Biogeochemical study of the periglacial slopes of the Nevado del Ruíz volcano (Colombia) as a terrestrial analog of Mars

Abstract

The Refugio sector of the Nevado del Ruiz Volcano, located in Colombia, has been the focus of multidisciplinary exploration aimed at understanding its geology, geochemistry, mineralogy, and microbiology, with the objective of evaluating its relevance as a potential terrestrial analog of astrobiological interest for Mars. Through detailed physicochemical analyses of soil samples, variability in properties such as pH, electrical conductivity, and nutrient content has been characterized, revealing the diversity of microenvironments within this volcanic region. Comparison with analog samples from Mars, taken from the ISAR collection, has highlighted significant differences in geochemical composition, particularly in MnO, Fe₂O₃, and SiO₂ content, underscoring the importance of Nevado del Ruiz as a key site for studying Martian geological processes. Furthermore, CRISM spectroscopy analyses have confirmed the presence of minerals similar to those found in Mawrth Vallis on Mars, further supporting the site's validity as a terrestrial analog for planetary studies. Finally, the isolation of bacterial species identified as Klebsiella spallanzanii and Bacillus cereus, two oligotrophic and psychrophilic microorganisms, capable of phosphate solubilization and nitrogen fixation, found at Nevado del Ruiz support the development of biological models of astrobiological relevance. Together with the other findings, this evidence reinforces the importance of Nevado del Ruiz as a natural laboratory for astrobiology and space exploration, with the potential to provide information for future planetary exploration missions.