Life at extreme elevations on Atacama volcanoes: the closest thing to Mars on Earth?
- 861 Downloads
Here we describe recent breakthroughs in our understanding of microbial life in dry volcanic tephra (“soil”) that covers much of the surface area of the highest elevation volcanoes on Earth. Dry tephra above 6000 m.a.s.l. is perhaps the best Earth analog for the surface of Mars because these “soils” are acidic, extremely oligotrophic, exposed to a thin atmosphere, high UV fluxes, and extreme temperature fluctuations across the freezing point. The simple microbial communities found in these extreme sites have among the lowest alpha diversity of any known earthly ecosystem and contain bacteria and eukaryotes that are uniquely adapted to these extreme conditions. The most abundant eukaryotic organism across the highest elevation sites is a Naganishia species that is metabolically versatile, can withstand high levels of UV radiation and can grow at sub-zero temperatures, and during extreme diurnal freeze–thaw cycles (e.g. − 10 to + 30 °C). The most abundant bacterial phylotype at the highest dry sites sampled (6330 m.a.s.l. on Volcán Llullaillaco) belongs to the enigmatic B12-WMSP1 clade which is related to the Ktedonobacter/Thermosporothrix clade that includes versatile organisms with the largest known bacterial genomes. Close relatives of B12-WMSP1 are also found in fumarolic soils on Volcán Socompa and in oligotrophic, fumarolic caves on Mt. Erebus in Antarctica. In contrast to the extremely low diversity of dry tephra, fumaroles found at over 6000 m.a.s.l. on Volcán Socompa support very diverse microbial communities with alpha diversity levels rivalling those of low elevation temperate soils. Overall, the high-elevation biome of the Atacama region provides perhaps the best “natural experiment” in which to study microbial life in both its most extreme setting (dry tephra) and in one of its least extreme settings (fumarolic soils).
KeywordsEndolithic microbes Acidic soils Fumaroles B12-WMSP1 Spartobacteria Hypoliths
We thank S.R.P. Halloy, P. Aráns, E.K. Costello, S.C. Reed, A. Seimon, G. Jesperson, T. Harris, M.E. Farias, C. Dorador, C. Vitry, P. Maciel, M. Perez, G. Zimmerman, and T. Bowen for advice and help in the field, and D.R. Bowling for help with measuring CO2.
This study was funded by the National Science Foundation of the U.S.A. (Grant Numbers DEB-1258160 and PLR-1443578).
Conflict of interest
The authors declare no conflicts of interest.
- Gonzalez SN, Romero N, Apella MC, Pesce de Ruiz Holgado A, Oliver G (1987) Existence of lactic acid bacteria in ecological pockets in highland areas. Microbiologie Alim Nut 5:317–323Google Scholar
- Janetschek H (1963) On the terrestrial fauna of the Ross-Sea area, Antarctica (preliminary report). Pac Insect 5:305–311Google Scholar
- King CE, King GM (2014) Description of Thermogemmatispora carboxidivorans sp. nov., a novel carbon-monoxide-oxidizing member of the class Ktedonobacteria isolated from a geothermally-heated biofilm, and analysis of carbon monoxide oxidation by members of the class Ktedonobacteria. Int J Syst Evol Microbiol 64:1244–1251CrossRefPubMedGoogle Scholar
- Lynch R, King AJ, Farías ME, Sowell P, Vitry C, Schmidt SK (2012) The potential for microbial life in the highest-elevation (> 6000 masl) mineral soils of the Atacama region. J Geophys Res 117:G02028Google Scholar
- Pulschen AA, Rodrigues F, Duarte RTD, Araujo GG, Santiago IF, Paulino-Lima IG, Rosa CA, Kato MJ, Pellizari VH, Galante D (2015) UV-resistant yeasts isolated from a high-altitude volcanic area in the Atacama Desert as eukaryotic models for Astrobiology. MicrobiologyOpen 4:574–588CrossRefPubMedPubMedCentralGoogle Scholar
- Reinhard J, Ceruti MC (2010) Inca rituals and sacred mountains. The Cotsen Institute of Archaeology Press, Los AngelesGoogle Scholar
- Richter M, Schmidt D (2002) Cordillera de la Atacama—das trockenste Hochgebirge der Welt. Petermanns Geogr Mitt 146:48–57Google Scholar
- Schmidt D (1999) Das Extremklima der nordchilenischen Hochatacama unter besonderer Berücksichtigung der Höhengradienten. Dresdener Geographische Beiträge 4:1–122Google Scholar
- Solon AJ, Vimercati L, Darcy JL, Arán P, Porazinska D, Dorador C, Farias ME, Schmidt SK (2018) Microbial communities of high-elevation fumaroles, penitentes and dry tephra “soils” of the Puna de Atacama Volcanic Zone. Microb Ecol. https://doi.org/10.1007/s00248-017-1129-1 PubMedCrossRefGoogle Scholar
- Vitry C (2016) Contribución al estudio de caminos se Sitios Arqueológicos de Altura. Volcán Llullaillaco (6739 m). Museo de Arqueologia de Alta Montana Salta, ArgentinaGoogle Scholar