From the Des Moines Register
Click this link for a video where environmental reporter Perry Beeman explores Iowa’s fertilizer runoff and Louisiana’s fisheries: http://www.desmoinesregister.com/article/20121029/NEWS/310290013/Dead-zone-s-size-tied-tightly-to-water-levels?archive&nclick_check=1
Its size appears to be closely tied to the amount of water running down the Mississippi River and especially to the amount of nitrogen rushing to the Gulf, scientists say.
When the Mississippi runs hard, as it did in 1993 and 2008, the dead zone balloons to the size of New Jersey. More water means more nitrogen dumping into the Gulf. That means more algae. And when those algae die and rot, that means more bacteria consuming more oxygen.
That’s why Nancy Rabalais, who has studied the Gulf dead zone for decades, warns that this year’s smaller dead zone doesn’t represent a turning point.