Examinando por Autor "Ascaso, C."

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Acceso Abierto
Crystalline water in gypsum is unavailable for cyanobacteria in laboratory experiments and in natural desert endolithic habitats
(National Academy of Sciences, 2020-10-22) Wierzchos, J.; Artieda, O.; Ascaso, C.; Nieto García, F.; Vítek, P.; Azua Bustos, A.; Fairén, Alberto G.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Nieto García, F. [0000-0001-6250-056X]; Wierzchos, J. [0000-0003-3084-3837]; Azua Bustos, A. [0000-0002-6590-4145]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Acceso Abierto
Dark microbiome and extremely low organics in Atacama fossil delta unveil Mars life detection limits
(Nature Publishing Group, 2023-02-21) Azua Bustos, A.; Fairén, A.; González Silva, C.; Prieto Ballesteros, O.; Carrizo, D.; Sánchez García, L.; Parro García, V.; Fernández Martínez, M. A.; Escudero, C.; Muñoz Iglesias, V.; Fernández Sampedro, M.; Molina, A.; García Villadangos, M.; Moreno Paz, M.; Wierzchos, J.; Ascaso, C.; Fornado, Teresa; Brucato, J. R.; Poggiali, G.; Manrique, J. A.; Veneranda, M.; López Reyes, G.; Sanz Arranz, A.; Rull, F.; Ollila, A. M.; Wiens, R. C.; Reyes Newell, Adriana; Clegg, S. M.; Millan, Maëva; Stewart Johnson, Sarah; McIntosh, Ophélie; Szopa, Cyril; Freissinet, Caroline; Sekine, Yasuhito; Fukushi, Keisuke; Morida, Koki; Inoue, Kosuke; Sakuma, Hiroshi; Rampe, E.; European Commission (EC); Ministerio de Economía y Competitividad (MINECO); Japan Society for the Promotion of Science (JSPS); Comunidad de Madrid; National Aeronautics and Space Administration (NASA); Agenzia Spaziale Italiana (ASI); Agencia Estatal de Investigación (AEI); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Identifying unequivocal signs of life on Mars is one of the most important objectives for sending missions to the red planet. Here we report Red Stone, a 163-100 My alluvial fan–fan delta that formed under arid conditions in the Atacama Desert, rich in hematite and mudstones containing clays such as vermiculite and smectites, and therefore geologically analogous to Mars. We show that Red Stone samples display an important number of microorganisms with an unusual high rate of phylogenetic indeterminacy, what we refer to as “dark microbiome”, and a mix of biosignatures from extant and ancient microorganisms that can be barely detected with state-of-the-art laboratory equipment. Our analyses by testbed instruments that are on or will be sent to Mars unveil that although the mineralogy of Red Stone matches that detected by ground-based instruments on the red planet, similarly low levels of organics will be hard, if not impossible to detect in Martian rocks depending on the instrument and technique used. Our results stress the importance in returning samples to Earth for conclusively addressing whether life ever existed on Mars.
Acceso Abierto
Inhabited subsurface wet smectites in the hyperarid core of the Atacama Desert as an analog for the search for life on Mars
(Nature Research Journals, 2020-11-05) Azua Bustos, A.; Fairén, Alberto G.; González Silva, C.; Carrizo, D.; Fernández Martínez, M. A.; Arenas Fajardo, C.; Fernández Sampedro, M.; Gil Lozano, C.; Sánchez García, L.; Ascaso, C.; Wierzchos, J.; Rampe, E. B.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Sánchez García, L. [0000-0002-7444-1242]; Lozano, C. G. [0000-0003-3500-2850]; Fernández Sampedro, M. [0000-0003-1932-7591]
The modern Martian surface is unlikely to be habitable due to its extreme aridity among other environmental factors. This is the reason why the hyperarid core of the Atacama Desert has been studied as an analog for the habitability of Mars for more than 50 years. Here we report a layer enriched in smectites located just 30 cm below the surface of the hyperarid core of the Atacama. We discovered the clay-rich layer to be wet (a phenomenon never observed before in this region), keeping a high and constant relative humidity of 78% (aw 0.780), and completely isolated from the changing and extremely dry subaerial conditions characteristic of the Atacama. The smectite-rich layer is inhabited by at least 30 halophilic species of metabolically active bacteria and archaea, unveiling a previously unreported habitat for microbial life under the surface of the driest place on Earth. The discovery of a diverse microbial community in smectite-rich subsurface layers in the hyperarid core of the Atacama, and the collection of biosignatures we have identified within the clays, suggest that similar shallow clay deposits on Mars may contain biosignatures easily reachable by current rovers and landers.