title: Relative Roles of Deterministic and Stochastic Processes in Driving the Vertical Distribution of Bacterial Communities in a Permafrost Core from the Qinghai-Tibet Plateau, China.
abstract: Understanding the processes that influence the structure of biotic communities is one of the major ecological topics, and both stochastic and deterministic processes are expected to be at work simultaneously in most communities. Here, we investigated the vertical distribution patterns of bacterial communities in a 10-m-long soil core taken within permafrost of the Qinghai-Tibet Plateau. To get a better understanding of the forces that govern these patterns, we examined the diversity and structure of bacterial communities, and the change in community composition along the vertical distance (spatial turnover) from both taxonomic and phylogenetic perspectives. Measures of taxonomic and phylogenetic beta diversity revealed that bacterial community composition changed continuously along the soil core, and showed a vertical distance-decay relationship. Multiple stepwise regression analysis suggested that bacterial alpha diversity and phylogenetic structure were strongly correlated with soil conductivity and pH but weakly correlated with depth. There was evidence that deterministic and stochastic processes collectively drived bacterial vertically-structured pattern. Bacterial communities in five soil horizons (two originated from the active layer and three from permafrost) of the permafrost core were phylogenetically random, indicator of stochastic processes. However, we found a stronger effect of deterministic processes related to soil pH, conductivity, and organic carbon content that were structuring the bacterial communities. We therefore conclude that the vertical distribution of bacterial communities was governed primarily by deterministic ecological selection, although stochastic processes were also at work. Furthermore, the strong impact of environmental conditions (for example, soil physicochemical parameters and seasonal freeze-thaw cycles) on these communities underlines the sensitivity of permafrost microorganisms to climate change and potentially subsequent permafrost thaw.
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Weigang
authors.initials: W
authors.lastname: Hu
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Tian
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Dingyao
authors.initials: D
authors.lastname: Li
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Mu
authors.affiliation: State Key Laboratory of Frozen Soil Engineering (SKLFSE), Cold and Arid Regions Environmental and Engineering Research Institute (CAREERI), Chinese Academy of Sciences, Lanzhou, China.
authors.forename: Qingbai
authors.initials: Q
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Frozen Soil Engineering (SKLFSE), Cold and Arid Regions Environmental and Engineering Research Institute (CAREERI), Chinese Academy of Sciences, Lanzhou, China.
authors.forename: Fujun
authors.initials: F
authors.lastname: Niu
authors.affiliation: Biological Sciences Division, Pacific Northwest National Laboratory, Richland, United States of America.
authors.forename: James C
authors.initials: JC
authors.lastname: Stegen
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Lizhe
authors.initials: L
authors.lastname: An
authors.affiliation: Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Huyuan
authors.initials: H
authors.lastname: Feng
mesh_terms: D001419:Bacteria / Q000145:classification / Q000254:growth & development*; D058448:Biota; D002681:China; D057231:Climate Change; D065946:Permafrost / Q000382:microbiology*; D010802:Phylogeny; D012988:Soil Microbiology; D013269:Stochastic Processes