JUN 11, 2019 09:45 AM PDT

The Annual Gulf of Mexico Dead Zone Forecast to be the Size of Massachusetts

WRITTEN BY: Tiffany Dazet

According to a news release from The National Oceanic and Atmospheric Association (NOAA), this summer’s hypoxic zone in the Gulf of Mexico will be approximately the size of Massachusetts—covering 8,717 square miles (22,557 km2) of the continental shelf off Louisiana and Texas. If a significant tropical storm occurs, the zone will be 70% smaller than the predicted size. Scientists from the Louisiana State University Department of Oceanography and Coastal Sciences—Nancy Rabalais and Eugene Turner—prepare this forecast each year.

Image: NOAA

A hypoxic zone, commonly referred to as a “dead zone,” is an area of low to no oxygen concentration in ocean waters—typically less than two parts per million—which can no longer support living organisms. Hypoxic events can occur naturally in marine habitats worldwide, but seem to be happening much more frequently in shallow coastal and estuarine areas as a result of human activities. 

In this region of the Gulf of Mexico, the annually recurring hypoxic zone is caused by excess nutrient pollution throughout the Mississippi River watershed due to agriculture and urbanization—also technically known as eutrophication. When the rain washes excess nutrients such as phosphorous or nitrogen into surrounding waters, they eventually reach the ocean leading to massive blooms of microscopic algae. When these algae decompose they consume oxygen, depleting resources for the rest of the surrounding marine life and creating a “dead zone.” 

LSU ocean ecologist Nancy Rabalais told National Geographic that “when the oxygen is below two parts per million, any shrimp, crabs, and fish that can swim away will swim away. The animals in the sediment [that can’t swim away] can be close to annihilation.” Shrimp in hypoxic waters may have their growth stunted, which can impact Gulf Coast shrimpers by lowering the price of shrimp and their profits.

According to a press release from LSU, this particular hypoxic zone in the Gulf of Mexico started to appear 50 years ago when agriculture production in the Midwest increased. This hypoxic zone is also the second-largest human-caused coastal hypoxic area worldwide.

NOAA believes that this year’s dead zone is significant because of “the abnormally high amount of spring rainfall in many parts of the Mississippi River watershed, which led to record high river flows and much larger nutrient loading to the Gulf of Mexico.” Discharge in the Mississippi and Atchafalaya rivers was 67% higher than average this past May, resulting in nitrate loads 18% higher than average and phosphorus loads 48% higher than average.

Sources: NOAA, LSU, Gulf Hypoxia, National Geographic
 

About the Author
  • Enthusiastic science geek passionate about wildlife, wild places, and environmental issues. With 13 years of science writing under her belt, Tiffany hopes to educate and inspire the public to protect our planet.
You May Also Like
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
New Study Assesses Key Indicators of Arctic Climate Change
A study recently published in Environmental Research Letters revealed increasing air temperatures—closely followed by precipitation—may be the...
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
Human Activities are Causing the Next Mass Extinction
One million animal and plant species—one in every four—are at risk of extinction at an unprecedented rate of decline. This dire fact is one key...
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
Vermont bans neonics to protect bees
After years of scientific evidence that neonicotinoid pesticides are harmful to bees and other pollinators (LABROOTS INFOGRAPHIC), Vermont took a crucial s...
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
Missouri's tornado disaster
The powerful tornado that swept across Jefferson City, Missouri last night has left havoc in its wake, with at least three people dead. According to the Na...
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
Atmospheric CO2 levels top the charts
We all know that the currents atmospheric carbon dioxide levels are not, shall we say, ideal. But according to recent measurements from NOAA’s Mauna ...
JUN 20, 2019
Earth & The Environment
JUN 20, 2019
Are sustainable logging practices possible in the Amazon?
New research published in Environmental Research Letters from the Tropical managed Forests Observatory (TmFO) concludes that despite the implementation of ...
Loading Comments...