Oxygen-depleted 'dead zone' in Gulf of Mexico larger than expected this year

Oxygen-depleted 'dead zone' in Gulf of Mexico larger than expected this year
by Doug Cunningham
Washington DC (UPI) Aug 1, 2024

The Gulf of Mexico's "dead zone" is the 12th largest on record this year, according to a Thursday report from NOAA-supported scientists. It's roughly 6,705 square miles this year, larger than expected.

The zone is an area of low to no oxygen in the water, and it can kill fish and other marine life.

"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," said NOAA's National Ocean Service assistant administrator Nicole LeBoeuf in a statement.

She said the long-term dataset on the gulf's dead zone "helps decision makers as they adjust their strategies to reduce the dead zone and manage impacts to coastal resources and communities."

Scientists had predicted an above-average dead zone of roughly 5,827 square miles, based mostly on Mississippi River discharge and runoff data.

"The area of bottom-water hypoxia was larger than predicted by the Mississippi River discharge and nitrogen load for 2024, but within the range experienced over the nearly four decades that this research cruise has been conducted," said Louisiana State University Professor Nancy Rabalais in a statement.

The average dead zone size over 37 years is 5,205 square miles, according to NOAA.

In 2023 the dead zone was a smaller-than-expected 3,058 square miles.

The five-year average dead zone size is 4,298 square miles.

Louisiana State University scientists and the Louisiana Universities Marine Consortium led the dead zone survey this year aboard the LUMCON research vessel.

The data collected is used by the Mississippi River/Gulf of Mexico Hypoxia task Force. That state and federal partnership wants to reach a goal of cutting the five-year average size of the Gulf of Mexico dead zone to fewer than 1,900 miles by 2035.

The Environmental Protection Agency's Bruno Pigott said in a statement, "EPA is committed to its partnership with state and local governments and Tribes in the Mississippi-Atchafalaya River Basin, working together to reduce nutrient pollution and protect the health of the Gulf. In fact, thanks to President Biden's Bipartisan Infrastructure Law, EPA is investing $60 million into this effort."

Dead zones are formed from an overgrowth of algae resulting from excess nutrient runoff into the gulf waters. When the algae die and decompose oxygen in the water is depleted.

The Gulf Hypoxia Program was created in June 2022 by the EPA to accelerate nutrient reduction actions aimed at cutting the amount of nutrients that feed the dead zone algae growth.