Ethylene rather than acetylene inhibits soil methane oxidation rates in a subtropical evergreen forest

Ethylene and acetylene have been widely applied as inhibitors for microbial processes such as denitrification, nitrification, methanogenesis, and methane oxidation. Here, we tested the inhibition effects of these two trace gases on methane oxidation rates in subtropical evergreen forest soils. One-week laboratory incubations showed that aerobic soil methane oxidation rates at ambient or 50 parts per million (ppm) methane concentration were not affected by the addition of 100 or 100,000 ppm acetylene. In contrast, increasing amounts of ethylene markedly reduced soil methane oxidation rates. Our results suggest the selective inhibition of soil methane oxidation rates between ethylene and acetylene in these subtropical evergreen forest soils, and highlight the importance of verifying the efficiency of commonly-applied inhibitors before investigating microbial processes in underrepresented environments.