A dead zone roughly the size of New Jersey is expected to appear in the Gulf of Mexico this year. The National Oceanic and Atmospheric Administration and the U.S. Geological Survey say that though the Gulf experiences dead zones every year, the area will be 50 percent larger than normal this year, at about 8,100 square miles.
Dr. Alan Lewitus of the National Centers for Coastal Ocean Science’s competitive research program says that the zone indicates an oxygen-deprived area where ocean wildlife will have difficulty surviving.
“The oxygen falls below a certain level where it becomes difficult to breathe, and that can kill organisms,” Lewitus says. “It’s really a barren area in terms of life.”
Mobile aquatic life, including fish, can flee the area but organisms that adhere to rocks and other surfaces will likely die off. Lewitus says the dead zone’s borders are “dynamic” but generally surround the area where the Mississippi River meets the Gulf.
“There’s two main areas where the Mississippi River flows in, and both of those flow with high nutrients,” Lewitus says. “Nutrients are a good thing for plants, like fertilizer, nitrogen and phosphorous, but when it comes down into the Gulf of Mexico and there’s too much of it, that causes an over-stimulation of the biology.”
The resulting excessive bacteria sucks up the oxygen in the water and creates an uninhabitable area for aquatic life.
Lewitus says while the area is projected to be at its third largest size since scientists began documenting the zone, there is also evidence of a decrease in its severity.
“There [are] some signs that nutrient loading into the Gulf might be getting a little bit lower,” he says. “There’s been a lot of action in the watershed to try to reduce these nutrient pollutions, and there’s been a very active interagency task force over the last decade or so, which has put a lot of effort into trying to come out with better practices.”
He says rainfall and other sources of water flow may increase nutrient levels in the rivers, so urging agricultural businesses, for example, to curb their pollution could help shrink the dead zones.
“It’s very disturbing we’re not seeing a decrease in the size,” Lewitus says. “But we think that if we keep up the effort, that we can turn the tide on this.”
Written by Lila Weatherly.