Science Serving Maryland's Coasts

R/WQ-3

Tracking the source of nutrients fueling brown tide blooms in Maryland

Principal Investigator: 

Patricia M. Glibert

Start/End Year: 

2005 to 2007

Institution: 

Horn Point Laboratory, University of Maryland Center for Environmental Science

Co-Principal investigator: 

Louis A. Codispoti, Horn Point Laboratory, University of Maryland Center for Environmental Science

Description: 

Objectives: The overall goal is to track the source of the anthropogenic organic nutrients that appear to be fueling brown tide blooms in the Coastal Bays. Our specific objectives are to: (1) Develop a small boat nutrient mapping system (year 1), and deploy it several times a year to resolve spatial gradients; (2) Deploy our suite of autonomous nutrient sensors to better resolve the timing of nutrient inputs, and their consumption and dissipation (year 2), and conduct these deployments in conjunction with MD DNR in situ water quality measurements; (3) Use the nutrient data and other measurements to resolve the source of these nutrients, their relationship with brown tide, and to recommend appropriate management strategies (Year 1 and 2). Methodology: Field surveys will be undertaken in the spring/summer by small boat each year. Nutrient fields will be resolved using a small mapping system, which will be developed under this project, and in situ nutrient monitors. To further resolve the source of the nutrients, we will also collect water column particulate samples for analysis of the stable isotopic composition of nitrogen; the isotopic signatures of sewage effluent and agricultural nutrients will differ. Deployments will be coordinated with MD DNR deployments of continuous monitors for salinity, oxygen, and temperature. Brown tide count will be made using the polyclonal technique. Rationale: Blooms of brown tide, Aureococcus anophagefferens, have occurred in the Coastal Bays and lower Chesapeake Bay for at least a decade. These blooms have been shown to have significant impacts on the ecosystem, including the growth of juvenile hard clams. These blooms appear to be fueled by the input of organic nutrients. In the past few years, we have developed new techniques for tracking these nutrients. Resolving the source of these nutrients will allow management strategies to be developed for their control.

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