title: Microbial functional potential and community composition in permafrost-affected soils of the NW Canadian Arctic.
abstract: Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic.
authors.affiliation: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam, Potsdam, Germany.
authors.forename: Béatrice A
authors.initials: BA
authors.lastname: Frank-Fahle
authors.affiliation: National Research Council, Montréal, Quebec, Canada.
authors.forename: Etienne
authors.initials: E
authors.lastname: Yergeau
authors.affiliation: National Research Council, Montréal, Quebec, Canada.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Greer
authors.affiliation: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam, Potsdam, Germany ; University of Potsdam, Potsdam, Germany.
authors.forename: Hugues
authors.initials: H
authors.lastname: Lantuit
authors.affiliation: GFZ German Center for Geosciences, Section 4.5 Geomicrobiology, Potsdam, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Wagner
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001110:Arctic Regions; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D002170:Canada; D003080:Cold Temperature; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis; D012988:Soil Microbiology