Paleoceanography and paleoclimatology
ICP-MS Trace Element Lab
Past abrupt climate change, ocean circulation, ocean biogeochemistry, marine carbon cycle, trace and minor elements in biogenic calcium carbonates
Improved knowledge of the modes and mechanisms of past climate variability is crucial for understanding our current and future climate. I am a paleoceanographer, studying large-scale changes in ocean circulation and biogeochemistry that occur over orbital, millennial, and shorter timescales. Most of my work has focused on the last full glacial-interglacial cycle, spanning roughly the past 150,000 years. Major variations in ocean circulation, from abyssal depths to the surface, are believed to have strongly influenced climate via the transport of heat. The oceans also exert control over atmospheric levels of carbon dioxide, an important "greenhouse" gas. Such changes are reflected in the physical and chemical properties of seawater, including temperature, salinity, carbonate system parameters, radiocarbon content, and the concentrations of various nutrients. I mainly use trace and minor elements in the calcitic shells of protozoa called foraminifera as recorders of these properties. By analyzing and dating sediment cores that contain foraminifera, we can reconstruct ocean chemistry and inferred circulation patterns during the past.
- Provost's Faculty Achievement Award, University of Colorado, Boulder, 2008