Direct measurement of microbial methane oxidation in peat soils in relation to vegetation cover

Carbon (C) storage in terrestrial ecosystems represents a major ecosystem service, due to its potential to mitigate climate forcing by anthropogenic CO₂ emissions, and assessment of the vulnerability of current C stocks therefore forms a major theme in the experimental work carried out across ecosystems. Methane (CH₄) emissions from peatlands are of particular interest due to the considerable greenhouse gas potential of methane and its likely response to both climate change and land management practices.

This project is linked to on-going activities at Lake Vyrnwy (N Wales) currently carried out by UKPopNet. Previous results clearly indicate that certain vegetation types appear to be consistent net sources of methane (dominance of methanogenesis), whilst others are actually sites of net methane uptake (methanotrophy), and on-going experiments aim to assess the net flux of methane in response to water table manipulations.

The work carried out in this project compliments the measurement of net methane fluxes by separating out the dominant component fluxes. This is achieved by measuring directly the level of methane oxidation across vegetation types at Lake Vyrnwy, using stable isotopes. The results will clarify the link between microbial activity and vegetation cover at the sites of the observed fluxes. These are the first field scale measurements of methane oxidation using novel methodologies at Lake Vyrnwy, and capture an important link in the C cycle and the greenhouse gas balance of these peatlands, which are directly transferable to a wide range of peatlands throughout the UK and indeed worldwide.