A swirl of Deepwater Horizon oil is seen near stained marsh grass near Pass a Loutre in Plaquemines Parish southeast of Venice Sunday August 8, 2010 during a tour with Ben Weber of the National Wildlife Federation said that the recent claims by National Oceanic Atmospheric Administration and the Department of Interior that three quarters of the oil is out of the Gulf includes areas that are already impacted like Pass a Loutre. MATTHEW HINTON / THE TIMES-PICAYUNE

SkyTruth
Wednesday, August 18, 2010 Scientists vehemently disagreed with the brief report issued by the federal government on August 4 that some interpreted as evidence that most of the oil spilled from BP’s Macondo well was … gone. Researchers at the University of Georgia issued their own report yesterday, claiming that nearly 80% of the oil spilled remains in the ecosystem, subject to evaporation and biodegradation but at unknown rates, meanwhile doing damage in a variety of different ways. And natural gas, mostly methane, was released in great quantities during this spill. Some scientists have estimated that as much as 40% of the flow from the Macondo well was natural gas, mostly methane (CH4) that dissolved rather than floating to the surface and escaping into the atmosphere. At 80 cubic meters of methane per barrel of oil, with a total spill of 4.1 million barrels (172 million gallons) of oil, we calculate 328 million cubic meters – 11.6 billion cubic feet (BCF) – of methane were injected into the Gulf. Researchers from Texas A&M University, the University of Georgia, and the University of California – Santa Barbara have measured levels of dissolved methane thousands of times above normal, thousands of feet below the surface. The microbial degradation of methane will consume oxygen from the water, possibly slowing biodegradation of the oil, particularly at deeper levels, and leading to the formation of additional oxygen-deficient dead zones devoid of fish, marine mammals, and much of the typical Gulf fauna. …

BP / Gulf Spill – 172 Million Gallons of Oil, 11.6 Billion Cubic Feet of Natural Gas