Examining Anaerobic Oxidation of Methane in a Northern Peat Bog

Abstract

Globally, about one-third of annual methane (CH4) emissions from natural sources come from freshwater wetlands. Scientists need a strong understanding of CH4 cycling to predict how climatic shifts will affect future CH4 emissions. Anaerobic oxidation of CH4 (AOM) is an important factor in CH4 cycle models in marine systems, but it has so far been excluded from freshwater CH4 cycle models which balance production and aerobic consumption. However, evidence for AOM as an influential part of CH4 cycling in freshwater ecosystems is mounting, revealing that traditional methods for measuring CH4 production and modeling CH4 cycling may need updating. Here, we present a new method for measuring AOM and gross CH4 production simultaneously during incubation using a 13CH4 tracer. This study supports existing evidence that AOM is an influential part of CH4 cycling in peatlands and presents evidence that the process can occur to a depth of at least 2 meters.