Drought May Be Shrinking Gulf Dead Zone
The dead zone in the Gulf of Mexico is about half the size it was a year ago. Photo by NASA Goddard Photo and Video, flickr.com/gsfc.Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.
Just a year after the worst drought on record here in Texas, the Midwest is in the midst of one of its worst droughts in decades. But some researchers say this might be good news for marine life in the Gulf of Mexico.
An area in the gulf known as the “dead zone” because of its lack of oxygen is half the size it was last year. That’s according to researchers at the Louisiana Universities Marine Consortium. They say the low amounts of rain lead to less runoff from farms, which means less nutrient-rich fertilizer out of nearby rivers and streams.
Every summer, algae feeds on the fertilizer and blooms on the ocean surface. When it dies, it sinks. The bacteria that feed off the decomposing algae use up the oxygen near the sea floor and leave a dead zone.
Edward Buskey with the University of Texas Marine Science Institute says these areas became known as dead zones because of their potentially toxic effects on marine life.
“So the mobile animals just tend to avoid that area,” Buskey said. “They’ll swim away from it as the oxygen gets lower. But things that don’t move as fast like some of the animals that live on the bottom, you know crabs and clams and shrimp and things like that, if they can’t get out of that area it will kill them.”
Buskey says the dead zones existed all over the world before artificial fertilizers. But they’ve recently become bigger.
“It’s something that occurs naturally,” Buskey said, “but is also something that is made worse by human activities.”
Buskey says farms with retention ponds near their fields see a substantially lower amount of fertilizer runoff.
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