GEOTRACES and chemical oceanography – I am studying the sources, sinks, and internal cycling of trace metals and their isotopes in the ocean. The main tools I use are the insoluble uranium-series isotopes 230Th and 231Pa. Their insolubility and well-known production rate by uranium decay makes these isotopes powerful tracers of scavenging (i.e. the removal of dissolved ions from solution via adsorption onto settling particles) and particle dynamics in the ocean. Some topics I’m interested in are trace metal removal by particles in hydrothermal plumes, the development of 230Th as a gauge to determine high-resolution vertical profiles of particulate matter flux and regeneration, and trace metal input rates from dust dissolution at the sea surface.
Noble Gas Oceanography – I am interested in oceanic gas uptake processes. I recently took part in the Hawaii Ocean Time Series HOT-303 cruise to measure argon isotopes, as well as the first oceanic profiles of krypton and xenon isotopes. Our goal is to develop noble gas isotopes as sensitive tracers of gas uptake mechanisms during deepwater formation. This work is underway with Alan Seltzer at Scripps Institute of Oceanography.
Paleoceanography – I took part in the NBP1702 cruise along 170ºW between McMurdo Station, Antarctica, and Christchurch, New Zealand, collecting gravity and piston cores from the Pacific Sector of the Southern Ocean. I am generating a record of the ventilation and sedimentary redox conditions from the last glacial maximum to present to test whether there were glacial-interglacial changes in the mechanisms of bottom water formation in the Southern Ocean.