AS polluted floodwater from the upper Midwest moves downriver, experts are predicting a doubling in size of the Gulf of Mexico's "dead zone," a region at the mouth of the Mississippi River where no fish live. This zone is caused by high levels of phosphorous and nitrogen in the water, mainly from fertilizers washing off farms and effluent from sewage systems. The nutrients promote algae blooms that deplete oxygen and cloud the water, blocking out sunlight.
The Gulf's dead zone is usually about 3,000 square miles. Scientists say it may double in size because of flooding, said William Whitson, chief of operations for the federal Gulf of Mexico Program.
"It's natural to be concerned, as we all are, with the human impact and the tragedy of the flood on ... daily lives," Mr. Whitson said from the program's office at the Stennis Space Center near Bay St. Louis, Miss. "But the environmental story is the Gulf .... This is where it all ends up."
The recently concluded program was sponsored by the Environmental Protection Agency. It was designed to generate public support to protect the Gulf.