title: Bacterial community composition of divergent soil habitats in a polar desert.
abstract: Edaphic factors such as pH, organic matter, and salinity are often the most significant drivers of diversity patterns in soil bacterial communities. Desert ecosystems in particular are model locations for examining such relationships as food web complexity is low and the soil environment is biogeochemically heterogeneous. Here, we present the findings from a 16S rRNA gene sequencing approach used to observe the differences in diversity and community composition among three divergent soil habitats of the McMurdo Dry Valleys, Antarctica. Results show that alpha diversity is significantly lowered in high pH soils, which contain higher proportions of the phyla Acidobacteria and Actinobacteria, while mesic soils with higher soil organic carbon (and ammonium) content contain high proportions of Nitrospira, a nitrite-oxidizing bacteria. Taxonomic community resolution also had a significant impact on our conclusions, as pH was the primary predictor of phylum-level diversity, while moisture was the most significant predictor of diversity at the genus level. Predictive power also increased with increasing taxonomic resolution, suggesting a potential increase in niche-based drivers of bacterial community composition at such levels.
authors.affiliation: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Geyer
authors.forename: Adam E
authors.initials: AE
authors.lastname: Altrichter
authors.forename: Cristina D
authors.initials: CD
authors.lastname: Takacs-Vesbach
authors.forename: David J
authors.initials: DJ
authors.lastname: Van Horn
authors.forename: Michael N
authors.initials: MN
authors.lastname: Gooseff
authors.forename: John E
authors.initials: JE
authors.lastname: Barrett
mesh_terms: D061271:Acidobacteria / Q000235:genetics*; D039903:Actinobacteria / Q000235:genetics*; D000864:Antarctic Regions; D044822:Biodiversity; D058893:DNA Barcoding, Taxonomic; D004269:DNA, Bacterial / Q000235:genetics; D003889:Desert Climate; D017753:Ecosystem; D006863:Hydrogen-Ion Concentration; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Antarctic Dry Valleys; environmental gradients; geochemical severity; microbial ecology