- 1MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- 2Max Planck Institute for Marine Microbiology, Bremen, Germany
- 3Alfred Wegener Institute Helmholtz, Center for Polar and Marine Research, Bremerhaven, Germany
- 4University of Kiel, Institute for Metabolomics, Kiel, Germany
- 5University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, United States
- 6U.S. Geological Survey, Woods Hole Coastal and Marine Science Center, Woods Hole, United States
- 7University of Bremen, Faculty of Geosciences, Bremen, Germany
The anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is a key microbial process in the sulfate-methane transition zones (SMTZ) of cold seeps. In this process, anaerobic methanotrophic archaea (ANME) oxidize methane to inorganic carbon and transfer gained electrons to their sulfate-reducing partner bacteria (SRB), which, in turn, reduce sulfate to sulfide. While electron transfer is a well-established interaction mechanism, interactions on the molecular level, involving, for example, low-molecular-weight organics, have not been investigated.
Here, we examined the presence of such molecules in cold seep sediments from Astoria Canyon. We found unusually high concentrations of the disaccharide’s trehalose and sucrose in both the pore water and the solid phase of the sediments. Elevated levels of these sugars in the SMTZ, along with negative δ¹³C values between -55 and -80‰, indicate the production by the AOM core community. The presence of ANME-2 and SRB lipids with similar δ¹³C values supports this interpretation. A stable isotope probing experiment on sediments from the same cold seep system confirms the AOM-dependent production of these disaccharides. There, trehalose and sucrose showed strong 13C-incorporation upon addition of ¹³C-labeled inorganic carbon, alongside the lipids of the autotrophic AOM community.
While the precise role of trehalose and sucrose production during AOM remains unclear, our findings suggest that they may serve as intermediates in ANME/SRB interactions and possibly in the production or conservation of the extracellular polymeric substance (EPS) that encases them. To further elucidate their biochemical significance and functional role, we aim to quantify trehalose and sucrose in both pore water and sediment. Understanding the role of these disaccharides in AOM consortia will provide deeper insights into microbial interaction and adaptations in methane-dominated and other extreme environments.
How to cite: Stock, L., Wegener, G., Torset, S., Lipp, J., Dirksen, L., Liebeke, M., Lapham, L. L., Hildebrand, A., Pohlman, J., Lalk, E., and Elvert, M.: Production of the disaccharide’s trehalose and sucrose by ANME‑2/SRB consortia in a cold seep at the Astoria Canyon , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5580, https://doi.org/10.5194/egusphere-egu25-5580, 2025.
