Eutrophication in Chesapeake Bay Mr. Bijesh Mishra Graduate Student Environment Science and Bioremediation (ENV 595) College of Agriculture, Food Science, and Sustainable Systems Kentucky State University (KYSU)

Chesapeake Bay Largest estuary with 64,000 Sq Miles area. Receives discharges from six states of USA [Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia and The District of Columbia.] 17 Million people More than 250 fish species More than 300 migratory birds. Watershed Area: 116,000 Km 2 Water surface: 11,5000 Km 2 Land use: 28% Agriculture and 58% Forest.

Eutrophication in Chesapeake Bay: History Initial evidence of organic enrichment: around 200 years ago. Increase in phytoplankton and decrease of water clarity: 170 Yr. ago. Process started: more than 2500 Yrs ago since human intervention.

Trends in Watershed Activities and Nutrient Loadings: Initially, Landscape was covered by temperate forest. (four century ago). Migration of human population to the Bay areas leads to increase in urban areas and agriculture land whereas the forest areas decreases. (Mid 1800s). In last two centuries urban land has expanded reducing agriculture land and gradual increase in forest lands. Increase pressure in watersheds because of human activities are the major factor contributing to increased nutrient loading to estuaries. Current estimate of total nitrogen and phosphorus to Bay and its tributaries are about 14 gNm -2 Yr -1 and 1.1 g P m -2 Yr -1 respectively.

Depletion of Bottom Water Oxygen: Organic matter produced in phytoplankton blooms sink into deep bay. The decomposition under water is oxygen consuming process. The increasing frequency and magnitude of seasonal oxygen depletion is closely related with the human activity that help to increase nutrient content in Bay. Direct measurements indicate that hypoxia (<2.0 mgO 2 l -1 ) occurred occasionally in deep water of the mainstem bay.

Declining water Clarity and Benthic Micro-algal production Sharply decline in water clarity in spring and summer can be directly related to algal blooms by watershed nutrient inputs. Nutrient enrichment has promoted an overall increase in production and biomass of phytoplankton which have contributed to decrease both water clarity and growth of benthic diatoms. Reduction in habitat due to eutrophication has reduced population of blue crab.

Nutrient Reduction Strategies Phosphorus is buried into the sea and nitrogen is lost into the atmosphere.

Chesapeake Bay Program to reduce the Nutrient: Chesapeake bay agreement in 1987 established Chesapeake Bay Program to reduce the amount of nutrient that enters into Chesapeake Bay. In June 2000, the Chesapeake Bay program adopted Chesapeake 2000, which is an agreement to guide restoration activities throughout the Chesapeake Bay. This agreement is organized into five different categories which are all intended to restoration and protection of different areas of bay’s health: living resources, vital habitat and water quality, and sound land use, steward and community engagement.

Chesapeake Bay Program to reduce eutrophication: The development of tributary-specific reduction strategies that take into account localized environmental quality goal as well as the baywide 40% reduction goal and involve local stakeholders. The adoption of living resources restoration of as the overarching goal, with specific numerical objectives for submerged aquatic vegetation beds recovered as a key living resource indicator. The adoption of the goal of restoration riparian forest buffer along 2010 miles (3234 Km) of stream and shoreline in the watershed by the year The conduct of two major mid-course reevaluations (in 1991 and 1997) of progress towards the 40% nutrient reduction goal.

Chesapeake Bay Program Progress in Restoration: Planning for the implementation of various point and non-point sources nutrient controls was intensified. Phosphorus reduction at wastewater treatment plants were initiated and implemented. Implementation of agricultural practices that reduce nutrient and sediments losses from agricultural land. Soil and Water Conservation Plans. Nutrient Management Plans. State Agriculture Cost-share Programs. Best Management Practices (special techniques to reduce soil erosion, heavy use of fertilizers, control nutrient management.)

References and Image Sources: Baird, D., & Ulanowicz, R., (1989). The seasonal dynamics of the Chesapeake Bay ecosystem. Ecol. Manogr. 59: Boesch, D.F., Brinsfiled, R.B., & Magnien, R.E., (2001). Chesapeake Bay Eutrophication: Scientific Understanding, Ecosystem Restoration, and Challenges for Agriculture. Journal of Environmental Quality. Vol Copper, S.R., & Brush, G.S. (1991). A 2,500-year history of anoxia and eutrophication in Chesapeake Bay. Estuaries 16: Chesapeake Bay Program. (1997). Chesapeake Bay Nutrient reduction progress and future directions: Nutrient reduction reevaluation summary report. EPA 903-R USEPA, Annapolis, MD. Curtin, P.D., Brush, G.S., Fisher, G.W. (eds). (2001). Discovering the Chesapeake: the history of an ecosystem. Johns Hopkins University Press, Baltimore, MD Jordan, T.E., Correll, D.L., 7 Weller, D.E. (1997). Effects of Agriculture discharges of nutrients from costal plane watersheds of Chesapeake Bay. J. Environ. Quailty. 26: Kemp, W.M., Smith, E.M., Marvin-DiPasquale, M., Boynton, W.R. (1997). Organic carbon-balance and net ecosystem metabolism in Chesapeake Bay. Mar Ecol Prog Ser 150:229–248. Kemp et. al. (2005). Eutrophication of Chesapeake Bay: Historical Trends and Ecological Interactions. Marine Ecology Progress Series.303: National Ocean Service. (2015). Where is the largest estuary in the United States?” National Oceanic and Atmospheric Administration. United States Department of Commerce. Retrieved in March 15, 2015 from Nixon, S.W. (1995). Costal Marine Eutrophication. A definition, social causes, and future concern. Ophelia 41: Smith, S.V., Swaney, D.P., Talaue-McManus, L., Bartley, J.D. & 7 others. (2003). Humans, hydrology, and the distribution of inorganic nutrient loading to the ocean. BioScience 53: 235–245 Sprague, L.A., Langland, M.J., Yochum, S.E., Edwards, R.E., Blomquist, J.D., Phillips, S.W., Shenk, G.W., Preston, S.D. (2000). Factors affecting nutrient trends in major rivers of the Chesapeake Bay watershed. Water Resources Investigations Report 00–4218. US Geological Survey, Richmond, VA Wikipedia (2015). Chesapeake Bay Program. Retrieved in March 16, 2015 from Images are collected from google searches.

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