Maps showing isotopic composition of methane in seawater of the Alaskan Beaufort Sea, 1994

We are engaged in a five-year study to test the hypothesis that methane from decomposing gas hydrates may contribute methane to the atmosphere. The release of methane, a "greenhouse" gas, can enhance global warming and be a factor in global climate change. 

As part of the study we have measured the methane concentration in the water column of the Beaufort Sea shelf out to water depths of 90 meters from 1992-1995. In 1994 the carbon isotopic composition of methane in seawater of the Beaufort Sea shelf from Cape Halkett to Mikkelsen Bay (total water depths from 3 to 56 m) was measured by gas chromatography-isotope-ratio mass spectrometry in an effort to define the source of methane. Concentrations of methane in water samples used for isotopic analysis ranged from 5.4 to 275 nM.