title: Diversity and distribution of the prokaryotic community in near-surface permafrost sediments in the Tianshan Mountains, China.
abstract: The community structures and diversity of bacteria and archaea were investigated at 4 depths (1.5, 2.0, 2.5, and 3.0 m) in permafrost sediments in the Tianshan Mountains, using denaturing gradient gel electrophoresis of 16S rRNA gene amplified by polymerase chain reaction. Phylogenetic analysis of the dominant bands sequenced revealed the presence of rich diversity of bacteria, which could be related to the Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes, Bacteroidetes, Firmicutes, and Chloroflexi. The Proteobacteria, consisting of the alpha, beta, gamma and epsilon subdivisions, were clearly the dominant group at all depths studied. Archaeal diversity was relatively low and archaeal 16S rRNA gene sequences were grouped into 3 phylogenetic clusters within the 2 kingdoms Euryarchaeota and Crenarchaeota. Within the Euryarchaeota, methanogen-related group II was most abundant at shallow depth (1.5 m), whereas halobacterium-related group I dominated at greater depths. The low-temperature Crenarchaeota group was detected only at 2.5 and 3.0 m. Specific-depth distribution of methanogen-related Euryarchaeota group II and denitrifying bacteria of the genus Pseudomonas dominated at 1.5 m depth, accompanied by a distinct peak in the ratio of NH4-N to NO3/NO2-N, implying the potential capacity of these organisms in near-surface permafrost to release the greenhouse gases N2O and CH4.
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China.
authors.forename: Daqun
authors.initials: D
authors.lastname: Yang
authors.forename: Jianhui
authors.initials: J
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.forename: Shijian
authors.initials: S
authors.lastname: Xu
authors.forename: Lizhe
authors.initials: L
authors.lastname: An
mesh_terms: D000531:Altitude; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D002681:China; D017753:Ecosystem; D004586:Electrophoresis / Q000379:methods; D014644:Genetic Variation; D019015:Geologic Sediments / Q000382:microbiology*; D007053:Ice; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D007053:Ice; D012336:RNA, Ribosomal, 16S