Gulf of Mexico dead zone in 2024 measured at 6,705 square miles

HOUSTON (ICIS)–National Oceanic and Atmospheric Administration (NOAA) supported scientists announced that this year’s Gulf of Mexico “dead zone” is approximately 6,705 square miles, the 12th largest zone on record in 38 years of measurement.

This equates to more than 4 million acres of habitat potentially unavailable to fish and bottom species, an area roughly the size of New Jersey.

Scientists at Louisiana State University and the Louisiana Universities Marine Consortium led the annual dead zone survey from 21-26 July.

The Gulf’s hypoxic (low oxygen) and anoxic (oxygen-free) zones are caused by excess nutrient pollution, which researchers attribute to being primarily from human activities such as agriculture and wastewater occurring in the watershed.

First documented in 1985 off the coast of Louisiana, many researchers have primarily placed blame on farmland fertilizer run-off as being the main culprit of the dead zone.

Yet evidence also shows that urban areas, human waste treatment, precipitation and atmospheric dust as well as natural sources also contribute large amounts.

With excess nutrients there is an overgrowth of algae, which sinks and decomposes causing low oxygen levels which are insufficient to support most marine life and habitats.

The Mississippi River/Gulf of Mexico Hypoxia Task Force, a state and federal partnership, has set a long-term goal of reducing the five-year average extent of the dead zone to fewer than 1,900 square miles by 2035.

The five-year average size of the dead zone is now 4,298 square miles, more than two times larger than their target.

“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 Nicole LeBoeuf, NOAA’s National Ocean Service assistant administrator.

“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.”

In June the agency had predicted an above-average sized dead zone of 5,827 square miles, based primarily on Mississippi River discharge and nutrient runoff data from the US Geological Survey.

“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 Nancy Rabalais, Louisiana State University professor.

“We continue to be surprised each summer at the variability in size and distribution.”