My research focuses on electro biogeochemistry and on the identity and activity of prokaryotes.
1) Electro biogeochemistry: We have provided geochemical evidence that electric currents running through defaunated sediment, possibly through bacterial nano wires, couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide. Ongoing experimentation suggests furthermore that electron donors such as iron sulfides and organic carbon can deliver electrons to the bioelectric system and that oxidized iron can act as electron acceptor. The goals for the nearest future is to is to explore in further details the role of various electron acceptors and donors in these systems and to constrain further the existence of an electrical network in marine sediments.
2) Activity and identity of prokaryotes on a single cell level: Our target is to determine both activity and identity of prokaryotes in deeply buried sediments. To accomplish that we use a combination of stable isotope incubations, Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization (CARD-FISH), and Secondary Ion Mass Spectrometry (nanoSIMS) . The current work has been focused on development and test of incubation systems, isolation of active cells from the sediment matrix, and localization of active cells in the nanoSIMS. The goal for the nearest future is to apply this methodology to sediments collected on an IODP cruise to the Bering Sea (leg 323).