Past changes in ocean circulation and climate using geochemical proxies.
Research Area
The primary focus of my research is to understand the link between ocean circulation and climate over earth history. The global deep ocean circulation is an important component of the earth’s climate system because the deep ocean hosts a large reservoir of carbon dioxide that exchanges with the atmosphere on short timescales, and ocean circulation also transports heat across the face of the planet. I am specifically interested in reconstructing changes in deep water mass source and structure, and determining how these are linked with changes in deep ocean nutrient contents and overturning rate.
My research group at Cambridge uses radiogenic isotopes and other geochemical tools, measured in marine sediment samples at globally distributed sites, to gain a wider view of past ocean circulation and geochemistry. A number of my recent PhD students have used Nd isotopes to reconstruct past changes in NADW formation in the Nordic Seas and Arctic Ocean (Larkin et al., 2022) and examine rare earth element cycling in Antarctic sediments and the South Atlantic (Wang et al., 2022). I am also involved in ongoing studies on marine sediment cores from the North Atlantic, Brazil Margin, Southern Ocean, and Indo-Pacific, as well as terrestrial and archaeological samples.
Project Interests
I am interested in supervising PhD students in these areas:
- Reconstructing global-scale water mass geometries using neodymium isotopes and other palaeoceanographic proxies.
- Examining Arctic neodymium cycling, water mass labelling, and changes in deep water formation (with Kate Hendry and Michael Meredith at BAS, Mohamed Ezat at Tromso).
- Reconstructing glacial-interglacial ice sheet dynamics by investigating source-to-sink detrital sediment transport on the Antarctic continental margin (with Claus-Dieter Hillenbrand at BAS).
- Relating the physical mixing of the deep ocean mixing with palaeoceanographic reconstructions (with Ali Mashayek at Dept Earth Sciences, Laura Cimoli at DAMTP, and David Munday at BAS).
