The Viking missions showed the martian soil to be lifeless and depleted in organic material and indicated the presence of one or more reactive oxidants. Here we report the presence of Mars-like soils in the extreme arid region of the Atacama Desert. Samples from this region had organic species only at trace levels and extremely low levels of culturable bacteria. Two samples from the extreme arid region were tested for DNA and none was recovered. Incubation experiments, patterned after the Viking labeled-release experiment but with separate biological and nonbiological isomers, show active decomposition of organic species in these soils by nonbiological processes.
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http://dx.doi.org/10.1126/science.1089143 | DOI Listing |
mLife
September 2024
Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China.
Earth's lower near space of 20-40 km above sea level with polyextreme conditions serves as a unique Mars analog for astrobiological research to investigate the limits of life on Earth and planetary protection considerations for Mars exploration. In this study, we exposed Mars-like desert regolith to near space at a float altitude of ~35 km and isolated four bacterial strains after exposure. In addition to stress tolerance to extreme environmental stressors, these strains represent a remarkable tolerance to perchlorate that is widespread in present-day Martian soils.
View Article and Find Full Text PDFAstrobiology
August 2022
David Rittenhouse Laboratory, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Life detection on Mars is an important topic that includes a direct search for biomarkers. This requires instruments for biomarker detection that are compact, lightweight, and able to withstand operations in space. Solid-state nanopores are excellent candidates that allow fast single-molecule detection.
View Article and Find Full Text PDFFront Microbiol
February 2019
Yale-NUS College, National University of Singapore, Singapore, Singapore.
Sediments in the hyper-arid core of the Atacama Desert are a terrestrial analog to Mars regolith. Understanding the distribution and drivers of microbial life in the sediment may give critical clues on how to search for biosignatures on Mars. Here, we identify the spatial distribution of highly specialized bacterial communities in previously unexplored depth horizons of subsurface sediments to a depth of 800 mm.
View Article and Find Full Text PDFAstrobiology
February 2019
2 German Aerospace Center, Institute of Planetary Research, Management and Infrastructure, Astrobiological Laboratories, Berlin, Germany.
In the ESA space experiment BIOMEX (BIOlogy and Mars EXperiment), dried Chroococcidiopsis cells were exposed to Mars-like conditions during the EXPOSE-R2 mission on the International Space Station. The samples were exposed to UV radiation for 469 days and to a Mars-like atmosphere for 722 days, approaching the conditions that could be faced on the surface of Mars. Once back on Earth, cell survival was tested by growth-dependent assays, while confocal laser scanning microscopy and PCR-based assay were used to analyze the accumulated damage in photosynthetic pigments (chlorophyll a and phycobiliproteins) and genomic DNA, respectively.
View Article and Find Full Text PDFAppl Environ Microbiol
December 2018
Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
The high-altitude atmosphere is a harsh environment with extremely low temperatures, low pressure, and high UV irradiation. For this reason, it has been proposed as an analogue for Mars, presenting deleterious factors similar to those on the surface of that planet. We evaluated the survival of extremophilic UV-resistant yeasts isolated from a high-elevation area in the Atacama Desert under stratospheric conditions.
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