Scientists Discover New Threat to Marine Life Possibly Linked to BP Oil Spill-

Scientists discovered two areas of low oxygen off the Alabama coast Tuesday, with levels below the limits that marine creatures require to sustain life. The first low-oxygen pocket was located on the ocean floor in about 60 feet of water 12 miles off the coast just south of the mouth of Mobile Bay, and the second was in about 100 feet of water 25 miles off the coast. The pocket layer was roughly 9 feet thick in both locations. During the analysis, scientists traveled a north/south line, so there is no evidence as to how wide the areas were. Researchers believe the peculiar existence of low-oxygen areas off the coast indicate that the number of oil-eating microbes have heavily increased due to the millions of gallons of oil in the Gulf. According to Monty Graham, a University of Alabama researcher working out of the Dauphin Island Sea Lab, water samples gathered during the test will be studied to establish whether oil and oil-consuming microbes were present along the sea floor. At present, scientists are in agreeance that underwater oil plumes in the Gulf may cause long-term damage to the marine ecosystem. “I think it adds to the weight of evidence coming from the other people working on those offshore plumes of oil,” said George Crozier, director of the Sea Lab. Oxygen levels have declined steadily since a sampling effort performed on May 28, Graham said, with levels between 4 and 6 milligrams per liter. By June 2, they had declined to 3 milligrams per liter or less. Tuesday, researchers measured 1.7 milligrams per liter. Scientists consider 2 milligrams per liter the threshold for survival. “Below 2 milligrams per liter, creatures are stressed. Fish will leave an area looking for more oxygen,” Graham said. Creatures that can’t move – barnacles, oysters, mussels and burrowing animals such as the marine worms – will simply die. Low oxygen levels in a broad expanse of the Louisiana Gulf is responsible for the infamous dead zone there. Extra nutrients in the water flowing into the Gulf from the Mississippi River feed microbial blooms. Those microbes, both while they are alive and after they die, consume oxygen. A comparable occurrence appears to be taking place off the Alabama coast. The debate, Graham said, is whether the Deepwater Horizon spill is responsible for increased microbial activity. He said that it is still possible that heavy rains in April and May caused a flush of nutrients to flow into the Gulf from the rivers that drain into Mobile Bay. Nevertheless, Graham says that he and other scientists have never before witnessed such a decline in oxygen off the coast despite years’ worth of data from the same sample locations.

Graham’s research is conducted through the Fisheries Oceanography of Coastal Alabama program, with funding from the Alabama Department of Conservation and Natural Resources and National Science Foundation. Data from the research cruises can be viewed here.