title: Carbon flow from volcanic CO2 into soil microbial communities of a wetland mofette.
abstract: Effects of extremely high carbon dioxide (CO2) concentrations on soil microbial communities and associated processes are largely unknown. We studied a wetland area affected by spots of subcrustal CO2 degassing (mofettes) with focus on anaerobic autotrophic methanogenesis and acetogenesis because the pore gas phase was largely hypoxic. Compared with a reference soil, the mofette was more acidic (ΔpH ∼0.8), strongly enriched in organic carbon (up to 10 times), and exhibited lower prokaryotic diversity. It was dominated by methanogens and subdivision 1 Acidobacteria, which likely thrived under stable hypoxia and acidic pH. Anoxic incubations revealed enhanced formation of acetate and methane (CH4) from hydrogen (H2) and CO2 consistent with elevated CH4 and acetate levels in the mofette soil. (13)CO2 mofette soil incubations showed high label incorporations with ∼512 ng (13)C g (dry weight (dw)) soil(-1) d(-1) into the bulk soil and up to 10.7 ng (13)C g (dw) soil(-1) d(-1) into almost all analyzed bacterial lipids. Incorporation of CO2-derived carbon into archaeal lipids was much lower and restricted to the first 10 cm of the soil. DNA-SIP analysis revealed that acidophilic methanogens affiliated with Methanoregulaceae and hitherto unknown acetogens appeared to be involved in the chemolithoautotrophic utilization of (13)CO2. Subdivision 1 Acidobacteriaceae assimilated (13)CO2 likely via anaplerotic reactions because Acidobacteriaceae are not known to harbor enzymatic pathways for autotrophic CO2 assimilation. We conclude that CO2-induced geochemical changes promoted anaerobic and acidophilic organisms and altered carbon turnover in affected soils.
authors.affiliation: Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Beulig
authors.affiliation: Organic Geochemistry Group, Dept. of Geosciences and MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
authors.forename: Verena B
authors.initials: VB
authors.lastname: Heuer
authors.affiliation: 1] Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany [2] U.S. Geological Survey, Reston, VA, USA.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Akob
authors.affiliation: Organic Geochemistry Group, Dept. of Geosciences and MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Viehweger
authors.affiliation: Organic Geochemistry Group, Dept. of Geosciences and MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Elvert
authors.affiliation: 1] Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany [2] German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Herrmann
authors.affiliation: Organic Geochemistry Group, Dept. of Geosciences and MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Hinrichs
authors.affiliation: 1] Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany [2] German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Küsel
mesh_terms: D000085:Acetates / Q000378:metabolism; D001105:Archaea / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D050356:Lipid Metabolism; D008697:Methane / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D018707:Volcanic Eruptions; D014867:Water / Q000737:chemistry; D053833:Wetlands
chemical_list: D000085:Acetates; D012987:Soil; D014867:Water; D002245:Carbon Dioxide; D002244:Carbon; D006859:Hydrogen; D008697:Methane