title: Unique pioneer microbial communities exposed to volcanic sulfur dioxide.
abstract: Newly exposed volcanic substrates contain negligible amounts of organic materials. Heterotrophic organisms in newly formed ecosystems require bioavailable carbon and nitrogen that are provided from CO2 and N2 fixation by pioneer microbes. However, the knowledge of initial ecosystem developmental mechanisms, especially the association between microbial succession and environmental change, is still limited. This study reports the unique process of microbial succession in fresh basaltic ash, which was affected by long-term exposure to volcanic sulfur dioxide (SO2). Here we compared the microbial ecosystems among deposits affected by SO2 exposure at different levels. The results of metagenomic analysis suggested the importance of autotrophic iron-oxidizing bacteria, particularly those involved in CO2 and N2 fixation, in the heavily SO2 affected site. Changes in the chemical properties of the deposits after the decline of the SO2 impact led to an apparent decrease in the iron-oxidizer abundance and a possible shift in the microbial community structure. Furthermore, the community structure of the deposits that had experienced lower SO2 gas levels showed higher similarity with that of the control forest soil. Our results implied that the effect of SO2 exposure exerted a selective pressure on the pioneer community structure by changing the surrounding environment of the microbes.
authors.affiliation: Ibaraki University College of Agriculture, Ibaraki 300-0332, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Fujimura
authors.affiliation: Department of Computational Biology, Graduate School of Frontier Science, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan.
authors.forename: Seok-Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: National Research Institute for Cultural Properties, Tokyo, Tokyo, 110-8713, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Computational Biology, Graduate School of Frontier Science, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan.
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Department of Computational Biology, Graduate School of Frontier Science, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan.
authors.forename: Masahira
authors.initials: M
authors.lastname: Hattori
authors.affiliation: Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kamijo
authors.affiliation: Ibaraki University College of Agriculture, Ibaraki 300-0332, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohta
mesh_terms: D002244:Carbon / Q000737:chemistry; D007564:Japan; D056186:Metagenomics; D064307:Microbiota; D009584:Nitrogen / Q000737:chemistry; D012336:RNA, Ribosomal, 16S; D012988:Soil Microbiology; D013458:Sulfur Dioxide / Q000032:analysis*; D018707:Volcanic Eruptions / Q000032:analysis*
chemical_list: D012336:RNA, Ribosomal, 16S; D013458:Sulfur Dioxide; D002244:Carbon; D009584:Nitrogen