The possible occurrence of iron-dependent anaerobic methane oxidation in an Archean Ocean analogue
Roland, F.A.E.; Borges, A.V.; Darchambeau, F.; Llirós, M.; Descy, J.-P.; Morana, C. (2021). The possible occurrence of iron-dependent anaerobic methane oxidation in an Archean Ocean analogue. NPG Scientific Reports 11(1): 1597. https://hdl.handle.net/10.1038/s41598-021-81210-x In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322; e-ISSN 2045-2322, more |   |
| Authors | | Top | | - Llirós, M.
- Descy, J.-P., more
- Morana, C., more
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| Abstract | In the ferruginous and anoxic early Earth oceans, photoferrotrophy drove most of the biological production before the advent of oxygenic photosynthesis, but its association with ferric iron (Fe3+) dependent anaerobic methane (CH4) oxidation (AOM) has been poorly investigated. We studied AOM in Kabuno Bay, a modern analogue to the Archean Ocean (anoxic bottom waters and dissolved Fe concentrations > 600 µmol L−1). Aerobic and anaerobic CH4 oxidation rates up to 0.12 ± 0.03 and 51 ± 1 µmol L−1 d−1, respectively, were put in evidence. In the Fe oxidation–reduction zone, we observed high concentration of Bacteriochlorophyll e (biomarker of the anoxygenic photoautotrophs), which co-occurred with the maximum CH4 oxidation peaks, and a high abundance of Candidatus Methanoperedens, which can couple AOM to Fe3+ reduction. In addition, comparison of measured CH4 oxidation rates with electron acceptor fluxes suggest that AOM could mainly rely on Fe3+ produced by photoferrotrophs. Further experiments specifically targeted to investigate the interactions between photoferrotrophs and AOM would be of considerable interest. Indeed, ferric Fe3+-driven AOM has been poorly envisaged as a possible metabolic process in the Archean ocean, but this can potentially change the conceptualization and modelling of metabolic and geochemical processes controlling climate conditions in the Early Earth. |
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