10.6084/m9.figshare.1011897.v1 Jakub D Zarsky Jakub D Zarsky Marek Stibal Marek Stibal Andy Hodson Andy Hodson Birgit Sattler Birgit Sattler Morten Schostag Morten Schostag Lars H Hansen Lars H Hansen Carsten S Jacobsen Carsten S Jacobsen Roland Psenner Roland Psenner Phylogenetic analysis of the nitrososphaeraceae sequences identified in the 454 pyrosequencing dataset from cryoconite sample A1 (in bold) IOP Publishing 2013 nitrososphaeraceae sequences nitrogen cycling supraglacial environments cryoconite sample likelihood tree 454 pyrosequencing dataset prokaryotic microbes valley glacier Methanocaldococcus jannaschii surface debris geochemical analysis glacier surface bird colonies polymerase chain reactions surface debris particles supraglacial meltwater flow Arctic glacier 16 S Environmental Science 2013-09-11 00:00:00 Figure https://iop.figshare.com/articles/figure/_Phylogenetic_analysis_of_the_nitrososphaeraceae_sequences_identified_in_the_454_pyrosequencing_data/1011897 <p><strong>Figure 6.</strong> Phylogenetic analysis of the nitrososphaeraceae sequences identified in the 454 pyrosequencing dataset from cryoconite sample A1 (in bold). The maximum likelihood tree was constructed based on 406-base-pair-long 16S rRNA sequences and rooted with <em>Methanocaldococcus jannaschii</em>.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p>