Regulating Watershed Nutrients Improves Coastal Health
Water quality in Tampa Bay has improved since nutrient regulations were established.
Tampa Bay, on Florida's west coast, is a major population center, a popular location for recreation and tourism, and is home to important coastal habitats, including mangroves, salt marshes and seagrass beds. Increasing nitrogen inputs in the 1970s led to declining water quality, including extensive algal blooms. These conditions resulted in a loss of more than half of the 39,500 acres of seagrass habitat of Tampa Bay.
In response to this decline, three major nutrient management strategies were implemented in the 1980s:
- wastewater treatment plants were required to reduce nitrogen concentrations in wastewater by 90 percent;
- stormwater treatment regulations were enacted; and
- the fertilizer industry instituted practices to reduce nitrogen and phosphorus spills.
These combined actions reduced nitrogen loads into Tampa Bay by 60 percent from 1985 to 2003. Following nutrient reductions, phytoplankton growth decreased, water clarity increased, and seagrass acreage increased to 27,024 acres by 2004.
This management success story text was adapted from Effects of Nutrient Enrichment in the Nation's Estuaries: A Decade of Change.
Nitrogen inputs to Tampa Bay before and after regulations were established. Source: H. Greening, 2007
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Seagrass loss in Tampa Bay between 1950-1990 (as indicated in red). Source: H. Greening, 2007
For more information:
Closer Look
Relevant Links
NOAA's National Estuarine Eutrophication Assessment
http://ian.umces.edu/neea/
NOAA NCCOS Hypoxia and Nutrient Pollution Page
http://www.cop.noaa.gov/stressors/pollution/default.aspx
Mississippi River/Gulf of Mexico Watershed Nutrient Task Force
http://www.epa.gov/msbasin/index.htm
