Introduction
Extreme environments are habitats where the persistence of life is considered difficult for humans and most conventional life forms. Even being impossible in some cases, due to the combination of several hazard conditions such as high or low temperatures, extreme pH values, high pressure, dry conditions and high levels of solar radiation. These locations are the result of complex interactions between geology, climate, geography and biological activity and are somehow difficult to find on our planet. Nevertheless, the biological diversity on Earth manifests itself not only in environments usually considered optimal, but also in places that are inhospitable for most living beings (Rampelotto, Reference Rampelotto2013; Shu and Huang, Reference Shu and Huang2021). Extreme environments are highly sought after by planetary scientists, since they are valuable scenarios to research the behavior of life in possible planetary settings. These studies usually involve extremophiles, resilient beings that have captured the attention of scientists and explorers since they have developed remarkable adaptations to survive and, in many cases, thrive in environments that challenge the limits of what is considered possible. The study of extreme environments and their extremophiles has proven extremely useful for medical, bioengineering and food applications, since their adaptations can lead to several practical advantages (Irwin, Reference Irwin2020; Kochhar et al., Reference Kochhar, Kavya, Shrivastava, Ghosh, Rawat, Sodhi and Kumar2022). However, probably their major role has been in the study of the limits of life (Pikuta et al., Reference Pikuta, Hoover and Tang2007; Thombre et al., Reference Thombre, Vaishampayan and Gomez2020), which is a key concept for astrobiology, the field of planetary sciences focused on the search of life outside our planet.
Extreme environments can serve as planetary analogs, which are places on Earth that can mimic one or more environmental conditions that will be likely found on other planets (Léveillé, Reference Léveillé2009). Analog environments vary greatly depending on the type of research they support; some locations are intended for engineering tests, human training and logistical operations, which may or may not need a great degree of natural accuracy (Groemer and Ozdemir, Reference Groemer and Ozdemir2020). Many analog environments (or locations) are man-made structures, which have controlled variables to solve specific problems or questions (Casini et al., Reference Casini, Mittler, Cowley, Schlüter, Faber, Fischer, Wiesche and Maurer2020; Romero et al., Reference Romero, Suarez, Ojeda, Mendez and Ochoa2024). Extreme environments serve a different purpose; as natural settings, they provide greater complexity and fidelity, allowing the study of natural processes and the testing of real-world conditions. An extreme environment is useful to study geological and biological processes, which can help us to identify the proxies and clues we should search in other planets (Martins et al., Reference Martins, Cottin, Kotler, Carrasco, Cockell, de la Torre Noetzel, Demets, de Vera, d’Hendecourt, Ehrenfreund, Elsaesser, Foing, Onofri, Quinn, Rabbow, Rettberg, Ricco, Slenzka, Stalport, ten Kate, van Loon and Westall2017). These characteristics make extreme environments especially useful for astrobiologists, who study the limits of life on Earth and extrapolate it to other planets.
Even if an exact match is not possible, similar conditions like temperature, pH, radiation and pluviosity are helpful to understand how life could emerge or behave in another world. Several researchers have conducted investigations in Earth environments considered extreme not only for human life but for a great number of living beings as well, with the aim of testing different ways to find extant life or simulating space exploration conditions. However, a considerable part of this research has been developed in North America, Europe and Asia, only a lesser proportion have been carried out in Latin America or Africa (Preston and Dartnell, Reference Preston and Dartnell2014; Shu and Huang, Reference Shu and Huang2021).
The absence of research in this region is not related to a lack of candidates; the vast landmass of South and Central America contains a diverse range of extreme environments and offers a unique setting for exploration and study of extremophile organisms. Climatic extremes, geology and unique conditions have shaped singular landscapes that host seemingly unusual forms of life. From the glaciers of the Andes to the volcanic geysers of the valleys, through arid saline regions and hot springs, Latin America hosts a collection of ecological niches that challenge traditional conventions about where and how life can thrive. Nevertheless, this diversity of environments has been overlooked or poorly studied due to several reasons, such as, difficult accessibility, safety conditions, and the lack of investment in basic and applied sciences.
This review highlights the diverse landscape of extreme environments across Latin America and the extremophile organisms that may inhabit them. It explores a wide range of unique and harsh ecosystems, from high-altitude regions and deep ocean trenches to areas of intense radiation, extreme temperatures and hypersaline conditions and identifies approximately 300 sites that have been studied to varying extents. The document aims to serve as a valuable resource for future researchers interested in these environments, not only to advance astrobiology and planetary science, but also to foster bioprospecting efforts in fields such as biotechnology and industry.
In the following sections, we will explain some of the most notable extreme environments in Latin America separated into four principal categories, desert and semi-arid environments, geothermal and hydrothermal environments, high mountain environments and glaciers and hypersaline environments. We examine the most prominent examples of these environments, the relevant extreme conditions they provide, the microorganisms that inhabit them and their potential value for research in astrobiology and planetary sciences.
The Latin-American extreme environments Atlas
The result of our extensive research is presented in Supplementary Table 1. This compilation summarizes the name, country, geographic location, type of environment and relevant research conducted in each environment. Given the complexity of defining a location as an extreme environment and the wide geodiversity of the continent, our selection contains a wide range of environments, varying in size, conservation, structure and access. Desert environments can go from semi-arid regions with scarce vegetation to the most arid locations on the planet. Geothermal environments can range from volcanoes to submarine hydrothermal vents; high mountain systems and glaciers contain both isolated mountains and mountain ranges and hypersaline environments go from brines to salt mines.
Supplementary Table 1 also contains a list of the extreme environmental conditions that these locations host. When information was available, we defined if each environment is under a condition that could serve as a planetary analogue and considered the following variables: high radiation, extreme temperatures, high salinity, high pressure, extreme pH values, and resemblance to an extraterrestrial terrain. These characteristics are only an approximation of the potential these locations offer, as each site possesses specific physicochemical conditions that can be useful for different research objectives. Extreme environments also have the capability to simulate the geological and topographical properties of extraterrestrial terrains, including variables like the mineralogical composition, the grain-size of the soil, the geological process that created these settings, or the morphometric variables of the landscape. This additional potential makes these sites viable for testing instrumentation, fields campaigns, sample collection and many more. Locations with this potential are highlighted in the “terrain” column on Supplementary Table 1.
We want this compilation to be a starting point for researchers interested in planetary analogue studies in Latin America. Given the continent’s vast size and the limited amount of research available on the topic, it is very likely that some potential locations have not yet been identified and certain classifications may be subject to revision as more accurate data becomes available.
Extreme environments in Latin America
Deserts and semi-arid environments
Desert biomes are arid regions that cover one fifth of the total surface of the Earth, usually located at middle latitudes where the atmospheric pressure is high, and thus the amount of precipitation is low. In desert environments, low rainfall, intense doses of radiation, extreme temperatures and low humidity are common conditions (Gargaud, Reference Gargaud2011). They can be categorized in terms of their temperature and aridity, in that way, hot, cold and polar deserts are differentiated (Peel et al., Reference Peel, Finlayson and McMahon2007). Deserts can also be defined as tropical sub-humid, semi-arid, arid, or hyper-arid depending on the level of moisture and precipitation deficit in the system (Middleton and Thomas, Reference Middleton and Thomas1992). Given the dry nature of most of the planetary bodies in our Solar System, deserts are excellent analogues for astrobiological purposes.
Latin America hosts a variety of deserts and dunes fields, the best-known ones are probably the Atacama Desert in Chile, the Sonora desert in Mexico and the Patagonia desert in Argentina. Nevertheless, almost every country in Latin America hosts deserts, expanding the possibilities to do research on the continent. Some of them are cold deserts, like the Siloli Desert in Bolivia, which being at 5000 m.a.s.l. has an average temperature of 3°C and an average annual rainfall of 65 mm. Other ones are hot, like the Chihuahua desert in Mexico, which can reach temperatures of 45°C in the summer and has an average annual precipitation of 430 mm (Quiroz-Jiménez et al., Reference Quiroz-Jiménez, Roy, Beramendi-Orosco, Lozano-García and Vázquez-Selem2018). A list of all the deserts and their characteristics can be found in Supplementary Table 1. In addition to the examples mentioned above, most of these environments have little associated with published research, and some of them have not been studied at all.
Microbiology research in arid and semi-arid regions
Nowadays one of the most studied deserts is Atacama (centered −25.1, −68.6), the oldest and driest non-polar desert on Earth. Microbiology exploration is relatively recent but both fundamental and applied research activities have grown dramatically in recent years (Bull et al., Reference Bull, Andrews, Dorador and Goodfellow2018a). Researchers are focused on its microbiome, ecology, biogeochemistry, natural product potential and Mars-analogue properties (Azua-Bustos et al., Reference Azua-Bustos, Fairén, Silva, Carrizo, Fernández-Martínez, Arenas-Fajardo, Fernández-Sampedro, Gil-Lozano, Sánchez-García, Ascaso, Wierzchos and Rampe2020; Azua-Bustos and González-Silva, Reference Azua-Bustos and González-Silva2014; Gómez-Silva and Batista-García, Reference Gómez-Silva and Batista-García2022; Shen et al., Reference Shen, Wyness, Claire and Zerkle2021; Vítek et al., Reference Vítek, Ascaso, Artieda and Wierzchos2016; Jacek Wierzchos et al., Reference Wierzchos, Davila, Sánchez-Almazo, Hajnos, Swieboda and Ascaso2012). For instance, Azua-Bustos and González-Silva (Reference Azua-Bustos and González-Silva2014) records how the finding of Dunaliella, a genus of halophilic organisms, could be used for biotechnological with astrobiological purposes.
Other studies have been conducted in Colombian semi-arid regions. Several areas commonly referred to as “deserts” are more accurately classified as semi-arid ecosystems or tropical dry forests. For instance, the Tatacoa region belongs to the tropical dry forest biome and is characterized by strong rainfall seasonality rather than extremely low precipitation, with annual rainfall around 1000 mm (Hermelin, Reference Hermelin2016). Despite this, its geomorphological and climatic characteristics make it a suitable terrestrial analogue for Mars. The Tatacoa region (Figure 1B; 3.3, −75) has therefore been proposed as an attractive site for future astrobiological and Mars-analogue studies due to its geological features, climatic conditions and accessibility (Ojeda et al., Reference Ojeda Ramirez and Pardo Spiess2017). However, microbiological research in this area remains limited and has mostly focused on the isolation of microorganisms. For example, Bolívar Torres et al. (Reference Bolívar Torres, Méndez, Sánchez Nieves, Leal, Ruiz, Bolívar Torres, Méndez, Sánchez Nieves, Leal and Ruiz2021) reported a high abundance of Actinobacteriota, a microbial group commonly associated with arid and semi-arid environments.
Some deserts and semi-arid enviroments in Latin America. A. La Guajira Desert, Colombia. Source: Photo taken by Camilo Delgado. B. La Tatacoa Desert, Colombia. Source: Photo taken by Hermes H. Bolivar-Torres. C. Gypsum Outcrop in Villa de Leyva —Note the poor vegetation and the arid landscape —. Source: Photo taken by Julian Andreas Corzo. D. The Pinacate and Gran Desierto de Altar Biosphere Reserve, Mexico. Sand dune area. Source: Photo taken by Cristal Ramos. E. Landscape view from La Guajira, Colombia. Source: Photo taken by Camilo Delgado. F. Ancient Jezero crater of Mars. Source: Taken from Witze (Reference Witze2022).
Another notable example is the La Guajira region (Figures 1A,E), located in northern Colombia (centered at 11, −71.5) and covering approximately 20,848 km2. This region contains some of the most arid environments in the country and is generally classified as arid to semi-arid based on aridity indices and hydrological balance analyses. Average temperatures range between 27 °C and 30 °C, with maximum values reaching up to 45 °C. The predominant climates include xerophytic savanna in the south and west and arid or semi-arid steppe in the north and east (Vanegas Chamorro et al., Reference Vanegas Chamorro, Villicaña Ortíz and Arrieta Viana2015). Microbial studies in this region have identified the presence of Actinobacteriota and Proteobacteria, including genera such as Massilia, Herbaspirillum and Altererythrobacter, which are considered indicators of dry environments Leal et al. (Reference Leal, Franco and Vanegas2024).
Another potential analogue location in Colombia and locally referred as “desert” is the Candelaria semi-arid region, here the rainfall regime is low with a poor vegetal coverture and, therefore, depletion of soil (Figure 1C; 5.7, −73.5) (Fischer and Lüdders, Reference Fischer and Lüdders2002; Öcal et al., Reference Öcal, Cramer and Siegesmund2007). Corzo-Acosta and Corzo (Reference Corzo-Acosta and Corzo2022) investigated endolithic microorganisms inhabiting quartz, K-feldspar and calcite substrates, evaluating their growth in mineral-enriched media under varying physicochemical conditions. Their results suggest that microbial pigmentation may be associated with tolerance to alkaline conditions, and that Gram-negative rod-shaped bacteria show greater adaptability to enriched minimal media. Additionally, ongoing studies aim to detect endolithic pigments in gypsum using Raman spectroscopy, scanning electron microscopy and optical microscopy to characterize phototrophic endolithic communities.
In Mexico, the Sonoran Desert (Figure 1D) (centered 29.4, −115) is one of the driest and hottest environments, and it harbor an active dune field, the largest in North America. Information of regional weather stations indicates that summer temperatures can reach 48°C. In 2021 a study published by the Bulletin of the American Meteorological revealed that the land surface temperature detected at the Sonoran Desert was 80.8°C, which was 10°C higher than the previous world record observed in 2005 (Zhao et al., Reference Zhao, Norouzi, Azarderakhsh and AghaKouchak2021). In addition, there is El Campo La Salina, an extensive salt flat. Recent exploration studies have been carried out in this reserve showing a high biodiversity of microorganisms such as fungi (Esqueda et al., Reference Esqueda, Coronado, Gutierrez Saldaña, Lizárraga, Raymundo and Valenzuela2013; Roth et al., Reference Roth, Griffis-Kyle and Barnes2023), bacteria and archaea (Ding et al., Reference Ding, Piceno, Heuer, Weinert, Dohrmann, Carrillo, Andersen, Castellanos, Tebbe and Smalla2013; Rainey et al., Reference Rainey, Ray, Ferreira, Gatz, Nobre, Bagaley, Rash, Park, Earl, Shank, Small, Henk, Battista, Kämpfer and da Costa2005; Ramos-Madrigal et al., Reference Ramos-Madrigal, Martínez-Romero, Tapia-Torres and Servín-Garcidueñas2024).
In Brazil, exist a couple of environments with microbial research, the most relevant is Caatinga semi-arid zone (centered −7, −40), where several studies have been conducted related to isolation and prospection of Cyanobacteria species. Moreover, several studies have been carried out to isolate Plant Growth Promoting Bacteria (Bonatelli et al., Reference Bonatelli, Lacerda Júnior, Reis Junior, Fernandes Júnior, Melo and Quecine2021). The other example is the Lençóis Maranhenses National Park, in northeast Brazil (−2.1, −43,1). This desert is characterized by white sand dunes and freshwater lagoons. It has a dry subhumid climate. Due to the aridity, temperature and radiation conditions of this site, coupled with the presence of freshwater lagoons that form between the sand dunes, it would be an excellent site to study the changes in microbial communities associated with the rainy and dry seasons in this desert. Despite its potential, there are no studies about the biological properties in this region, which could be rich in microorganisms, microalgae or Cyanobacteria and that could have value in astrobiology.
In summary, the previous places mentioned in this section are only a small proportion of the possibilities in microbial research in Latin America. The information gathered in Supplementary Table 1 shows the wide number of arid places that exist from the north of Mexico to the south of American continent. Specific examples include the extensive Patagonia desert in Argentina, which, despite its scale and multi-extreme conditions, remains poorly explored, as well arid environments in Bolivia, such as Salvador Dali desert and Dunas de Tajzara, which currently lack microbial studies. Furthermore, several places in Ecuador, Perú and Venezuela also remain unexplored e.g Palmira desert, De Ica desert and Medanos de Coro. These environments could be the perfect locations to encourage research in the microbiology of arid and hypersaline environments and promote astrobiological research through the development of international collaboration networks.
Astrobiology research possibilities
From the point of view of astrobiology, desert and semi-arid environments are interesting due to -mars-like or moon-like features, current conditions on Mars include extreme aridity and high UV-flux and are damaging to living organisms and their organic molecules, decreasing the chances for life to be present (Pavlov et al., Reference Pavlov, Blinov and Konstantinov2002). Dry environments on Earth are valuable to astrobiologists due to their environmental and geological similarities to both present and past conditions on Mars. Deserts and other hyper-arid regions, among the most isolated places on our planet, serve as natural laboratories for studying how life survive under extreme conditions. Investigating these environments and the effects they impose on life and the preservation of its biomarkers has significantly advanced our understanding of the potential for life on Mars and other planetary bodies (Jones, Reference Jones2008). The effect of Martian extreme conditions on life and its detection can currently only be inferred from research on terrestrial extreme environments. Constant sunlight exposure, high UV radiation, desiccation, high temperatures and salinity make these environments home to the most resilient organisms (Aerts et al., Reference Aerts, Röling, Elsaesser and Ehrenfreund2014).
Much of the training of future astronauts takes place in deserts that are similar to the landscapes of the Moon or Mars, including the Atacama Desert in Chile, Death Valley or the Mojave Desert. These analogues are used to define and evaluate scientific models and test new instruments and analytical equipment, which in the future will be useful for the investigation of other planets and moons by identifying their paleoenvironments and habitability conditions (Secretaría de Medio Ambiente y Recursos Naturales., Reference de Medio Ambiente and Naturales1994; Flores et al., Reference Flores, Manuel and Valdivia2023).
Colombia hosts several regions with Mars-Analogue potential, where environmental stress affects both vegetation and microbial communities that develop on the surface or within rocks. One notable example is the La Guajira desert, located in northern Colombia. From a geological perspective, La Guajira offers a substrate with significant potential for studies related to the search for life on Mars. This region contains extensive gypsum (CaSO4·H2O) deposits (Montaña, Reference Montaña1970), a substrate that is highly colonizable across diverse environments, regardless of water availability (Jehlička et al., Reference Jehlička, Oren, Vítek and Wierzchos2024). Gypsum can provide effective protection against UV radiation (Edwards et al., Reference Edwards, Villar, Parnell, Cockell and Lee2005; Fishbaugh et al., Reference Fishbaugh, Poulet, Chevrier, Langevin and Bibring2007; Massé et al., Reference Massé, Bourgeois, Le Mouélic, Verpoorter, Spiga and Le Deit2012), but its natural translucence also allows light to penetrate its surface, enabling colonization by phototrophic microorganisms such as Algae and Cyanobacteria. These organisms produce UV-protective pigments that can be detected in situ within the rock, making gypsum an excellent candidate for detecting potential biosignatures and identifying traces of life on Mars (Jehlička et al., Reference Jehlička, Oren, Vítek and Wierzchos2024). In addition to its mineralogical similarities, La Guajira Desert exhibits morphological features that closely resemble Martian landscapes (Witze, Reference Witze2022). Strong winds that flow across the region erode sandstones and limestones, producing yardangs and other desertland forms that are also characteristic of hyper-arid Martian environments, like the deposits observed in regions such as Gale Crater and Meridiani Planum (Delgado-Correal et al., Reference Delgado-Correal, Hernández and Castaño2012; Grotzinger et al., Reference Grotzinger, Gupta, Malin, Rubin, Schieber, Siebach, Sumner, Stack, Vasavada, Arvidson, Calef, Edgar, Fischer, Grant, Griffes, Kah, Lamb, Lewis, Mangold, Minitti, Palucis, Rice, Williams, Yingst, Blake, Blaney, Conrad, Crisp, Dietrich, Dromart, Edgett, Ewing, Gellert, Hurowitz, Kocurek, Mahaffy, McBride, McLennan, Mischna, Ming, Milliken, Oehler, Parker, Vaniman, Wiens and Wilson2015; Guerrero, Reference Guerrero2002).
There are another two potential locations in Colombia. On the one hand the Candelaria Desert is characterized by a semi-arid climate, and it is situated at altitudes between 2150 and 2300 m.a.s.l., the area has an average annual temperature of 17.4°C. The region receives an annual precipitation of 837 mm, and it is also exposed to intense ultraviolet (UV) radiation, with levels reaching 1294 mW/m2 (Fischer and Lüdders, Reference Fischer and Lüdders2002; Öcal et al., Reference Öcal, Cramer and Siegesmund2007). On the other hand, the Tatacoa Desert is a semi-arid region located in the south-west of Colombia that covers around 330 km2 with a mean temperature of 29°C and a mean rainfall of 1000 mm per year distributed in strong storms in two short periods during the year, promoting the erosion and keeping a long dry period (Hermelin, Reference Hermelin2016). Those features make la Tatacoa a good place for astronomical observation. In addition, la Tatacoa offers great attractiveness due to mars like landscapes derived from erosion processes caused by their geological and climatological features.
The Pinacate and Gran Desierto de Altar Biosphere Reserve, located in the Sonoran Desert of Mexico (29.5, −112.5) (Jaramillo-Flores et al., 2023), bears a striking resemblance to certain Martian and lunar landscapes. Because of these similarities, NASA selected this site to train Apollo astronauts for their missions. It is characterized by arid landscapes, volcanoes, craters, salt flats and dunes, making them a planetary analogue of great value for science. The reserve encompasses two major geological provinces: the mobile and fixed dune field, which covers more than three-quarters of the reserve, and the El Pinacate Volcanic Shield, which occupies the remaining quarter.
In summary, deserts and semi-arid regions in Latin America offer multiple opportunities for conducting astrobiology and planetary analogue experiments. In the same sense, environmental information in literature demonstrates that this region has a big potential in the use of those environments as astrobiology laboratories along the continent. Additionally, it is important to promote research in the unexplored sites mentioned in this article (see Supplementary Table 1), with the goal of creating opportunities for both early-career and senior astrobiology researchers in the region, contributing to the advancement of studies on arid environments.
Geothermal and hydrothermal environments
Geothermal and hydrothermal environments are typically characterized by high temperatures and extreme pH conditions (either acidic or alkaline). Many of these environments also present additional stress factors, such as high concentrations of heavy metals and toxic compounds. These kinds of environments are strongly related to the early stages of Earth, and according to several authors, life may have emerged in hydrothermal vents and geothermal environments (Damer and Deamer, Reference Damer and Deamer2020; Deamer et al., Reference Deamer, Damer and Kompanichenko2019; Longo and Damer, Reference Longo and Damer2020; Matsuno and Imai, Reference Matsuno and Imai2023).
These environments are found in various regions across the globe, particularly in areas with intense geological activity. This activity plays a key role in shaping features such as steam vents, geysers, hot springs and solfataras on land, as well as hydrothermal vents and submarine volcanoes in the deep ocean. In Latin America, the formation of the Andes Cordillera and the presence of numerous volcanoes greatly influence the occurrence of geothermal manifestations. For this reason, we found a great amount of different geothermal parks along the Andes mountains from Colombia to Chile, existence of volcanoes in central America and geothermal manifestations into the Trans Mexican Volcanic Belt (TMVB) bringing the essential conditions to hot springs, geysers, steam vents and solfataras formation in this Latin American region.
Geothermal environments are arguably the most extensively studied type of extreme environment in Latin America. This trend is driven by several factors. Primarily, the increasing interest in geothermal energy exploration and exploitation has spurred research across numerous geothermal systems in the region. Additionally, we identified a significant number of studies on microbial communities inhabiting geothermal areas in nearly every Latin American country where such environments occur. This topic will be explored further in the following section. While our main focus is microbial research, it is important to note that many of the reviewed studies also highlight interest in geothermal energy development and tourism (see Supplementary Table 1).
Microbiology research in geothermal and hydrothermal environments
The most extensively studied geothermal environments in Latin America, in terms of microbiological research, include the Los Azufres geothermal field in Mexico, the Copahue geothermal field in Argentina, the Miravalles and Poás volcanoes in Costa Rica, the Paipa hot springs and Los Nevados National Park in Colombia, El Tatio in Chile, the hot springs of the Cordillera Blanca and the Aguas Calientes plateau in Peru (See Supplementary Table 1). Research activities at these sites span a wide range of objectives, from descriptive microbial ecology to bioprospecting, with a smaller number of studies focused on astrobiology and planetary sciences.
Los Azufres geothermal field in Mexico (Figure 2A) (19.8, −100.6) has wide research in microbial exploration of Bacteria, Archaea and viral communities. The findings from these studies have contributed to the reclassification of the order Sulfolobales, driven by the discovery of new Parvarchaeota and Thermoproteota (formerly Crenarchaeota) lineages. In addition, the findings of archaeal viruses from Fusellovirus genus show complex interactions inside the microbial communities in thermal conditions. Regarding Bacteria communities, the research in Los Azufres shows the presence of typical genera from geothermal zones such as Leptospirillum, Ferrimicrobium, Acidithiobacillus and novelty genus such as Acidibrevibacterium. (Bolivar-Torres et al., Reference Bolivar-Torres, Marín-Paredes, Ramos-Madrigal and Servín-Garcidueñas2022; Brito et al., Reference Brito, Villegas-Negrete, Sotelo-González, Caretta, Goñi-Urriza, Gassie, Hakil, Colin, Duran, Gutiérrez-Corona, Piñón-Castillo, Cuevas-Rodríguez, Malm, Torres, Fahy, Reyna-López and Guyoneaud2014; Chen et al., Reference Chen, Méndez-García, Dombrowski, Servín-Garcidueñas, Eloe-Fadrosh, Fang, Luo, Tan, Zhi, Hua, Martinez-Romero, Woyke, Huang, Sánchez, Peláez, Ferrer, Baker and Shu2018; Marín-Paredes et al., Reference Marín-Paredes, Bolívar-Torres, Coronel-Gaytán, Martínez-Romero and Servín-Garcidueñas2023, Reference Marín-Paredes, Tapia-Torres, Martínez-Romero, Quesada and Servín-Garcidueñas2021; Marín-Paredes and Servín-Garcidueñas, Reference Marín-Paredes and Servín-Garcidueñas2020; Servín-Garcidueñas et al., Reference Servín-Garcidueñas, Xu, G.R. and Esperanza2013c, Reference Servín-Garcidueñas, Garrett, Amils and Martínez-Romero2013a, Reference Servín-Garcidueñas, Xu, G.R. and Esperanza2013b; Servín-Garcidueñas and Martínez-Romero, Reference Servín-Garcidueñas and Martínez-Romero2014, Reference Servín-Garcidueñas and Martínez-Romero2012). The combination of multiple extreme conditions and diverse microbial communities makes Los Azufres and nearby geothermal sites, such as the Araró hot springs, well-suited for future astrobiology studies. In addition, Mexico hosts several geothermal sites that should be considered as promising prospects for astrobiology research. For example, the Chichón and Paricutín volcanoes (17.4, −93.2; and 19.4, −102.2) exhibit multiple extreme conditions similar to those found in Los Azufres. Studies at these sites have revealed a diverse range of microorganisms adapted to various stress factors, particularly the Actinobacteria, Proteobacteria and Firmicutes phyla. (Medrano-Santillana et al., Reference Medrano-Santillana, Souza-Brito, Duran, Gutierrez-Corona and Reyna-López2017; Peña-Ocaña et al., Reference Peña-Ocaña, Ovando-Ovando, Puente-Sánchez, Tamames, Servín-Garcidueñas, González-Toril, Gutiérrez-Sarmiento, Jasso-Chávez and Ruíz-Valdiviezo2022; Velázquez-Ríos et al., Reference Velázquez-Ríos, Rincón-Rosales, Gutiérrez-Miceli, Alcántara-Hernández and Ruíz-Valdiviezo2022).
Some thermal enviroments in Latin America. A. Los Azufres geothermal field, Mexico. B. Paipa Hot springs, Colombia. Source: Photos taken by Hermes H. Bolivar-Torres.
In Colombia, Los Nevados National Park (4.9, −75.3) is a major site for research on thermophiles and geothermal environments. Located in the Central Cordillera, this place shares glacier places and volcanic activity, and there are a wide number of hot springs, where several kinds of thermophiles have been isolated. For example, Acidicaldus sp. Strain isolated by (López et al., Reference López, Chow, Bongen, Lauinger, Pietruszka, Streit and Baena2014). The same research group studied the thermophiles in this place and their possible biotechnological applications (Bohorquez et al., Reference Bohorquez, Delgado-Serrano, López, Osorio-Forero, Klepac-Ceraj, Kolter, Junca, Baena and Zambrano2012; Delgado-Serrano et al., Reference Delgado-Serrano, López, Bohorquez, Bustos, Rubiano, Osorio-Forero, Junca, Baena and Zambrano2014). Also, in the eastern cordillera exist several geothermal places where the most studied are Paipa hot springs (See Figure 2B) (5.8, −73.1). The literature reported a variety of thermophiles from Thermoanaerobacter, Desulfomicrobium, Anoxybacillus, Anoxybacillus and Caloranaerobacter genera in this place (Posada et al., Reference Posada, Agudelo, Álvarez, Díaz, Joulian, Ollivier and Baena2004; Rubiano-Labrador et al., Reference Rubiano-Labrador, Díaz-Cárdenas, López, Gómez and Baena2019). In Peru, the Calientes river receives attention because of the flows of hot water (−17.2, −70.1). This place has been studied as a possible source of geothermal energy (Barragán et al., Reference Barragán, Arellano, Birkle, Portugal and Díaz1999; Taillefer et al., Reference Taillefer, Truche, Audin, Donzé, Tisserand, Denti, Manrique Llerena, Masías Alvarez, Braucher, Zerathe, Monnin, Dutoit, Taipe Maquerhua and Apaza Choquehuayta2024). Moreover, there are a couple of studies that report on the study of microbial communities and the insolation and characterization of thermophiles (Castellanos et al., Reference Castellanos, Santos, Ticona, Ramirez-Arua, Bornás-Acosta, Silva, Hamann and Lopes2024; Valdez et al., Reference Valdez, de la Vega, Pairazaman, Castellanos and Esparza2023).
Another interesting place is El Tatio geysers located in Andes altiplano in Chile (−22.3, −68), several studies have been conducted and show the presence of a complex microbial community composed principally by Proteobacteria, Cyanobacteria and Chlroflexi phylum (Megevand et al., Reference Megevand, Carrizo, Lezcano, Moreno-Paz, Cabrol, Parro and Sánchez-García2022). Additionally, (Sanchez-Garcia et al., Reference Sanchez-Garcia, Fernandez-Martinez, García-Villadangos, Blanco, Cady, Hinman, Bowden, Pointing, Lee, Warren-Rhodes, Lacap-Bugler, Cabrol, Parro and Carrizo2019) found a high abundance of Actinobacteria, Acidobacteria and Archaea. The presence of Archaea was reported by (Plenge et al., Reference Plenge, Engel, Omelon and Bennett2017; Santos et al., Reference Santos, Bruna, Martinez-Urtaza, Solís, Valenzuela, Zamorano and Barrientos2021) as well. Some of the microorganisims that inhabit this place have been isolated successfully by (Valenzuela et al., Reference Tavernier, Pinto, Valenzuela, Garcia, Ulloa, Oses and Foing2023, Reference Valenzuela, Solís-Cornejo, Araya and Zamorano2024). Due to the combination of several extreme conditions and logistic access, El Tatio has been considered a good place to simulate Martian life detection experiments (Barbieri et al., Reference Barbieri, Cavalazzi, Kolb and Martinez-Frias2014).
Even though we show some examples of studied geothermal places in Latin America, there are several geothermal places that remains unexplored or poorly studied in Ecuador, Brazil, Bolivia, Perú, El Salvador, Cuba, Guatemala, Haiti, Nicaragua, Paraguay and Uruguay. The research is focused on potential geothermal energy exploration, tourism or medical treatments. However, we consider that those places show great potential to expand the research of microbial communities that probably inhabit those places.
The existence of submarine hydrothermal vents in Latin America has been less explored. It is probable that their existence is being underestimated, since the extensional geological activity in the Galapagos rift, and the subduction of the Caribbean plate below the Atlantic plate likely results in the formation of hydrothermal vents. We only found articles that reported the existence of this kind of environment in Costa Rica (Wang et al., Reference Wang, Dragone, Avard and Hynek2022), western Mexico, the Gulf of Mexico, Brazil and the Caribbean Sea (See Supplementary Table 1). Perhaps the most relevant hydrothermal vent studied in Latin America is Cuenca de Guaymas hydrothermal vent located in the Gulf of California (27, -111). Microbial research shows a great abundance of Proteobacteria and Chloroflexi phylum and the presence of Bathyarcheota and Thermoplasmata close to the core of the hydrothermal vents (Ramírez et al., Reference Ramírez, Mara, Sehein, Wegener, Chambers, Joye, Peterson, Philippe, Burgaud, Edgcomb and Teske2021). In the Gulf of Mexico hydrothermal vents, Merlino et al. (Reference Merlino, Barozzi, Michoud, Ngugi and Daffonchio2018) report a microbial community composed by Deltaproteobacteria, sulfate-reducing bacteria and methanogens. But in general, the research in those environments remains restricted to specific places. The lack of research in those areas could be due to the high cost to finance this kind of exploration, as well as the disinterest from the local scientific community to explore deep ocean environments.
Astrobiology research possibilities
The geothermal and hydrothermal environments described in this article represent promising new sites for the development of astrobiology and space exploration research. Particularly for planification and testing of biosignature detection, not only for currently existing life forms but also for ancient life. Places like Los Azufres, Central American volcanoes and hot springs and Calientes river could contribute to the research of primitive earth and the origin of life (Wang et al., Reference Wang, Dragone, Avard and Hynek2022). On the other hand, sites with multiple extremophile conditions such as Los Nevados National Park and high-altitude geothermal areas in the Andes can serve as analogues for Mars, as has been proposed for the El Tatio Geysers (Barbieri et al., Reference Barbieri, Cavalazzi, Kolb and Martinez-Frias2014; Megevand et al., Reference Megevand, Carrizo, Lezcano, Moreno-Paz, Cabrol, Parro and Sánchez-García2022a; Ruff and Farmer, Reference Ruff and Farmer2016). In addition, hydrothermal environments also serve as natural laboratories for the exploration of ancient life on Mars (Hays et al., Reference Hays, Graham, Des Marais, Hausrath, Horgan, McCollom, Parenteau, Potter-McIntyre, Williams and Lynch2017; Ruff et al., Reference Ruff, Campbell, Van Kranendonk, Rice and Farmer2020), and for the study of the geological activity of outer solar system moons, such as Europa, Enceladus and Io. This is a key aspect in the encouragement of astrobiology and space research in Latin America that could be extended for biotechnology, environmental and industry applications. Finally, advancing geothermal and hydrothermal studies will prepare highly qualified professionals in the region through increased investments in scientific research.
High mountain environments and glaciers
Low temperatures and high radiation levels are common features among solar system bodies. In Latin America, two types of environments exhibit cold conditions: high altitude mountains, which have freezing temperatures, and year-round glaciers located in the southernmost regions of the continent. High mountain systems also provide the advantage of being more exposed to UV radiation, as well as having a reduced amount of plant and animal life. Some of these locations are among the best planetary analogues, since they recreate both the landscapes and the environmental properties of extraterrestrial locations.
Latin America is home to several mountain ranges, mainly thanks to the subduction of the Cocos and Nazca plates below the South American and Caribbean plates (Flament et al., Reference Flament, Gurnis, Müller, Bower and Husson2015). These subduction zones have been active for hundreds of millions of years, at least since the Jurassic period (Seton et al., Reference Seton, Müller, Zahirovic, Gaina, Torsvik, Shephard, Talsma, Gurnis, Turner, Maus and Chandler2012), resulting in large and elevated mountain ranges. The major structure among these is the Andean Mountain range, which spans almost 9000 km from Venezuela to Chile, and host many high mountains, like the Sajama or the Tolima volcanoes (Figure 3A,B). From this main structure emerge smaller mountain ranges and massifs, like the Cordillera Madre in Peru or the Cordillera Central in Colombia, a list with the most relevant ones can be seen in the Supplementary Table 1. Many of these landforms surpass 4000 m in altitude, which makes them potential planetary analogues for cold locations. Others high mountains exist outside of the Andes, like the Sierra Madre in Mexico and volcanoes in central America. Low temperatures can be also found south of the continent, in Tierra del Fuego and Patagonia; these locations have large glacier masses like the Perito Moreno glacier in Argentina.
Some high mountain and glacier environments in Latin America. A. Water pond at 4150 m in altitude, in the background is the Sajama Volcano, in the Bolivian Andes. Source: Photo taken by Nicol Rodriguez. B. Nevado del Tolima, Colombia. Source: Photo taken by Julian Andreas Corzo. C. Nevado Ojos del Salado, Argentina-Chile. D. Pastoruri Glacier. Source: Taken from González-Toril et al., (Reference González-Toril, Santofimia, Blanco, López-Pamo, Gómez, Bobadilla, Cruz, Julio and Aguilera2015).
Microbiology research in high mountain environments and glaciers
The temperatures of high mountain systems vary across the continent, in tropical latitudes like Colombia and Ecuador mountains higher than 5000 m have average temperatures between –2 and 15°C, although their media temperatures have increased by approximately 0.1°C per decade, which implies a risk for the conservation of these ecosistems (Turner et al., Reference Turner, Marshall, Clem, Colwell, Phillips and Lu2020). In contrast, places closer to the poles reach average temperatures between −25 and 2°C, but temperatures on the Antarctic Peninsula have increased by around 3.2 °C during the second half of the 20th century (Turner et al., Reference Turner, Marshall, Clem, Colwell, Phillips and Lu2020). Organisms that can grow within these temperature ranges are known as psychrophiles, and they include Bacteria, Lichens, Fungi and even some insects (Dasauni and Nailwal, Reference Dasauni and Nailwal2020). They usually have a stronger metabolic activity above 10°C, but they can multiply at lower rates at temperatures as low as −20°C (Feller et al., Reference Feller, Bottomley and Malykhina2013). Psychrophiles have special adaptations for these extreme environments, such as thicker cell walls, slower rates of oxidative metabolism and the production of solutes that protect the cell against freezing and generate energy more efficiently (Irwin, Reference Irwin2020). These organisms can growth in the substrate, inside rocks, or in the fluid phases inside ice. Given these properties, psychrophiles could be studied in glaciers and high mountains across Latin America.
Another important environmental constraint present in high mountain systems is an elevated amount of solar radiation. There is a direct correlation between altitude and the amount of high energy radiation that reaches the surface, which is particularly dangerous to organisms. (Blumthaler et al., Reference Blumthaler, Ambach and Ellinger1997) observed an increment in the irradiance between 8–18% for every 1000 m of altitude. This effect occurs because the atmosphere becomes thinner at higher altitudes, reducing the amount of UV rays that are absorbed by ozone and other atmospheric molecules. Many mountains in the Andes surpass 4500 m.a.sl., which make them suitable analogs for high UV environments. UV radiation is especially damaging for microbial life by affecting RNA and DNA due to dimers formation, which interfere with cellular transcription and replication (Cutler and Zimmerman, Reference Cutler and Zimmerman2011). Organisms that have adaptations to survive high levels of radiation are known radiophiles, they can synthesize resistant proteins, but more importantly, they have the capacity to repair their DNA quickly and accurately (Basu and Apte, Reference Basu and Apte2012; Khan et al., Reference Khan, Liu, Zhang and Li2024; Núñez et al., Reference Núñez, Naciff, Cuadros, Rojas, Carvallo and Yáñez2025), reducing the potential lethal damage of high radiation.
The extreme temperatures and radiation levels of high mountain systems are often accompanied by other interesting characteristics such as low rainfall, absence of vegetation and plenty of volcanic rocks and volcanic landforms. The combination of these features results in scenarios that are similar to planetary environments, especially martian ones. The best example is the Atacama Desert in Chile, which is the dryest non-polar place on Earth, while being 3500 m.a.s.l. (Azua-Bustos et al., Reference Azua-Bustos, González-Silva and Fairén2022). Nevertheless, several less known locations in Latin America also share these properties; places like the Eduardo Abaroa National Reserve in Bolivia or the national parks in the Argentinian Andes are excellent locations for analogue studies.
A good example of a high mountain environment is the Ojos del Salado Volcano (−27, −68.2), located in the Dry Andes Mountain range, in Argentina. It is an inactive stratovolcano with a summit at 6893 m.a.s.l., which makes it the highest volcano on Earth. This site brings together conditions such as strong UV radiation, the presence of permafrost, ephemeral snow, hot springs, volcanic alluviums and dissected lacustrine floors eroded by strong icy winds (Kereszturi et al., Reference Kereszturi, Aszalós, Heiling, Ignéczi, Kapui, Király, Leél-Össy, Nagy, Nemerkényi, Pál, Skultéti and Szalai2020). The combination of these features creates a setting that is close to what we observe in the Tharsis region on Mars, which makes Ojos del Salado a good analogue for this location (Aszalós et al., Reference Aszalós, Szabó, Felföldi, Jurecska, Nagy and Borsodi2020). The analysis of sediments around the summit and inside fumarolic streams revealed the existence of several genera of extremophilic and even polyextremophilic bacteria. Aszalós et al., (2020) found psychrophilic, acidophilic and thermophilic bacteria adapted to low temperatures, acidic pH values and a low nutrient medium. Also, eleven genera of psychrophilic and oligocarbophilic bacteria were identified both in the permafrost and in a pond located at 5900 m.a.s.l.
In the tropical Andes (Colombia, Peru, Ecuador and Venezuela), most of the mountain ranges and their associated environments are also volcanic in origin. An example of a high-altitude environment that is not associated with volcanism is the Cordillera Blanca in Perú (centered −9, −77.1). This sedimentary mountain range extends for more than 200 km, and it contains ∼70% of the glaciers located in tropical areas of the planet ( Rabatel et al., Reference Rabatel, Francou, Soruco, Gomez, Cáceres, Ceballos, Basantes, Vuille, Sicart, Huggel, Scheel, Lejeune, Arnaud, Collet, Condom, Consoli, Favier, Jomelli, Galarraga, Ginot, Maisincho, Mendoza, Ménégoz, Ramirez, Ribstein, Suarez, Villacis and Wagnon2013; Vuille et al., Reference Vuille, Francou, Wagnon, Juen, Kaser, Mark and Bradley2008). The Nevado Pastoruri glacier, located within this mountain range, has a maximum height of 5250 m.a.s.l. (González-Toril et al., Reference González-Toril, Santofimia, Blanco, López-Pamo, Gómez, Bobadilla, Cruz, Julio and Aguilera2015) investigated the sediments of lakes near the summit, where they found psychrotolerant members of Cyanobacteria, Bacteroidetes and Polaromonas. Additionally, microorganisms associated with soils, permafrost and deglaciation zones were found around the glacier, including members of Sphingomonadales, Caulobacter and Comamonadaceae. These microbial families include psycrophilic taxa, with organisms that are also resistant to high levels of radiation and low nutrient levels. Certain zones are subjected to acid drainages due to the exposure of sulfide-rich lithologies as the glacier retreats, this results in ponds with low pH and an elevated concentration of heavy metals, where sulfur and iron-oxidizing acidophilic species were identified. Although these acidic environments are partially a product of microbial metabolism, they are also of interest for astrobiology research. Metal sulfides are commonly found in ancient martian rocks (Gil-Lozano et al., Reference Gil-Lozano, Mateo-Martí, Gago-Duport, Losa-Adams, Sampedro, Bishop, Chevrier and Fairén2025; Greenwood et al., Reference Greenwood, Mojzsis and Coath2000), and they have also been detected on the icy and rocky moons of Jupiter and Saturn (Lodders and Fegley, Reference Lodders and Fegley2024).
Mexico contains some relevant glacier environments where microbial research had been conducted, the best example is Iztaccihuatl volcano (19.2, −98.6), located in the border of the state of Mexico and Puebla, this place shares multiple extreme conditions like low and high temperatures and heavy metal concentrations. In this place, microbial diversity from prokaryotes and fungi have been carried. 16S rRNA amplicon analysis showed the presence of Proteobacteria, Actinobacteria and Bacteroidetes from glacier samples (Calvillo-Medina et al., Reference Calvillo-Medina, Reyes-Grajeda, Moreno-Andrade, Barba-Escoto, Bautista-de Lucio, Jones and Campos-Guillén2019). On the other hand, fungi isolations recovered from glacier samples were composed principally of Cladosporium and Alternaria genera that show adaptations to low temperatures and of heavy metals (Calvillo-Medina et al., Reference Calvillo-Medina, Gunde-Cimerman, Escudero-Leyva, Barba-Escoto, Fernández-Tellez, Medina-Tellez, Bautista-de Lucio, Ramos-López and Campos-Guillén2020).
Research of extremophiles on the glaciers located in the southernmost part of the continent is also restricted. One of the few examples is a study done by (Pittino et al., Reference Pittino, Ambrosini, Seeger, Azzoni, Diolaiuti, Alviz Gazitua and Franzetti2023) in cracks, snow and cryoconites over glaciers in the Central and Southern Andes. They found bacterial orders such as Betaproteobacteriales, Cytophagales, Chitinophagales, Frankiales and Micrococcales, the latter two being highly resistant to UV radiation. These same organisms were found in major numbers in low-elevation glaciers, meaning that even if they thrive in less extreme conditions, they can still survive high UV radiation levels and oxidative stress, as well as lower partial pressures of oxygen and low availability of nutrients.
Astrobiology research possibilities
High mountain systems host low temperatures, high radiation levels and sometimes even acidic waters. These conditions are commonly found in extraterrestrial environments. The surface temperature of the bodies in the solar system greatly decreases as they are located further away from the Sun. Martian temperatures range between –100 and 20°C (Piqueux et al., Reference Piqueux, Kass, Kleinböhl, Slipski, Hayne, McCleese, Schofield and Heavens2024), while the far away Pluto has surface temperatures ranging between −226 to −200°C (Earle et al., Reference Earle, Binzel, Young, Stern, Ennico, Grundy, Olkin and Weaver2017). The result is that many extraterrestrial environments are exposed to low temperatures, many of which also have an abundance of glaciers of varied compositions. The study of organisms living under cold conditions, as well as the development of techniques and technologies to explore these kinds of environments on Earth are important for future missions to planetary bodies alike. The elevated level of UV radiation in high mountains systems is another valuable property to be considered in astrobiology research. Many planetary bodies have weak atmospheres, which results in elevated levels of high-energy radiation. As an example, the Martian surface is on average exposed to higher levels of UV radiation than Earth (Cockell, Reference Cockell2000a, Reference Cockell2000bb, Reference Cockell2002). Research on terrestrial radiophiles could give us clues about how living beings evolve and survive under these conditions, and what to expect in similar environments on other planets.
This study presents a great number of glaciers in Latin America that remain unexplored or poorly studied; places in Mexico, like the Citlaltépetl volcano and the Pico de Orizaba, offer the opportunity for future astrobiology researchers to propose and develop multiple projects and experiments. In Central America, high mountain environments are a good alternative to promote this kind of research for early career scientists from a local perspective that encourages not only the space sciences research, but the local basic sciences and innovation as well. Finally, in South America, the Andean cordillera shows great potential as an astrobiology laboratory; as an example, the Sierra Nevada de Santa Marta is a poorly explored location, but its unique geology, weather and geographic position make it a potential place for research. In summary, glacier environments in Latin America offer great possibilities to conduct astrobiology research and encourage the development of collaborative projects to promote early career scientists to study these places before they disappear because of climate change (Battin et al., Reference Battin, van Wijngaarden, Sattler, Anesio, Cook, Huss and Edwards2025).
Hypersaline environments
Hypersaline environments are characterized by extreme salinity levels, exceeding the one of seawater (∼35 g/L) (Saccò et al., Reference Saccò, White, Campbell, Allard, Humphreys, Pringle, Sepanta, Laini and Allentoft2021) and support extremophiles adapted to high osmotic stress and fluctuating salinity conditions (Filker et al., Reference Filker, Forster, Weinisch, Mora-Ruiz, González, Farías, Rosselló-Móra and Stoeck2017). These environments include coastal lagoons, salt and soda lakes, salterns (human-made hypersaline ponds for producing salt) (McGenity and Oren, Reference McGenity and Oren2012; Oren, Reference Oren2015), deep-sea brine pools (formed from the dissolution of salt during safloor tectonic activity) and brine channels in sea ice (Rich and Maier, Reference Rich and Maier2015). Examples of those systems include the Great Salt Lake (Perl and Baxter, Reference Perl and Baxter2020), the Dead Sea (Sass and Ben-Yaakov, Reference Sass and Ben-Yaakov1977) and the Sambhar Salt Lake (Pathak et al., Reference Pathak2015).
Microorganisms adapted to survive these conditions are known as halophiles. Some of their adaptations include the use of osmotic organic and inorganic solutes, changes in the lipid composition of the cell membrane, modified proteins optimized for high salt concentrations (Gunde-Cimerman et al., Reference Gunde-Cimerman, Plemenitaš and Oren2018), and the use of the hygroscopic properties of salt to obtain water under extremely dry conditions (Ruginescu et al., Reference Ruginescu, Purcarea, Dorador, Lavin, Cojoc, Neagu, Lucaci and Enache2019; J. Wierzchos et al., Reference Wierzchos, Davila, Sánchez-Almazo, Hajnos, Swieboda and Ascaso2012). These adaptations could be expected in living beings on dry planetary bodies like Mars.
In Latin America, several conditions contribute to the existence of hypersaline environments, from the coastal regions to the high mountains in the Andes. We identified a variety of them, including hypersaline lakes, salterns, salt pans and salt mines (Supplementary Table 1). Many of these locations were known due to the importance of salt as a resource for the human communities that inhabit Central and South America. For this reason, most of the research done in hypersaline environments is related to the extraction of mineral resources such as salt and lithium.
Microbiology research in hypersaline environments
The Salar de Atacama (centered −25.1, −68.6), located in Chile, is a major salt flat in the Atacama Desert, characterized by high salinity, alkalinity and the presence of lithium-rich brines. These conditions support unique microbial communities, including halophilic and polyextremophilic microorganisms (Osman et al., Reference Osman, Viedma, Mendoza, Fernandes, DuBow and Cotoras2021); (Joseph, Reference Joseph2023). This site is probably the hypersaline environment that attracts the most attention from microbiologists and astrobiologists. Hypersaline environments in the Atacama Desert and Andean lakes harbor halophilic bacteria such as Halomonas and Salinibacter, as well as polyextremophiles that tolerate high salinity, UV radiation and temperature fluctuations. These microorganisms have evolved unique survival strategies, including the production of osmolytes and UV-protective compounds (Albarracín et al., Reference Albarracín, Kurth, Ordoñez, Belfiore, Luccini, Salum, Piacentini and Farías2015; Osman et al., Reference Osman, Viedma, Mendoza, Fernandes, DuBow and Cotoras2021). The discovery of novel bacterial and archaeal species in these environments has expanded our understanding of microbial diversity. For example, the identification of novel Streptomyces species in the Salar de Huasco (−20.2, −68.9), Chile, highlights the potential for discovering new antimicrobial and pharmaceutical compounds (Cortés-Albayay et al., Reference Cortés-Albayay, Silber, Imhoff, Asenjo, Andrews, Nouioui and Dorador2019).
The southern Bolivian Altiplano has a high potential for astrobiology and planetary geology studies. It is a volcanic area that contains numerous undrained basins occupied by playas and saline lakes, locally named salars. Solutes carried by springs and rivers into the salars originate mostly from the alteration of the volcanic rocks and the re-solution of ancient buried evaporites. The most significant environment in this area is the Uyuni salt flat (Figure 4A,B) (centered −20.1, −67.5), at an elevation of more than 3,600 m.a.s.l. in the central Bolivian Altiplano, is an active ephemeral saline lake (salt-crusted saline pan) where substantial salt thicknesses have accumulated across an area of a little less than 10,000 km2, making it the world’s largest salt-filled saline pan (Risacher and Fritz, Reference Risacher and Fritz1991). Archaea from the phyla Euryarchaeota, Nanoarchaeota and Hadesarchaeota have been found in salt crusts from this salar, as well as Bacteria of the phyla Bacteroidetes, Proteobacteria and Patescibacteria (Pecher et al., Reference Pecher, Martinez, Priya, Guzmán and DasSarma2020). Genera such as Halorubrum, Halomonas, Salinibacter, Natronomonas and Halobacterium were some of the halophiles that have been found in this place.
Some hypersaline environments in Latin America. A–B. Salt crust and the famous mirage in the Salar de Uyuni, Bolivia. Source: Photos taken by Nicole Jimeno. C–D. Salt formation in the Campo La Salina, northern Mexico. Source: Photos taken by Karen Reyes. E. Salt crusts in the Campo La Salina, northern Mexico. Source: Photo taken by Karen Reyes.
In Mexico, the most studied of those extreme environments is Cuatro Cienegas Basin (26,9, −102.1), located in the north of the country, which is described as a “lost world” due to the primitive characteristics preserved in the microbial community that inhabit in this place (Souza et al., Reference Souza, Moreno-Letelier, Travisano, Alcaraz, Olmedo and Eguiarte2018). Several studies in Cuatro Cienegas Basin show microbial communities not only have typical adaptations for multiple extreme conditions, i.e., oxidative stress, heat and cold shock and osmotic stress regulation, but also, microbial communities develop strategies to survive under low phosphorus concentrations. On the other hand, there exists a great variety of archaea and bacterial genera. For instance, Halorubrum, Haloferax and Haloarcula. Additionally, Cuatro Cienegas Basin contains endemic bacteria that are related to the Bacillus genus. This lineage is strongly connected to Bacillus microorganisms that inhabited the oceans millions of years ago, being Cuatro Cienegas Basin a reflection of the marine microbial communities in the past. Those features become Cuatro Cienagas Basin, one of the most relevant planetary analogues in the region (Medina-Chávez et al., Reference Medina-Chávez, Rodriguez-Cruz, Souza, De la Torre-Zavala and Travisano2025, Reference Medina-Chávez, Viladomat-Jasso, Zarza, Islas-Robles, Valdivia-Anistro, Thalasso-Siret, Eguiarte Luis, Olmedo-Álvarez, Souza and De la Torre-Zavala2023; Moreno-Letelier et al., Reference Moreno-Letelier, Olmedo-Alvarez, Eguiarte and Souza2012; Rodríguez-Cruz et al., Reference Rodríguez-Cruz, Castelán-Sánchez, Madrigal-Trejo, Eguiarte and Souza2024; Souza et al., Reference Souza, Moreno-Letelier, Travisano, Alcaraz, Olmedo and Eguiarte2018, Reference Souza, Siefert, Escalante, Elser and Eguiarte2012).
Campo La Salina (29.6, −112.4), located in northern Mexico within the coastal zone of the Sonoran Desert (Figure 4C,D), has been the focus of studies employing both culture-dependent and culture-independent methods. This research has revealed the presence of archaeal-dominated microbial communities inhabiting marine salt crusts. Remarkably, only members of the phylum Halobacterota were detected. Among the identified species, the extremely halophilic Natronococcus occultus and Halalkalicoccus jeotgali were detected to be the most abundant (Ramos-Madrigal et al., Reference Ramos-Madrigal, Martínez-Romero, Tapia-Torres and Servín-Garcidueñas2024). Another interesting place in Mexico is Guerrero Negro Saltern (27.9, −114.1), located in Baja California Sur, Mexico is known for its hypersaline microbial mats. These mats are dominated by methanogenic archaea, particularly the order Methanosarcinales, although other methanogenic groups such as Methanomassiliicoccales have also been identified (García-Maldonado et al., Reference García-Maldonado, Latisnere-Barragán, Escobar-Zepeda, Cadena, Ramírez-Arenas, Vázquez-Juárez, Rojas-Contreras and López-Cortés2023; Ramírez-Arenas et al., Reference Ramírez-Arenas, Latisnere-Barragán, García-Maldonado and López-Cortés2024). These communities are of interest in understanding methanogenesis in extreme environments. Also, microbial mats were studied by 16S amplicon sequencing, and the bacterial phyla Cloroflexi and Cyanobacteria occupied most of the biomass in the samples. According to this study, the strong relationship between Cyanobacteria and Cloroflexi microorganisms not only contributes to microbial biofilm survival, but this relationship could change depending on environmental conditions as well (Ley et al., Reference Ley, Harris, Wilcox, Spear, Miller, Bebout, Maresca, Bryant, Sogin and Pace2006). The study of microbial mats and stromatolites in hypersaline environments helps in understanding how biosignatures are preserved. For example, the carbonate precipitation in microbialites of Laguna Negra (−25.2, −68.7), Argentina, provides insights into the formation and preservation of biosignatures in both terrestrial and extraterrestrial settings (Gomez et al., Reference Gomez, Kah, Bartley and Astini2014). The survival strategies of microorganisms in hypersaline environments, such as the production of UV-protective biomolecules and osmolytes, offer clues about how life might adapt to extreme conditions on other planets (Albarracín et al., Reference Albarracín, Kurth, Ordoñez, Belfiore, Luccini, Salum, Piacentini and Farías2015; Vítek et al., Reference Vítek, Edwards, Jehlička, Ascaso, De Los Ríos, Valea, Jorge-Villar, Davila and Wierzchos2010).
Although we have highlighted some of the most extensively studied hypersaline environments for microbial research, it is important to acknowledge that many other sites – despite being less explored – hold significant scientific potential. Examples include Laguna Verde and Laguna Blanca in Bolivia; the Zipaquirá salt mine and Manaure saltern in Colombia; the Maras salt ponds in Peru; and Salina Grande in Argentina. These environments exhibit multiple extreme conditions, making them ideal candidates for future studies not only in astrobiology and planetary science, but also in biotechnology and bioprospecting. We therefore encourage researchers in these respective countries to include these sites in future investigations, helping to expand the scientific understanding of extremophiles in Latin America.
Astrobiology research possibilities
Many satellites and planets in our Solar System, such as Europa or Mars, are believed to harbor salty subsurface water bodies (Carr et al., Reference Carr, Belton, Chapman, Davies, Geissler, Greenberg, McEwen, Tufts, Greeley, Sullivan, Head, Pappalardo, Klaasen, Johnson, Kaufman, Senske, Moore, Neukum, Schubert, Burns, Thomas and Veverka1998; Lauro et al., Reference Lauro, Pettinelli, Caprarelli, Guallini, Rossi, Mattei, Cosciotti, Cicchetti, Soldovieri, Cartacci, Di Paolo, Noschese and Orosei2020). Earth’s halophilic extremophiles offer us a model of how life could survive in these extraterrestrial environments (Dassarma, Reference Dassarma2006), as demonstrated by the presence of microbial communities in halite deposits and evaporitic systems (Phillips et al., Reference Phillips, McInenly, Hofmann, Hinman, Warren-Rhodes, Rivera-Valentín and Cabrol2023; Vítek et al., Reference Vítek, Ascaso, Artieda and Wierzchos2016). High-altitude Andean lakes, such as those in the Argentinean Puna, and salt flats, like in the Atacama Desert and Uyuni, are characterized by hypersalinity, high UV radiation, and in some cases, low oxygen levels. These systems support polyextremophilic microbial ecosystems, including microbial mats and stromatolites, which are considered modern analogs of early Earth and martian environments, and have implications for astrobiology (Saona et al., Reference Saona, Soria, Villafañe, Lencina, Stepanenko and Farías2020); (Farías and Saona Acuña, Reference Farías and Saona Acuña2020).
According to our findings, several hypersaline environments do not have any kind of microbial research. For example, the Salinas Grandes is a salt flat that extends across the provinces of Jujuy and Salta, in Argentina (−24.3, −66.7). It is the fourth largest salt flat in South America, and it is in the Andean Altiplano region. It is 3,450 m.a.s.l., so it is also a region with high elevation conditions and probably solar radiation. The existence of multiple extreme conditions in Salinas Grandes makes this place an excellent candidate for astrobiology experiments in the future. In addition to this, similar environments in Bolivia, such as Laguna Chiarkota and Laguna Cañapa, represent an enormous unexplored potential for these studies. Numerous other hypersaline lakes in the southern region of Bolivia remain entirely unstudied and unexplored. This extensive network of hypersaline environments could offer future researchers the possibility to work in Martian-like settings and could facilitate the development of research collaboration networks to improve space exploration research projects in Latin America.
Concluding remarks
Distribution of extreme environments
Based on the information compiled from the four types of environments considered (Supplementary Table 1), geothermal and hydrothermal systems stand out as the most extensively studied sites in Latin America. Hypersaline and high-mountain or glacial environments have also received substantial attention. In contrast, arid environments remain comparatively underrepresented, even within the generally limited research focused on extreme environments.
A map of Latin America showing around 300 extreme environments described in this work can be seen in Figure 5. Most of the environments are located along the western margin of the continent. This is concordant with the active geological margins that involve the Nazca and South American tectonic plates to the south (Espurt et al., Reference Espurt, Baby, Brusset, Roddaz, Hermoza, Regard, Antoine, Salas-Gismondi and Bolanos2007), the Cocos and Caribbean Plate in Central America (Van Benthem et al., Reference Van Benthem, Govers, Spakman and Wortel2013) and the Pacific and North American plates to the north (DeMets and Merkouriev, Reference DeMets and Merkouriev2016). There is a clear relation between geological activity, geography, climate and the diversity of extreme environments. Most of the geothermal and hydrothermal environments are located inside mountain ranges and volcanic arcs, the biggest one being the Andean Mountain range that crosses South America. This is expected, given that the energy that feed these systems usually comes from magmatic activity under the crust (Gómez Díaz and Mariño Arias, Reference Gómez Díaz and Mariño Arias2020), even in the occurrences that are away from the western margin of the continent, like in Brazil and Uruguay, the thermal water are likely related to local volcanic systems (Zuo et al., Reference Zuo, Wang, Lan, Zhang, Zuo, Yang, Wang, Pang, Song and Yang2023). The glacial and high mountain environments are mainly constrained by geography; most of the locations that surpass 3500 m.a.s.l. are in the Andes or in the Sierra Madre, which in turn are the result of the regional geological activity mentioned before. However, glaciers do persist at lower altitudes in the southern latitudes of the continent, since temperatures are low enough to maintain them. Hypersaline environments are mainly concentrated in the Puna of the central Andes, which is also the location that hosts the environments with the most extreme conditions. This is the result of a combination of geological and climatic factors. The central Andes have the highest peaks, and it is the wider portion of the mountain range (Tassara, Reference Tassara2005), which makes the mobilization of wet winds from the east or west difficult, generating a dry environment (Garreaud et al., Reference Garreaud, Vuille, Compagnucci and Marengo2009). Most of the basins in these regions are endorreic, so the water bodies become saline over time due to constant evaporation (Alvarez et al., Reference Alvarez, Carol, Eymard, Bilmes and Ariztegui2022). Other hypersaline environments are associated with arid environments, these ones are mainly controlled by climatic factors; the deserts in Mexico, Colombia and Brazil are controlled by high-pressure Hadley cells (Seager et al., Reference Seager, Cane, Henderson, Ting, Kushnir, Seager, Cane, Henderson, Ting and Kushnir2008, Reference Seager, Kushnir, Kelley, Seager, Kushnir and Kelley2007), while the ones in Peru and Chile are mainly defined by the dynamics of the Humboldt marine current and rainshadow (Garreaud et al., Reference Garreaud, Vuille and Clement2003, Garreaud et al., Reference Garreaud, Vuille, Compagnucci and Marengo2009).
Map of Latin America showing the location of the extreme environments presented in this review.
The study of these environments has been carried out at macroscales (landscapes, regional lithology and basins), mesoscales (outcrops, facies analysis, or in situ sampling) and microscales (mineralogical, geochemical, microbiological, isotopic analysis and biomarker identification). This hierarchical approach allows for a comprehensive interpretation of the analog environment and its applicability to astrobiology (Chan et al., Reference Chan, Bowen, Corsetti, Farrand, Law, Newsom, Perl, Spear and Thompson2019). Furthermore, fidelity and feasibility are important for evaluating analogs. Fidelity refers to determining the extent to which the site can be considered to reproduce the processes or parameters of the planetary body of interest, for example, extreme aridity, temperature, salinity, radiation, etc. (Stern et al., Reference Stern, Graham, Burcar, Martin, Noell, Hand, Bowman, Doran, Edgcomb, Holden, Howells, Malaska, Nunn, Radebaugh, Rodriguez, Borges, Bower, Courville, Diaz, Hockman, Huber, Lawrence, Vick-Majors, Nixon, Spear, Steckel, Solomonidou, Schmerr, Schmidt, Schrenk, Seyler, Smith, Walker, Whelley, Wolfenbarger and Vance2025) propose that rather than seeking a one-to-one match, studies should focus on which processes and parameters should be mapped directly. In terms of feasibility, accessibility, equipment or infrastructure, as well as permits, cost, necessary access documentation and site replicability should be evaluated to conduct the studies. In the Latin American context, environments such as salt flats, alkaline lagoons and Andean highlands stand out, offering high accessibility and diversity; however, they also present challenges in terms of infrastructure and site conservation.
Studies conducted in the less explored environments discussed in this paper have focused on the macro and meso levels with less integration at the micro level (biomarkers, microorganisms). Moving forward, it would be advisable to promote integration between levels, the use of specific biomarkers that allow quantifying biological preservation in extreme environments,and the adoption of analogy assessment frameworks (fidelity/feasibility) when selecting sites and reporting results. It would also be important to consider the creation of integrated databases of Latin American analogues, in line with the idea of an “Astrobiology Information System” (Chan et al., Reference Chan, Bowen, Corsetti, Farrand, Law, Newsom, Perl, Spear and Thompson2019). Ultimately, while no terrestrial environment is an exact analogue of other worlds, a rigorous assessment of the levels of study and the quality of the analogues allows for robust conclusions to be drawn for planetary exploration and astrobiology.
Advantages in developing research in Latin America extreme environments and recommendations
This review shows that many extreme environments throughout Latin America offer easy access to researchers for gathering samples, conducting in-place experiments and obtaining novel results. The limited amount of research that has been done in these locations is also an opportunity for new studies to be carried out in them, broadening our general knowledge of extreme environments and finding conditions that are suitable for analog experiments. In that same line, many of the locations described here host multiple extreme conditions in a single place, thus generating natural environments that are closer to planetary settings (for example, martian-like environments). This level of fidelity could give us a better approximation of the expected behavior of life on other planetary bodies. Many activities can take place in these locations. Including the test of protocols, equipment and experiments that could increase the success of extant life detection in real conditions. Latin American environments are also geologically and climatically diverse, allowing direct comparison with planetary surfaces.
Latin America is home to a remarkable variety of extreme environments, from high-altitude Andean lakes to hypersaline coastal lagoons, many of which remain poorly explored despite their scientific potential. These ecosystems, besides challenging our understanding of the limits of life on Earth, are natural laboratories for astrobiological research. As the search for life beyond Earth becomes increasingly intensive, particularly on Mars and the icy moons of certain planets in the Solar System, the study of these analogous environments becomes increasingly important. This review collects knowledge about the extreme environments in the region and discusses their potential in basic and applied sciences, contributing to the global search for planetary analogs. We hope that this compilation opens opportunities for researchers in Latin America, as well as broadens cooperation with researchers and institutions around the world.
While the extreme environments of Latin America present significant advantages for astrobiological and analog research, studies must be conducted under a framework of ethical responsibility and robust collaboration. There has recently been much discussion in the scientific community in Chile, Bolivia and Argentina about ethical issues related to the work in extreme environments as planetary analogues, such as those in the Puna and Altiplano regions (Marino et al., Reference Marino, Franchi, Lebogang, Gomez, Azua-Bustos, Cavalazzi, Balcha, Lynch, Bhagwat and Olsson-Francis2023). Researchers must actively address and avoid practices such as “scientific colonialism” and “parachute research,” prioritizing instead genuine collaboration with local scientists and ensuring the involvement and respect of local communities, including native communities, who have been working in these regions for many years. Furthermore, adherence to relevant sampling and work permits is vital (e.g., considering the Nagoya protocol), as is the need to prevent oversampling and minimize any environmental modification of these irreplaceable sites. Incorporating these ethical and collaborative considerations is fundamental to ensuring that international and local research is conducted responsibly and sustainably.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S1473550426100330.
Data availability statement
The datasets used to create the map and the shapefile with the extreme environments can be reached at a Zenodo repository (Suarez-Valencia, 2025).
Acknowledgements
We thank Bruno Cevallos Gil for suggesting the organization of the environment on a table. To Diego Gomez and Sergio Montes for the support in the early stages of this work. And finally, to the University of Stuttgart for supporting the publishing of the paper.
Open access
