Thursday, January 28, 1999
Scientists studying the 7,000-square-mile 'dead zone' in the Gulf of Mexico have placed much of the blame on fertilizer runoff from American farms. Only changes in farming practices, they say, will help alleviate the hypoxic area.
Scientists estimate that to eliminate the hypoxic zone in the gulf -- an area that cannot sustain life because it has too little oxygen -- the United States should reduce the amount of excess nitrogen flowing into the Gulf by 20 percent or more. Much of this burden would be placed on farmers.
Every spring and summer, nitrogen from agricultural fertilizer washes down the Mississippi River and into the northern Gulf of Mexico. The nutrient-rich waters trigger a bloom of algae which strips the water of oxygen.
The dead zone doesn't actually kill any fish, because they are able to swim away from the area. However, other types of sea life, such as starfish and sea anemones, may not be able to escape and may die.
Although other hypoxic zones exist -- in the Black Sea, Baltic Sea, Chesapeake Bay and New York Bight -- the Gulf of Mexico is unique. Because the Gulf of Mexico is open to ocean currents, unlike other enclosed seas, scientists think that the problem can be corrected
Otto Doering, a professor of agricultural economics at Purdue University, believes that farmers can use a variety of methods to cut the flow of excess nitrogen by 20 percent to 25 percent without hurting food prices or farm exports.
He presented his findings Jan. 23 at the annual meeting of the American Association for the Advancement of Science in Anaheim, Calif.
Farmers aren't completely to blame, said Doering. Huge amounts of nitrogen are found naturally in the air, in the soil and in living organisms, and all of these contribute to the nitrogen moving down the Mississippi. "If farmers stopped putting nitrogen on the fields today, we would still get nitrogen leaking out of the system," Doering says.
But he quickly adds that agriculture doesn't get off the hook. "Agriculture still has to be concerned about all of this," he says. "Municipalities and industries release a total of 270,000 metric tons of nitrogen per year into streams and rivers, and the excess nitrogen delivered just to the gulf is 1.5 million tons per year. So agriculture, which uses 6.5 million metric tons of nitrogen a year, is clearly the major player."
Doering believes farmers could reduce nitrogen runoff by 20 percent if they stopped fertilizing in the fall and if major wetlands were restored along the Mississippi River watershed.
Doering says that wetlands have their own economic benefits for those living near them. "There is increased wildlife habitat, more hunting opportunities, water quality improvements, things that are very direct in the basin where the wetlands are," he says. "With wetlands the benefits accrue, if not to the farmer, at least to his immediate neighbors. That makes a certain amount of wetland reconstruction an attractive component of reducing nitrogen loss."
"We found that you can adjust farm practices and reduce
nitrogen losses by about 20 percent without causing serious dislocation
in agriculture," Doering says. "Beyond that, there is serious disruption
in terms of high food prices, an increasing drop in exports, and a loss
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