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Wed, Feb

NOAA Forecast Predicts Large "Dead Zone" for Gulf of Mexico this Summer

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A team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University, and the University of Michigan is forecasting that the “dead zone” off the coast of Louisiana and Texas in the Gulf of Mexico this summer could be one of the largest on record. The dead zone is an area in the Gulf of Mexico where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters.

A new study from NOAA was released and it predicts that the "dead zone" off the coast of Louisiana and Texas in the Gulf of Mexico this summer could be one of the largest on record. The dead zone is an area in the Gulf of Mexico where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters. The research comes from NOAA-supported scientists at the Louisiana Universities Marine Consortium, Louisiana State University, and the University of Michigan. Dead zones are caused by nutrient runoff, principally from agricultural activity, which stimulates an overgrowth of algae that sinks, decomposes, and consumes most of the life-giving oxygen supply in the water.

The dead zone size was predicted after researchers observed large amounts of nitrogen feeding into the Gulf from the Mississippi and Atchafalaya Rivers. The rivers experienced heavy water flows in April and May that were 11 percent above average.

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Scientists are predicting the area could measure between 7,450 and 8,456 square miles, or an area roughly the size of New Jersey. However, additional flooding of the Mississippi River since May may result in a larger dead zone. The largest one on record occurred in 2002, measuring 8,484 square miles.

This forecast helps coastal managers, policy makers, and the public better understand and combat the sources of the dead zones. For example, the models that generate this forecast have been used to determine nutrient reduction targets required to reduce the size of the dead zone. This hypoxic, or low-to-no oxygen area, is of particular concern because it threatens valuable commercial and recreational Gulf fisheries by destroying critical habitat.

Dead zones are caused by nutrient runoff, principally from agricultural activity, which stimulates an overgrowth of algae that sinks, decomposes, and consumes most of the life-giving oxygen supply in the water.

The dead zone size was predicted after researchers observed large amounts of nitrogen feeding into the Gulf from the Mississippi and Atchafalaya Rivers. The rivers experienced heavy water flows in April and May that were 11 percent above average.

"The high water volume flows coupled with nearly triple the nitrogen concentrations in these rivers over the past 50 years from human activities has led to a dramatic increase in the size of the dead zone," said Gene Turner, Ph.D., a lead forecast modeler from Louisiana State University.

For more information: http://www.cop.noaa.gov/stressors/extremeevents/hab/features/hypoxiafs_report1206.html