title: Microbial diversity and the presence of algae in halite endolithic communities are correlated to atmospheric moisture in the hyper-arid zone of the Atacama Desert.
abstract: The Atacama Desert is one of the oldest and driest deserts in the world, and its hyper-arid core is described as 'the most barren region imaginable'. We used a combination of high-throughput sequencing and microscopy methods to characterize the endolithic microbial assemblages of halite pinnacles (salt rocks) collected in several hyper-arid areas of the desert. We found communities dominated by archaea that relied on a single phylotype of Halothece cyanobacteria for primary production. A few other phylotypes of salt-adapted bacteria and archaea, including Salinibacter, Halorhabdus, and Halococcus were major components of the halite communities, indicating specific adaptations to the unique halite environments. Multivariate statistical analyses of diversity metrics clearly separated the halite communities from that of the surrounding soil in the Yungay area. These analyses also revealed distribution patterns of halite communities correlated with atmospheric moisture. Microbial endolithic communities from halites exposed to coastal fogs and high relative humidity were more diverse; their archaeal and bacterial assemblages were accompanied by a novel algae related to oceanic picoplankton of the Mamiellales. In contrast, we did not find any algae in the Yungay pinnacles, suggesting that the environmental conditions in this habitat might be too extreme for eukaryotic photosynthetic life.
authors.affiliation: Biology Department, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Courtney K
authors.initials: CK
authors.lastname: Robinson
authors.forename: Jacek
authors.initials: J
authors.lastname: Wierzchos
authors.forename: Celeste
authors.initials: C
authors.lastname: Black
authors.forename: Alexander
authors.initials: A
authors.lastname: Crits-Christoph
authors.forename: Bing
authors.initials: B
authors.lastname: Ma
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
authors.forename: Carmen
authors.initials: C
authors.lastname: Ascaso
authors.forename: Octavio
authors.initials: O
authors.lastname: Artieda
authors.forename: Sergio
authors.initials: S
authors.lastname: Valea
authors.forename: Mònica
authors.initials: M
authors.lastname: Roldán
authors.forename: Benito
authors.initials: B
authors.lastname: Gómez-Silva
authors.forename: Jocelyne
authors.initials: J
authors.lastname: DiRuggiero
mesh_terms: D001105:Archaea / Q000145:classification*; D001419:Bacteria / Q000145:classification*; D018533:Biomass; D000458:Cyanobacteria / Q000145:classification*; D003889:Desert Climate; D006358:Hot Temperature; D006813:Humidity; D059013:Microbial Consortia; D009997:Osmotic Pressure; D012492:Salts
chemical_list: D012492:Salts