Exploring the efficiency of anaerobic oxidation of methane as a sink to hydrate-sourced methane
- 1BGeoSys, Department Geoscience, Environment & Society (DGES), Université Libre de Bruxelles,1050 Brussels, Belgium (maria.de.la.fuente.ruiz@ulb.be)
- 2School of Ocean and Earth Science, University of Southampton, European Way, Southampton SO14 3ZH, UK
- 3Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
Ocean warming threatens methane hydrate stability in continental margins, potentially leading to methane release into marine sediments, the water column, and ultimately the atmosphere. Over the decadal to millennial timescales during which hydrate-sourced methane release is anticipated, microbially mediated anaerobic oxidation of methane (AOM) in marine sediments may mitigate benthic methane efflux. While traditionally considered a highly efficient biofilter, recent studies reveal significant variability in the AOM sink efficiency. For instance, in cold seep settings, efficiency ranges from 80% to 20% with slow to high fluid flow, respectively, and this decreases to around 10% in pristine seepage environments. This variability is directly related to the balance between multiphase methane transport and the growth dynamics of microbial communities.
In this study, we use a novel 1D multiphase reaction-transport model to investigate the transient evolution of the AOM sink efficiency and its impact on seafloor methane emissions in response to a centennial-scale methane release caused by climate-driven hydrate destabilization. We examine the combined influence of gaseous methane transport, including induced tensile fracturing by pore fluid overpressure, and methanotrophic biomass dynamics on weakening the efficiency of the AOM sink. Preliminary findings suggest that the AOM sink is notably limited to mitigating benthic methane emissions in gassy sediments. Additionally, the slow growth rate of methane-oxidizing microorganisms may lead to significant temporal windows for methane to escape into the ocean. This integrated analysis provides insights into the intricate dynamics governing the efficiency of the benthic AOM sink subjected to hydrate-sourced methane. It contributes to a more comprehensive assessment of potential methane emissions in continental margins in the context of global warming.
How to cite: De La Fuente Ruiz, M., Arndt, S., Marín-Moreno, H., Minshull, T. A., and Vaunat, J.: Exploring the efficiency of anaerobic oxidation of methane as a sink to hydrate-sourced methane, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16392, https://doi.org/10.5194/egusphere-egu24-16392, 2024.
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This is Yuki Ota from National Institute of Advanced Industrial Science and Technology in Japan.
Thank you very much for listening to my poster presentation (EGU24-3316) in the EGU24.
You asked about methane efflux in the methane hydrate-bearing area in Japan Sea , which is my research site.
I was not able to answer this question at the time of presentation, but my colleagues have summarized the methane efflux (14 mmol m-2 d-1) at this study site in the following paper:
DOI: 10.1021/acs.est.3c09484
If you cannot see the paper, please contact me (y.ota@aist.go.jp) directly and I will send it to you.
We hope it will be of help to you.
Dear Yuki,
It was a pleasure talking to you at EGU and many thanks for the paper (I could already download it).
I will keep in touch if I have further questions.
Kind regards,
Maria
Thanks for the reply.
Please contact me anytime.
I will continue to share any interesting results as well.
best
Yuki
Thanks for the reply.
Please contact me anytime.
I will continue to share any interesting results as well.
best
Yuki