ECOVIEWS: What will our leaders do about Gulf’s dead zone?By Whit Gibbons, Tuscaloosa News
6 September 2014
Off the Louisiana coastline, where the Mississippi River enters the Gulf, a story is unfolding that is scarier than any TV show about flesh-eating zombies. The area of more than 5,000 square miles, which extends into coastal waters from Alabama to Texas, has dangerously low oxygen levels. It is known as the Gulf of Mexico dead zone — and it is anything but fictitious.
Unsustainable agriculture practices upstream may be the prime culprit in this alarming narrative. Though food production is obviously essential, siltation and pesticide runoffs from some agricultural practices are threats to a healthy environment. The Gulf’s oxygen-depleted waters are attributed primarily to excessive use of chemical fertilizers by agricultural systems upstream. The primary players in this drama are likely be Gulf Coast fishermen versus agricultural enterprises in the Midwest.
For some folks who make a living catching the Gulf shrimp and fish the rest of us eat, conditions have gotten very bad. Everyone remembers the BP disaster, with its images of oil-covered animals and floating tar balls. But the oil spill can be likened to a compound fracture, a bad injury that will eventually heal. The Gulf of Mexico dead zone is like a virulent cancer.
Fish can swim away from the dead zone. Slow-moving, bottom-dwelling life forms such as clams, starfish and marine worms cannot escape. They suffocate due to lack of oxygen. Most people spend little time considering the fate of ocean invertebrates, but they are an essential prey base for commercial fish. Widespread loss of prey in such an immense area does not bode well for people who rely on healthy seas to make a living. And for those of us who rely on the fisheries and shrimping industry for food.
Ecological research has identified an insidious byproduct of some large-scale agricultural practices along the Mississippi River and its tributaries. The Mississippi River carries thousands of tons of nitrogen to the Gulf of Mexico each year. The high nitrogen levels and their environmental effects are alarming. The annual runoff into rivers is considered a likely cause of the Gulf’s dead zone.
When nitrogen is available in vast quantities for consumption by the ocean’s microscopic plants and animals, the organisms prosper. When they die and sink to the bottom, they are consumed by bacteria. But here’s the catch-22: all of this increasingly abundant living matter requires more and more oxygen. Animals that get their oxygen from the water, from jellyfish and zooplankton to sharks and tarpon, must either leave the area or die.
The economic impact of a continuation, or worse, an expansion, of the dead zone in once-fertile fishing and shrimping grounds will not be trivial. The direst predictions are that it could be the beginning of the end for Louisiana’s coastal fisheries industry, a multimillion-dollar enterprise, sometimes generating as much as $3 billion a year.
Based on annual surveys NOAA reports that "the largest Gulf dead zone ever recorded" was 8,481 square miles in 2002, which means a major chunk of that marine environment went belly up. More frighteningly, 550 other dead zones have been discovered in the world’s oceans, presumably caused by environmentally unsound practices. To avoid the worst case long-range environmental projections, we must make some changes.
Incontrovertible proof is still being sought, but current farming practices are strongly indicted by some for the problem in the Gulf. Should immediate sanctions be placed on the Midwest agriculture industry’s excessive use of nitrogen? If we wait, do we risk making the entire Gulf of Mexico a dead zone, where marine life of economic worth cannot survive?
No easy answers are apparent, although continuing ecological research can help us understand long-term agro-environmental processes and their consequences. Elected officials at the state and federal level need to step forward and address this increasingly serious problem, crossing party lines as necessary. Finding a solution is essential.
Whit Gibbons, professor emeritus of ecology, University of Georgia, and head of the Environmental Outreach Program at the Savannah River Ecology Laboratory, grew up in Tuscaloosa. Send environmental questions to email@example.com.
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