I use isotope geochemistry to understand the carbon cycle and other biogeochemical cycles.
Research Area
My research focuses on the carbon cycle, which refers to how carbon moves among various reservoirs on the planet; the amount in the atmosphere is critical for determining the surface temperature. In my research, I focus on the exchange of carbon between the surface and subsurface and how this exchange has varied over the course of Earth history; this understanding underpins our interpretation of how Earth has moved through greenhouse and icehouse phases and the role these play in the evolution of Earth’s surface environment and its habitability. Recently, my work has also focused on the carbon cycle in modern environments including soils and melting permafrost. I use a novel combination of geochemical techniques, geomicrobiological techniques, and numerical modelling to understand the flow of carbon through Earth’s surface and how it links to other biogeochemical (e.g. elemental) cycles. Recently my group has been working on methane fluxes from glaciated catchments and soils, microbially-driven diagenesis of anoxic sediments, use of isotope ratios to trace microbial processes, carbon mineralisation in the oceanic crust during hydrothermal circulation and evolution of ocean chemistry over time. With industry we have worked on novel ways to trace chemical reactions during enhanced rock weathering, carbon capture and storage, and bioremediation of contaminated groundwater.
Project Interests
Submarine basalt weathering may represent a major, and understudied, process in the global carbon cycle. Basalt is one of the most chemically reactive rocks on the planet, and covers 70% of the Earth’s surface. The role of the submarine alteration of basalt in the global carbon cycle remains a mystery; the role that basalt-hosted microbial communities play is also a mystery. I would like to explore experiments involving basalt and isotope doping to trace slow reactions, test the role that microbial populations play in basalt alteration, and/or identify an isotope tracer of submarine basalt weathering that can be measured in samples from the last 120 million years as ocean chemistry and temperature have changed.
