Description du projet
Découvrir les nouvelles recettes de la Terre pour produire de l’hydrogène et du méthane en profondeur
Le méthane et l’hydrogène sont des sources d’énergie cruciales pour les microbes, en particulier dans les sous-sols. La plupart des hydrocarbures sont d’origine biologique, mais les réactions eau-roche, à l’instar du processus appelé serpentinisation, créent de l’hydrogène et du méthane abiotique qui se forment indépendamment de la vie, notamment en profondeur dans les zones de subduction. Ces gaz contribuent probablement au cycle mondial de l’hydrogène et du carbone et à la croissance des microbes souterrains, mais la taille de ces réservoirs et leur impact ne sont pas bien compris. Le projet DeepSeep, financé par l’UE, cherche à estimer la quantité d’hydrogène et de méthane abiotiques profonds produits dans les zones de subduction. Ce que les chercheurs vont découvrir pourrait changer radicalement notre compréhension de la formation des sources d’énergie profonde et de leurs effets sur le cycle mondial du carbone, voire même de la climatologie au niveau des échelles de temps géologiques, et fournir un aperçu de la distribution et de l’ampleur de la vie profonde sur Terre et potentiellement ailleurs.
Objectif
The deep subsurface biosphere is the largest microbiological habitat on Earth, with biomass and contribution to biogeochemical cycles comparable to surface biosphere. Deciphering the parameters that control and sustain deep subsurface life is vital in understanding the functioning of our planet, and additionally provides key information on how life emerged and where it could exist elsewhere. Among these parameters are the sources of essential energy for deep life, such as H2 and CH4. Great effort has been made to identify geological processes producing these compounds within the subsurface biosphere. Conversely, the identification of deeper sources of H2 and CH4 produced outside the parameter space for life is lacking, even though they could dramatically change our understanding of the distribution and magnitude of deep life on Earth and potentially beyond. Convergent margins focus the largest recycling of C from the deep Earth to the biosphere and atmosphere. Current models of deep C cycling do not include H2-CH4 deep fluxes and therefore cannot assess their potential role in sustaining deep life. My recent work indicates that H2 and CH4 can be produced in large amounts abiotically in subduction zones well below the biosphere by high-P serpentinization processes. This opens new fundamental questions: What is the magnitude of deep H2 and CH4 at convergent margins? How do they affect deep C cycling? To what extent deep H2 and CH4 fluxes sustain the biosphere? DeepSeep will answer these questions by providing the first ever estimates of deep H2-CH4 fluxes, as well as the missing means to detect source areas at depth, and will establish deep H2-CH4 role on deep C cycling and on deep biosphere processes. By bridging the two most striking peculiarities of Earth, subduction and life, DeepSeep has the potential for transformative discoveries, with long-term implications for global C cycle modeling, climatology, and the emergence and search for life on Earth and beyond.
Champ scientifique
- engineering and technologyenvironmental engineeringwaste managementwaste treatment processesrecycling
- natural sciencesphysical sciencesastronomyplanetary sciencesplanets
- natural sciencesearth and related environmental sciencesgeologyseismologyplate tectonics
- natural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologybiosphera
- natural sciencesearth and related environmental sciencesatmospheric sciencesclimatology
Programme(s)
Régime de financement
ERC-COG - Consolidator GrantInstitution d’accueil
40126 Bologna
Italie