title: Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments.
abstract: The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g-1d-1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.
authors.affiliation: Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark. kac.geus@gmail.com.|Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark. kac.geus@gmail.com.|Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, SY23 3FL, UK. kac.geus@gmail.com.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Cameron
authors.affiliation: Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark.|Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.|Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 43, Prague, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Stibal
authors.affiliation: Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark.|Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
authors.forename: Nikoline S
authors.initials: NS
authors.lastname: Olsen
authors.affiliation: Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Mikkelsen
authors.affiliation: Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
authors.forename: Bo
authors.initials: B
authors.lastname: Elberling
authors.affiliation: Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark.|Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.|Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark.
authors.forename: Carsten S
authors.initials: CS
authors.lastname: Jacobsen
mesh_terms: D019015:Geologic Sediments / Q000382:microbiology*; D006116:Greenland; D046448:Ice Cover / Q000382:microbiology*; D008697:Methane; D017018:Methanomicrobiales; D019640:Methanosarcinales; D064307:Microbiota; D010459:Peptococcaceae; D045483:Rivers / Q000382:microbiology*; D013431:Sulfates
chemical_list: D013431:Sulfates; D008697:Methane
keywords: Meltwater export; Methane oxidation; Methanogenesis; River delta; Subglacial environment; Sulphate reduction