On early Earth the oceans were Fe(II)-rich and the atmosphere was O2-poor. We study how phototrophic Fe(II)-oxidizing microorganisms could have contributed to the deposition of Banded Iron Formations and to which extent biotic and abiotic diagenesis and metamorphism have contributed to the transformation of the sedimented cell-Fe(III)-mineral aggregates. We also determine the protection of phototrophic organisms from UV radiation by the silica-Fe-minerals precipitated in the ocean water column. Biogeochemical fingerprints are investigated in biogenic magnetite nanoparticles produced by iron-metabolizing bacteria, aiming to determine how and to which extent bacterial metabolic activity leaves imprints on the ancient rock record. To this end classic geomicrobiological techniques are combined with trace element- and isotope geochemistry. Finally, modern Fe- and S-rich habitats are analyzed as modern analogues of ancient oceans.
Team members: Carolin Dreher, Jan-Peter Duda, Prachi Joshi, Muammar Mansor, Eric Runge, Andreas Kappler
Collaborators: Kurt Konhauser, Ronny Schönberg, Manuel Schad