title: Niche specialization of bacteria in permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica.
abstract: Perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are chemically stratified with depth and have distinct biological gradients. Despite long-term research on these unique environments, data on the structure of the microbial communities in the water columns of these lakes are scarce. Here, we examined bacterial diversity in five ice-covered Antarctic lakes by 16S rRNA gene-based pyrosequencing. Distinct communities were present in each lake, reflecting the unique biogeochemical characteristics of these environments. Further, certain bacterial lineages were confined exclusively to specific depths within each lake. For example, candidate division WM88 occurred solely at a depth of 15 m in Lake Fryxell, whereas unknown lineages of Chlorobi were found only at a depth of 18 m in Lake Miers, and two distinct classes of Firmicutes inhabited East and West Lobe Bonney at depths of 30 m. Redundancy analysis revealed that community variation of bacterioplankton could be explained by the distinct conditions of each lake and depth; in particular, assemblages from layers beneath the chemocline had biogeochemical associations that differed from those in the upper layers. These patterns of community composition may represent bacterial adaptations to the extreme and unique biogeochemical gradients of ice-covered lakes in the McMurdo Dry Valleys.
authors.affiliation: Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea.|School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea.
authors.forename: Miye
authors.initials: M
authors.lastname: Kwon
authors.affiliation: Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea.
authors.forename: Mincheol
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque, NM, 87043, USA.
authors.forename: Cristina
authors.initials: C
authors.lastname: Takacs-Vesbach
authors.affiliation: Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea.
authors.forename: Jaejin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea.
authors.forename: Soon Gyu
authors.initials: SG
authors.lastname: Hong
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea.
authors.forename: Sang Jong
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, 59717, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Priscu
authors.affiliation: Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea.
authors.forename: Ok-Sun
authors.initials: OS
authors.lastname: Kim
mesh_terms: D000864:Antarctic Regions; D001419:Bacteria / Q000145:classification* / Q000235:genetics*; D001483:Base Sequence; D044822:Biodiversity; D046448:Ice Cover / Q000382:microbiology*; D060106:Lakes / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S