Gulf of Mexico dead zone now as big as Connecticut and Rhode Island combined

Distribution of bottom water dissolved oxygen July 28-August 3, 2015 west of the Mississippi River delta. (Data source: Nancy N. Rabalais, LUMCON, and R. Eugene Turner, LSU)

The Gulf Coast Dead Zone is a massive area of water near Louisiana and Texas, where most marine life cannot live at the bottom due to low oxygen levels. It’s caused by an excess of nitrogen and phosphorus pollutants that flow into the Mississippi River and into the Gulf of Mexico. The dead zone is at its largest during the summer months. Researchers just conducted their annual measurements and found this year’s dead zone measures nearly 6,500 square miles. That’s the size of Connecticut and Rhode Island combined. FSRN’s Nell Abram speaks with Dr. Nancy Rabalais. She’s executive director of the Louisiana Universities Marine Consortium and a leading expert on gulf hypoxia.

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Nell Abram: First, Dr. Rabalais can you explain what gulf hypoxia is and where the nitrogen and phosphorus pollution that causes it comes from?

Dr. Rabalais: The dead zone as its known, it really not completely dead. But it’s an area of low oxygen in the Gulf of Mexico that forms every year now, at least since the 1970s. And it’s a result of the fresh water from the river creating a layered system and the nutrients – nitrogen and phosphorus – stimulating phytoplankton excess growth which sinks to the bottom and then in the decomposition process uses up the oxygen on the bottom. So we have very large areas with insufficient oxygen for fish, crabs, shrimp – things that you can think of living on the bottom – cannot, they have to flee the area.


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