Current Projects |
Recently Completed Projects |
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Current Projects
NOAA South Florida Program: Measuring and Modeling Nutrient Fluxes in Florida Bay
South Florida is undergoing continued environmental stress which has led to the widespread deterioration of estuarine and oceanic ecosystems throughout Florida Bay and the Everglades. The proposed restoration of freshwater, surface-flow through the Florida Everglades is expected to alter the forms, sources, and ratios of nutrient inputs to Florida Bay, especially dissolved inorganic and organic nitrogen (DIN and DON). The biological and chemical responses to such a dramatic alteration in nutrient inputs to Florida Bay are unknown. However, previous research in coastal oceans and estuaries have recognized that alterations in nitrogen cycling has the potential to promote selection and succession of phytoplankton species, change the distribution and magnitude of primary production and associated trophic levels, cause degradation of benthic habitats leading to mass mortality, and destroy recreational and commercial interests. The research undertaken herein focuses on the current ecological significance of DON and DIN cycling in Florida Bay, and the links between DON/DIN inputs from the Everglades watershed and the phytoplankton community structure in the Bay.
We have applying a multi-faceted approach in this project. Nutrient fluxes have been measured using both isotopic techniques and longer-term bioassays. In the current phase of the research we aim to 1) provide a practical application of our research for Everglades restoration efforts through incorporation of our results (measured parameters and nutrient rate constants) in ongoing modeling efforts to predict downstream impacts of alterations in nutrient availability and composition, and 2) further refine our current understanding of bulk dissolved organic matter (DOM) bioavailability in Florida Bay by applying new methodology (Electrospray Mass Spectrometry, ESI-MS) to the characterization of the DON pools and their bioavailability. We are particularly focused on the recent (2005-present) algal blooms in eastern Florida Bay.
This effort is a partnership between P. Glibert, Horn Point Laboratory, C. Heil, Florida Fish and Wildlife Research Institute, C. Madden, The South Florida Water Management District, and S. Seitzinger, Rutgers University.
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MERHAB: In situ monitoring nutrient monitoring and eutrophication-related blooms
The overarching objective of this effort is to develop and apply a “smart” monitoring system for nutrients and water quality that will ultimately improve prediction, and detection of eutrophication-related HABs. The overall approach is to deploy our in situ nutrient monitors and to couple these instruments with the in situ detection of chlorophyll and the automated collection of water samples that will allow us to more accurately identify the nutrient-bloom response.
Through this project and support from Maryland Sea Grant, we have also developed an in situ urea sensor.
This system was recently applied during a fish kill that occurred in the Corsica River, a tributary of Chesapeake Bay. Instruments were deployed on the dock of the Gunston Day School and students were involved in monitoring and in collection of calibration samples.
This project is a collaboration with L. Codispoti.
 
 
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NOAA Non-native Oyster Program: The Use of Non-Native Oysters in the Restoration of Chesapeake Bay Oyster Populations and the Potential Threats Posed by Harmful Algae
Introduction of the Asian oyster, Crassostrea ariakensis, to Chesapeake Bay is of considerable interest in the broader plans for Chesapeake Bay restoration. It is estimated that stocks of the native Chesapeake Bay oyster, Crassostrea virginica, now approximate 1% of their historical levels. Overfishing, loss of habitat and disease have been the major causes of the dramatic losses in native oysters Evidence is mounting, however, that harmful algae, particularly species common to the Chesapeake Bay also have detrimental impacts on oysters. There is strong evidence to date that some HABs common in Chesapeake Bay contribute to shellfish toxicity and/or mortality, induce physiological stress, inhibit oyster spawning, and reduce larval survival and settlement. Critical to the restoration of native oysters as well as the understanding of the potential threat to the introduction of Asian oysters to Chesapeake Bay is knowledge of the impact these common HABs may have on oyster growth, behavior and potential toxicity.
Our goal in this project is to compare the impacts of two common harmful algal bloom (HAB) species, Prorocentrum minimum and Karlodinium veneficum (formerly K. micrum) on Crassostrea ariakensis and C. virginica in terms of: 1) spawning success; 2) larval growth and survival when exposed to HABs; 3) larval settlement when exposed to HABs; and 4) the rate of spat growth. To date we have shown that adult oysters of both species had differential production of feces and pseudofeces upon exposure to these HABs, and the impacts of exposure also included damage to the oyster digestive system and reduced assimilation of co-occurring non-HAB species as well as of the HAB. We have also demonstrated acute toxicity of some HAB species on embryos/larvae.
This project is collaboration between D. Meritt, D. Stoecker and P. Glibert, Horn Point Laboratory, and makes use of the state of the art quarantine facilities in our Aquatic and Restoration Ecology Laboratory for studying non native oysters.
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Recently Completed Projects
Biocomplexity: Relating Diversity of Microorganisms
to Ecosystem Function
The goal of this project was to investigate the functional relationship between complexity in microbial communities and the biogeochemical cycles of natural ecosystems. Our study sites include the Chesapeake Bay, one of its branches, the Choptank River, and the open ocean of the Sargasso Sea, which is the major ocean basin into which water from the Chesapeake Bay flows. Gradients in the Chesapeake Bay, in terms of nutrient composition and physical forcing, provide an ideal site for investigating the relationships between nutrient processes and microbial biocomplexity.
We characterized the physical/chemical complexity of these systems in terms of chemical and hydrographical variables and related these parameters to the composition of the microbial community and the rates of biogeochemical processes. Our work focused on the measurements of rates of nitrogen uptake and release, and measurements of the activity of some of the enzymes that are involved in the assimilation of nitrogen.
This project is a collaboration among B. Ward, Princeton, P. Glibert, T. Kana, J. Cornwell, B. Boicort, Horn Point Laboratory, J. Collier, Stony Brook, J. Zehr, Santa Cruz, M. Voytek, USGS, and G. Jackson, Texas A&M.
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Maryland Sea Grant: Tracking the source of nutrients fueling brown tide blooms
The
overall goal of this proposal is to track the source of the
anthropogenic nutrients that appear to be fueling the brown tide blooms
in the Maryland Coastal Bays. These blooms have increased in magnitude
since the 1990’s, when records are first available. The increase
in bloom strength parallels the increase in total N, and particularly
dissolved organic N over the same period. We are developing a new
nutrient mapping system to supplement our in situ systems so that so that we can better resolve the spatial gradients in nutrient inputs supporting these blooms.
This project is a collaboration with L. Codispoti.
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