Prof. Dr. Stephen Giovannoni 

This research is a partnership with Professor A. Murat Eren at the Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at Universität Oldenburg. We are studying the evolution of organic carbon metabolism in SAR202, a group of marine bacteria that evolved roughly 2 billion years ago. These cells are 10-30% of all cells in today's oceans. While studying their genomes we discovered unprecedented metabolic parallelism—multiple versions of related pathways for organic carbon oxidation. We postulate that the evolution of these pathways enabled these cells to harvest a sector of complex organic matter that is not used effectively by other organisms, precipitating a major geohistorical event 2.3 to 2.1 billion years ago known as the Lomagundi isotopic excursion. During my visit to the HIFMB, Professor Eren and I will explore the evolution of metabolic pathways in these cells. This research is relevant to understanding the mechanisms of the oceanic biological carbon pump and proposed schemes for carbon dioxide removal.