Bringing New Life to the Dead Zone.

The Gulf of Mexico "dead zone" reached a record 7,700 square miles in the summer of 1999. That year, heavier flow in the Mississippi River brought an abundance of nutrients to the Gulf, resulting in hypoxia, or inadequate dissolved oxygen in bottom waters that forces bottom-dwelling animals to either flee or die. With the year 2001 have come legislative efforts to reduce the dead zone--if not kill it outright.

On 18 January 2001, the U.S. Environmental Protection Agency (EPA) proposed a plan to reduce nitrate runoff from farms in the Mississippi River watershed. The 11-item plan focused on improving farming practices, restoring natural habitats (such as wetlands) that are capable of filtering nutrients from water, and promoting flood control projects. The plan also proposed increased monitoring of the hypoxic zone and the waters flowing into it. R. Eugene Turner, a professor of oceanography and coastal sciences at Louisiana State University in Baton Rouge, says the plan--which would have cut nitrate runoff by 30% by 2015--could possibly have reduced the dead zone's area by about 50%. Attorney Scott Faber of the group Environmental Defense says many of the proposed practices could also reduce demand for natural gas, help combat climate change, and restore endangered species habitat. No federal legislation has been introduced to enact the EPA proposal, however.

In April 2001, Senator Kit Bond (R-Missouri) introduced the Fishable Waters Act (S. 678). This act would provide $350 million each year for voluntary, community-led, incentive-based partnerships to reduce runoff of agricultural chemicals. According to Bond, the act is not intended specifically to heal the dead zone in the Gulf but rather to improve the nearly 40% of lakes and rivers now considered unfishable for a variety of reasons related to pollution (including hypoxia). The bill has since been referred to the Senate Committee on Environment and Public Works.

Most scientists attribute the dead zone to nitrates, primarily from fertilizer runoff. But the Fertilizer Institute, a Washington, D.C., trade group, maintains that nitrate runoff is only one factor in hypoxia. Still, says institute spokesperson Kathy Mathers, "[Farmers] ought to have a nutrient management plan, with field maps, soil tests." Gary Goldberg, CEO of the American Corn Growers Foundation, an offshoot of the 14,000-member American Corn Growers Association, adds that many farmers apply the same amount of nitrogen each year, and that regular soil tests to determine how much fertilizer is actually needed could save money and reduce runoff at the same time.

Because the Mississippi drains 41% of the U.S. land area, scientists believe only a broad effort at reducing nitrate runoff would have a chance at succeeding. And because nitrogen is stored in the soil and continues leaching for many years, any solution must be a long-term effort, says Turner. In Eastern Europe, he points out, nitrates from the Danube River contributed to hypoxia and ecologic havoc in the Black Sea. After the Soviet Union collapsed, the economic decline hit farmers hard; fertilizer use fell by more than 50%, and Black Sea oxygen levels slowly rose.

Hypoxia in the Gulf of Mexico exists in a larger ecological context, says Len Bahr, a marine biologist who is coastal advisor to Louisiana governor Mike Foster. Channelization of the Mississippi River to improve navigation and reduce flooding has starved wetlands of necessary sediment, helping to cause erosion and destruction of the state's wetlands. Bahr argues that allowing more water to leave the channel levees and enter wetlands would nourish those areas. Once in the wetlands, water would lose some nitrates, ameliorating the dead zone. However, says Turner, "The main issue for removing nitrogen is at the headwaters, not at this end of the pipe."