Every late spring, it forms 12 miles off the Louisiana coast and lasts for months: a sprawling, lifeless band of water known as the "dead zone."
It's not a natural phenomenon. Waste water and fertilizer runoff from farms and towns
Every late spring, it forms 12 miles off the Louisiana coast and lasts for months: a sprawling, lifeless band of water known as the "dead zone."
It's not a natural phenomenon. Waste water and fertilizer runoff from farms and towns hundreds of miles up the Mississippi pour billions of pounds of excess nutrients into the Gulf, sparking unnatural algae blooms that choke off the oxygen needed for the food chain to survive.
Under a process that's been in place for the past decade, a federal task force and a team of scientists appointed by the federal Environmental Protection Agency will meet in New Orleans this week to tackle the problem.
But more than five years after the task force pledged to reduce the dead zone to a quarter of its size by 2015, it's still getting bigger. A boom in corn production for ethanol is bringing more farmland on line, leading experts to predict near-record sizes this year.
Targeted federal funding for the dead zone is unlikely to appear, and scientists say voluntary measures to reduce the runoff have fallen short.
Meanwhile, researchers fear that the dead zone's persistence could permanently alter the Gulf's ecology, from the worms and bottom-dwelling organisms that anchor it all the way to the prized fish at the top.
"You reach a point where you've shifted the ecosystem to a completely different domain, and the recovery from that may be impossible," said Don Scavia, a professor of natural resources and environment at the University of Michigan and former National Oceanic and Atmospheric Administration scientist who led one of the first federal studies on the dead zone in 2000. "There will be a time where the critters that typically occupy the sediment in those areas can no longer recover."
Evidence of the dead zone goes back to the 1940s, but research shows it has grown exponentially in the past four decades.
Scientists point to widespread increases in the use of fertilizers and manure by large farms in the heartland. Nutrients such as nitrogen and phosphorus from these compounds then wash into Mississippi River tributaries.
Small amounts of these nutrients are essential for a healthy Gulf, improving the ocean bottom and contributing to the historically rich fisheries. But there can be too much of a good thing.
Snow melts and spring rains accelerate the flow of these nutrients down the river, and the heat of the summer sun lets them simmer when they reach the Mississippi delta.
The same nutrients that fuel corn and wheat in the Midwest feed explosive blooms of microscopic algae in the Gulf of Mexico. When algae eventually dies and sinks to the bottom, it sucks up all the available oxygen, leading to a prolonged hypoxic, or oxygen-depleted, state.
Fish and shrimp must escape to survive; smaller organisms and bottom-feeders perish.
Sources of the dead zone are as diffuse as the rivulets and tributaries that feed the Mississippi. With almost two-thirds of continental United States draining into the Mississippi, figuring out where to point the finger can be tough.
In 2001, the federal government, nine states and two American Indian tribes signed an agreement that, among other things, pledged to cut down on nitrogen in the river by 20 percent to 40 percent and reduce the size of the dead zone to 1,930 square miles by 2015. Last year, the dead zone measured more than 6,600 square miles, and early predictions for this year point to it being even larger.
One of the key roadblocks for reducing the dead zone is a lack of federal funding. From the beginning, the task force went forward knowing it would have to reduce nutrients in the Mississippi through a maze of existing federal programs spread across numerous agencies.
"The key challenge is uniting a wide array of states and other organizations that may be hundreds if not thousands of miles away from each other," said Ben Grumbles, the EPA's assistant administrator for water and chairman of the federal hypoxia task force, which meets Tuesday in New Orleans. "We have to be providing incentives for states with many different interests to focus in on the Gulf hypoxia challenge. It's not always the technology that's the issue; it's the sociology."
Programs in the U.S. Department of Agriculture, the EPA, the Fish and Wildlife Service, and the Army Corps of Engineers all address bits of the problem: installing buffers on planted fields near streams to prevent runoff, restoring wetlands along the river that would soak up more nutrients, setting discharge limits for nutrients at wastewater treatment plants.
But many of the measures are voluntary and require individual farmers or landowners to pony up the cash for unseen benefits down the road.
"A lot of this is 'Until my neighbor does it, why do I want to do it? What's the incentive?' " said Nancy Rabalais, a lead researcher on the dead zone at the Louisiana Universities Marine Consortium laboratory in Cocodrie. "It's not as obvious an issue up there. It's not the Erie Canal on fire."
Some of the programs have had success over the years, but they've failed to put a large dent in overall nutrient runoff coming into the river.
According to a report being dr