A draft report from the Science Advisory Board (SAB) to the US Environmental Protection Agency published earlier this month suggests that changes to the current structure of economic incentives favoring corn-based ethanol may be necessary to prevent a dramatic increase in nutrient loadings in the Mississippi and Atchafalaya River Basin (MARB) that would lead to an expansion of the annual dead zone. (Earlier post.)

The NOAA project will provide data to verify water quality models and help resource managers determine the quantitative relationships between nutrient pollution and development, magnitude, longevity, and distribution of the dead zone. Findings will also support the development of more accurate predictive models of hypoxia development on the Louisiana continental shelf.

The dead zone is an area in the Gulf of Mexico where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters. It is caused by a seasonal change where algal growth, stimulated by input of nutrients such as nitrogen and phosphorus from the Mississippi and Atchafalaya rivers, settles and decays in the bottom waters. The decaying algae consume oxygen faster than it can be replenished from the surface, leading to decreased levels of dissolved oxygen.

This past summer off the coast of Louisiana and Texas, an area of deep water covering 7,900 square miles was declared hypoxic. It is the third largest Gulf of Mexico dead zone on record since measurements began in 1985, and represents an area approximately the size of the state of New Jersey. Also, it is more than one and a half times the average annual dead zone area measured since 1990, 4,800 square miles. The largest dead zone ever recorded covered 8,494 square miles in 2002.