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Methanogenesis in subglacial sediments
Author(s) -
Boyd Eric S.,
Skidmore Mark,
Mitchell Andrew C.,
Bakermans Corien,
Peters John W.
Publication year - 2010
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/j.1758-2229.2010.00162.x
Subject(s) - archaea , methanogenesis , sediment , population , carbon cycle , methane , geology , crenarchaeota , environmental chemistry , earth science , geochemistry , ecology , biology , ecosystem , chemistry , geomorphology , paleontology , bacteria , sociology , demography
Summary Methanogenic archaea have a unique role in Earth's global carbon cycle as producers of the greenhouse gas methane (CH 4 ). However, despite the fact that ice covers 11% of Earth's continental landmass, evidence for methanogenic activity in subglacial environments has yet to be clearly demonstrated. Here we present genetic, biochemical and geochemical evidence indicative of an active population of methanogens associated with subglacial sediments from Robertson Glacier (RG), Canadian Rockies. Porewater CH 4 was quantified in two subglacial sediment cores at concentrations of 16 and 29 ppmv. Coenzyme M (CoM), a metabolic biomarker for methanogens, was detected at a concentration of 1.3 nmol g sediment −1 corresponding to ∼3 × 10 3 active cells g sediment −1 . Genetic characterization of communities associated with subglacial sediments indicated the presence of several archaeal 16S rRNA and methyl CoM reductase subunit A ( mcrA ) gene phylotypes, all of which were affiliated with the euryarchaeal order Methanosarcinales . Further, CH 4 was produced at 9–51 fmol g dry weight sediment −1 h −1 in enrichment cultures of RG sediments incubated at 4°C. Collectively, these findings have important implications for the global carbon cycle in light of recent estimates indicating that the Earth's subglacial biome ranges from 10 4 to 10 6 km 3 sediment.