Current Research and Scholarly Interests
My group specializes in high resolution studies of climatic and oceanic variability during modern times as well as over the past 50 to 12,000 years. Our most productive archives for this work include the skeletons of long-lived corals from the tropics and the deep sea, as well as sediments from lakes and marine environments. We use chemical, isotopic, and morphological measurements of these materials to investigate the timing and rates of change associated with past climate and C cycle excursions. Current field areas include the American Samoa, Antarctica, the Line Islands, Easter Island, Chile, Patagonian Argentina, and Palau. We also collect deep sea corals to better understand their ecology as well as their self-contained records of change in the deep sea. We do this work using deep diving research submersibles in the Gulf of Alaska and the central tropical and north Pacific. We dive with the Hawaii Undersea Research Lab, using their two submersibles Pisces IV and Pisces V. We are currently working on several projects in Antarctica to assess the impacts of climate change on Southern Ocean ecosystems and C-system chemistry. Much of this work focuses on the Ross Sea where we are studying the modern uptake of carbon dioxide by the ocean and the sensitivity of primary production to changes in nutrients, temperature, sea ice cover, and CO2. We are also using sediment cores from fjords and shelf basins of East Antarctica and the Antarctic Peninsula to study past and changes in the Antarctic Ice Sheet. My lab participated in the ANDRILL program as shore-based and field-based scientists exploring the history of Antarctic climate at Windless Bight (McMurdo Ice Shelf Drilling) and Southern McMurdo Sound. I am also a proponent and participant on the 2010IODP Expedition 318 to Wilkes Land, Antarctica.
We have recently engaged in an extensive collaboration with colleagues in Civil and Environmental Engineering at Stanford to develop instrumentation and methodologies for directly measuring C system transformations (production/ respiration and calcification/ dissolution) in coastal marine systems. We are instrumenting coral reefs at several Pacific locations as well as a kelp forest in Monterey Bay. In parallel with our studies of field-scale variability in carbon system chemistry we have also been engaged in a series of efforts to understand the controls on carbonate biomineralization in organisms ranging from reef-building corals to clams from the deep sea. We hope that a better understanding of this process leads to better predictions for the impact of global environmental change on marine organisms.
I teach both undergraduate and graduate courses in climate and global change, geochemistry, oceanography, marine geology, and paleoclimatology. I am particularly intrigued with teaching in the field and have taken over 250 Stanford students to remote locations such as Antarctica and the Line Islands to participate in educational and research expeditions.