Gulf Dead Zone Much Smaller Than Average

Jul 31, 2018
Originally published on July 31, 2018 4:33 pm

Every summer, a dead zone forms in the Gulf of Mexico. It’s an area with so little oxygen that marine life can’t survive, caused mostly by agricultural fertilizers that wash down the Mississippi River.


According to a new study from the Louisiana Universities Marine Consortium (LUMCON), it’s much smaller this year. But, that might not necessarily be a sign of progress.

Agricultural fertilizers wash into the Mississippi River and are carried to the Gulf, where they cause algae to bloom. As the algae dies, it sucks up oxygen in the water. The sea critters who can move, do. Those that can’t, die.


Every summer, scientists from LUMCON go on a research cruise to measure the dead zone. Last year they measured the biggest dead zone on record: 8,776 square miles -- about the size of New Jersey. The five-year average is 5,770 square miles.


This year they got a much smaller measurement: 2,720 square miles. But that doesn’t necessarily mean the problem is getting better, says Dr. Nancy Rabalais, lead scientist of the research cruise.


“The size this year was modified primarily by weather conditions,” she says.


Rabalais says it might have been much bigger, but rough seas mixed it around and made it appear much smaller. In any case, Rabalais says this year’s dead zone is still bigger the federal and state goal.


“It’s definitely too early to say that we have made much progress,” she says


Scientists say reducing agricultural runoff will help shrink the dead zone.


Support for the Coastal Desk comes from the Walton Family Foundation, the Greater New Orleans Foundation, the Foundation for Louisiana, and local listeners.

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