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McAfee Professor of Engineering
Department of Civil and Environmental Engineering, Department of Biology, MIT
B.A. (Biology/Chemistry), Skidmore College, 1969; Cornell
University 1970; Ph.D. (Biology), S.U.N.Y. Albany, 1974.
Sallie W. Chisholm has been a professor of engineering at MIT since 1976 and since 1993 has had a joint appointment in biology. Her research interests encompass the general areas of biological oceanography, plankton ecology, phytoplankton physiology, and ecological genomics. Her current specific interests are in ecology, evolution, and comparative genomics of marine cyanobacteria; environmental control of cell cycle regulation in cyanobacteria; ocean fertility and planktonic size spectra; and the ecological and policy dimensions of large-scale ocean fertilization. In Dr. Chisholm's words: "The general goal of the research in my lab is to advance our understanding of the ecology of phytoplankton in the oceans. The broader context of this work is quantifying the role marine phytoplankton play in the global carbon cycle, and in regulating the dynamics of higher trophic levels in the sea. In recent years our work has focused primarily on the ecology of Prochlorococcus, which serves as a model system for understanding microbial ecology in the sea, and for developing the field of ecological genomics."
Thursday, April 25, 2002
|Prochlorococcus: A Window into the Photosynthetic Machinery of the Oceans|
Fifteen years ago, a tiny (0.7 mm diameter) prokaryotic phytoplankter was discovered in the North Atlantic Ocean, which has proven to be an important primary producer in the sea. Members of this group - which we named Prochlorococcus - sometimes comprise over half of the total chlorophyll in regions of the oligotrophic oceans. Multiple ?ecotypes” of Prochlorococcus have been identified, which are adapted for optimal growth and photosynthesis at different light intensities. Thus what appears to be a stable homogeneous population is actually a mixture of genetically distinct physiological types - ?ecotypes” - which alternate in dominance as the mixed layer of the surface oceans changes. This genetic diversity allows the group to thrive over a broad range of environmental conditions in the oligotrophic oceans. We now have the complete genome sequence of two Prochlorococcus ecotypes, and they have proven to be quite different: One has roughly 1700 genes, and the other 2400. We are working on ?decoding” these genomes, which is yielding some new insights into oceanic processes.
|Thursday, April 25, 2002
5:15 p.m. - 6:30 p.m.