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Lookup NU author(s): Professor Richard DaviesORCiD, Dr Mark IrelandORCiD, Dr Miguel Morales MaquedaORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2023, The Author(s).Marine methane hydrate is an ice-like substance that is stable in sediment around marine continental margins where water depths are greater than ~450–700 m. The release of methane due to melting of hydrates is considered to be a mechanism for past global carbon-cycle perturbations and could exacerbate ongoing anthropogenic climate change. Increases in bottom-water temperature at the landward limit of marine hydrate around continental margins, where vulnerable hydrate exists at or below the seabed, cause methane to vent into the ocean. However, this setting represents only ~3.5% of the global hydrate reservoir. The potential for methane from hydrate in deeper water to reach the atmosphere was considered negligible. Here we use three-dimensional (3D) seismic imagery to show that, on the Mauritanian margin, methane migrated at least 40 km below the base of the hydrate stability zone and vented through 23 pockmarks at the shelf break, probably during warmer Quaternary interglacials. We demonstrate that, under suitable circumstances, some of the 96.5% of methane bound in deeper water distal hydrates can reach the seafloor and vent into the ocean beyond the landward limit of marine hydrate. This reservoir should therefore be considered for estimating climate change-induced methane release during a warming world.
Author(s): Davies RJ, Yang J, Ireland MT, Berndt C, Maqueda MAM, Huuse M
Publication type: Article
Publication status: Published
Journal: Nature Geoscience
Year: 2023
Pages: epub ahead of print
Online publication date: 06/12/2023
Acceptance date: 23/10/2023
Date deposited: 18/12/2023
ISSN (print): 1752-0894
ISSN (electronic): 1752-0908
Publisher: Nature Research
URL: https://doi.org/10.1038/s41561-023-01333-w
DOI: 10.1038/s41561-023-01333-w
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