Nature & Environment

This Year's Massive Gulf of Mexico Dead Zone Could be Among Top Ten on Record

Catherine Griffin
First Posted: Jun 19, 2013 07:23 AM EDT

The Gulf of Mexico is known for its yearly dead zones, a condition that leaches all of the oxygen from coastal waters and leaves them lifeless. Now, NOAA scientists have discovered that this year's dead zone could be massive--and possibly record-setting.

Dead zones aren't necessarily restricted to summer, though that's when they usually occur. They're the product of excessive nutrient pollution, which is usually associated with human activities like agriculture. As the nutrients seep into the water, massive algal blooms occur. While algae and other small photosynthetic organisms produce oxygen while alive, they will eventually die. As they decompose, essential oxygen is sucked from the water near the ocean bottom. Since little water mixing occurs during the summer, the issue is exacerbated and leaves areas where no marine life can survive.

These dead zones can have huge implications for fisheries, which can suffer greatly from the phenomenon. It can cause species to move location or can even kill entire populations of slower-moving animals. That makes it crucial to predict these dead zones in advance--if possible

 "Monitoring the health and vitality of our nation's oceans, waterways and watersheds is critical as we work to preserve and protect coastal ecosystems," said Kathryn D. Sullivan, acting NOAA administrator, in a news release. "These ecological forecasts are good examples of the critical environmental intelligence products and tools that help shape a healthier coast, one that is so inextricably linked to the vitality of our communities and livelihoods."

In order to predict the dead zone for the Gulf, scientists examined several different factors. More specifically, they looked at how many nutrients have entered the Gulf and how weather patterns might affect runoff.

In the end, the scientists found that the dead zone in the Gulf will be between 7,286 and 8,561 square miles, which could place it among the ten largest recorded. In fact, the dead zone could be the size of Connecticut, Rhode Island and the District of Columbia combined on the low end.

So why the big prediction? It's all about the nutrients. About 153,000 metric tons of nutrients flowed down the Mississippi and Atchafalaya rivers to the northern Gulf of Mexico in May. That's an increase of 94,900 metric tons over last year's 58,100 metric tons. The main reason for this massive increase is the fact that last year, the area was experiencing drought. That means there was no rain to wash excess nutrients into the rivers.

"Understanding the sources and transport of nutrients is key to developing effective nutrient management strategies needed to reduce the size of hypoxia zones in the Gulf, Bay and other U.S. waters where hypoxia is an ongoing problem," said Lori Caramanian, deputy assistant secretary of the interior for water and science, in a news release.

It looks like we're in for a big one this summer, but there are some positives. Scientists are continually gathering information in order to help reduce this dead zone. Currently, the Mississippi River/Gulf of Mexico Nutrient Task Force aims to reduce the zone to less than 2,000 square miles by implementing new actions that they outlined in 2008.

See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone

More on SCIENCEwr