Large CO2 seeps and hydrate field on the seafloor offshore Mayotte Island
10 affiliations
- 1Geo-Ocean, Unité Mixte de Recherche 6538 CNRS, Ifremer, UBO, UBS, Plouzané, France
- 2LSCE/IPSL, CEA-CNRS-UVSQ, UMR 8212, CEA-Orme des Merisiers, Gif-sur-Yvette, France
- 3Laboratoire de Mesure du Carbone 14 (LMC14), LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
- 4PMEL/NOAA, Seattle, WA, USA
- 5GET, UMR 5563 CNRS, UR 234 IRD, UM 97 UPS, CNES, Observatoire Midi-Pyrénées, Toulouse, France
- 6Dipartimento di Scienze dell’Ambiente e della Terra, Università degli Studi di Milano-Bicocca, Milan, Italy
- 7INGV Istituto Nazionale di Geofisica e Vulcanologia (INGV), Milan, Italy
- 8LDCM, IFREMER, Plouzané, France
- 9Université Brest, Ifremer, BEEP, Plouzané, France
- 10Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, France
Abstract
About 80% of Earth volcanic activity occurs underwater, releasing deep carbon to submarine environments and impacting Earth’s climate over geological timescales. The CO 2 emitted during submarine eruptions and/or hydrothermal degassing creates local ocean acidification, affecting the seawater carbonate equilibrium and oceanic ecosystems at large regional scales. Here, we report for the first time the existence of a major CO 2 hydrates field at the seafloor offshore Mayotte Island (Indian Ocean) associated with liquid CO 2 venting, following the submarine eruption that occurred in 2018. Using detailed acoustic surveys and in situ Raman spectroscopy, we reveal multiple hydrate mounds and seep zones distributed over an area of 0.06 km². We show that the gas seeps are mainly composed of CO 2 , with minor contributions of CH 4 and H 2 , with noble gas ratios and stable and radio-carbon isotopes clearly demonstrating their magmatic origin. Estimates of the CO 2 emitted over the entire area represent about 0.5% of the global magmatic carbon flux. Our discovery also suggests that CO 2 hydrates may potentially be stable at the seafloor at the right pressure-temperature conditions, bringing new prospects into CO 2 sequestration and decarbonization pathways in the ocean, in particular regarding kinetics of hydrates dissolution and environmental impacts.
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BibTeX
@article{cathalot2026large,
title = {{Large CO2 seeps and hydrate field on the seafloor offshore Mayotte Island}},
author = {Cécile Cathalot and Emmanuel Rinnert and Carla Scalabrin and Olivia Fandiño and Thomas Giunta and Hélène Ondréas and Olivier J. Rouxel and Christophe Rabouille and Jean‐Pascal Dumoulin and Bruno Bombled and Marine Manoux and Sharon L. Walker and Valérie Chavagnac and Andrea Luca Rizzo and Morgan Tardivel and Énora Prado and Manon Mastin and Jean‐Pierre Donval and Vivien Guyader and Anne‐Sophie Alix and G. Page and Marjolaine Matabos and Valentine Puzenat and Nathalie Feuillet and on behalf of the GEOFLAMME scientific cruise party and Valentine Puzenat and N. Feuillet},
journal = {Nature Geoscience},
year = {2026},
month = jun,
doi = {10.1038/s41561-026-02004-2},
url = {https://doi.org/10.1038/s41561-026-02004-2},
note = {CC BY},
}
RIS
TY - JOUR
TI - Large CO2 seeps and hydrate field on the seafloor offshore Mayotte Island
AU - Cécile Cathalot
AU - Emmanuel Rinnert
AU - Carla Scalabrin
AU - Olivia Fandiño
AU - Thomas Giunta
AU - Hélène Ondréas
AU - Olivier J. Rouxel
AU - Christophe Rabouille
AU - Jean‐Pascal Dumoulin
AU - Bruno Bombled
AU - Marine Manoux
AU - Sharon L. Walker
AU - Valérie Chavagnac
AU - Andrea Luca Rizzo
AU - Morgan Tardivel
AU - Énora Prado
AU - Manon Mastin
AU - Jean‐Pierre Donval
AU - Vivien Guyader
AU - Anne‐Sophie Alix
AU - G. Page
AU - Marjolaine Matabos
AU - Valentine Puzenat
AU - Nathalie Feuillet
AU - on behalf of the GEOFLAMME scientific cruise party
AU - Valentine Puzenat
AU - N. Feuillet
PY - 2026
DA - 2026/06/12
JO - Nature Geoscience
DO - 10.1038/s41561-026-02004-2
UR - https://doi.org/10.1038/s41561-026-02004-2
AB - About 80% of Earth volcanic activity occurs underwater, releasing deep carbon to submarine environments and impacting Earth’s climate over geological timescales. The CO 2 emitted during submarine eruptions and/or hydrothermal degassing creates local ocean acidification, affecting the seawater carbonate equilibrium and oceanic ecosystems at large regional scales. Here, we report for the first time the existence of a major CO 2 hydrates field at the seafloor offshore Mayotte Island (Indian Ocean) associated with liquid CO 2 venting, following the submarine eruption that occurred in 2018. Using detailed acoustic surveys and in situ Raman spectroscopy, we reveal multiple hydrate mounds and seep zones distributed over an area of 0.06 km². We show that the gas seeps are mainly composed of CO 2 , with minor contributions of CH 4 and H 2 , with noble gas ratios and stable and radio-carbon isotopes clearly demonstrating their magmatic origin. Estimates of the CO 2 emitted over the entire area represent about 0.5% of the global magmatic carbon flux. Our discovery also suggests that CO 2 hydrates may potentially be stable at the seafloor at the right pressure-temperature conditions, bringing new prospects into CO 2 sequestration and decarbonization pathways in the ocean, in particular regarding kinetics of hydrates dissolution and environmental impacts.
SN - 1752-0894
SN - 1752-0908
ER -