosystem, including a negative effect on the growth of juvenile hard clams. Brown tide blooms appear to be fueled by the input of organic nutrients. The goal of this study is to track the source of the anthropogenic organic nutrients that appear to be fueling brown tide blooms in the Coastal Bays in order to develop effective management strategies.
Specifically, the researchers will develop a small boat nutrient mapping system and will use their previously developed suite of autonomous nutrient sensors to better resolve the timing of nutrient inputs, their consumption, and dissipation. So far, researchers have analyzed a nearly two–decade record (1987–2004) of nutrients and phytoplankton biomass and composition for one location in the Coastal Bays of Maryland. They have found that both the long–term increases in chlorophyll a and the abundance of brown tide strongly correlate with increases in dissolved organic nitrogen concentration. These results demonstrate that long–term changes in nutrient quantity and composition have occurred in the Coastal Bays during the past decade, and that total phytoplankton biomass, as well as the proliferation of brown tide, are related to these changes. Whether or not these changes are evidence of a long–term trajectory, or whether they represent a short–term anomaly, will be revealed in future monitoring.
Linking Algae Blooms to Fish Recruitment
Primary production, spring blooms and control of recruitment in pelagic fish (R/WQ–2) (extended from 2005-2007)
PIs: Edward D. Houde, University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory; Lawrence W. Harding, Jr, University of Maryland Center for Environmental Science Horn Point Laboratory
Over the past few decades, primary productivity in the Chesapeake Bay has increased and the estuary has become increasingly algae–dominated (eutrophic). Recruitment levels of the bay anchovy, a key forage fish for striped bass, weakfish, and bluefish, has declined from two to five–fold in concert with increasing eutrophication. However, no study has yet shown a causative linkage between the dynamics of algal blooms and declining recruitment rates of bay anchovy, information that would be valuable to fishery and resource managers.
Specifically, this study aims to determine if bay anchovy recruitment levels in the Chesapeake Bay relate to the timing, intensity, spatial pattern, or quality of algal blooms — as measured by remotely sensed aircraft data. Researchers will develop statistical models to describe, hindcast, and potentially forecast bay anchovy recruitment. Additionally, this study will evaluate how the growth and mortality of young bay anchovy relate to algal bloom dynamics and determine whether the carrying capacity of the Bay for the production of bay anchovy depends on primary production associated with algal blooms. Preliminary results, suggest that there is no strong relationship between bay anchovy recruitment and primary productivity, measured by levels of chlorophyll (chl–a) and by a metric for primary producers known as annual integrated production (AIP). Researchers anticipate, however, that lagged effects and complex interactions among environmental variables may link bay anchovy recruitment to primary production.
Predicting Restoration Impacts on Water Quality
Predicting the Restoration Trajectory and Water Quality Value of Benthic Microalgae in Shallow Water Chesapeake Sediments (R/WQ–1) (extended from 2005-2007)
PIs: Jeffrey C. Cornwell and Todd Kana, University of Maryland Center for Environmental Science Horn Point Laboratory
Restoring the Bay to a state that more closely resembles the Chesapeake of years past implies a return to a system dominated by benthic (bottom–dwelling) plants and animals. Nutrient reduction efforts, combined with a potential increase in oyster grazing, should increase the extent of illuminated sediments. Such sediments are conducive to the growth of benthic microalgae and, in turn, help to sequester nutrients. The goal of this study is to estimate the impact of Bay restoration efforts on shallow water sediments and to assess the importance of benthic algae in a whole system context.
Specifically, researchers are measuring the rates of primary production and nutrient retention by benthic microalgae in the northern Chesapeake Bay to provide data to the modeling community — with the hope of improving predictions related to shallow water processes. Preliminary results show that benthic microalgal production is high in shallow water but tapers off quickly with a decrease in light. Additionally, there is a large seasonal signal as the amount of illuminated habitat changes. Researchers are observing high winter benthic microalgal photosynthetic rates and biomass when phytoplankton photosynthesis is low. This suggests that benthic microalgae are light, not nutrient, limited, and that the efficacy of restoration strategies hinges upon increasing the extent of available illuminated habitat.
Aquatic Invasive Species
Environmental Implications of Ballast Water Treatment
Chronic Toxicity Testing to Determine the Environmental Risks of Proposed Ballast Water Treatment Biocides (R/IS-20) (extended from 2005-2007)
PIs: Carys L. Michelmore and David A. Wright, University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory
Many options are being considered for the control of invasive aquatic species in ship's ballast water. Control measures must be effective, affordable, safe, and environmentally benign. Chemical biocides show perhaps the best promise at satisfying the first three criteria. However residual toxicity of the compounds has yet to be fully investigated. Since similar chemicals have been implicated as endocrine disruptors in the past, the potential for these chemicals to have similar implications will be investigated. Until lower-effects thresholds are determined, a proper risk assessment of these compounds cannot be completed.
The researchers are investigating the chronic sub-lethal toxicities of three quinone compounds in order to characterize the environmental threat that their discharge might pose to non-target organisms if used as ballast treatment biocides. The data generated will be made available for future risk assessment models of biocide-treated ballast water discharge.
Invasive Species in the Tropics
Aquatic Invasive Species Research: Invasive Species in Key Tropical U.S. Ports- Extending Standardized Surveys for Islands and Continents (R/IS-19) (extended from 2005-2007)
PIs: Anson H. Hines and Gregory M. Ruiz, Smithsonian Environmental Research Center
Despite numerous documented invasions of tropical marine systems, the perception that lower latitudes are less susceptible to invasions may result in part from reduced sampling effort and our poor taxonomic grasp of high native biodiversity in these systems. Tropical systems urgently need more study with standard surveys to test hypotheses and to predict risk of invasion. We will focus on fouling and wood-boring communities because fouling organisms comprise more than 180 species of approximately 300 non-native marine invertebrate species in North America and Hawai'i. These have large economic impacts on ships and in coastal waters. Many of the invasions derive from transfer in ballast water or on hull surfaces.
The researchers will focus on tropical and subtropical sites that are of particular importance to U.S. trade interests and that are strategically positioned for biogeographic considerations. Their research hypotheses include: (1) Number of invasive species increases, or conversely decreases, with decreasing latitude and increasing native diversity, i.e., tropical, high diversity ports are more or less at risk of biological invasion than temperate, lower diversity sites; (2) Number and proportion of invasive species is greater in island than continental ecosystems; (3) Rate of spread of invasive species among sites is related to life history characteristics; (4) Rate of new invasions is associated with vectors transporting species (e.g., shipping) and will decline with management efforts (e.g., ballast water exchange); (5) Invasive species do not respond to the same biogeographic boundaries in invaded regions as the native species present.
Deoxygenating Ballast Water to Prevent Transfer of Invasive Species
Ballast Water Technology Demonstration Program (Shipboard Evaluations of Venturi Oxygen Stripping: Determining Mechanical and Biological Efficacy) (R/IS-18) (extended from 2005-2007)
PI: Mario M. Tamburri, University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory
This research project involves a real-world evaluation of Venturi Oxygen Stripping (VOS) — a process by which oxygen is removed from ballast water to reduce the survival of organisms (including aquatic invasive species). The researchers will first install VOS systems onboard vessels and verify their operation and ability to produce the intended conditions. Next, they will test the ability of VOS to reduce concentrations of living ballast water organisms during normal vessel operations, to meet draft International Maritime Organization (IMO) standards.
Patterns of Invasive Species
Quantitative Analysis Of Spatial Patterns Of Marine Invasions For North America: Establishing A National Baseline And Database (R/IS-17) (extended from 2005-2007)
PIs: Gregory M. Ruiz and Jeffrey A. Crooks, Smithsonian Environmental Research Center
We currently lack the necessary data to rigorously evaluate space and time patterns of marine invasions. This foundation of basic knowledge is of paramount importance to identify the relative importance of different transfer mechanisms that are driving contemporary invasions, to develop effective management strategies to reduce risk of invasions, and to evaluate the effect of management actions (e.g., ballast water exchange) on invasions. There is also a critical need for synthesis, access, and analysis of such data. This research project will develop baseline data on marine invasions throughout North America and provide access to these data through a web-based information system.
Transporting Invasive Species
Presence, Dynamics, and Fate of Pathogenic Microorganisms in Ballast Water and Ballast Water Microcosms (R/IS-16) (extended from 2005-2007)
PIs: A. Whitman Miller and Gregory M. Ruiz, Smithsonian Environmental Research Center
Oyster Disease Research Program
How Does Water Quality Influence the Eastern Oyster’s Susceptibility to Dermo Disease?
Effects of diel cycling hypoxia on acquisition and progression of Perkinsus marinus (R/ODR-30)
PI: Denise Breitburg, Smithsonian Environmental Research Center
Despite a rich body of literature, much remains unclear about the link between water quality and fisheries in the Chesapeake Bay. A better understanding of this relationship will prove critical to improving the health and sustainability of fisheries and water quality –– an important step toward ecosystem-based management in the Bay.
Using field and laboratory experiments, researchers will test the relationship between low oxygen (hypoxia) in shallow waters within Chesapeake Bay and the rate of infection with Perkinsus marinus — the parasite that causes Dermo, the disease blamed for devastating oyster populations throughout the Bay. Specifically, the researchers will examine: 1) the effect of 24-hour cycles of hypoxia in shallow waters on the acquisition and progression of Dermo infections in Eastern oysters, and 2) how the interactive effects of varying hypoxia and Dermo infections influence oyster mortality and growth. Results will provide an important basis for targeting locations for water quality and oyster restoration efforts.
A Study of Disease-Resistant Oyster Strains
Genetic Rehabilitation And Conservation Of Chesapeake Oysters Using Disease-Resistant Oyster Strains: A Study Of Their Recruitment And Introgression Potential (R/ODR-25) (extended from 2005-2007)
PIs: Matthew P. Hare, University of Maryland College Park; Mark Luckenbach, Kimberly S. Reece and Ryan Carnegie, Virginia Institute of Marine Science
This project seeks to estimate the recruitment distance distributions around focal reefs planted with disease-tolerant DEBY strain oysters. It will also quantify the rates of interbreeding between disease-tolerant DEBY strain oysters and wild background oysters, to inform an analysis of genetic factors contributing to disease tolerance. Finally, it will analyze inbreeding in DEBY strain broodstock.
Genetics of Dermo Disease
Identification Of Candidate Genes For Chemotherapeutic and/or Genetic Intervention Against Dermo Disease Using Expression Sequence Tags (EST) (R/ODR-24) (extended from 2005-2007)
PIs: Gerardo R. Vasta, Jose A. Fernandez-Robledo and Eric J. Schott, University of Maryland Center of Marine Biotechnology
The main objective of this study is to generate genetic data from clones of 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). Expression Sequence Tag data will be generated using two approaches: (1) clones directly sequenced from the cDNA libraries, and (2) clones sequenced from subtracted cDNA libraries using P. marinus grown in standard culture medium
The characterization of the expressed genome (ESTs) may result in the identification of suitable targets for genetic intervention.
The Dynamics of Dermo Disease Transfer
Performance Of Genetically Improved CROSBreed Oysters and Disease-Resistant Delaware Bay Oysters (DEBYs) Planted At Three Salinity Regimes In A Dermo Disease Enzootic Chesapeake Bay Oyster Recovery Area (R/ODR-23 A) (extended from 2005-2007)
PIs: George R. Abbe, Morgan State University; Christopher F. Dungan, Maryland Department of Natural Resources
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 during much of the 20th century, but decreased to 80 thousand bushels by the 1993-94 season. Subsequent harvests climbed above 400 thousand bushels as recently as 1998-99, but populations are clearly not recovering as expected. Recent efforts to increase population size have tried to manage around disease by planting disease-free oysters in lower salinity areas that are less prone to disease pressures. However, after 3 years of drought, former lower-salinity areas are now 4-6 ppt above their normal ranges.
Ongoing work funded by the National Sea Grant Oyster Disease Program in Maryland's Patuxent River, has shown that during drought conditions, initial SPF (specific-pathogen-free) oysters grew faster at the two higher-salinity sites, but survival was only 2-3% after 2 years. At the up-river site, survival was only slightly better. These survival rates are not acceptable for reestablishing oyster populations. To determine if disease transmission rates, growth, and survival can be improved by the use of disease-resistant seed oysters, the researchers will compare the dynamics of Dermo disease transmission in generic and disease-resistant strains of oyster spat planted at three sites with different salinites where dermo disease is present.
Potential New Strains of Dermo Oyster Disease
Infectivity and pathogenecity of recently described Perkinsus species present in the Eastern Oyster Crassostrea virginica (R/ODR-22) (extended from 2005-2007)
PIs: Gerardo R. Vasta and Jose A. Fernandez-Robledo, University of Maryland Center of Marine Biotechnology
The aim of this project is to continue the characterization of the infectivity and pathogenicity of newly identified Perkinsus species for eastern oysters, relative to that of Perkinsus marinus.P. marinus causes Dermo disease in oysters.
The researchers have identified and characterized new Perkinsusspecies and strains that may be present in the Eastern oyster. Using molecular probes they will look for these strains in oysters and clams in Chesapeake Bay and the northeastern coast of USA. Once the distribution of these Perkinsus species is revealed, they will determine if they are equally capable of producing a "Dermo-like" disease. Field and laboratory observations suggest that not all Perkinsus species are equally pathogenic for the host. This information is critical for the decision-making process concerning oyster seed and marketable stocks for both oyster farmers and regulatory agencies.
Comparison of a Non-native Asian Oyster to the Native Eastern Oyster
Characterizing the performance of the Suminoe Oyster, Crassostrea ariakensis, in Maryland waters (R/ODR-21) (extended from 2005-2007)
PIs: Kennedy T. Paynter, Jr., University of Maryland Center for Environmental Science Chesapeake Biological Laboratory; Donald Meritt, University of Maryland Center for Environmental Science Horn Point Laboratory; and Standish Allen, Virginia Institute of Marine Science
This study will 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.