August 7, 2017 — Right now, in the depths of the Gulf of Mexico, lies an area the size of New Jersey that’s so oxygen-deprived it’s void of almost all marine life.
The so-called “dead zone” isn’t a new phenomenon: It appears in the Gulf, and other bodies of water, every summer. But what makes this year’s Gulf dead zone unique is its magnitude: At 8,776 square miles, it’s the largest ever since tracking began in 1985, the National Oceanic and Atmospheric Administration announced this week.
Its size is projected to affect local fishing economies and is raising questions over the amount of pollutants that flow into our water — particularly nutrients from excessive use of nitrogen fertilizers.
“It’s a symptom of an ecosystem that’s not functioning,” said Dr. Nancy Rabalais, a professor in oceanography and coastal science at Louisiana State University who has been leading survey missions of dead zones since NOAA started tracking them.
What causes dead zones
The dead zones occur as a result of nitrogen and phosphorus flowing into water from farmers using nutrients on crops as fertilizer, and those nutrients getting washed into streams and rivers by rain.
Once it gets to the Gulf of Mexico, the nutrients stimulate the growth of algae. The algae then sinks to the bottom of the ocean and bacteria start decomposing the organic matter in the algae. That process uses oxygen, drawing it from the water.