Intersecting Methane Production and Oxidation Zones in Freshwater Sediments

Abstract. Methane is produced and emitted when organic carbon accumulates in the sediments of reservoirs. Before being released into the water body, methane can be oxidised microbially by multiple electron accepters in the sediment, and which were traditionally considered to be spatially separated from methanogens. This study provides geochemical and microbiological evidence to firstly demonstrate that methane production and oxidisation zones intersected each other in the sediment of a freshwater reservoir. Methanogens were distributed along the sediment depth profile. Hydrogenotrophic Methanomicrobiales were found to be responsible for methane production in the upper layer (