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Transitory microbial habitat in the hyperarid Atacama Desert.

Authors :
Schulze-Makuch D
Wagner D
Kounaves SP
Mangelsdorf K
Devine KG
de Vera JP
Schmitt-Kopplin P
Grossart HP
Parro V
Kaupenjohann M
Galy A
Schneider B
Airo A
Frösler J
Davila AF
Arens FL
Cáceres L
Cornejo FS
Carrizo D
Dartnell L
DiRuggiero J
Flury M
Ganzert L
Gessner MO
Grathwohl P
Guan L
Heinz J
Hess M
Keppler F
Maus D
McKay CP
Meckenstock RU
Montgomery W
Oberlin EA
Probst AJ
Sáenz JS
Sattler T
Schirmack J
Sephton MA
Schloter M
Uhl J
Valenzuela B
Vestergaard G
Wörmer L
Zamorano P
Source :
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2018 Mar 13; Vol. 115 (11), pp. 2670-2675. Date of Electronic Publication: 2018 Feb 26.
Publication Year :
2018

Abstract

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: ( i ) a physico-chemical characterization of the soil habitability after an exceptional rain event, ( ii ) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], ( iii ) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and ( iv ) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity.<br />Competing Interests: The authors declare no conflict of interest.<br /> (Copyright © 2018 the Author(s). Published by PNAS.)

Details

Language :
English
ISSN :
1091-6490
Volume :
115
Issue :
11
Database :
MEDLINE
Journal :
Proceedings of the National Academy of Sciences of the United States of America
Publication Type :
Academic Journal
Accession number :
29483268
Full Text :
https://doi.org/10.1073/pnas.1714341115