Prokaryotic diversity and community composition in the Salar de Uyuni,a large scale,chaotropic salt flat |
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Authors: | Sergio S dC Rubin Irma Marín Manuel J Gómez Eduardo A Morales Ivar Zekker Patxi San Martín‐Uriz Nuria Rodríguez Ricardo Amils |
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Institution: | 1. Centro Nacional de Investigaciones Biotecnológicas, CNIB, Bolivia;2. Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain;3. Centro Nacional de Investigaciones Cardiovasculares, Melchor Fernández Almagro 3, Madrid 28029, Spain;4. Herbario Criptogámico, Universidad Católica Boliviana, Cochabamba, Bolivia;5. Institute of Chemistry, University of Tartu, Tartu, Estonia;6. Centro de Astrobiología (INTA‐CSIC), Torrejón de Ardoz, Madrid 28055, Spain;7. Centro de Biología Molecular Severo Ochoa (CSIC‐UAM), Universidad Autónoma de Madrid, Madrid 28049, Spain |
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Abstract: | Salar de Uyuni (SdU), with a geological history that reflects 50 000 years of climate change, is the largest hypersaline salt flat on Earth and is estimated to be the biggest lithium reservoir in the world. Its salinity reaches saturation levels for NaCl, a kosmotropic salt, and high concentrations of MgCL2 and LiCl, both salts considered important chaotrophic stressors. In addition, extreme temperatures, anoxic conditions, high UV irradiance, high albedo and extremely low concentrations of phosphorous, make SdU a unique natural extreme environment in which to contrast hypotheses about limiting factors of life diversification. Geophysical studies of brines from different sampling stations show that water activity is rather constant along SdU. Geochemical measurements show significant differences in magnesium concentration, ranging from 0.2 to 2M. This work analyses the prokaryotic diversity and community structure at four SdU sampling stations, selected according to their location and ionic composition. Prokaryotic communities were composed of both Archaea (with members of the classes Halobacteria, Thermoplasmata and Nanohaloarchaea, from the Euryarchaeota and Nanohaloarcheota phyla respectively) and Bacteria (mainly belonging to Bacteroidetes and Proteobacteria phyla). The important differences in composition of microbial communities inversely correlate with Mg2+ concentration, suggesting that prokaryotic diversity at SdU is chaotropic dependent. |
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