The Production of Methane, Hydrogen, and Organic Compounds in Ultramafic-Hosted Hydrothermal Vents of the Mid-Atlantic Ridge
| Autor: | Nils G. Holm, Olivier Mousis, Cecile Konn, Jean-Luc Charlou |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
010504 meteorology & atmospheric sciences
Oceans and Seas Origin of Life Geochemistry Mineralogy Review Article Mid-Atlantic Ridge 010502 geochemistry & geophysics 01 natural sciences Methane Hydrothermal circulation chemistry.chemical_compound Hydrothermal Vents Ultramafic rock Abiogenesis 14. Life underwater Mid-Atlantic Region Organic Chemicals 0105 earth and related environmental sciences Chemistry Agricultural and Biological Sciences (miscellaneous) Abiogenic petroleum origin 13. Climate action Space and Planetary Science Ridge (meteorology) Hydrogen Hydrothermal vent |
| Zdroj: | Astrobiology (1531-1074) (Mary Ann Liebert, Inc), 2015-05, Vol. 15, N. 5, P. 381-399 Astrobiology |
| ISSN: | 1557-8070 1531-1074 |
| DOI: | 10.1089/ast.2014.1198 |
| Popis: | Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize hydrothermal vents, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle hydrothermal geochemistry. This understanding is of prime importance considering the implications of hydrothermal H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. Key Words: Hydrogen—Methane—Organics—MAR—Abiotic synthesis—Serpentinization—Ultramafic-hosted hydrothermal vents. Astrobiology 15, 381–399. |
| Databáze: | OpenAIRE |
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