01816nas a2200181   4500008004100000245008400041210006900125260001200194300001200206490000700218520117800225100002101403700002501424700003301449700002501482700002201507856010501529       2014                        eng d00aBacterial community composition of divergent soil habitats from a polar desert.0 aBacterial community composition of divergent soil habitats from   c08/2014  a490-4940 v893 aEdaphic 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 nic1 aGeyer, Kevin, M.1 aAltrichter, Adam, E.1 aTakacs-Vesbach, Cristina, D.1 aGooseff, Michael, N.1 aBarrett, John, E.  uhttps://mcm.lternet.edu/content/bacterial-community-composition-divergent-soil-habitats-polar-desert00652nas a2200181   4500008004100000245007600041210006900117260001200186300001100198490000600209100002100215700002500236700002400261700003300285700002500318700002200343856010500365       2013                        eng d00aEnvironmental controls over bacterial communities in polar desert soils0 aEnvironmental controls over bacterial communities in polar deser  c10/2013  aart1270 v41 aGeyer, Kevin, M.1 aAltrichter, Adam, E.1 aVan Horn, David, J.1 aTakacs-Vesbach, Cristina, D.1 aGooseff, Michael, N.1 aBarrett, John, E.  uhttps://mcm.lternet.edu/content/environmental-controls-over-bacterial-communities-polar-desert-soils00764nas a2200205   4500008004100000245015000041210006900191260001200260300001100272490000600283100002400289700001800313700002200331700002500353700002500378700002100403700002200424700003300446856007900479       2013                        eng d00aFactors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale0 aFactors Controlling Soil Microbial Biomass and Bacterial Diversi  c06/2013  ae661030 v81 aVan Horn, David, J.1 aVan Horn, Lee1 aBarrett, John, E.1 aGooseff, Michael, N.1 aAltrichter, Adam, E.1 aGeyer, Kevin, M.1 aZeglin, Lydia, H.1 aTakacs-Vesbach, Cristina, D.  uhttp://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.006610302518nas a2200205   4500008004100000245010700041210006900148260003400217490000700251520182600258653002502084653003402109653002402143653002702167653002202194653001102216100002502227700002202252856003802274       2010                        eng d00aLandscape history and contemporary environmental drivers of microbial community structure and function0 aLandscape history and contemporary environmental drivers of micr  aBlacksburg, VAbVirginia Tech0 vMS3 a<p>Recent work in microbial ecology has focused on elucidating controls over biogeographic patterns and connecting microbial community composition to ecosystem function. My objective was to investigate the relative influences of landscape legacies and contemporary environmental factors on the distribution of soil microbial communities and their contribution to ecosystem processes across a glacial till sequence in Taylor Valley, Antarctica. Within each till unit, I sampled from dry areas and areas with visible evidence of recent surface water movement generated by seasonal melting of ephemeral snow packs and hillslope ground ice. Using T-RFLP 16S rRNA gene profiles of microbial communities, I analyzed the contribution of till and environmental factors to community similarity, and assessed the functional potential of the microbial community using extracellular enzyme activity assays. Microbial communities were influenced by geochemical differences among both tills and local environments, but especially organized by variables associated with water availability as the first axis of an NMDS ordination was strongly related to shifts in soil moisture content. CCA revealed that tills explained only 3.4% of the variability in community similarity among sites, while geochemical variables explained 18.5%. Extracellular enzyme activity was correlated with relevant geochemical variables reflecting the influence of nutrient limitation on microbial activity. In addition, enzyme activity was related to changes in community similarity, particularly in wet environments with a partial Mantel correlation of 0.32. These results demonstrate how landscape history and environmental conditions can shape the functional potential of a microbial community mediated through shifts in microbial community composition.</p>10acommunity similarity10aextracellular enzyme activity10aMcMurdo Dry Valleys10amicrobial biogeography10asoil geochemistry10aT-RFLP1 aAltrichter, Adam, E.1 aBarrett, John, E.  uhttp://hdl.handle.net/10919/31883