Rationalising methane production in oxygen rich streambed sediment

Methane is a strong greenhouse gas and there is growing interest in environmental emissions. Only 15 years ago methane production was thought to be confined to the anoxic, water-logged soils and sediments of peatlands and lakes, but many studies are now reporting high methane production potentials in oxygenated riverbed sediments. This poses the question of how an obligate anaerobic microbial metabolism is sustained in oxygenated sediments? We have shown that fine sediment from agriculture may provide part of the answer but we, and others, have also measured methane production in pristine streams. Hence, our understanding of methane production in is incomplete which impedes our ability to predict change in emissions from a changing landscape. Here you will combine fieldwork and laboratory incubations with mass-spectrometry, gas-chromatography and oxygen dynamics to understand the regulation of methane production in riverbeds. You will also use molecular microbial techniques to characterise the microbial communities, especially any differences to classic anoxic, communities. There is scope to develop the molecular aspects of the project to identify mechanisms for oxygen tolerance in methanogens, along with kinetic effects. We know fine sediment pollution, correlated with elevated methane emissions, is widespread in streams, which has drawn attention from UK-based retailers and the potential for impact via better understanding of river-based methane production is strong.