title: Potential sources of bacteria colonizing the cryoconite of an Alpine glacier.
abstract: We investigated the potential contribution of ice-marginal environments to the microbial communities of cryoconite holes, small depressions filled with meltwater that form on the surface of Forni Glacier (Italian Alps). Cryoconite holes are considered the most biologically active environments on glaciers. Bacteria can colonize these environments by short-range transport from ice-marginal environments or by long-range transport from distant areas. We used high throughput DNA sequencing to identify Operational Taxonomic Units (OTUs) present in cryoconite holes and three ice-marginal environments, the moraines, the glacier forefield, and a large (> 3 m high) ice-cored dirt cone occurring on the glacier surface. Bacterial communities of cryoconite holes were different from those of ice-marginal environments and hosted fewer OTUs. However, a network analysis revealed that the cryoconite holes shared more OTUs with the moraines and the dirt cone than with the glacier forefield. Ice-marginal environments may therefore act as sources of bacteria for cryoconite holes, but differences in environmental conditions limit the number of bacterial strains that may survive in them. At the same time, cryoconite holes host a few OTUs that were not found in any ice-marginal environment we sampled, thus suggesting that some bacterial populations are positively selected by the specific environmental conditions of the cryoconite holes.
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Franzetti
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Navarra
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Ilario
authors.initials: I
authors.lastname: Tagliaferri
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Gandolfi
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Bestetti
authors.affiliation: "A. Desio" Dept. of Earth Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Minora
authors.affiliation: "A. Desio" Dept. of Earth Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Roberto Sergio
authors.initials: RS
authors.lastname: Azzoni
authors.affiliation: "A. Desio" Dept. of Earth Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Guglielmina
authors.initials: G
authors.lastname: Diolaiuti
authors.affiliation: "A. Desio" Dept. of Earth Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Smiraglia
authors.affiliation: Dept. of Earth and Environmental Sciences (DISAT) - University of Milano-Bicocca, Milano, Italy.
authors.forename: Roberto
authors.identifier: http://orcid.org/0000-0002-7148-1468
authors.initials: R
authors.lastname: Ambrosini
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics*; D017753:Ecosystem; D019015:Geologic Sediments / Q000382:microbiology; D046448:Ice Cover / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S
chemical_list: D012336:RNA, Ribosomal, 16S