The "Bagno dell'Acqua" lake of Pantelleria: a new Mars-like environment for the study of prebiotic chemistry and as a source of microorganisms adapted to live in extreme environments

Data from space exploration of planets such as Mars are crucial for a better understanding of potentially habitable environments beyond Earth. The atmosphere of Mars is composed predominantly of carbon dioxide (CO2) and recently some minerals have been identified which indicate the presence of neutral/alkaline aqueous activities. Studying similar terrestrial environments allows us to develop a better understanding of where life may have developed, what kinds of organisms may exist, and what evidence of that life may be preserved. The endorheic lake Bagno dell'acqua, formerly known as “Specchio di Venere”, partly occupies the Cinque Denti caldera on the island of Pantelleria. Its structure makes it similar to depressions on Mars, such as Huygens Crater, Jazero, Columbia Hill and Gusev which probably hosted water in the past. The mineralogical characteristics of these sites are similar to those observed in the sediments of the Bagno dell'acqua lake and in other sites on the island of Pantelleria. The lake is characterized by frequent CO2 emission sites, alkaline waters (pH=9) and Eh values which indicate strongly oxidizing conditions and with characteristics similar to Martian Noachian deposits. All these physical characteristics reinforce the idea of Baliva et al., who already in 1999 proposed the Bagno dell'acqua lake as a Martian analogue and make this site an environment that could be favorable to the synthesis of prebiotic polymers. A typical feature of the Pantelleria lake is the presence of actively growing microbialites rich in calcium carbonates and silica precipitates, products found on the surface of Mars. The role of microorganisms in the formation of carbonates and amorphous silica deposits described in alkaline lakes makes the study of these places of fundamental importance for future sample return missions to Mars. Furthermore, the isolation and characterization of microorganisms that have evolved to live in extremely CO2-rich environments and that are hyper-effective at capturing CO2 may prove critical to achieving biological CO2 conversion during long-term space travel (Santomartino et al., 2023). Preliminary data on polymerization of 3',5-cGMP in situ and biomineralization activity of microbial isolates will be presented.