PhD project offered by the IMPRS-gBGC in Jan 2025

From Sea to Land – mapping the provenience of atmospheric sulfur

Georg Pohnert, Gerd Gleixner

Project description

Dimethylsulfide (DMS) is an environmentally important trace gas with roles in sulfur cycling, signaling to higher organisms, and in atmospheric chemistry.(1) In the sea the major DMS precursor is dimethylsulfoniopropionate which contributes via lysis to DMS production in a teragram scale annually.(2)
DMS is believed to be predominantly produced in marine environments, but significant amounts are also generated from terrestrial environments, for example, peat bogs can emit ~6 µmol DMS m^-2 per day, likely via the methylation of methanethiol (MeSH).(1)
We recently discovered potential alternative sources for DMS, namely the metabolite gonyol or dimethyl acetate.(3) In addition, we show that this natural product family also provides a direct precursor of dimethylsulfoxide, dimethylsulfoxoniopropionate which extends our view of the global sulfur cycle.(4,5)
With this project, we aim to investigate in land/sea sampling transects, to elucidate which different precursors of DMS and DMSO contribute along the coastal lines to the ecosystem-wide formation of these molecules. The sampling is underway in the Tara Trec program and, for the first time allows a systematic assignment of terrestrial and marine metabolites that contribute to atmospheric sulfur.

Working group & planned collaborations

The PhD candidate will work in the Department of Bioorganic Analytics (Pohnert Group) at the Friedrich Schiller University Jena and in close collaboration with the Department of Biogeochemical Processes at the Max Planck Institute for Biogeochemistry (Gleixner group). The international teams are devoted in developing and applying analytical techniques to generate knowledge about ecosystem functioning and biogeochemical cycling.

Requirements

We welcome applications from highly motivated and curious students from any country who have

A Master’s degree in chemistry, biology, chemical biology, or all other disciplines related to environmental sciences.
A passion for solving analytical puzzles and assembling a bigger global picture
Experience in the utilization of analytical techniques, ideally in mass spectrometry
Good English written and communication skills

The Max Planck Society (MPS) strives for gender equality and diversity. The MPS aims to increase the proportion of women in areas where they are underrepresented. Women are therefore explicitly encouraged to apply. We welcome applications from all fields. The Max Planck Society has set itself the goal of employing more severely disabled people. Applications from severely disabled persons are expressly encouraged.

References

(1) Hopkins, F. E., Archer, S. D., Bell, T. G., Suntharalingam, P. & Todd, J. D. The biogeochemistry of marine dimethylsulfide. Nature Reviews Earth & Environment 4, 361-376, doi:10.1038/s43017-023-00428-7 (2023).
(2) Johnston, A. W. B., Green, R. T. & Todd, J. D. Enzymatic breakage of dimethylsulfoniopropionate - a signature molecule for life at sea. Current Opinion in Chemical Biology 31, 58-65, doi:10.1016/j.cbpa.2016.01.011 (2016).
(3) Gebser, B. & Pohnert, G. Synchronized Regulation of Different Zwitterionic Metabolites in the Osmoadaption of Phytoplankton. Marine Drugs 11, 2168-2182, doi:10.3390/md11062168 (2013).
(4) Carrion, O., ... Pohnert, G., ... Todd J (2023) Function and wide distribution of DMSOP cleaving enzymes in marine organisms. Nature Microbiology 8, 2326–2337.
(5) Thume, K., Gebser, B., Chen, L., Meyer, N., Kieber, D.J., Pohnert G. (2018) The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle. Nature 563: 412.