title: Meltwater export of prokaryotic cells from the Greenland ice sheet.
abstract: Microorganisms are flushed from the Greenland Ice Sheet (GrIS) where they may contribute towards the nutrient cycling and community compositions of downstream ecosystems. We investigate meltwater microbial assemblages as they exit the GrIS from a large outlet glacier, and as they enter a downstream river delta during the record melt year of 2012. Prokaryotic abundance, flux and community composition was studied, and factors affecting community structures were statistically considered. The mean concentration of cells exiting the ice sheet was 8.30 × 104cells mL-1and we estimate that ∼1.02 × 1021cells were transported to the downstream fjord in 2012, equivalent to 30.95 Mg of carbon. Prokaryotic microbial assemblages were dominated by Proteobacteria, Bacteroidetes, and Actinobacteria. Cell concentrations and community compositions were stable throughout the sample period, and were statistically similar at both sample sites. Based on our observations, we argue that the subglacial environment is the primary source of the river-transported microbiota, and that cell export from the GrIS is dependent on discharge. We hypothesise that the release of subglacial microbiota to downstream ecosystems will increase as freshwater flux from the GrIS rises in a warming world.
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: 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: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, BS8 1SS, Bristol, UK.
authors.forename: Jon R
authors.initials: JR
authors.lastname: Hawkings
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: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, BS8 1SS, Bristol, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Telling
authors.affiliation: Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 43, Prague, Czech Republic.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Kohler
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: Erkin
authors.initials: E
authors.lastname: Gözdereliler
authors.affiliation: Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 43, Prague, Czech Republic.
authors.forename: Jakub D
authors.initials: JD
authors.lastname: Zarsky
authors.affiliation: Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, BS8 1SS, Bristol, UK.
authors.forename: Jemma L
authors.initials: JL
authors.lastname: Wadham
authors.affiliation: 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: D039903:Actinobacteria / Q000302:isolation & purification; D001105:Archaea / Q000302:isolation & purification; D041963:Bacteroidetes / Q000302:isolation & purification; D063366:Estuaries; D006116:Greenland; D046448:Ice Cover / Q000382:microbiology*; D064307:Microbiota; D020560:Proteobacteria / Q000302:isolation & purification; D045483:Rivers / Q000382:microbiology*; D014872:Water Movements