Bacterioplankton Dynamics in the Patuxent River:
Response to Nitrogen Abatement
With the Chesapeake Bay Agreements of 1983 and 1987 calling for a 40-percent reduction in controllable nitrogen and phosphorus flow into the Bay, waste water treatment plants in particular have been retrofitted in order to reduce their nutrient outputs–most recently through the addition of biological nitrogen removal. Yet current assessments show that while nitrogen loadings to the Patuxent River are coming down, largely because of waste treatment upgrades, they are still high (in 1995, calculated to be five times what they were before Colonial settlement). Researcher Cynthia Gilmour and her team are using the Patuxent River, the Bay's sixth largest tributary, as a natural laboratory to study microbial changes in the river, as nutrients ultimately decline. Through a Sea Grant-funded biweekly testing program now in its fifth year, and coordinated with the Maryland Department of the Environment's Biomonitoring Program, Gilmour is tracking plankton and bacterioplankton dynamics to determine the effects of nutrient-reduction on the river. Some resurgence of underwater grasses in the lower Patuxent suggests improved water quality; however, only by analyzing the river's dynamic algal community will we be able to gauge the actual long-term effect of current nutrient-reduction strategies.
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1998-1999
Cynthia C. Gilmour
The Academy of Natural Sciences
Estuarine Research Center
1994-1997
Cynthia C. Gilmour and Douglas Capone
Chesapeake Biological Laboratory
University of Maryland Center for Environmental Science
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