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Abstract EANA2025-51


Cataloguing the Limits of Life and Modelling Potential Niches on Mars and Exoplanets

Afonso Mota (1,2,3), Catarina Magalhães (1,4), Nuno Santos (2,3) and Marta Cortesão (2)
(1) Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Portugal, (2) Instituto de Astrofísica e Ciências do Espaço, Portugal, (3) Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal, (4) Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Portugal


To detect life on other worlds, we must study the only known planet harbouring life in the Universe: Earth. Although they often go unnoticed, microorganisms dominate our biosphere and can thrive in any environment, from active volcanoes to polar ice, from the depths of Earth's crust to its upper atmosphere. 

We compiled data covering 22,181 cultured prokaryotic species (Bacteria and Archaea), representing 86% of the currently 25,737 cultured prokaryotes, gathering the minimum, optimal, and maximum growth conditions for temperature, pH, and salinity (NaCl). Our dataset builds upon previous work, extending the known limits of life, as well the conditions to sustain active microbial reproduction beyond simple survival without growth (dormancy). We then used this data to develop a proof-of-concept ecological niche modeling framework to predict microbial growth under various planetary conditions, including non-Earth-like ones. Ecological niche (or species distribution) models are traditionally used in ecology, but rarely for microbes. We also explore the possibility of how psychrophilic organisms may be able to grow on current Mars environments, and how their distribution could vary depending on environmental factors like temperature and pH. 

Our catalogue is a powerful tool for querying organisms with combinations of traits, and to be used as an up-to-date tool to get information on microbial minimum, optimal, and maximum growth conditions. The database provides empirical constraints that are important to refine habitability predictions, guide biosignature selection, and ultimately improve the search for life beyond Earth. Furthermore, as more information about exoplanets is revealed, and, in particular, looking forward into the next generation of telescopes, microbial ecology models like the one developed here will be crucial to estimate what kinds of communities could inhabit certain exoplanets, and in turn what biosignatures are more likely to be detectable by the current and future observations.