Submitted to: Ecological Society of America Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2000
Publication Date: 12/15/2000
Citation: Howarth, R., Anderson, D., Cloern, J., Elfring, C., Hopkinson, C., Lapointe, B., Malone, T., Marcus, N., Mcglathery, K., Sharpley, A.N. 2000. Nutrient pollution of coastal rivers, bays, and seas. Issues in Ecology. 7:1-15. Interpretive Summary: Antipollution laws enacted and enforced over the past 40 years have increasingly restricted the discharge of toxic substances into the coastal waters of the United States. While this effort has greatly reduced point- source pollution of toxic materials, oxygen-consuming organic materials, and to some extent phosphorus from industrial and municipal effluent pipes, ,no comparable attempt has been made to restrict the input of nitrogen from municipal effluent, nor to control the flows of nitrogen and phosphorus that enter waterways from dispersed or nonpoint sources, such as agricultural and urban runoff or windborne deposits. As a consequence, inputs of nonpoint pollutants, particularly nitrogen, have increased dramatically. Today, pollution from the nutrients nitrogen and phosphorus represents the largest source of degradation in our coastal waters, which include some of the richest and most productive habitats in the oceans. Roughly half of the world's fisheries harvest occurs in or is dependent upon these coastal waters. The National Academy of Sciences recently reviewed the causes and consequences of this neglected pollution problem. All of the authors of this article participated -- as members, staff, or consultants -- in the work of the Committee on Causes and Management of Coastal Eutrophication. This article summarizes the ecological damage caused by nutrient pollution in coastal systems, discusses why nitrogen is of particular concern in these systems, and outlines the sources of nitrogen inputs to the coast.
Technical Abstract: Over the past 40 years, antipollution laws have greatly reduced discharges of toxic substances into our coastal waters. This effort, however, has focused largely on point-source pollution of industrial and municipal effluent. No comparable effort has been made to restrict the input of nitrogen (N) from municipal effluent, nor to control the flows of N and P that enter waterways from dispersed or nonpoint sources, such as agricultural and urban runoff or as airborne pollutants. As a result, inputs of nonpoint pollutants, particularly N, have increased dramatically. Nonpoint pollution from N and P now represents the largest pollution problem facing the vital coastal waters of the United States. Nutrient pollution is the common thread that links an array of problems along the nation's coastline, including eutrophication, harmful algal blooms, "dead zones," fish kills, some shellfish poisonings, loss of seagrass and kelp beds, some coral reef destruction, and even some marine mammal and seabird deaths. More than 60 percent of our coastal rivers and bays in every coastal state of the continental U.S. are moderately to severely degraded by nutrient pollution. This degradation is particularly severe in the mid- Atlantic states, in the southeast, and in the Gulf of Mexico. We recommend that, as a minimum goal, the nation should work to reverse nutrient pollution in 10 percent of its degraded coastal systems by 2010 and 25 percent of them by 2020. Also, action should be taken to assure that the other 40 percent of coastal areas now ranked as healthy, do not develop symptoms of nutrient pollution. Meeting these goals will require an array of strategies and approaches tailored to specific regions and coastal ecosystems.