While the BP oil spill has been labeled the worst environmental catastrophe in recent U.S. history, a biofuel is contributing to a Gulf of Mexico "dead zone" the size of New Jersey that scientists say could be every bit as harmful to the gulf.
Each year, nitrogen used to fertilize corn, about a third of which is made into ethanol, leaches from Midwest croplands into the Mississippi River and out into the gulf, where the fertilizer feeds giant algae blooms. As the algae dies, it settles to the ocean floor and decays, consuming oxygen and suffocating marine life.
Known as hypoxia, the oxygen depletion kills shrimp, crabs, worms and anything else that cannot escape. The dead zone has doubled since the 1980s and is expected this year to grow as large as 8,500 square miles and hug the Gulf Coast from Alabama to Texas.
As to which is worse, the oil spill or the hypoxia, "it's a really tough call," said Nathaniel Ostrom, a zoologist at Michigan State University. "There's no real answer to that question."
Some scientists fear the oil spill will worsen the dead zone, because when oil decomposes, it also consumes oxygen. New government estimates on Thursday indicated that the BP oil spill had gushed as much as 141 million gallons since an oil-rig explosion and well blowout on April 20 that killed 11 workers.
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