Decoding the Mysteries of the Gulf Dead Zone

Environmental News Service; October 18, 2007

AUSTIN, Texas, October 18, 2007 (ENS) – Off the coast of Louisiana and Texas this summer, an area of deep water covering 7,900 square miles in the Gulf of Mexico was declared hypoxic. This area of low oxygen water called the dead zone was about the size of the state of New Jersey.

It is the third largest Gulf of Mexico dead zone on record since measurements began in 1985. The largest dead zone ever recorded covered 8,494 square miles in 2002.

To develop a better understanding of how nutrient pollution from the Mississippi River affects Gulf dead zone, researchers at the University of Texas at Austin Marine Science Institute have been awarded funding for the first year of a three year project.

The grant from the National Oceanic and Atmospheric Administration, NOAA, amounts to $284,000, as part of the total $781,000 project. Funds were awarded through NOAA’s Northern Gulf of Mexico Hypoxia and Ecosystems Research Program.

"A better understanding of the underlying causes of the dead zone is essential for predicting its effect on the Gulf fisheries and the region," said NOAA AdministratorConrad Lautenbacher.

"The goal of this research is to help develop a range of options that coastal and upriver resource managers can use to prevent and reduce nutrient pollution that contributes to the dead zone," he said.

Scientists already know that nutrient over-enrichment can lead to excessive production of algae. When this organic material sinks and becomes decomposed, dissolved oxygen in bottom waters is reduced, resulting in seasonal hypoxia – very low oxygen water – over the Louisiana continental shelf.

The northern portion of the Gulf of Mexico ecosystem contains almost half of the nation’s coastal wetlands and supports commercial and recreational fisheries which generate $2.8 billion annually.

The Marine Science Institute will investigate how the dead zone affects commercially and recreationally important fish and shellfish.

Every summer, large areas of hypoxic bottom water form in the Gulf. Hypoxic waters can cause habitat loss, stress and death to marine organisms; affecting commercial harvests and ecosystem health.

This project will provide data to verify water quality models and help resource managers determine the quantitative relationships between nutrient pollution and development, magnitude, longevity, and distribution of the dead zone.

Findings are expected to support the development of more accurate predictions of hypoxia development on the Louisiana continental shelf.

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