ENVIRONMENTAL MICROBIOLOGY Microbial Communities of High-Elevation Fumaroles, Penitentes, and Dry Tephra BSoils^ of the Puna de Atacama Volcanic Zone Adam J. Solon 1 & Lara Vimercati 1 & J. L. Darcy 1 & Pablo Arán 2,3 & Dorota Porazinska 1 & C. Dorador 2,3 & M. E. Farías 4 & S. K. Schmidt 1 Received: 5 July 2017 /Accepted: 12 December 2017 # Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract The aim of this study was to understand the spatial distribution of microbial communities (18S and 16S rRNA genes) across one of the harshest terrestrial landscapes on Earth. We carried out Illumina sequencing using samples from two expeditions to the high slopes (up to 6050 m.a.s.l.) of Volcán Socompa and Llullaillaco to describe the microbial communities associated with the extremely dry tephra compared to areas that receive water from fumaroles and ice fields made up of nieves penitentes. There were strong spatial patterns relative to these landscape features with the most diverse (alpha diversity) communities being associated with fumaroles. Penitentes did not significantly increase alpha diversity compared to dry tephra at the same elevation (5825 m.a.s.l.) on Volcán Socompa, but the structure of the 18S community (beta diversity) was significantly affected by the presence of penitentes on both Socompa and Llullaillaco. In addition, the 18S community was significantly different in tephra wetted by penitentes versus dry tephra sites across many elevations on Llullaillaco. Traditional phototrophs (algae and cyanobacteria) were abundant in wetter tephra associated with fumaroles, and algae (but not cyanobacteria) were common in tephra associated with penitentes. Dry tephra had neither algae nor cyanobacteria but did host potential phototrophs in the Rhodospirillales on Volcán Llullaillaco, but not on Socompa. These results provide new insights into the distribution of microbes across one of the most extreme terrestrial environments on Earth and provide the first ever glimpse of life associated with nieves penitentes, spire-shaped ice structures that are widespread across the mostly unexplored high-elevation Andean Central Volcanic Zone. Keywords Water availability . Nieves penitentes . Naganishia . Snow algae . Astrobiology . Altiplano Introduction In the last several decades, environments once thought to be devoid of life have been revealed to be populated by varying levels of biodiversity, supporting the almost inescapable no- tion that life, at least on Earth, always finds a way. Life in Earth’s most extreme environments has been uncovered from the depths of the oceans [1] and terrestrial subsurface [2], to the high reaches of the stratosphere [3] and terrestrial moun- tains [4, 5], and from the freezing poles [6] to sweltering active geologic features [7]. Indeed, life has been found anywhere liquid water is at least occasionally available. Investigations into microbial communities and water avail- ability in extreme Earth environments serve an important role in determining habitability parameters not only for life on Earth but also assist in the search for extraterrestrial life [8]. The most extreme Earth environments, in terms of water Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00248-017-1129-1) contains supplementary material, which is available to authorized users. * S. K. Schmidt steve.schmidt@colorado.edu 1 Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA 2 Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta & Centre for Biotechnology and Bioengineering (CeBiB), Universidad de Antofagasta, Antofagasta, Chile 3 Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile 4 Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas, PROIMI, Tucumán, Argentina Microbial Ecology https://doi.org/10.1007/s00248-017-1129-1