Methanogenesis exceeds <scp>CH<sub>4</sub></scp> consumption in eutrophic lake sediments
Sofia D'Ambrosio, John A. Harrison
Abstract
Abstract Lakes and reservoirs collectively contribute significant amounts of methane (CH 4 ) to the global atmosphere. If CH 4 production were not at least partially balanced by consumption (oxidation) in most of these systems, they could potentially emit an order of magnitude or more CH 4 . The impacts of environmental drivers such as trophic status, temperature, and latitude on CH 4 production, CH 4 oxidation, and the balance of the two processes influence current and future patterns of freshwater CH 4 emissions. Using CH 4 production and oxidation rates measured with a common methodology (incubations) from over 60 different lakes and reservoirs, we provide novel evidence for lower sediment CH 4 oxidation efficiency at high sediment CH 4 production rates. We also show a strong positive correlation between sediment CH 4 production and lake trophic status. Our results suggest that less efficient CH 4 consumption at high CH 4 production rates could help explain greater surface emissions often observed in eutrophic lakes globally.