FIG 1.

(A) Location of sampling sites at the Exportadora de Sal, S.A. de C.V., salt company near the city of Guerrero Negro in Baja California Sur, Mexico. Soft microbial mats were sampled in Area 1 (B), and gypsum-hosted endoevaporite mats were sampled in Area 9 (C). (D) Sampling sites in the Atacama Desert, northern Chile. Endoevaporitic gypsum crusts (LL1, LL2, and LL3) were collected from the main hypersaline pond (E), whereas LL8, a soft mat, was sampled from a smaller pond (F) at Salar de Llamara. (G) Muddy sediments, ET2, were collected from a cool pond at the El Tatio geyser field. Within the Salar de Atacama, soft mats, Cejar1 (H) and Cejar2 (I), and endoevaporite mats, Cejar3 (J), were sampled at Laguna Cejar, and a soft mat overlying mud, Chaxa1, was sampled at Laguna Chaxa (K). Insets of representative soft mats/mud and gypsum-hosted endoevaporite mats at the sites are also included. (The maps in panel A are traced from images from the CIA World Factbook [https://www.cia.gov/library/publications/the-world-factbook/geos/mx.html] and NASA Earth Observatory [http://earthobservatory.nasa.gov/IOTD/view.php?id=77499]. The maps in panel D are traced from an image from the CIA World Factbook [https://www.cia.gov/library/publications/the-world-factbook/geos/ci.html]. The inset in panel B is courtesy of Alejandro López-Cortéz.)