Dr. Nancy Rabalais, Chief Scientist for Northern Gulf of Mexico Hypoxia Studies, has reported that Louisiana’s “Dead Zone” was recently mapped as 6,662 square miles (the size of Connecticut and Rhode Island put together). The “Dead Zone” was 4,800 square miles in 1990 and rose to its largest size of 8,500 square miles, the size of Israel, in 2002. Although the current extent of the dead zone is below the record, it’s still far from its long-term goal of shrinking to 2,500 square miles.

The new figures reflect the excessive agricultural runoff in the Mississippi River that flows into the Gulf of Mexico, depositing huge amounts of nitrogen , phosphorus and other nutrients that feed a growing algae population. When the Algae die, their decay consumes oxygen at a rate higher than currents can diffuse. This, in turn, creates a zone in which most marine life cannot survive.

It was expected that a there will be a smaller Dead Zone this year due to the lower-than-average flow of the Mississippi River. However, Gene Turner, of Louisiana State University, and his colleagues estimated a figure of 6,700 square miles which turned out to be very accurate. Turner says the larger Dead Zone in 2006 is the result of “nitrate loading this May, a critical month influencing the size of the area, is higher than last year, despite the lower river flow.”

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