Gulf of Mexico plagued by record “dead zones”By Jeff Franks
August 3, 2007; Reuters.com
HOUSTON (Reuters) – Researchers have found 9,650 square miles of "dead zones," or oxygen-depleted water, in the
They say humans are mostly to blame for the dead waters, and that increased planting of corn to make ethanol is adding to the problem.
The dead zones, which have been appearing each summer since at least 1970, threaten marine life and over time have altered the gulf’s ecology, scientists say.
Usually researchers, who began measuring the dead zones in 1985, find only one large zone each year, just off the
But this summer, for the first time, a separate zone has developed off
Recent measurements taken in separate studies show the
The previous largest amount was 8,495 square miles found in 2002, Nancy Rabalais, chief scientist for the Louisiana Universities Marine Consortium, said on Friday.
The U.S. Department of Agriculture said in March corn planting would rise 15 percent this year to feed increased demand for ethanol, a motor fuel distilled from corn and now promoted as an alternative to gasoline.
Corn needs more fertilizer than other crops, which is probably why tests have found more nitrogen in the
She said only the
The fresh water, he said, sits on top of salt water "like oil and water" and prevents it from being oxygenated by air.
Water in the dead zones cannot support most life, DiMarco said. There were already signs of problems on the
"I’m getting reports there have been some fishkills," he said.
Rabalais said dead zones reduce the amount and variety of marine life and, as a result, "have already changed the Gulf of
The dead zones form in the calm summer waters and break up when the summer doldrums end or a hurricane churns through the gulf, she said.