Physiological and Molecular Diversity of Atmospheric Methane (CH4) Oxidizers in Soil

Marine Biological Laboratory, Woods Hole MA

Investigators

Abstract

Atmospheric methane contributes substantially to the greenhouse effect and has increased dramatically in the past century because of expanding agriculture and industry. Bacterial consumption of methane in soils is an important regulator of atmospheric methane concentration. The significance of the soil sink lies in its potential to mediate long-term, anthropogenic effects on atmospheric methane through its response to disturbances such as agriculture, forest clearcutting, drought, and soil warming. Because the amount of atmospheric methane consumed annually in soils is comparable to the annual increase in atmospheric methane, the cumulative effects of disturbance on the soil methane sink over time could contribute significantly to methane accumulation in the atmosphere. However, the biology of the soil sink is poorly understood because researchers have yet to identify and fully describe the soil bacteria that actually oxidize atmospheric methane in situ. In this project, Dr. Steudler and colleagues will investigate the physiology and molecular ecology of atmospheric methane oxidizers in five temperate and taiga forest ecosystems where disturbance effects on atmospheric methane consumption are well characterized. Their goal is to assess the role of cross-site diversity among the methane oxidizing organisms in controlling the soil methane consumption response to disturbances, including N fertilization, drought and soil warming. This research will provide an estimate of microbial diversity among soil atmospheric methane oxidizers across geographically distant and ecologically distinct forest ecosystems, examine how this diversity is distributed in nature relative to biogeochemical process dynamics and ecological gradients, and assess how important this diversity is in controlling the ecosystem-level response of soil methane consumption to disturbance and climate change.