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HYPOXIA IN THE GULF OF MEXICO: ASSESSING AND MANAGING RISKS FROM NONPOINT SOURCE POLLUTANTS IN THE MISSISSIPPI RIVER BASIN
Citation:
SchubauerBerigan, J, H K. Austin, AND M. L. Belefski. HYPOXIA IN THE GULF OF MEXICO: ASSESSING AND MANAGING RISKS FROM NONPOINT SOURCE POLLUTANTS IN THE MISSISSIPPI RIVER BASIN. Presented at Presentation to School of Public and Environmental Affairs, University of Indiana, Bloomington, IN, 12/1/2000.
Description:
. Hypoxia is the condition in which dissolved oxygen levels are below that necessary to sustain most animal life. The largest zone of oxygen depletion in U.S. coastal waters is found in the northern Gulf of Mexico (NGOM) on the Louisiana/Texas continental shelf. In response to growing public concerns, the Environmental Protection Agency (EPA) participating in a Federal interagency effort (under the Office of Science and Technology Policy=s Committee on Environment and Natural Resources), developed an integrated assessment (IA) of the causes and consequences of hypoxia in the NGOM. We describe the process to develop the IA (based on a series of six peer-reviewed scientific reports) and review it=s significant findings. Hypoxia in the NGOM is caused primarily by excess nitrogen from the Mississippi-Atchafalaya River Basin (the Basin) in combination with stratification of Gulf waters. River nutrient flux has increased significantly since the early 1900's, due to major changes in the Basin such as landscape alterations (deforestation and artificial agricultural drainage), river channelization (flood control and navigation), and dramatic increases in fertilizer nitrogen input. We review results of modeling approaches to improve nitrogen management, including agricultural N management and wetland and riparian buffer restoration. The results of the IA and other scientific information will be used by the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (chaired by EPA=s Office of Water) to develop a plan of action (the AAction Plan@) to reduce, mitigate, and control hypoxia in the NGOM. The IA significantly advances scientific understanding of hypoxia in the NGOM, but specific scientific uncertainties remain. We discuss both the research priorities required to reduce uncertainties and next steps towards completing the Action Plan.