Agreement to Shrink Dead Zone

BATON ROUGE, LOUISIANA--Negotiations have been raging for months over how to shrink the "dead zone" in the Gulf of Mexico (Science, 23 June, p. 2111). On 11 October, federal and state officials finally agreed on an ambitious $1-billion-per-year plan to revive as much as 30% of the dead zone by 2015. The plan could also help head off a crash of Gulf fisheries, officials say.

Dead zones are becoming more common worldwide in areas where coastal waters are swamped with nutrients, particularly nitrogen, from sewage or fertilizer. The excess nitrogen allows algae populations to explode. Dead algae in turn feed bacteria, which gobble up most of the oxygen in the water. Shellfish suffocate, and fish must swim for more healthful waters. The Gulf of Mexico's dead zone swells each summer to about 18,000 square kilometers--roughly the size of New Jersey. Researchers blame the 1.6 million metric tons of nitrogen, much of it from farm fields, that washes down the mighty Mississippi River each year.

The new plan aims to reduce that total. Under the plan, more money would go to programs that reduce excess nutrients in streams and rivers feeding into the Mississippi, which drains 40% of the continental United States. These programs would cut fertilizer use on farms, establish wetlands and buffer strips near streams to soak up excess nitrogen, and reduce discharges from sewage treatment plants. The plan also calls for funding scientific efforts to track the flow of nitrogen.

Efforts to reduce farm runoff provoked most of the controversy. Environmentalists wanted to specify nitrogen reduction goals. Farmers and agriculture officials balked, fearing that they might be forced to use less fertilizer and thereby possibly cut crop yields. In the end, officials agreed on a flexible plan to try to reduce nitrogen in the Mississippi by 30%, which researchers say will increase oxygen enough to partly restore the dead zone.

The consensus plan is "real progress," says Len Bahr, an environmental adviser to Louisiana Governor Mike Foster. Getting the farmers and environmentalists to agree was a major achievement, says Susan Heathcote of the Iowa Environmental Council: "Without consensus, it wasn't going to go anywhere."

Related sites

Information about the task force and a draft of the plan

More about the dead zone from NOAA