New study on N2 fixation
Congratulations to Jon Graf...
...on the successful defense of his doctoral dissertation on January 18th at the Faculty of Geosciences of the University of Bremen. His doctoral dissertation was entitled:
'Microbial oxidation of methane in stratified freshwater lakes'
Congratulations to one of the pioneers of the Biogeochemistry Group, our technician Kirsten Imhoff...
... on her 25 year anniversary! We are looking forward to the next years.
Research in the Biogeochemistry Group focuses on microbiological and geochemical processes that control bioactive element cycling in the marine environment. We employ geochemical, microbiological, modeling, molecular and single-cell techniques to study the environmental regulation of these processes, and their effects on the global biogeochemical cycles.
Our goal is to provide fundamental insights into microbial mediated processes in the Ocean that ultimately affect Ocean chemistry, biology and climate, and vital input for models used to predict potential future changes resulting from human activities.
13. December 2017
New study on N2 fixation
Dinitrogen (N2) fixation is the largest source of new nitrogen (N) to the ocean. The diversity of N2-fixing microorganisms in the ocean is dominated by heterotrophic organisms, yet, very little is known about this particular group. A new study by researchers of the MPI Bremen and the University of Kiel now describes a novel N2-fixing Alphaproteobacterium that was isolated from the oxygen-minimum zone off Peru, a region that has been hypothesized to harbor significant N2 fixation rates. The study gives insights into the metabolic potential and versatility of this newly-isolated N2-fixing microorganism that, based on molecular studies, is potentially widespread in the ocean.
13. June 2017
New studies on carbon and nitrogen cycling
New studies published online with scientists from the Biogeochemistry Group:
Eichner et al.
Marchant et al. (see press release HERE)
Oswald, Graf et al. (see press release HERE)
Bristow et al.
4. April 2017
Glacier bacteria’s contribution to carbon cycling
A new study published in the journal Nature Geoscience by Dr. Heidi Smith (Montana State University) and colleagues shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a finding that has global implications as the bulk of Earth’s glaciers shrink in response to a warming climate. See full MPI press release HERE.
29. March 2017
Phosphorus cycling in the dark ocean
A new study by Dr. Sarah Sokoll and colleagues is coming out in Geophysical Research Letters. This study describes experiments using radiolabeled phosphate that show the rapid uptake of phosphate into particles in sub-euphotic waters off the coasts of Mauritania and Namibia. The experiments and analyses demonstrate that this uptake is biologically mediated, and thus P cycling in the dark ocean is more intense than originally thought. In other words, P associated with sinking organic matter in the ocean is not simply degraded and released into the water column, but cycles several times through a microbial loop. Such intensified P cycling in sinking particles may have implications for the composition of phosphorus bearing organic matter reaching the seafloor, and for global ocean biogeochemical models.
This work was conducted as cooperation between the University Bremen (Marum) and the Max Planck Institute for Marine Microbiology (MPIMM) in Bremen.