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Title: Microbial Community Structure and the Persistence of Cyanobacterial Populations in Salt Crusts of the Hyperarid Atacama Desert from Genome-Resolved Metagenomics

Although once thought to be devoid of biology, recent studies have identified salt deposits as oases for life in the hyperarid Atacama Desert. To examine spatial patterns of microbial species and key nutrient sources, we genomically characterized 26 salt crusts from three sites along a fog gradient. The communities are dominated by a large variety of Halobacteriales and Bacteroidetes, plus a few algal and Cyanobacterial species. CRISPR locus analysis suggests the distribution of a single Cyanobacterial population among all sites. This is in stark contrast to the extremely high sample specificity of most other community members. Only present at the highest moisture site is a genomically characterized Thermoplasmatales archaeon (Marine Group II) and six Nanohaloarchaea, one of which is represented by a complete genome. Parcubacteria (OD1) and Saccharibacteria (TM7), not previously reported from hypersaline environments, were found at low abundances. We found no indication of a N 2 fixation pathway in the communities, suggesting acquisition of bioavailable nitrogen from atmospherically derived nitrate. Samples cluster by site based on bacterial and archaeal abundance patterns and photosynthetic capacity decreases with increasing distance from the ocean. We conclude that moisture level, controlled by coastal fog intensity, is the strongest driver of community membership.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [1] ;  [5]
  1. Univ. of California, Berkeley, CA (United States). Department of Environmental Science, Policy, and Management
  2. Univ. of California, Berkeley, CA (United States). Department of Earth and Planetary Sciences
  3. Univ. of California, Berkeley, CA (United States). Department of Environmental Science, Policy, and Management; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Ecology Department, Earth Sciences Division
  4. Universidad Catolica del Norte, Antofagasta (Chile). Centro de Biotecnologia
  5. Univ. of California, Berkeley, CA (United States). Department of Environmental Science, Policy, and Management and Department of Earth and Planetary Sciences
Publication Date:
Report Number(s):
LLNL-JRNL-706877
Journal ID: ISSN 1664-302X
Grant/Contract Number:
AC52-07NA27344; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Frontiers in Microbiology
Additional Journal Information:
Journal Volume: 8; Journal ID: ISSN 1664-302X
Publisher:
Frontiers Research Foundation
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; metagenome; Atacama Desert; salt crust; hyperarid; hypersaline; environmental genomics; salar
OSTI Identifier:
1393344
Alternate Identifier(s):
OSTI ID: 1408450