Gulf’s dead zone bigger than Connecticut

By Spencer Hunt, The Columbus Dispatch
29 July 2013


The bad news is that this year’s dead zone in the Gulf of Mexico is bigger than average.

Big is relative when it comes to tracking and forecasting the region off Louisiana where dissolved oxygen levels are so low that fish and other aquatic wildlife can’t breathe. The good news is this 5,840 square-mile region, which is bigger than Connecticut, is actually smaller than what experts expected.

Researchers with the National Oceanic and Atmospheric Administration had predicted a Gulf’s dead zone in the range of 7,286 to 8,561 square miles.  Nancy Rabalais, executive director of theLouisiana Universities Marine Consortium, said winds helped mix the water and force the oxygen-depleted zone towards the east.The zone forms from decomposing algae that grow thick feeding primarily on nitrogen and some phosphorus from manure, fertilizers and sewage that rains wash into streams that drain to the Mississippi River. Ohio farms and cities along streams that drain to the Ohio River, which flows to the Mississippi, help make this state a key contributor to the Gulf’s dead zone.

The Ohio Environmental Protection Agency has a proposal with the U.S. EPA to enact numeric limits for phosphorus and nitrogren runoff to streams, mostly to help fight blooms of toxic, blue-green algae that appear each summer in Lake Erie and inland lakes. The state agency also has targeted Ohio stream systems, including the Scioto, which help pollute the Gulf, for runoff reduction efforts.