title: Hydrocarbons in hydrothermal vent fluids: the role of chromium-bearing catalysts.
abstract: Fischer-Tropsch type (FTT) synthesis has long been proposed to account for the existence of hydrocarbons in hydrothermal fluids. We show that iron- and chromium-bearing minerals catalyze the abiotic formation of hydrocarbons. In addition to production of methane (CH4aq), we report abiotic generation of ethane (C2H6aq) and propane (C3H8aq) by mineral-catalyzed hydrothermal reactions at 390 degrees C and 400 bars. Results suggest that the chromium component in ultramafic rocks could be an important factor for FTT synthesis during water-rock interaction in mid-ocean ridge hydrothermal systems. This in turn could help to support microbial communities now recognized in the subsurface at deep-sea vents.
authors.affiliation: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA. fous0009@umn.edu
authors.forename: Dionysis I
authors.initials: DI
authors.lastname: Foustoukos
authors.forename: William E
authors.initials: WE
authors.lastname: Seyfried
mesh_terms: D001105:Archaea / Q000254:growth & development; D001419:Bacteria / Q000254:growth & development; D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D002857:Chromium / Q000737:chemistry*; D017608:Chromium Compounds / Q000737:chemistry; D017753:Ecosystem; D004777:Environment; D004980:Ethane / Q000138:chemical synthesis / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D006838:Hydrocarbons / Q000138:chemical synthesis* / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000138:chemical synthesis / Q000737:chemistry; D011312:Pressure; D011407:Propane / Q000138:chemical synthesis / Q000737:chemistry; D013696:Temperature
chemical_list: D017608:Chromium Compounds; D005290:Ferric Compounds; D006838:Hydrocarbons; D002857:Chromium; D002245:Carbon Dioxide; C000499:ferric oxide; D006859:Hydrogen; D004980:Ethane; D008697:Methane; D011407:Propane; C023600:chromic oxide