They call it the "DEAD ZONE." It sure makes good copy. The two words appear in headlines in Newsweek, the New York Times and the Washington Post. In Science, its "death by suffocation." The articles are all about fertilizer runoff that flushes down the Mississippi River basin, giving rise to algae blooms in the Gulf. When these die and decay, they suck the oxygen out of the ocean water, allegedly killing fish.
Proposed solution to this environmental problem: Cut way back on nitrate fertilizer on farms and the number of farms themselves within the drainage basin of the Mississippi. It could be done, but it would be massively expensive and it might not accomplish any improvement in the Gulf. The truth is that no one knows exactly whats going on there, or what all the causes are.
World food demand is rising, but this farm on the Mississippi could become wetlands.
The dead zone is big about 7,500 square miles and it has doubled in size since 1985. In this space plant growth is above normal and the oxygen level in the Gulf water falls so low that it becomes difficult or impossible for fish to breathe what scientists call hypoxia.
Fertilizer runoff clearly contributes to the Gulf hypoxia. But how much? The problem, says Jonathan Pennock, an associate professor of oceanography at the University of Alabama, is that since 1950 there has been a tremendous increase in nitrate concentrations in the Mississippi, and there has been an increase in hypoxia in the Gulf.
But since 1985 the hypoxic area has doubled, even as the fertilizer concentration has gone down.
The area of the zone increased tremendously in 1993 following a massive flood in the Midwest. Is that because the flood washed nitrates out of fields into rivers, eventually dumping them into the Gulf? Maybe. But then why did the zone last year finally fall back to essentially its pre-flood level, only to balloon to its largest size ever this past summer? How can that be traced to the flood?
"To me it points to the multiple factors that go into affecting the hypoxic zone," says Pennock, "and shows its not a simple problem with any one cause."
Pennock might be considered biased since the Fertilizer Institute paid for a study he did of Gulf hypoxia. But then, is the antifertilizer crowd without taint? The most quotable authorities on the evils of nitrate runoff are Nancy Rabalais, a marine biologist at the Louisiana Universities Marine Consortium in Chauvin, La., and her husband, R. Eugene Turner, a coastal ecologist at Louisiana State University in Baton Rouge. They have become environmentalist darlings, including winning the San Diego Foundations Blasker Award for environmental science and engineering and a check for $250,000.
The government report admits theres no evidence fisheries in the Gulf of Mexico are suffering.
Derek Winstanley, chief of the Illinois State Water Survey in Champaign, notes that the hypoxic zone is off to the west of the Mississippi, "but when you look at the satellite photos from 1993 you see the flood debris do an immediate U-turn, go east, and are taken up into the Gulf Stream past the Carolinas." Why would fertilizer nitrates follow an opposite path? You also rarely hear that hypoxia zones are common throughout the world, usually where fertilizer couldnt be a problem.
"There are millions of square miles of ocean that are naturally hypoxic," says Winstanley, "including the whole of the Pacific Ocean offshore from the Canadian-American border to Chile." Causes and contributors aside, the underlying current of all the fuss is fish. Something has to be done because fish are dying and fishermen are suffering, right? Wrong.
"Economic assessment based on fisheries data failed to detect effects attributable to hypoxia," the CENR report admits. The dead zone is a bad spot to fish but fishermen working the edge of the zone pull up net-ripping catches. Still, says the report, if the zone grows larger, it could eventually affect the industry.
Being a federal creature, the CENR cant imagine alternatives requiring less than iron-fisted regulation and vast expenditures. But farmers have already begun employing high-tech solutions to reduce both fertilizer use and runoff, such as using satellites to determine which acres might need less fertilizer.
New crops are also under development that need less nitrogen fertilizer. One wheat strain developed at the University of Florida may allow the same yield with a third less fertilizer. Such crops could be blanketing the country faster than the Army Corps of Engineers could put into gear a scheme to convert some of Americas most productive farmland into muskrat metropolises.
Read Michael Fumentos additional work on the environment.