02435nas a2200277   4500008004100000245011000041210006900151260001200220300000700232490000700239520155100246653001501797653002601812653002401838653001301862653003001875100001901905700002401924700002101948700002401969700002101993700002302014700002202037700003302059856006502092       2022                        eng d00aLimits to the three domains of life: Lessons from community assembly along an Antarctic salinity gradient0 aLimits to the three domains of life Lessons from community assem  c04/2022  a150 v263 a<p>Extremophiles exist among all three domains of life; however, physiological mechanisms for surviving harsh environmental conditions differ among Bacteria, Archaea and Eukarya. Consequently, we expect that domain-specific variation of diversity and community assembly patterns exist along environmental gradients in extreme environments. We investigated inter-domain community compositional differences along a high-elevation salinity gradient in the McMurdo Dry Valleys, Antarctica. Conductivity for 24 soil samples collected along the gradient ranged widely from 50 to 8355 &micro;S cm<sup>-1</sup>. Taxonomic richness varied among domains, with a total of 359 bacterial, 2 archaeal, 56 fungal, and 69 non-fungal eukaryotic operational taxonomic units (OTUs). Richness for bacteria, archaea, fungi, and non-fungal eukaryotes declined with increasing conductivity (all <em>P</em>&thinsp;&lt;&thinsp;0.05). Principal coordinate ordination analysis (PCoA) revealed significant (ANOSIM <em>R</em>&thinsp;=&thinsp;0.97) groupings of low/high salinity bacterial OTUs, while OTUs from other domains were not significantly clustered. Bacterial beta diversity was unimodally distributed along the gradient and had a nested structure driven by species losses, whereas in fungi and non-fungal eukaryotes beta diversity declined monotonically without strong evidence of nestedness. Thus, while increased salinity acts as a stressor in all domains, the mechanisms driving community assembly along the gradient differ substantially between the domains.</p>10aAntarctica10ainter-domain response10aMcMurdo Dry Valleys10asalinity10aspecies richness patterns1 aJiang, Xiaoben1 aVan Horn, David, J.1 aOkie, Jordan, G.1 aBuelow, Heather, N.1 aSchwartz, Egbert1 aColman, Daniel, R.1 aFeeser, Kelli, L.1 aTakacs-Vesbach, Cristina, D.  uhttps://link.springer.com/article/10.1007/s00792-022-01262-302931nas a2200205   4500008004100000245011300041210006900154260001200223490000600235520222200241100002202463700002402485700002402509700002302533700002402556700002102580700002102601700003302622856007002655       2018                        eng d00aLocal and Regional Scale Heterogeneity Drive Bacterial Community Diversity and Composition in a Polar Desert0 aLocal and Regional Scale Heterogeneity Drive Bacterial Community  c08/20180 v93 a<p>The distribution of organisms in an environment is neither uniform nor random but is instead spatially patterned. The factors that control this patterning are complex and the underlying mechanisms are poorly understood. Soil microbes are critical to ecosystem function but exhibit highly complex distributions and community dynamics due in large part to the scale-dependent effects of environmental heterogeneity. To better understand the impact of environmental heterogeneity on the distribution of soil microbes, we sequenced the 16S rRNA gene from bacterial communities in the microbe-dominated polar desert ecosystem of the McMurdo Dry Valleys (MDV), Antarctica. Significant differences in key edaphic variables and alpha diversity were observed among the three lake basins of the Taylor Valley (Kruskal&ndash;Wallis; pH: χ2 = 68.89, P &lt; 0.001, conductivity: χ2 = 35.03, P &lt; 0.001, observed species: χ2 = 7.98, P = 0.019 and inverse Simpson: χ2 = 18.52, P &lt; 0.001) and each basin supported distinctive microbial communities (ANOSIM R = 0.466, P = 0.001, random forest ratio of 14.1). However, relationships between community structure and edaphic characteristics were highly variable and contextual, ranging in magnitude and direction across regional, basin, and local scales. Correlations among edaphic factors (pH and soil conductivity) and the relative abundance of specific phyla were most pronounced along local environmental gradients in the Lake Fryxell basin where Acidobacteria, Bacteroidetes, and Proteobacteria declined while Deinococcus&ndash;Thermus and Gemmatimonadetes increased with soil conductivity (all P &lt; 0.1). Species richness was most strongly related to the soil conductivity gradient present within this study system. We suggest that the relative importance of pH versus soil conductivity in structuring microbial communities is related to the length of edaphic gradients and the spatial scale of sampling. These results highlight the importance of conducting studies over large ranges of key environmental gradients and across multiple spatial scales to assess the influence of environmental heterogeneity on the composition and diversity of microbial communities.</p>1 aFeeser, Kelli, L.1 aVan Horn, David, J.1 aBuelow, Heather, N.1 aColman, Daniel, R.1 aMcHugh, Theresa, A.1 aOkie, Jordan, G.1 aSchwartz, Egbert1 aTakacs-Vesbach, Cristina, D.  uhttps://www.frontiersin.org/article/10.3389/fmicb.2018.01928/full01634nas a2200217   4500008004100000245010200041210006900143260001200212300001400224490000600238520092200244100002401166700002901190700002201219700002101241700002501262700002401287700001301311700002101324856007101345       2017                        eng d00aHigh-resolution elevation mapping of the McMurdo Dry Valleys, Antarctica, and surrounding regions0 aHighresolution elevation mapping of the McMurdo Dry Valleys Anta  c07/2017  a435 - 4430 v93 a<p>We present detailed surface elevation measurements for the McMurdo Dry Valleys, Antarctica derived from aerial lidar surveys flown in the austral summer of 2014&ndash;2015 as part of an effort to understand geomorphic changes over the past decade. Lidar return density varied from 2 to &gt; 10 returns  m&minus;2&nbsp;with an average of about 5  returns  m&minus;2. Vertical and horizontal accuracies are estimated to be 7 and 3 cm, respectively. In addition to our intended targets, other ad hoc regions were also surveyed including the Pegasus flight facility and two regions on Ross Island, McMurdo Station, Scott Base (and surroundings), and the coastal margin between Cape Royds and Cape Evans. These data are included in this report and data release. The combined data are freely available at&nbsp;<a href="https://doi.org/10.5069/G9D50JX3" target="_blank">https://doi.org/10.5069/G9D50JX3</a>.</p>1 aFountain, Andrew, G1 aFernandez-Diaz, Juan, C.1 aObryk, Maciek, K.1 aLevy, Joseph, S.1 aGooseff, Michael, N.1 aVan Horn, David, J.1 aMorin, P1 aShrestha, Ramesh  uhttps://www.earth-syst-sci-data.net/9/435/2017/essd-9-435-2017.pdf02255nas a2200193   4500008004100000245007900041210006900120260001200189300001400201490000800215520163600223100002001859700002501879700002401904700002101928700002201949700002401971856006601995       2017                        eng d00aImpacts of permafrost degradation on a stream in Taylor Valley, Antarctica0 aImpacts of permafrost degradation on a stream in Taylor Valley A  c05/2017  a205 - 2130 v2853 a<p>The McMurdo Dry Valleys (MDV) of Antarctica are an ice-free landscape that supports a complex, microbially dominated ecosystem despite a severely arid, cold environment (b 5 cm water equivalent/y, &minus; 18 &deg;C mean annual air temperature). Recent observations of permafrost degradation in the coastal zones of the MDV suggest that this region is nearing a threshold of rapid landscape change. In 2012, substantial thermokarst development was observed along several kilometers of the west branch of Crescent Stream in Taylor Valley mostly in the form of bank failures, whereas the adjacent east branch was unaffected. The objective of this study was to quantify the changes to the stream banks of the west branch of Crescent Stream and to determine the impacts on the composition of the stream bed material. Three annually repeated terrestrial LiDAR scans were compared to determine the rates of ground surface change caused by thermokarst formation on the stream bank. The areal extent of the thermokarst was shown to be decreasing; however, the average vertical rate of retreat remained constant. Field measurements of bed materials indicated that the west branch and the reach downstream of the confluence (of east and west branches) consistently contained more fines than the unaffected east branch. This suggests that the finer bed material is a result of the thermokarst development on the west branch. These finer bed material compositions are likely to increase the mobility of the bed material, which will have implications for stream morphology, stream algal mat communities, and downstream aquatic ecosystems.</p>1 aSudman, Zachary1 aGooseff, Michael, N.1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aObryk, Maciek, K.1 aVan Horn, David, J.  uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X1630846700676nas a2200181   4500008004100000245012900041210006900170260001200239490000600251100002400257700002000281700002400301700002200325700002500347700002100372700003300393856006800426       2016                        eng d00aMicrobial Community Responses to Increased Water and Organic Matter in the Arid Soils of the McMurdo Dry Valleys, Antarctica0 aMicrobial Community Responses to Increased Water and Organic Mat  c07/20160 v71 aBuelow, Heather, N.1 aWinter, Ara, S.1 aVan Horn, David, J.1 aBarrett, John, E.1 aGooseff, Michael, N.1 aSchwartz, Egbert1 aTakacs-Vesbach, Cristina, D.  uhttp://journal.frontiersin.org/article/10.3389/fmicb.2016.0104002591nas a2200193   4500008004100000245013100041210006900172260001200241300001100253490000700264520191200271100002202183700002402205700002402229700003302253700002402286700001702310856007002327       2016                        eng d00aNutrient treatments alter microbial mat colonization in two glacial meltwater streams from the McMurdo Dry Valleys, Antarctica0 aNutrient treatments alter microbial mat colonization in two glac  c03/2016  afiw0490 v923 a<p><span style="color: rgb(3, 3, 3); font-family: Helvetica, Arial, sans-serif; font-size: 14px; line-height: 21px; background-color: rgb(255, 255, 254);">Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom,&nbsp;</span><em style="outline: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 14px; line-height: 21px; font-family: Helvetica, Arial, sans-serif; color: rgb(3, 3, 3); background-color: rgb(255, 255, 254);">Fistulifera pelliculosa</em><span style="color: rgb(3, 3, 3); font-family: Helvetica, Arial, sans-serif; font-size: 14px; line-height: 21px; background-color: rgb(255, 255, 254);">. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere.</span></p>1 aKohler, Tyler, J.1 aVan Horn, David, J.1 aDarling, Joshua, P.1 aTakacs-Vesbach, Cristina, D.1 aMcKnight, Diane, M.1 aWagner, Dirk  uhttp://femsec.oxfordjournals.org/lookup/doi/10.1093/femsec/fiw04902226nas a2200229   4500008004100000245011100041210006900152260001200221300001100233490000700244520146700251100002401718700002201742700002301764700001901787700002201806700002401828700002101852700002001873700003301893856007001926       2016                        eng d00aPatterns of bacterial biodiversity in the glacial meltwater streams of the McMurdo Dry Valleys, Antarctica0 aPatterns of bacterial biodiversity in the glacial meltwater stre  c08/2016  afiw1480 v923 a<p>Microbial consortia dominate glacial meltwater streams from polar regions, including the McMurdo Dry Valleys (MDV), where they thrive under physiologically stressful conditions. In this study, we examined microbial mat types and sediments found in 12 hydrologically diverse streams to describe the community diversity and composition within and across sites. Sequencing of the 16S rRNA gene from 129 samples revealed &sim;24 000 operational taxonomic units (&lt;97% DNA similarity), making streams the most biodiverse habitat in the MDV. Principal coordinate analyses revealed significant but weak clustering by mat type across all streams (ANOSIM R-statistic = 0.28) but stronger clustering within streams (ANOSIM R-statistic from 0.28 to 0.94). Significant relationships (P &lt; 0.05) were found between bacterial diversity and mat ash-free dry mass, suggesting that diversity is related to the hydrologic regimes of the various streams, which are predictive of mat biomass. However, correlations between stream chemistry and community members were weak, possibly reflecting the importance of internal processes and hydrologic conditions. Collectively, these results suggest that localized conditions dictate bacterial community composition of the same mat types and sediments from different streams, and while MDV streams are hotspots of biodiversity in an otherwise depauperate landscape, controls on community structure are complex and site specific.</p>1 aVan Horn, David, J.1 aWolf, Caitlin, R.1 aColman, Daniel, R.1 aJiang, Xiaoben1 aKohler, Tyler, J.1 aMcKnight, Diane, M.1 aStanish, Lee, F.1 aYazzie, Terrill1 aTakacs-Vesbach, Cristina, D.  uhttp://femsec.oxfordjournals.org/lookup/doi/10.1093/femsec/fiw14801836nas a2200193   4500008004100000245013000041210006900171260001200240300001600252490000700268520116600275100002501441700002401466700002001490700002401510700002401534700001701558856006701575       2016                        eng d00aStream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica0 aStream biogeochemical and suspended sediment responses to permaf  c03/2016  a1723 - 17320 v133 a<p><span style="color: rgb(106, 106, 106); font-family: Verdana, Arial, sans-serif; font-size: 12px; line-height: 20px;">&nbsp;Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of the Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream (&thinsp;&sim;&thinsp; 20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams.</span></p>1 aGooseff, Michael, N.1 aVan Horn, David, J.1 aSudman, Zachary1 aMcKnight, Diane, M.1 aWelch, Kathleen, A.1 aLyons, Berry  uhttp://www.biogeosciences.net/13/1723/2016/bg-13-1723-2016.pdf02696nas a2200217   4500008004100000022001400041245013900055210006900194260001200263300000900275490000800284520194700292100002102239700002402260700001802284700002202302700002502324700001902349700003302368856007702401       2015                        eng d  a0962-845200aNiche and metabolic principles explain patterns of diversity and distribution: theory and a case study with soil bacterial communities0 aNiche and metabolic principles explain patterns of diversity and  c05/2015  a26300 v2823 a<p><span style="font-family: inherit; font-size: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; color: rgb(51, 49, 50);">The causes of biodiversity patterns are controversial and elusive due to complex environmental variation, covarying changes in communities, and lack of baseline and null theories to differentiate straightforward causes from more complex mechanisms. To address these limitations, we developed general diversity theory integrating metabolic principles with niche-based community assembly. We evaluated this theory by investigating patterns in the diversity and distribution of soil bacteria taxa across four orders of magnitude variation in spatial scale on an Antarctic mountainside in low complexity, highly oligotrophic soils. Our theory predicts that lower temperatures should reduce taxon niche widths along environmental gradients due to decreasing growth rates, and the changing niche widths should lead to contrasting α- and β-diversity patterns. In accord with the predictions, α-diversity, niche widths and occupancies decreased while β-diversity increased with increasing elevation and decreasing temperature. The theory also successfully predicts a hump-shaped relationship between α-diversity and pH and a negative relationship between α-diversity and salinity. Thus, a few simple principles explained systematic microbial diversity variation along multiple gradients. Such general theory can be used to disentangle baseline effects from more complex effects of temperature and other variables on biodiversity patterns in a variety of ecosystems and organisms.</span></p><div class="section abstract" id="abstract-1" style="-webkit-font-smoothing: antialiased; outline: 0px; font-stretch: inherit; font-size: 14px; line-height: 26.04px; font-family: Arial, Helvetica, sans-serif; clear: both; color: rgb(51, 49, 50);"><div>&nbsp;</div></div><p>&nbsp;</p>1 aOkie, Jordan, G.1 aVan Horn, David, J.1 aStorch, David1 aBarrett, John, E.1 aGooseff, Michael, N.1 aKopsova, Lenka1 aTakacs-Vesbach, Cristina, D.  uhttp://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2014.263002223nas a2200205   4500008004100000245012900041210006900170260001200239300001200251490000700263520146400270100001701734700002401751700002401775700002501799700002201824700003301846700001501879856012301894       2014                        eng d00aCharacterization of Growing Bacterial Populations in McMurdo Dry Valley Soils through Stable Isotope Probing with 18O-water.0 aCharacterization of Growing Bacterial Populations in McMurdo Dry  c08/2014  a415-4250 v893 aSoil microbial communities of the McMurdo Dry Valleys, Antarctica (MDV) contain representatives from at least fourteen bacterial phyla. However, given low rates of microbial activity, it is unclear whether this richness represents functioning rather than dormant members of the community. We used stable isotope probing (SIP) with (18) O-water to determine if microbial populations grow in MDV soils. Changes in the microbial community were characterized in soils amended with H2 (18) O and H2 (18) O-organic matter. Sequencing the 16S rRNA genes of the heavy and light fractions of the bacterial community DNA shows that DNA of microbial populations was labeled with (18) O-water, indicating these micro-organisms grew in the MDV soils. Significant differences existed in the community composition of the heavy and light fractions of the H2 (18) O and H2 (18) O-organic matter amended samples (Anosim P < 0.05 of weighted Unifrac distance). Control samples and the light DNA fraction of the H2 (18) O amended samples were dominated by representatives of the phyla Deinococcus-Thermus, Proteobacteria, Planctomyces, Gemmatimonadetes, Actinobacteria and Acidobacteria, whereas Proteobacteria were more prevalent in the heavy DNA fractions from the H2 (18) O-water and the H2 (18) O-water-organic matter treatments. Our results indicate that SIP with H2 (18) O can be used to distinguish active bacterial populations even in this low organic matter environment.1 aSchwartz, E.1 aVan Horn, David, J.1 aBuelow, Heather, N.1 aGooseff, Michael, N.1 aBarrett, John, E.1 aTakacs-Vesbach, Cristina, D.1 aOkie, J.G.  uhttps://mcm.lternet.edu/content/characterization-growing-bacterial-populations-mcmurdo-dry-valley-soils-through-stable02542nas a2200181   4500008004100000022001300041245006800054210006300122260001200185300001200197490000800209520181900217100002402036700002102060700002502081700002402106856023002130       2014                        eng d  a0169555X00aThe McMurdo Dry Valleys: A landscape on the threshold of change0 aMcMurdo Dry Valleys A landscape on the threshold of change  c11/2014  a25 - 350 v2253 a<p><span style="color: rgb(46, 46, 46); font-family: Arial, Helvetica, 'Lucida Sans Unicode', 'Microsoft Sans Serif', 'Segoe UI Symbol', STIXGeneral, 'Cambria Math', 'Arial Unicode MS', sans-serif; font-size: 16px; line-height: 23.6800003051758px; word-spacing: -1.24453127384186px;">Field observations of coastal and lowland regions in the McMurdo Dry Valleys suggest they are on the threshold of rapid topographic change, in contrast to the high elevation upland landscape that represents some of the lowest rates of surface change on Earth. A number of landscapes have undergone dramatic and unprecedented landscape changes over the past decade including, the Wright Lower Glacier (Wright Valley) &mdash; ablated several tens of meters, the Garwood River (Garwood Valley) has incised &gt;&nbsp;3&nbsp;m into massive ice permafrost, smaller streams in Taylor Valley (Crescent, Lawson, and Lost Seal Streams) have experienced extensive down-cutting and/or bank undercutting, and Canada Glacier (Taylor Valley) has formed sheer, &gt;&nbsp;4&nbsp;meter deep canyons. The commonality between all these landscape changes appears to be sediment on ice acting as a catalyst for melting, including ice-cement permafrost thaw. We attribute these changes to increasing solar radiation over the past decade despite no significant trend in summer air temperature. To infer possible future landscape changes in the McMurdo Dry Valleys, due to anticipated climate warming, we map &lsquo;at risk&rsquo; landscapes defined as those with buried massive ice in relative warm regions of the valleys. Results show that large regions of the valley bottoms are &lsquo;at risk&rsquo;. Changes in surface topography will trigger important responses in hydrology, geochemistry, and biological community structure and function.</span></p>1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aGooseff, Michael, N.1 aVan Horn, David, J.  uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X14001780http://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/plain02505nas a2200193   4500008004100000245011800041210006900159260001200228300001400240490000700254520178100261100002402042700001502066700002402081700002502105700002202130700003302152856012602185       2014                        eng d00aSoil microbial responses to increased moisture and organic resources along a salinity gradient in a polar desert.0 aSoil microbial responses to increased moisture and organic resou  c05/2014  a3034-30430 v803 aMicrobial communities in extreme environments often have low diversity and specialized physiologies suggesting a limited resistance to change. The McMurdo Dry Valleys (MDV) are a microbially dominated, extreme ecosystem currently undergoing climate change-induced disturbances, including the melting of massive buried ice, cutting through of permafrost by streams, and warming events. These processes are increasing moisture across the landscape, altering conditions for soil communities by mobilizing nutrients and salts and stimulating autotrophic carbon inputs to soils. The goal of this study was to determine the effects of resource addition (water/organic matter) on the composition and function of microbial communities in the MDV along a natural salinity gradient representing an additional gradient of stress in an already extreme environment. Soil respiration and the activity of carbon-acquiring extracellular enzymes increased significantly (P < 0.05) with the addition of resources at the low- and moderate-salinity sites but not the high-salinity site. The bacterial community composition was altered, with an increase in Proteobacteria and Firmicutes with water and organic matter additions at the low- and moderate-salinity sites and a near dominance of Firmicutes at the high-salinity site. Principal coordinate analyses of all samples using a phylogenetically informed distance matrix (UniFrac) demonstrated discrete clustering among sites (analysis of similarity [ANOSIM], P < 0.05 and R > 0.40) and among most treatments within sites. The results from this experimental work suggest that microbial communities in this environment will undergo rapid change in response to the altered resources resulting from climate change impacts occurring in this region.1 aVan Horn, David, J.1 aOkie, J.G.1 aBuelow, Heather, N.1 aGooseff, Michael, N.1 aBarrett, John, E.1 aTakacs-Vesbach, Cristina, D.  uhttps://mcm.lternet.edu/content/soil-microbial-responses-increased-moisture-and-organic-resources-along-salinity-gradient00652nas 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.0066103