title: Shifts of tundra bacterial and archaeal communities along a permafrost thaw gradient in Alaska.
abstract: Understanding the response of permafrost microbial communities to climate warming is crucial for evaluating ecosystem feedbacks to global change. This study investigated soil bacterial and archaeal communities by Illumina MiSeq sequencing of 16S rRNA gene amplicons across a permafrost thaw gradient at different depths in Alaska with thaw progression for over three decades. Over 4.6 million passing 16S rRNA gene sequences were obtained from a total of 97 samples, corresponding to 61 known classes and 470 genera. Soil depth and the associated soil physical-chemical properties had predominant impacts on the diversity and composition of the microbial communities. Both richness and evenness of the microbial communities decreased with soil depth. Acidobacteria, Verrucomicrobia, Alpha- and Gamma-Proteobacteria dominated the microbial communities in the upper horizon, whereas abundances of Bacteroidetes, Delta-Proteobacteria and Firmicutes increased towards deeper soils. Effects of thaw progression were absent in microbial communities in the near-surface organic soil, probably due to greater temperature variation. Thaw progression decreased the abundances of the majority of the associated taxa in the lower organic soil, but increased the abundances of those in the mineral soil, including groups potentially involved in recalcitrant C degradation (Actinomycetales, Chitinophaga, etc.). The changes in microbial communities may be related to altered soil C sources by thaw progression. Collectively, this study revealed different impacts of thaw in the organic and mineral horizons and suggests the importance of studying both the upper and deeper soils while evaluating microbial responses to permafrost thaw.
authors.affiliation: Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Deng
authors.forename: Yunfu
authors.initials: Y
authors.lastname: Gu
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.forename: Kai
authors.initials: K
authors.lastname: Xue
authors.forename: Yujia
authors.initials: Y
authors.lastname: Qin
authors.forename: Mengting
authors.initials: M
authors.lastname: Yuan
authors.forename: Huaqun
authors.initials: H
authors.lastname: Yin
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.forename: Liyou
authors.initials: L
authors.lastname: Wu
authors.forename: Edward A G
authors.initials: EA
authors.lastname: Schuur
authors.forename: James M
authors.initials: JM
authors.lastname: Tiedje
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000413:Alaska; D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D019641:DNA, Archaeal / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D065946:Permafrost / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D065929:Tundra
chemical_list: D019641:DNA, Archaeal; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012987:Soil
keywords: 16S rRNA; Illumina MiSeq sequencing; permafrost thaw; soil bacterial and archaeal communities