||[Sep. 28th, 2015|12:50 pm]
In light of the -- SQUEEE -- surface water (brine) on Mars paper, i did some reading about the Atacama Desert (thanks ArsTechnica). An excellent overview paper is
Azua-Bustos, Armando, Catalina Urrejola, and Rafael Vicuña. “Life at the Dry Edge: Microorganisms of the Atacama Desert.” FEBS Letters 586, no. 18 (August 2012): 2939–45. doi:10.1016/j.febslet.2012.07.025.
Google maps supports visits, with some local photos and Wikipedia has many articles of varying brevity regarding features of the desert.
The most delightful thing i learned is how algae and other bacteria form colonies under quartz rock. (Domes!) The quartz transmits some light, cuts out the UV that zaps many bacteria with in days at the altitude, and provides a surface for fog condensation.
Oh, and the algae that live on spiderwebs in some of the caves in the "twilight zone."
Parro, Victor, Graciela de Diego-Castilla, Mercedes Moreno-Paz, Yolanda Blanco, Patricia Cruz-Gil, José A. Rodríguez-Manfredi, David Fernández-Remolar, et al. “A Microbial Oasis in the Hypersaline Atacama Subsurface Discovered by a Life Detector Chip: Implications for the Search for Life on Mars.” Astrobiology 11, no. 10 (December 1, 2011): 969–96. doi:10.1089/ast.2011.0654.
Logan, Bruce E., Husen Zhang, Peter Mulvaney, Michael G. Milner, Ian M. Head, and Richard F. Unz. “Kinetics of Perchlorate- and Chlorate-Respiring Bacteria.” Applied and Environmental Microbiology 67, no. 6 (June 1, 2001): 2499–2506. doi:10.1128/AEM.67.6.2499-2506.2001.
Ojha, Lujendra, Mary Beth Wilhelm, Scott L. Murchie, Alfred S. McEwen, James J. Wray, Jennifer Hanley, Marion Massé, and Matt Chojnacki. “Spectral Evidence for Hydrated Salts in Recurring Slope Lineae on Mars.” Nature Geoscience advance online publication (September 28, 2015). doi:10.1038/ngeo2546.
In 2008, the Phoenix Mars Lander detected perchlorates on the surface of Mars at the same site where water was first discovered. Perchlorates are also found in the Atacama and associated nitrate deposits have contained organics, leading to speculation that signs of life on Mars are not incompatible with perchlorates. The Atacama is also a testing site for the NASA-funded Earth-Mars Cave Detection Program.
-23.506528, -68.359527: http://www.sqm.com/en-us/acercadesqm/recursosnaturales/salmuera.aspx
Salar brines are located in the nucleus of the Salar de Atacama. They contain the greatest lithium and potassium concentrations ever known, in addition to considerable sulphate and boron concentrations. From this natural resource lithium carbonate, potassium chloride, potassium sulphate, boric acid and magnesium chloride are produced.
The Salar de Atacama is a source of underground salar brines, formed through natural leaching from the Andes Mountains: throughout time, diverse minerals found under the salt surface crust have descended from the mountains, accumulating in increasing concentrations.
If production levels are equivalent to current ones, confirmed reserves of the salar that belong to SQM, will last at least for 30 more years.
Stromatolites or stromatoliths (/strɵˈmætoʊlaɪts/; from Greek στρώμα, strōma, mattress, bed, stratum, and λίθος, lithos, rock) are layered bio-chemical accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms (microbial mats) of microorganisms, especially cyanobacteria. Stromatolites provide ancient records of life on Earth by fossil remains which might date from more than 3.5 billion years ago. Lichen stromatolites are a proposed mechanism of formation of some kinds of layered rock structure that is formed above water, where rock meets air, by repeated colonization of the rock by endolithic lichens.
hypolithic adjective hy·po·lithic
Definition of HYPOLITHIC, of plants : growing beneath rocks
Origin of HYPOLITHIC: hypo- + Greek lithos stone + English -ic
On the other hand, the underside of translucent stones has been demonstrated to offer an environment protected from the intense radiation typical of deserts. Sequencing 16S rRNA from samples obtained from hypolithic biofilms under quartzes showed the presence of members of the gamma, alpha, and beta-Proteobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi and Cyanobacteria, Chroococcidiopsis being the dominant among the latter .