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Anaerobic methanotrophy is stimulated by graphene oxide in a brackish urban canal sediment |
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| Authors: | Koen A J Pelsma Niels A G M van Helmond Wytze K Lenstra Thomas Röckmann Mike S M Jetten Caroline P Slomp Cornelia U Welte |
| Institution: | 1. Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands;2. Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands Contribution: Conceptualization (supporting), Data curation (supporting), ?Investigation (supporting), Methodology (equal), Visualization (supporting), Writing - original draft (supporting), Writing - review & editing (supporting);3. Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands Netherlands Earth System Science Centre, Utrecht University, Utrecht, The Netherlands Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands Contribution: Conceptualization (supporting), Data curation (supporting), ?Investigation (supporting), Methodology (equal), Visualization (supporting), Writing - review & editing (supporting);4. Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands Contribution: Data curation (supporting), Methodology (supporting), Writing - review & editing (supporting);5. Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands Netherlands Earth System Science Centre, Utrecht University, Utrecht, The Netherlands Contribution: Conceptualization (equal), Project administration (equal), Resources (equal), Supervision (supporting), Writing - original draft (supporting), Writing - review & editing (supporting);6. Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands Netherlands Earth System Science Centre, Utrecht University, Utrecht, The Netherlands Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands Contribution: Conceptualization (supporting), Writing - original draft (supporting), Writing - review & editing (supporting) |
| Abstract: | Anthropogenic activities are influencing aquatic environments through increased chemical pollution and thus are greatly affecting the biogeochemical cycling of elements. This has increased greenhouse gas emissions, particularly methane, from lakes, wetlands, and canals. Most of the methane produced in anoxic sediments is converted into carbon dioxide by methanotrophs before it reaches the atmosphere. Anaerobic oxidation of methane requires an electron acceptor such as sulphate, nitrate, or metal oxides. Here, we explore the anaerobic methanotrophy in sediments of three urban canals in Amsterdam, covering a gradient from freshwater to brackish conditions. Biogeochemical analysis showed the presence of a shallow sulphate–methane transition zone in sediments of the most brackish canal, suggesting that sulphate could be a relevant electron acceptor for anaerobic methanotrophy in this setting. However, sediment incubations amended with sulphate or iron oxides (ferrihydrite) did not lead to detectable rates of methanotrophy. Despite the presence of known nitrate-dependent anaerobic methanotrophs (Methanoperedenaceae), no nitrate-driven methanotrophy was observed in any of the investigated sediments either. Interestingly, graphene oxide stimulated anaerobic methanotrophy in incubations of brackish canal sediment, possibly catalysed by anaerobic methanotrophs of the ANME-2a/b clade. We propose that natural organic matter serving as electron acceptor drives anaerobic methanotrophy in brackish sediments. |
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