Bo Barker Jørgensen, Aarhus University, Denmark
Recipient of the 2023 Urey Award
Bo Barker Jørgensen is a professor of Geomicrobiology at Aarhus University, Denmark. He was the founding director of the Max Planck Institute for Marine Microbiology in Bremen, Germany, and head of the Center for Geomicrobiology at Aarhus University. He is a member of the National Academy of Sciences, USA.
Research Statement
My research focus is on the biogeochemistry and microbial ecology of marine sediments – from microscale to global perspectives. I use radiotracers combined with geochemical analyses to unravel processes of the sulfur and carbon cycles and determine their interactions and quantitative significance. Over the years, this approach has demonstrated the important contribution of sulfate reduction for the mineralization of sediment organic matter and for the anaerobic oxidation of methane. The approach has revealed the key role of sulfur disproportionation reactions and quantified the importance of sulfide oxidation for oxygen consumption in the seabed. The data have also revealed cryptic cycling of sulfur and methane.
Through the IODP, I have been deeply engaged in the exploration of the deep sub-seafloor biosphere. In the Center for Geomicrobiology, we studied this important component of the global biosphere and demonstrated how deeply buried microorganisms thrive under extreme energy limitation with generation times of up to thousand years. Their slow metabolism in million-year-old sediments control the balance between burial and mineralization of organic matter over geological time. By diverse DNA-sequencing techniques for phylogenetic and functional genes we have shown how these communities assemble already in near-surface sediments and become specialized only at depth. To conserve energy, they possess genes involved in the repair of critical macromolecules in the cells, for example to combat the racemization of amino acids.
The main objective of my current research remains to unravel the sulfur and methane cycles. We try to understand and reconcile the discrepancy between modeled and experimentally measured process rates and their use in global budgets. We study how the opposite processes of methane production and methane oxidation are controlled in the seabed, and which are the microorganisms responsible for cryptic methane cycling. We test the potential role of conductive minerals as capacitors by extracellular electron transfer in bacteria and archaea.
Additional information and a list of publications can be found here.