Temperature and precipitation are key drivers of the Earth’s major biogeochemical cycles (carbon, nitrogen, sulphur, and phosphorus). I am particularly interested in terrestrial carbon cycle feedbacks and whether these act as positive or negative feedback mechanisms.

terrestrial methane cycling

Methane emissions from wetlands contribute significantly to atmospheric methane levels and play an essential role in the global carbon cycle. However, until recently, the response of the methane cycle to past climate perturbations remained unknown. We demonstrated that bacterial-derived lipids (“hopanoids”) can be linked to methanotrophy on the basis of their carbon isotopic compositions (Fig. 1). Crucially, as hopanoids are very resistant to degradation, this approach could provide insights into methane cycling dynamics over the last 300 million years.

Figure 1. Schematic representation of how the wetland methane cycle operates. Methane can be released to atmosphere via plants, bubbles or diffusion. However, it can also be consumed by methanotrophic bacteria (Credit: G. Inglis)

Figure 1. Schematic representation of how the wetland methane cycle operates. Methane can be released to atmosphere via plants, bubbles or diffusion. However, it can also be consumed by methanotrophic bacteria (Credit: G. Inglis)

Key publications

  • Inglis. G.N., Rohrssen, M., Kennedy, E., Crouch, E., Raine, I., Strogen, D., Naafs, B.D.A. and Pancost, R.D. Terrestrial methane cycle perturbations during the onset of the Paleocene-Eocene Thermal Maximum. Geology. 49. 520-524. https://doi.org/10.1130/G48110.1

  • Inglis, G.N, Naafs, B.DA., Zheng, Y., Schellekens, J., Pancost, R.D and ‘T-GRES Peat Database collaborators. δ13C values of bacterial hopanoids and leaf waxes as tracers for methanotrophy in peatlands. Geochimica et Cosmochimica Acta. 260. 244-256

  • Carmichael, M.J., Inglis, G.N., Badger, M.P.S., Naafs, B.D.A., Behrooz, L., Remmelzwaal, S., Montiero, F., Rohrssen, M., Farnsworth, A., Buss, H., Dickson, A.J., Valdes, P.J., Lunt, D.J and Pancost, R.D. Hydrological and associated biogeochemical consequences of rapid global warming during the Paleocene-Eocene Thermal Maximum. Global and Planetary Change. 157. 114-138

  • Naafs, B.D.A., Inglis, G.N. Blewett, J., McClymont, E., Lauretano, V., Xie, S, and Pancost, R.D. The potential of biomarker proxies to trace climate, vegetation, and biogeochemical processes in peat: a review. Global and Planetary Change. 179. 57-79