Methane production in a flooded soil in response to elevated atmospheric carbon dioxide concentrations

Abstract

CH4 production in a flooded soil as affected by elevated atmospheric CO2 was quantified in a laboratory incubation study. CH4 production in the flooded soil increased by 19.6%, 28.2%, and 33.4% after a 2-week incubation and by 38.2%, 62.4%, and 43.0% after a 3-week incubation under atmospheres of 498, 820, and 1050 μl l–1 CO2, respectively, over that in soil under the ambient CO2 concentration. CH4 production in slurry under 690, 920, and 1150 μl l–1 CO2 increased by 2.7%, 5.5%, and 5.0%, respectively, after a 3-day incubation, and by 6.7%, 12.8%, and 5.4%, respectively, after a 6-day incubation over that in slurry under the ambient CO2 concentration. The increase in CH4 production in the soil slurry under elevated CO2 concentrations in a N2 atmosphere was more pronounced than that under elevated CO2 concentrations in air. These data suggested that elevated atmospheric CO2 concentrations could promote methanogenic activity in flooded soil.