Title: Isotopic tracing of methane in water and exchange with the atmosphere
Abstract: Sediments of Lake Constance are rich in bacterial methane (yield CH4 < 130 μg CH4/g wet sample; δ13CH4 > −85 ‰). However, methane flux from the sediment into the water was not detected. Deep water (below ca. 50 m) has “background” signature (yield < 50 nL/L; −40< δ13CH4 < −30 ‰). Surface water is enriched in methane relative to atmospheric equilibrium, most probably the methane is produced by methanogens in the surface layers. The surface water is a source for atmospheric methane; calculated flux rates exceed high values reported for ocean water. Deep water of the Bay of Bengal is generally low in methane (“background” signature). At two locations at the continental slope, bacterial methane (δ13CH4< −50 ‰) seeps from the sediments into the water. Methane concentration in the surface water is close to atmospheric equilibrium in the equatorial area but higher in the Ganges/Bramaputra mouth, where methane flux to the atmosphere reaches up to 30 kg km−2yr−1.
Publication Year: 1996
Publication Date: 1996-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 8
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