title: Life at the hyperarid margin: novel bacterial diversity in arid soils of the Atacama Desert, Chile.
abstract: Nearly half the earth's surface is occupied by dryland ecosystems, regions susceptible to reduced states of biological productivity caused by climate fluctuations. Of these regions, arid zones located at the interface between vegetated semiarid regions and biologically unproductive hyperarid zones are considered most vulnerable. The objective of this study was to conduct a deep diversity analysis of bacterial communities in unvegetated arid soils of the Atacama Desert, to characterize community structure and infer the functional potential of these communities based on observed phylogenetic associations. A 454-pyrotag analysis was conducted of three unvegetated arid sites located at the hyperarid-arid margin. The analysis revealed communities with unique bacterial diversity marked by high abundances of novel Actinobacteria and Chloroflexi and low levels of Acidobacteria and Proteobacteria, phyla that are dominant in many biomes. A 16S rRNA gene library of one site revealed the presence of clones with phylogenetic associations to chemoautotrophic taxa able to obtain energy through oxidation of nitrite, carbon monoxide, iron, or sulfur. Thus, soils at the hyperarid margin were found to harbor a wealth of novel bacteria and to support potentially viable communities with phylogenetic associations to non-phototrophic primary producers and bacteria capable of biogeochemical cycling.
authors.affiliation: Department of Soil, Water and Environmental Science, University of Arizona, Shantz Bldg Room 429, P.O. Box 210038, Tucson, AZ 85721-0038, USA. jneilson@email.arizona.edu
authors.forename: Julia W
authors.initials: JW
authors.lastname: Neilson
authors.forename: Jay
authors.initials: J
authors.lastname: Quade
authors.forename: Marianyoly
authors.initials: M
authors.lastname: Ortiz
authors.forename: William M
authors.initials: WM
authors.lastname: Nelson
authors.forename: Antje
authors.initials: A
authors.lastname: Legatzki
authors.forename: Fei
authors.initials: F
authors.lastname: Tian
authors.forename: Michelle
authors.initials: M
authors.lastname: LaComb
authors.forename: Julio L
authors.initials: JL
authors.lastname: Betancourt
authors.forename: Rod A
authors.initials: RA
authors.lastname: Wing
authors.forename: Carol A
authors.initials: CA
authors.lastname: Soderlund
authors.forename: Raina M
authors.initials: RM
authors.lastname: Maier
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D002677:Chile; D041862:Chloroflexi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D003889:Desert Climate; D012329:RNA, Bacterial / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S