The 2022 summer dead zone in the Gulf of Mexico is expected to encompass more than 5,300 square miles, according to researchers with the National Oceanic and Atmospheric Administration (NOAA).
NOAA released its fifth-annual forecast June 2, stating the area "will be approximately 5,364 square miles, making it about average" compared to previous dead-zone measurements taken in the past 35 years of data collection. Dead zones, also known as hypoxic areas, are regions where oxygen levels are too low to support fish and other marine life, the forecast reports.
“The Gulf dead zone remains the largest hypoxic zone in United States waters," Nicole LeBoeuf, assistant administrator of NOAA’s National Ocean Service, said in the forecast, "and we want to gain insights into its causes and impacts.”
The run-off of nutrient-rich pollution from cities and agriculture throughout the Mississippi River Basin causes dead zones in the Gulf every summer, according to the report. The run-off causes excessive algae growth, which in turn chokes out oxygen. NOAA researchers work with scientists at the U.S. Geological Service (USGS) and from several universities to track nutrient levels in the watershed's rivers and identify "hot spots" of excess nutrient pollution.
"NOAA’s hypoxia forecast models and USGS monitoring of nutrients in rivers help to predict how hypoxia in the Gulf of Mexico is linked to nutrients coming from throughout the Mississippi River Basin," the agency states in the report.
Don Cline, Associate Director of the USGS Water Resources Mission Area, noted that since 1985, nitrogen-loading in the Gulf decreased then stabilized while phosphorous loading increased.
“A new USGS study indicates these trends are partly explained by nutrient inputs like fertilizer," Cline said in the forecast, "but notes other factors such as agricultural management practices and nutrients accumulated in the past were also likely important, particularly for phosphorus.”
Although the forecast size of this summer's dead zone is smaller than the five-year average of 5,380 square miles, it's still substantially larger than the long-range goal of decreasing the zone to less than 2,000 square miles set by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force (HTF).
The U.S. Environmental Protection Agency (EPA) is funding $60 million over five years to develop and implement strategies to reduce the amount of nutrient pollution released into the gulf, according to NOAA. The investment is part of President Joe Biden's Bipartisan Infrastructure Law, NOAA reports
“The Hypoxia Task Force has a transformational opportunity to further control nutrient loads in the Mississippi River Basin and reduce the size of the hypoxic zone using Bipartisan Infrastructure Law funding,” said John Goodin, director of U.S. EPA Office of Wetlands, Oceans and Watersheds.
“This annual forecast is a key metric for assessing the progress the Hypoxia Task Force is making.”
