NOAA Scientists Issue “Dead Zone” Forecast

A team of NOAA scientists is forecasting that the “Dead Zone” off the coast of Louisiana and Texas this summer should be significantly smaller than the average size since 1990. 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. It is caused by a seasonal change where algal growth, stimulated by input of nutrients such as nitrogen and phosphorus from the Mississippi and Atchafalaya rivers, settles and decays in the bottom waters. The decaying algae consume oxygen faster than it can be replenished from the surface, leading to decreased levels of dissolved oxygen.

This summer’s “Dead Zone” is predicted to be less than 1,400 square miles, an area the size of Rhode Island. The average annual hypoxia-affected area since 1990 has been approximately 4,900 square miles. The forecast is based on nutrient loads from the Mississippi and Atchafalaya rivers in May and June. Nutrient loads were lower than average this year, probably due to below average precipitation across much of the Mississippi River Basin. The nutrient data is provided by the U.S. Geological Survey. NOAA funds research cruises to track development of hypoxia. These have been conducted monthly since January and will be completed by the end of July.

These research, observational, and modeling studies are part of a larger effort by NOAA’s Center for Sponsored Coastal Ocean Research Center to develop a fundamental understanding of the northern Gulf of Mexico ecosystem, with a focus on the causes of the hypoxic zone and the prediction of its future extent and impacts to aquatic species.

A team of NOAA scientists is forecasting that the “Dead Zone” off the coast of Louisiana and Texas this summer should be significantly smaller than the average size since 1990. 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. It is caused by a seasonal change where algal growth, stimulated by input of nutrients such as nitrogen and phosphorus from the Mississippi and Atchafalaya rivers, settles and decays in the bottom waters. The decaying algae consume oxygen faster than it can be replenished from the surface, leading to decreased levels of dissolved oxygen.

This summer’s “Dead Zone” is predicted to be less than 1,400 square miles, an area the size of Rhode Island. The average annual hypoxia-affected area since 1990 has been approximately 4,900 square miles. The forecast is based on nutrient loads from the Mississippi and Atchafalaya rivers in May and June. Nutrient loads were lower than average this year, probably due to below average precipitation across much of the Mississippi River Basin. The nutrient data is provided by the U.S. Geological Survey. NOAA funds research cruises to track development of hypoxia. These have been conducted monthly since January and will be completed by the end of July.

These research, observational, and modeling studies are part of a larger effort by NOAA’s Center for Sponsored Coastal Ocean Research Center to develop a fundamental understanding of the northern Gulf of Mexico ecosystem, with a focus on the causes of the hypoxic zone and the prediction of its future extent and impacts to aquatic species.