Tanja Bosak
Associate Professor
Chair of the Program in Geology, Geochemistry & Geobiology
MIT

Reconstructing the record of oxygenic photosynthesis on the Early Earth

The evolution of Cyanobacteria, photosynthetic microbes that split water and produce molecular oxygen, preceded the greatest biogeochemical transition that befell Earth - the addition of molecular oxygen to our planet’s atmosphere. How much time passed between the evolution of this clade and metabolism and the accumulation of oxygen in the atmosphere (the Great Oxidation Event, GOE, ~ 2.3 billion years ago) is an open question. This talk will present and evaluate textural, geochemical and molecular evidence for the presence of oxygenic photosynthesis more than 0.5 billion years before the GOE. Discrepancies between the long pre-GOE cyanobacterial presence and the first diagnostic cyanobacterial fossils will be discussed in the light of recent experiments that suggest an increased silicification potential of marine cyanobacteria in sulfate-rich seawater.

The Earth History and Paleobiology (EHAP) Seminar Series is jointly hosted by OEB and EPS.