To all - article about fertilizer runoff from Miss. River into Gulf of Mexico.
January 24, 1999
Fertilizer Found To Damage Gulf
Filed at 9:54 p.m. EST
By The Associated Press
ANAHEIM, Calif. (AP) -- A 7,000-square-mile dead zone in the Gulf of
Mexico caused by the runoff of fertilizer is getting worse and the only
solution may be to change farming practices throughout the Corn Belt, experts
say.
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.
Researchers attending the national meeting of the American Association for
the Advancement of Science this weekend said that by midsummer, an area of
the Gulf extending from Louisiana to Texas becomes so oxygen-deprived that
most fish and shrimp escape to healthier waters, leaving behind a vast ''dead
zone.''
Nancy N. Rabalais of Louisiana State University said the average size of the
dead zone has doubled in size since 1992 and is now persisting from May until
October in some areas.
Shrimp, menhaden and other valuable species have not been affected because
these animals simply flee the bad water, said Rabalais, but bottom-dwellers,
such as worms, starfish and some single-celled animals are killed. At the same
time, some microbes that prefer low-oxygen waters explode, forming a white,
cotton-like mass that floats on the surface.
''We don't know what the long-term effects of this will be on the ecology of
the Gulf,'' said Rabalais. ''The hypoxia (lack of oxygen) has decimated a
number of organisms living in the sediments'' and such a change is bound to
affect the ecology of the Gulf, she said.
The Mississippi River drains about 40 percent of the United States and carries
more than a million tons of nitrogen, much of it washed from the agricultural
fields in the Midwestern farm belt, said Otto Doering, a professor at Purdue
University.
Some of the nitrogen dumped into the Gulf comes from natural sources and
from cities and industry, but ''agriculture uses 6.5 million metric tons of
nitrogen a year and is clearly a major player.''
Doering said farmers could reduce nitrogen runoff by 20 percent by changing
farm management practices.
He said the goal could be reached if farmers stopped fertilizing in the fall and
if major wetlands were restored along the Mississippi River watershed.
Wetlands retain the nitrogen and the chemical then tends to disappear into the
atmosphere, he said. The wetlands also would increase wildlife habitat and
improve water quality.
Using less fertilizer would reduce crop yield and a 20 percent reduction is
about the limit before there would serious economic consequences for
farmers and the nation, according to a scientific assessment by Doering and
others.
''Beyond 20 percent, there is a serious disruption in terms of high food prices,
an increasing drop in exports and a loss of farmland,'' he said.
Doering said it may take regulation or a tax on nitrogen fertilizer to force
changes in farming practices. Just how this will be done, he said, has not
been determined.
''Farm groups may need to be compensated,'' he said. ''We don't know how
this would affect the individual farmers.''
Copyright 1999 The New York Times Company |
