Scientists find dead zone in Chandeleur Sound off Louisiana, Mississippi coast

By Chris Kirkham, The Times-Picayune
October 12, 2010, 4:21 PM The sprawling band of lifeless ocean water known as the “dead zone” that forms each summer in the Gulf of Mexico has been well-documented for decades, with teams of government and research scientists analyzing the ecological impacts every year. But much less is known about smaller low-oxygen dead zones along the state’s coastline. According to research done by the Lake Pontchartrain Basin Foundation and another local volunteer group this summer, scientists have found a 250-square-mile dead zone in Chandeleur Sound, east of the Mississippi River. Scientists first found evidence of the low-oxygen area in 2008, which prompted the Basin Foundation to partner with the Marine Research and Assistance Council this summer to study water quality in the sound, off the coasts of Louisiana and Mississippi. There is no direct connection between the dead zone and this summer’s massive oil spill in the Gulf, said John Lopez, the coastal sustainability director for the Basin Foundation. He pointed out the similar dead zone observation in 2008, when there was no oil spill. A more likely connection is the amount of nutrients from Mississippi River water that are being delivered to the coastal estuaries. In 2008, there were unusually high river levels, prompting the state to open the Bonnet Carre Spillway to relieve flooding concerns along the river. In an attempt to keep oil out of the marshes, the state this summer opened several freshwater diversions along the river, which funneled more fresh water and nutrients into the marshes. “It seems unlikely that this is primarily being caused by the oil spill,” Lopez said. “But because of all the unknowns about the oil spill, with the freshwater diversions and the effect on the biological aspects of the Gulf and maybe the sound … You can’t rule out that maybe it wouldn’t influence it.” …