Dealing with Dead
Zones
TUESDAY, August 17, 1999
Newsweek.com ©
1999
| |
Iowa
farmers are in the middle of a fertilizer fight about
environmental dead zones(Craig Chandler, Quad-City
Times—AP) |
Is the fertilizer that's used to grow corn
in the Midwest also damaging the industry and environment of
the Gulf of Mexico? Areas in the Gulf develop seasonally low
oxygen levels that cannot sustain shrimp, crabs and other
marine life. Six recent government reports from the Committee
on the Environment and Natural Resources point to nutrient
runoff discharged from the Mississippi River as the culprit
behind the ecological change.
Nitrogen, phosphorus and silica originating
in states from Montana to western New York—more than 40
percent of the continental US—wash off from farmlands and
run down the river. "Most of the evidence points to
nitrogen as the nutrient that's most important," says
Nancy Rabalais, a biologist at the Louisiana Universities
Marine Consortium and author of one of the reports. Once
discharged into the Gulf, the nutrients stimulate algal
blooms. Deteriorating blooms are decomposed by bacteria, which
in the process use up oxygen dissolved in the water. The lack
of oxygen threatens other sea life, which either dies off or
is forced to relocate. The dead zone—which usually appears
in the spring, grows during the summer, and disappears in the
fall—this year grew to approximately 7,728 square miles, an
area the size of New Jersey.
What can be done? The federal reports
suggest that cutting fertilizer use by 20 percent would
decrease the dead zone. Other options include converting
farmland to wetlands that would help regulate the water flow
toward the Gulf. But the American Farm Bureau Federation and
other organizations responding to the reports question the
science behind such moves and worry about potential economic
consequences. "There is no scientifically identifiable
link between farmers' use of fertilizer in the Mississippi
River Basin and the appearance of a low-oxygen zone in some
waters of the Gulf of Mexico," Farm Bureau officials
responded in an August 10 statement. And Farm Bureau
representatives add that farmers have become better at
preventing fertilizers from leeching out of their soil.
Government scientists will take these comments into
consideration as they prepare an "integrated
assessment" with final policy recommendations, due out
around the end of September. — Yuval Rosenberg
Related Links:
Deep Damage
Suffering
Seas
TOP
