NOAA reports 2024 ‘dead zone’ in Gulf of Mexico larger than average
Image credit: NOAA
The Gulf of Mexico’s “dead zone,” an area with dangerously low oxygen levels, spans approximately 17 365 km2 (6 705 miles2) this year, making it the 12th largest recorded in 38 years, according to NOAA-supported scientists. This expanse threatens over 1.6 million ha (4 million acres) of marine habitat, an area comparable to the size of New Jersey.
NOAA-supported scientists announced on August 1, 2024, that this year’s Gulf of Mexico’s “dead zone,” an area of low to no oxygen that can kill fish and marine life, spans approximately 17 365 km2 (6 705 miles2).
This expanse is the 12th largest on record in the 38 years of measurement, equating to more than 1.6 million ha (4 million acres) of habitat potentially unavailable to fish and bottom species, an area roughly the size of New Jersey.
The annual dead zone survey was conducted by scientists from Louisiana State University and the Louisiana Universities Marine Consortium (LUMCON) aboard the research vessel Pelican from July 21 to July 26.
This measurement is crucial for the Mississippi River/Gulf of Mexico Hypoxia Task Force, a state and federal partnership aiming to reduce the five-year average extent of the dead zone to fewer than 4 921 km2 (1 900 miles2) by 2035.
“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, assistant administrator of NOAA’s National Ocean Service,
The five-year average size of the dead zone now stands at 11 129 km2 (4 298 miles2), more than twice the 2035 target.
In June, NOAA predicted an above-average dead zone of 15 093 km2 (5 827 miles2), based on Mississippi River discharge and nutrient runoff data from the U.S. Geological Survey. The measured size of 17 365 km2 (6 705 miles2) fell within the forecast’s uncertainty range.
“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, Ph.D., professor at Louisiana State University and LUMCON.
The images below show a map of the measured Gulf hypoxia zone, July 21 – 26, 2024. The red area denotes 2 mg/L of oxygen or lower, the level which is considered hypoxic, at the bottom of the seafloor, below that is the graph of the long-term measured size of the hypoxic zone (green bars) measured during the ship surveys since 1985, including the target goal established by the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force and the 5-year average measured size (black dashed lines).
The formation of dead zones is primarily due to excess nutrients reaching the Gulf via the Mississippi-Atchafalaya River Basin, stimulating an overgrowth of algae. When these algae decompose, they deplete oxygen in the water, causing hypoxia and forcing animals like fish and shrimp to leave the area. This exposure affects fish diets, growth rates, reproduction, habitat use, and the availability of commercially harvested species such as shrimp.
In June 2022, the Environmental Protection Agency (EPA) launched the Gulf Hypoxia Program to accelerate nutrient reduction actions by the Task Force, aiming to make significant progress toward the Gulf Hypoxia Action Plan.
“Nutrient pollution impacts water bodies across the country and in the Gulf of Mexico it has resulted in a dead zone, where low to no oxygen does not support fish and marine life,” said Bruno Pigott, acting assistant administrator of EPA’s Office of Water.
The Task Force states are scaling up their nutrient reduction strategies to increase climate resiliency and ensure benefits reach disadvantaged communities. “The importance of the Mississippi River to the strength and growth of our states’ economies and communities cannot be understated,” said Mike Naig, Iowa Secretary of Agriculture.
Through various programs, NOAA also supports the development of monitoring technologies and studies the impacts of hypoxia on fish and fisheries. This year, several autonomous surface vehicles (ASVs) were deployed alongside traditional ship-based measurements to map hypoxia in the Gulf of Mexico, marking a significant step in utilizing emerging technologies for environmental monitoring.
Reference:
1 Gulf of Mexico ‘dead zone’ larger than average, scientists find – NOAA – August 1, 2024
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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