Jon Graf

Main research interest

  • Biogeochemistry of phosphorus, iron and sulfur mediated by the anaerobic oxidation of methane (AOM)
  • Biochemistry of archaeal sulfate reduction and bacterial sulfur disproportionation associated with AOM
Sedimentary cycling of P, Fe and S mediated by AOM

Anaerobic oxidation of methane (AOM) is a process recognized for its crucial role in the cycling of carbon and sulfur in marine environments. However, recent data suggest that in addition to carbon and sulfur, organisms involved in AOM might also play a role in the sedimentary iron and phosphorus cycle. High-resolution imaging studies demonstrate the presence of intracellular particles enriched with iron and phosphorus in Deltaproteobacteria associated with AOM but role iron and phosphorus remains unclear. We use radioactive isotope labeling experiments as well as single-cell imaging techniques to investigate the role and function of those particles in a cellular and biogeochemical context.

Biochemistry of sulfate reduction and sulfur disproportionation in AOM

Recently, two sulfur-metabolizing pathways associated with AOM have been identified: Bacterial sulfur disproportionation and archaeal sulfate reduction. While both pathways aren't novel per se, it is their association with AOM which makes the biochemical study of those pathways vital for our understanding of the microbial sulfur cycling coupled to AOM.

We employ a targeted approach using metagenomics and metatranscriptomics to identify candidate proteins. Further we want to biochemically isolate, purify and investigate those candidate proteins to eventually reconstruct the enzymatic pathways underlying bacterial sulfur disproportionation and archaeal sulfate reduction in AOM.

Jon Graf

PhD student

Department of Biogeochemistry

MPI for Marine Microbiology
Celsiusstr. 1
D-28359 Bremen




+49 421 2028-653

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