Lakes produce natural methane emissions from bacterial decomposition of organic remains in bottom sediments. By examining the isotopic signal of fossil plankton that consume bacteria, we can assess levels of methane production through time, using past warm periods to test whether methane production will increase with future climate warming.
Funding source: NERC
Start date: TBA
End date: TBA
Collaborative award with the University of Newcastle
Methane is x28 more potent than CO2 as a greenhouse gas, and lakes are a major source of natural emissions via bacterial breakdown of organic material in bottom sediments. In the near future, emissions from high-latitude lakes are expected to increase significantly because the high latitudes are the fastest warming region of the planet. Permafrost thaw will release large amounts of stored soil carbon into streams and lakes, and this, together with higher temperatures, should lead to greater methane production. Models that simulate lake methane emissions under anticipated future warming lack contemporary empirical data to validate their simulations, because there are no locations that can provide real-world analogues for expected future conditions. This project uses past warm periods as analogues of future environmental conditions by examining sediment archives in the lakes. Working with researchers in the USA, we will be using an innovative method based on biogeochemical signatures preserved in lake sediment to attempt a quantification of past greenhouse gas emissions. Through the integration of data and modelling approaches, this study will provide critical new insights into how climate affects methane production under conditions well beyond the envelope of modern observations. The project will now start in 2021.