Professor and Chair:
Phone: +1 401 863 1207
Phone 2: +1 401 863 3339
Understanding how the earth's climatic system, particularly the ocean, adjusts itself to perturbation on various timescales drives most aspects of my research. My recent projects include application of alkenone paleotemperature determinations to reconstructing El Nino conditions in the eastern Pacific, and to understanding drivers of Plio-Pleistocene climate change. I also work on developing new tools to scan sediment cores non-destructively, and applying orbital stratigraphy to solve problems in earth history over Cenozoic and Mesozoic time.
I received my B.S. in Geological Sciences from Yale College in 1980 (Magna Cum Laude), and my Ph.D. from Princeton University in Geological Sciences, in 1987. I have been recognized for my research in the area of Earth Systems History and paleoceanography which has earned me a leadership role in the paleoclimate community. My research has led to a better understanding of the history of global change. Within the University community, I have worked hard to develop strong links between the Department of Geological Sciences and Environmental Studies, the Environmental Change Initiative and Ecology and Evolutionary Biology groups. I teach broad-reaching courses such as "Ecology and Climate", "Ocean Biogeochemistry", and "The Enigma of Warm Climates in the Geological Record."
Most of my current research centers on reconstructing two vital aspects of the past surface ocean: the distribution of temperatures and patterns of biological production. The ocean holds nearly all the heat at the surface of our planet, and therefore plays a crucial role in determining past global and regional temperatures. In addition, conditions in the ocean drive the cycle of water vapor in the atmosphere, and this cycle very much depends on ocean surface temperatures. The surface ocean also exchanges large quantities of CO 2 with the atmosphere. The net transfer of carbon into or out of the atmosphere depends on both the surface temperature of the ocean and on carbon synthesis in the upper ocean by plankton. Plankton activity in turn responds in a complex way to climate change; we do not yet understand how these feedbacks work between global climate, carbon cycle changes, and paleoecological changes in the ocean.
Some of the exciting areas that my group is now investigating include high-resolution oceanographic reconstructions (decadal to century-scale) in the El Nino-dominated regions off the Peru and California coasts, and the evolution high and low latitude climate linkages as the Earth has moved from a warm state in the Pliocene (3-5 Ma) to its present heavily glaciated state.
The principal tools for my work include:
- Alkenone paleotemperature determinations
- Alkenone and other biomarker determinations for estimating past ocean productivity
- Sediment Nitrogen isotope analyses for estimating the past intensity of oceanic anoxic zones (in collaboration with Mark Altabet, UMass Dartmouth)
- Oxygen isotope stratigraphy
- Non-destructive methods of sediment core analysis
- Time series analysis for extracting cyclic patterns from sediment data in order to develop paleoclimatic models
Yale College Wilde Prize in Marine Geology, 1980
National Science Foundation Graduate Fellowship, 1982-1985
Fellow, American Association for the Advancement of Science
Reviewer of approximately 5 journal articles/year
Member, Ocean History Panel, Ocean Drilling Program (1991-1994)
Co-director, SIO summer undergraduate research program for minorities in science
National Science Foundation Marine Geology and Geophysics panelist
Member, United States Scientific Advisory Committee for the Ocean Drilling Program (1997-2000)
Member, "Extreme Climates" international advisory group to the O.D.P. (1998-2000)
Editorial Board Member, Geology (2002-2006)
Principal Investigator, NSF GK-12 outreach program to Providence Public Schools
GEOL 0160: First Year Seminar: Global Change: Ecology & Climate
GEOL 0240: Earth: Evolution of a Habitable Planet
GEOL 1120: Paleoceanography (w/Warren Prell)
GEOL 1130: Biogeochemical Cycles in the Ocean
GEOL 2920: Past Variations in the Global Carbon Cycle
GEOL 2920: The Enigma of Warm Climates in the Geological Record
Current Graduate Students:
Former Graduate Students:
Caitlin Chazen, Ph.D. '10
Laura Cleaveland, Ph.D. '08
Scott Kreitz, Sc.M. '98
Kira Lawrence, Ph.D. '06
Lorraine Lisiecki, Ph.D. '05
Zhonghui Liu, Ph.D. '04
Lauren Wincze, Sc.M. '02
National Science Foundation, "Collaborative Research: High resolution
paleoceanography in the heart of the Equatorial Pacific Cold Tongue",
National Science Foundation, "SGER: Coring in the Eastern Equatorial Pacific to Obtain Long Climate Records".
Petroleum Research Fund of the American Chemical Society "Preservation of Biomarker Environmental Proxies in Uplifted Marine Sections: a Test from the Mediterranean Region".
National Science Foundation Educational Division, "GK-12: Physical Processes in the Environment".
National Science Foundation, "Collaborative Research: High Latitude Temperature and Biological Responses to Plio-Pleistocene Global Change".
National Science Foundation, "SGER: The Deuterium-Hydrogen Ratio in Alkenones as a Proxy for the Paleo-hydrological Cycle".
National Science Foundation, "A polar signal dominating the tropical oceans, 1.2-1.8 Ma?".
- Peru Margin Paleoceanography: Does the El Nino Model Apply?
- Brown University Geologists Create 5-Million-Year Climate Record
- Alkenone Paleotemperature Measurements
- Orbital Forcing - Cenozoic and Mesozoic
- Stalking el Niño
- Brown's Earth Systems History Group
- More about my research
- Data from Cruise to the Galapagos/Peru Margin
- Environmental History of the Coastal Zone
- GK-12 Science Outreach