Gulf of Mexico ‘dead zone’ twice what it was last year, but not a record
This year’s so-called “dead zone” in the Gulf of Mexico, an area where a lack of oxygen kills sea life that can’t swim away, is twice the size of last year’s, according to scientists, but it’s not a record.
The recurring area of low oxygen covers 5,840 square miles of the Gulf floor this year. Scientists had expected a record zone area due to a wet spring.
The zone is created each year when farm fertilizer from the Mississippi River Basin washes into the Gulf of Mexico, feeding algae blooms that, in turn, die and sink to the bottom of the mouth of the river. There they decompose and use up the oxygen.
Scientists from Louisiana State University and the University of Michigan had expected a wet spring to bring record levels of nutrients to the Gulf, leading to a dead zone that could have approached or exceeded the largest ever recorded — the one in 2002 that encompassed 8,481 square miles of the Gulf.
“A near-record area was expected because of wet spring conditions in the Mississippi watershed and the resultant high river flows which deliver large amounts of nutrients,” said Nancy Rabalais, Ph.D. executive director of the Louisiana Universities Marine Consortium (LUMCON), in a press release from the National Oceanic and Atmospheric Administration. “But nature’s wind-mixing events and winds forcing the mass of low oxygen water towards the east resulted in a slightly above average bottom footprint.”
The zone threatens commercial and recreational fisheries across the region. The low oxygen kills animals that cannot swim away, and hurts the quality of food for fish that return in the fall when oxygen levels rise, according to Rabalais.
The Mississippi River Collaborative, a partnership of environmental organizations and legal centers in states along the Mississippi River, sued the U.S. Environmental Protection Agency last year over the levels of fertilizer pollution.
The suit called for set standards for nitrogen and phosphorus pollution.