Blurring the boundaries – discovering how anaerobic metabolisms persist in oxygenated environments

The cycling of nutrients on Earth is a key ecosystem service that sustains life, driven largely by microbes. Until recently, this microbial activity was thought to be divided between oxygen-rich and oxygen-poor environments — between aerobic and anaerobic metabolisms. Our recent work shows that processes once considered strictly anaerobic, such as nitrogen recycling and methane production, can also occur where oxygen is still present. This project will explore how these anaerobic metabolisms persist in oxygenated environments, combining fieldwork and laboratory experiments with analytical and molecular techniques to uncover the microbial communities and processes responsible. There is scope to develop the molecular aspects of the project further, particularly oxygen tolerance in anaerobic microbes, along with kinetic effects. We know fine sediment pollution, correlated with elevated methane emissions, and perhaps nitrous oxide too, is widespread in rivers and streams. This has drawn attention from UK-based retailers, and the potential for impact via a better understanding of environmental stressors and river-based greenhouse gas production is strong. Understanding these boundary-blurring processes will provide valuable insight into how the Earth system operates and how it may respond to future environmental pressures.