Oxic methanogenesis is only a minor source of lake-wide diffusive CH4 emissions from lakes
F. Peeters, Hilmar Hofmann
Abstract
Methane emissions from lakes are a major natural source in the global budget of atmospheric methane. A large fraction of these emissions result from diffusive CH 4 emissions, i.e., the diffusive transport of oversaturated methane from the surface waters to the atmosphere. CH 4 is typically produced in anoxic sediments and oxidized in oxic waters 1 but can also be produced in oxic waters 2 , 3 . Schmidt and Conrad 4 suggested that the oversaturation of CH 4 in surface waters of lakes results from two processes: CH 4 release from littoral sediments in combination with horizontal transport to the open water and in situ net production of CH 4 in oxic surface water. The relative importance of the two processes for diffusive emissions of CH 4 from lakes is the focus of this discussion.