'Tiny cells, global impact': MIT oceanographer to tell why

Penny Chisholm '69

What goes on under the sea is a mystery to most land-dwellers, but what happens there profoundly affects life on earth. Skidmore graduate Sallie (Penny) Chisholm ?69, a biological oceanographer at MIT, explains how and why in her talk on ?Tiny Cells, Global Impact: Why You Should Care (and Worry) About Marine Microbes,? beginning at 4 p.m. Wednesday, March 26, in Emerson Auditorium. The lecture is one in the College?s Distinguished Scientist Lecture Series.

?The general goal of the research in my lab is to advance our understanding of microbial ecology and evolution in the oceans,? Chisholm explains on her MIT web site. ?In recent years we have focused our attention on the cyanobacterium Prochlorococcus, which is the smallest and most abundant microbe in ocean ecosystems.?

These tiny, teeming blue-green algae are the basis of the ocean?s food chain, and more. They turn sunlight into food through photosynthesis while also taking up carbon and pumping out oxygen, thus playing a key role in regulating the earth?s atmosphere and climate.

Chisholm?s laboratory was the first to publish a genome of Prochlorococcus?finding that it contains only 2,000 genes (compared to 30,000 for a human being). This, says Chisholm, is the smallest number of genes that can convert solar energy into living biomass. ?It behooves us to understand exactly how?this tiny cell converts solar energy into living biomass,? Chisholm said in a press release. Cyanobacteria are ?not just some esoteric little creatures,? she added. ?They dominate the oceans.?

Chisholm is the Lee and Geraldine Martin Professor of Environmental Studies at MIT, where she has taught since 1976. Her research interests include microbiology, ecology, oceanography, and ecological genomics. In 2003 she was elected to the National Academy of Sciences for her ?pioneering studies? into ?the Earth?s primary production.?