(The Center Square) – A low-oxygen “dead zone” in the Gulf of Mexico was larger than average but smaller than predicted, a recent survey found.
The “dead zone” with little to no oxygen can kill fish and marine life is approximately 6,705 square miles, or 4 million acres, the 12th largest found in 38 years of surveys. Work was done by scientists from Louisiana State University and the Louisiana Universities Marine Consortium supported by the National Oceanographic and Atmospheric Administration.
This “dead zone” is the size of New Jersey, and is larger than NOAA predicted in June.
The agency predicted an above-average sized “dead zone” of 5,827 square miles, utilizing data on Mississippi River discharge and nutrient runoff data from the U.S. Geological Survey.
A map of the Gulf of Mexico’s hypoxia zone. A red area on the map denotes 2 mg/L of oxygen or lower, the level which is considered hypoxic, at the bottom of the seafloor.
The average size of the hypoxia zone in the Gulf over the past five years has been 4,298 square miles.
These zones of low to no oxygen are caused by excessive nutrients, such as fertilizer runoff from farmland, and from the Mississippi and Atchafalaya river systems.
These nutrients set off an overgrowth of algae that dies and decomposes, depleting oxygen from the water as it sinks to the bottom. Research has shown this depletion causes fish and other marine life to vacate the area.
“It’s critical that we measure this region’s hypoxia as an indicator of ocean health, particularly under a changing climate and potential intensification of storms and increases in precipitation and runoff,” Nicole LeBoeuf, assistant administrator of NOAA’s National Ocean Service, said in a release. “The benefit of this long-term data set is that it helps decision makers as they adjust their strategies to reduce the dead zone and manage impacts to coastal resources and communities.”
The Environmental Protection Agency started the Gulf Hypoxia Program to reduce excessive nutrients and reduce the “dead zones” to 3,100 square miles or less by 2035. It is funded by $60 million from the $1.2 trillion Infrastructure Investment and Jobs Act of 2021.
