Bacterial and fungal community structure in Arctic tundra tussock and shrub soils

Authors

  • Matthew David Wallenstein,

    1. Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
    2. Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado, USA
    Search for more papers by this author
  • Shawna McMahon,

    1. Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
    Search for more papers by this author
  • Joshua Schimel

    1. Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
    Search for more papers by this author

  • Editor: Max Häggblom

Correspondence: Matthew Wallenstein, Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA. Tel.: +970 556 2591; fax: +970 491 1965; e-mail: wallenstein@lifesci.ucsb.edu

Abstract

Fungal and bacterial community structure in tussock, intertussock and shrub organic and mineral soils at Toolik Lake, Alaska were evaluated. Community structure was examined by constructing clone libraries of partial 16S and 18S rRNA genes. The soil communities were sampled at the end of the growing season in August 2004 and just after the soils thawed in June 2005. The communities differed greatly between vegetation types, although tussock and intertussock soil communities were very similar at the phyla level. The communities were relatively stable between sample dates at the phyla and subphyla levels, but differed significantly at finer phylogenetic scales. Tussock and intertussock bacterial communities were dominated by Acidobacteria, while shrub soils were dominated by Proteobacteria. These results appear consistent with previous work demonstrating that shrub soils contain an active, bioavailable C fraction, while tussock soils are dominated by more recalcitrant substrates. Tussock fungi communities had higher proportions of Ascomycota than shrub soils, while Zygomycota were more abundant in shrub soils. Recent documentation of increasing shrub abundance in the Arctic suggests that soil microbial communities and their functioning are likely to be altered by climate change.

Ancillary