A7 - Nitrogen or phosphorus? Update on hypoxia in the Gulf of Mexico.
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Dean W. Lemke, P.E., Chief, Water Resource Bureau, Division of Soil Conservation,
Iowa Department of Agriculture and Land Stewardship. The hypoxic zone in the
Gulf of Mexico has been attributed to nitrogen enrichment which accelerates
phytoplankton growth and results in oxygen depletion. This analysis of a single
nutrient causing and needing reduction to address hypoxia has increasingly
been questioned, most recently in three “white papers” developed by scientists
of the Region IV Atlanta office of the U.S. Environmental Protection Agency.
Questions raised about the cause of Gulf hypoxia as well as the plan adopted
by the Mississippi River/Gulf of Mexico Watershed Nutrients Task Force to re-assess
the science of the Gulf and the Hypoxia Action Plan will be reviewed.
