Prokaryotic diversity and community composition in the Salar de Uyuni, a large scale, chaotropic salt flat Sergio S. Rubin 1,2 , Irma Marín 2 , Manuel J. Gómez 3 , Eduardo A. Morales 1,4 , Ivar Zekker 5 , Patxi San Martín 6 , Nuria Rodríguez 6 , Ricardo Amils 1,6,7 . 1 Centro Nacional de Investigaciones Biotecnológicas, CNIB, Bolivia 2 Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain 3 Centro Nacional de Investigaciones Cardiovasculares, Melchor Fernández Almagro 3, 28029 Madrid, Spain 4 Herbario Criptogámico, Universidad Católica Boliviana, Cochabamba, Bolivia 5 Institute of Chemistry, University of Tartu, Tartu, Estonia 6 Centro de Astrobiología (INTA-CSIC), 28055 Torrejón de Ardoz, Madrid, Spain 7 Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Madrid, Spain Corresponding author: Sergio S. Rubin Georges Lemaître Centre for Earth and Climate Research Earth and Life Institute Université catholique de Louvain Place Louis Pasteur 3 bte L4.03.08 Tel: +32 10478501 sergio.rubin@uclouvain.be 1348 Louvain-la-Neuve Belgium Key words: magnesium, chaotropicity, water activity, halophiles, diversity, Salar de Uyuni Running title: Mg dependent prokaryotic diversity in the Salar de Uyuni This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as an ‘Accepted Article’, doi: 10.1111/1462-2920.13876 This article is protected by copyright. All rights reserved.