My current research focuses on the role of the Southern Ocean during past intervals of climate change. I use geochemical tools to investigate two main topics: (1) the past variability of dust transport in the Southern Hemisphere and (2) past changes in Southern Ocean circulation.
1. The input of dust-borne Fe to the Southern Ocean is considered to have stimulated the primary production in the Southern Ocean and thus the drawdown of atmospheric CO2 during past ice ages. Rare earth elements and the isotopic compositions of strontium, neodymium and lead provide a chemical fingerprint which I use to identify the terrestrial source regions of dust recovered from deep-sea sediments.
2. The Southern Ocean is a key region for the overturning and mixing of water masses within the global ocean circulation system. These processes influence the exchange of CO2 between the ocean and the atmsophere. I use neodymium isotopes extracted from seawater-derived precipitates to learn about past changes in Southern Ocean circulation.