Increased ethanol interest fuels risk of Gulf dead zone spreading

U.S. farmers planted the largest corn crop since 1944 this year after growing demand for corn-based ethanol helped propel corn prices to their highest level in more than a decade.

But the expansion of corn production in America’s Heartland is fueling concerns farther south where agriculture-related runoff funneled into the Gulf of Mexico via the Mississippi River is threatening ecosystems and one of the nation’s most productive fisheries, already stressed by dramatically declining wetlands.
Corn production in Iowa, Missouri and Nebraska, scientists say, is killing fish in the Gulf.

Agricultural runoff is blamed for more than half the pollutants that make their way into the Gulf each year, contributing to an expansive area of oxygen depletion known as hypoxia. This creates a dead zone where it is nearly impossible for marine life to survive.

The seasonal phenomenon begins in the spring as nutrients such as nitrogen and phosphorus, commonly found in crop fertilizer, flow down the river after rain runoffs and into the Gulf where they spur the growth of micro-organisms. As these organisms die and decompose, the water is depleted of oxygen, suffocating aquatic animals unable to flee. The problem peaks around July before tropical storms and cold fronts later stir up the water and replenish oxygen.

Corn production is the primary source of pollutants responsible for the dead zone, said Don Scavia, a professor of natural resources and environment at the University of Michigan. “That’s the dominant crop … and corn is very, very leaky,” he said. Nitrogen used in corn fertilizer tends to drain off the crops into nearby waterways.

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