Geomicrobiological heterogeneity of lithic habitats in the extreme environment of Antarctic nunataks: a potential early Mars analog

Nunataks are permanent ice-free rocky peaks that project above ice caps in polar regions, thus being exposed to extreme climatic conditions throughout the year. They undergo extremely low temperatures and scarcity of liquid water in winter, while receiving high incident and reflected (albedo) UVA-B radiation in summer. Here, we investigate the geomicrobiology of the permanently exposed lithic substrates of nunataks from Livingston Island (South Shetlands, Antarctic Peninsula), with focus on prokaryotic community structure and their main metabolic traits. Contrarily to first hypothesis, an extensive sampling based on different gradients and multianalytical approaches demonstrated significant differences for most geomicrobiological parameters between the bedrock, soil, and loose rock substrates, which overlapped any other regional variation. Brevibacillus genus dominated on bedrock and soil substrates, while loose rocks contained a diverse microbial community, including Actinobacteria, Alphaproteobacteria and abundant Cyanobacteria inhabiting the milder and diverse microhabitats within. Archaea, a domain never described before in similar Antarctic environments, were also consistently found in the three substrates, but being more abundant and potentially more active in soils. Stable isotopic ratios of total carbon (δ 13C) and nitrogen (δ 15N), soluble anions concentrations, and the detection of proteins involved in key metabolisms via the Life Detector Chip (LDChip), suggest that microbial primary production has a pivotal role in nutrient cycling at these exposed areas with limited deposition of nutrients. Detection of stress-resistance proteins, such as molecular chaperons, suggests microbial molecular adaptation mechanisms to cope with these harsh conditions. Since early Mars may have encompassed analogous environmental conditions as the ones found in these Antarctic nunataks, our study also contributes to the understanding of the metabolic features and biomarker profiles of a potential Martian microbiota, as well as the use of LDChip in future life detection missions.This project has been funded by the Spanish Ministry of Science and Innovation (MICINN)/European Regional Development Fund (FEDER) project no. RTI2018-094368-B-I00; the European Research Council Consolidator grant no. 818602; and the Spanish State Research Agency (AEI) project no. MDM-2017-0737, Unidad de Excelencia “María de Maeztu” to Centro de Astrobiología

Aeolian transport of viable microbial life across the Atacama Desert, Chile : Implications for Mars

A.A.B. and A.G.F. thank the Project “icyMARS”, funded by the European Research Council, ERC Starting Grant No. 307496. M.P.Z., C.G.S., R.F. and F.J.M.T. thank the funding received from the Dubai Future Foundation through the Guaana.com open research platform (https://www.guaana.com/projects/jeGEimuX6DLCLsbQP).Peer reviewedPublisher PD

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

86 pags, 49 figs, 24 tabsNASA's Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R), ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de Tecnica Aeroespacial; Ministry of Science and Innovation's Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602.Peer reviewe

Three ages for the Martian lithosphere

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Extreme environments as Mars terrestrial analogs: The Rio Tinto case

12 pages, 5 figures, 2 tables.-- ISI Article Identifier: 000244695500010.-- Available online Sep 28, 2006.-- Issue title: "Planet Mars II".The geomicrobiological characterization of the Río Tinto (Iberian Pyritic Belt) has recently proven the importance of the iron cycle, not only in the generation of the extreme conditions of the habitat (low pH, high concentration of heavy metals), but also in the maintenance of a high level of microbial diversity. The presence of vast deposits of sulfates and iron oxides on Mars, the main products of the bioleaching of iron containing sulfides found in Río Tinto, and the physico-chemical properties of iron as a source of energy, protection from radiation and oxidative stress as well as pH control, make Río Tinto an interesting Mars terrestrial analog.This work was supported by Grant BOS2002-02148 from the CICYT and Institutional Grants to the Centro de Astrobiología.Peer reviewe

Aeolian transport of viable microbial life across the Atacama Desert, Chile: Implications for Mars

Here we inspect whether microbial life may disperse using dust transported by wind in the Atacama Desert in northern Chile, a well-known Mars analog model. By setting a simple experiment across the hyperarid core of the Atacama we found that a number of viable bacteria and fungi are in fact able to traverse the driest and most UV irradiated desert on Earth unscathed using wind-transported dust, particularly in the later afternoon hours. This finding suggests that microbial life on Mars, extant or past, may have similarly benefited from aeolian transport to move across the planet and find suitable habitats to thrive and evolve..A.B. and A.G.F. thank the Project “icyMARS”, funded by the European Research Council, ERC Starting Grant No. 307496. M.P.Z., C.G.S., R.F. and F.J.M.T. thank the funding received from the Dubai Future Foundation through the Guaana.com open research platform (https://www.guaana.com/projects/jeGEimuX6DLCLsbQP)

Author Correction : Aeolian transport of viable microbial life across the Atacama Desert, Chile: Implications for Mars (Scientific Reports, (2019), 9, 1, (11024), 10.1038/s41598-019-47394-z)

Peer reviewedPublisher PD

Unprecedented rains decimate surface microbial communities in the hyperarid core of the Atacama Desert

© The Author(s) 2018.The hyperarid core of the Atacama Desert, the driest and oldest desert on Earth, has experienced a number of highly unusual rain events over the past three years, resulting in the formation of previously unrecorded hypersaline lagoons, which have lasted several months. We have systematically analyzed the evolution of the lagoons to provide quantitative field constraints of large-scale impacts of the rains on the local microbial communities. Here we show that the sudden and massive input of water in regions that have remained hyperarid for millions of years is harmful for most of the surface soil microbial species, which are exquisitely adapted to survive with meager amounts of liquid water, and quickly perish from osmotic shock when water becomes suddenly abundant. We found that only a handful of bacteria, remarkably a newly identified species of Halomonas, remain metabolically active and are still able to reproduce in the lagoons, while no archaea or eukaryotes were identified. Our results show that the already low microbial biodiversity of extreme arid regions greatly diminishes when water is supplied quickly and in great volumes. We conclude placing our findings in the context of the astrobiological exploration of Mars, a hyperarid planet that experienced catastrophic floodings in ancient times.The research leading to these results is a contribution from the Project “icyMARS”, funded by the European Research Council, Starting Grant No. 307496. A.G.F. and V.P. acknowledge funding support from Grant No. ESP2015-69540-R (MINECO/FEDER). We thank V. Souza-Egipsy and BIOPHYM (IEM-CSIC) for TEM observations; C. Arroyo (MNCN-CSIC), and the Geomaterials 2 Program (S2013/MIT_2914), financed by the Comunidad Autónoma de Madrid and the European Social Fund; and Y. Blanco for providing LDChip antibody microarrays