Event

The Department of Earth & Environmental Science

University of Pennsylvania

Invites you to attend a EES Seminar Series

Friday, March 17th - 3:00 PM

"How Microbes Make Rocks"

Silica, carbonate and silicate minerals preserve a nearly 3.5 billion-year long record of life on our planet. We are only beginning to understand how the interplay among environmental chemistry, organismal evolution and microbial stress responses contributed to the secular changes in the fossil record. In this talk, I will use the genomic and the fossil records of Cyanobacteria, the organismal lineage with the oldest fossil record, to ask when this photosynthetic lineage evolved the critical ability to produce oxygen. I will then present results of experimental work that shows the ability of cyanobacteria to promote their own fossilization by precipitating silica and carbonate minerals. These results help constrain the concentrations of silica in Proterozoic marine environments, explain the preservation of exquisite cyanobacterial fossils in chert lenses associated with Proterozoic carbonate deposits and can inform the attempts to remove CO2 from the modern atmosphere and search for signs of life on Mars.

Dr. Tanja Bosak

Professor

Chair of the Program in Geology, Geochemistry & Geobiology

Tanja Bosak was born in Croatia and graduated from the Zagreb University with a degree in Geophysics. After a summer of research at JPL and a short stint as a meteorologist at the Zagreb Airport, she moved to the California Institute of Technology in Pasadena, where she studied signatures of microbial processes in ancient sedimentary rocks and earned a Ph.D. in Geobiology. She spent two years at Harvard as a Microbial Initiative Postdoctoral Fellow, joined the Department of Earth, Atmospheric and Planetary Sciences at MIT in 2007 and is now a professor of Geobiology.