The image of an ocean dead zone is stark: a barren, underwater desert of silt, littered with the bodies of suffocated crabs and asphyxiated fish.
Caused when agricultural runoff feeds huge algae blooms that suck oxygen out of the water when they decay, so-called hypoxic zones are increasingly common in U.S. waters, a recent government study finds.
Thirty times more common, in fact.
In a report released by the National Oceanic and Atmospheric Administration (NOAA) and a White House commission September 3, researchers said the 30-fold increase has occurred since 1960. At least 300 U.S. waterways now have “stressful” or hypoxic zones.
The problem is so sweeping that it now affects all of the nation’s coasts and even the Great Lakes, AOL’s David Knowles reports. Climate change is also suspected to be a factor.
The Gulf of Mexico dead zone is the largest and best known, caused mainly by runoff spewing out of the Mississippi. The zone was predicted to spread over an area up to 7,800 square miles in 2010, putting it about the size of New Jersey.
Waters off of Oregon and Washington are perhaps the most in trouble, constituting the third-largest seasonal dead zone in the world, Knowles writes.
Dead zones are also on the rise globally, according to Helium. The number of dead zones worldwide increased from 146 in 2004 to 405 in 2008.
In U.S. waters, the report mainly blames the rise in industrial agriculture for the increase in hypoxic areas. Efforts to stem the activity “have not made significant headway,” a release on the report reads.
“It is imperative that we move forward to better understand and prevent hypoxic events, which threaten all our coasts,” wrote experts in a letter accompanying the report.
The largest dead zone in the world is in the Baltic Sea, where the oxygen depleted waters stretch to the size of Denmark.