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

Written by on June 21, 2009 in Marine Life
Gulf of Mexico - Courtesy of NOAA

Gulf of Mexico - Courtesy of NOAA

A team of university scientists, supported by NOAA, is forecasting the likeliest largest-on-record “dead zone” in the Gulf of Mexico, off the coasts of Louisiana and Texas this summer.

A dead zone is an area where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters and is 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 team is predicting the area could measure between 7,450 and 8,456 square miles – roughly the size of New Jersey. Additional flooding of the Mississippi River may result in a larger dead zone.

Researchers observed large amounts of nitrogen feeding into the Gulf from the Mississippi and Atchafalaya Rivers, which experienced heavy water flow in April and May that were 11 percent above average.

Gene Turner, Ph.D., a lead forecast modeler from Louisiana State University said. “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.”

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.

The team of scientists was supported by NOAA and composed 0f experts from the Louisiana Universities Marine Consortium, Louisiana State University and the University of Michigan.

Bottom life in the Gulf of Mexico  -  Credit: NURC/UNCW and NOAA/FGBNMS

Bottom life in the Gulf of Mexico - Credit: NURC/UNCW and NOAA/FGBNMS

Copyright ©  2009 by Marine Science Today, a publication of OceanLines LLC

About the Author

About the Author: Celia is Director of Business Operations for OceanLines LLC and is a frequent contributor to both OceanLines and Marine Science Today. She is a certified diver and her favorite topic is marine biology, especially stories about whales. .


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  1. Timbre says:

    The NOAA Gulf of Mexico map under the headline is misleading: it has nothing to do with the calculated “dead zone.” It is simply a map of the Gulf’s depths.

  2. Emily says:

    You’re right, thanks for bringing it to my attention. Here’s a link that has a graphic showing the measured size of the Gulf of Mexico dead zone from 1985 to the present
    2012 Gulf of Mexico “Dead Zone” Size:

    Here is an update from NOAA, posted on July 27, explaining that the “Midwest drought brings fourth smallest Gulf of Mexico ‘Dead Zone’ since 1985.”