Microbial diversity and the presence of algae in halite endolithic communities are correlated to atmospheric moisture in the hyper‐arid zone of the A tacama D esert

Abstract

Summary The A tacama D esert 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 H alothece cyanobacteria for primary production. A few other phylotypes of salt‐adapted bacteria and archaea, including S alinibacter , H alorhabdus , and H alococcus 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 Y ungay 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 M amiellales . In contrast, we did not find any algae in the Y ungay pinnacles, suggesting that the environmental conditions in this habitat might be too extreme for eukaryotic photosynthetic life.

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