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Abstract EANA2025-84


Volcanic lakes as Martian analogues: Biosignature preservation in the hydrothermal system of Lake Bagno dell’Acqua (Pantelleria, Italy)

Marlisa Martinho de Brito (1,2), Mario Borrelli (3), Dmitri Rouwet (4), Giovannella Pecoraino (5), Giovanni Birarda (6), Assimo Maris (1), Nina Kopacz (7), Fabiana Canini (7), Rebecca Martellotti (2), Andrea Biddittu (8) , Micol Bellucci (9), Claudia Pacelli (9), Edoardo Perri (3), Monica Pondrelli (10) , Laura Zucconi (7) and Barbara Cavalazzi (1,2)
(1) CIRI Aerospace, Alma Mater Studiorum, University of Bologna, Bologna, Italy; (2) Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy; (3) Department of Environmental Engineering, University of Calabria, Rende, Italy; (4) Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Italy; (5) Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Italy; (6) SISSI Beamline, Elettra Synchrotron Source, Basovizza, Italy; (7) Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy; (8) Pantelleria Island National Park, Pantelleria, Italy; (9) Science and Innovation Directorate, Italian Space Agency, Rome, Italy; (10) International Research School of Planetary Sciences, Università d'Annunzio, Pescara, Italy;


Ancient crater lakes on Mars, dating to the Noachian period (~3.7 Ga), are among the most promising targets for astrobiological exploration due to their potential to host habitable conditions and preserve traces of past life. Remote sensing and rover missions have revealed lacustrine sediments enriched in clay minerals, notably Fe- and Mg-smectites, as well as carbonates and chlorides, all indicative of environments favorable for the long-term preservation of organic matter. However, a major challenge remains: establishing robust criteria for the identification and interpretation of biosignatures in these ancient Martian deposits.

To address this, we investigate terrestrial analogues that replicate the environmental and geochemical conditions of early Mars. Lake Bagno dell’Acqua (also known as Specchio di Venere), a volcanic and endorheic alkaline lake (pH ~ 9) located on Pantelleria Island, Italy, represents a particularly relevant setting. The lake is influenced by active hydrothermal activity characterized by emissions of CO₂, CH₄ and other gases that sustain the growth of microbial mats on the lakebed. These microbial communities play an active role in mediating the precipitation of authigenic silicate and carbonate minerals, enhancing the entrapment and preservation of biomolecular traces.

We employed an integrated field approach that combines sedimentology and geochemistry coupled with advanced techniques such as SEM-EDS/TEM microscopy and Raman/Optical Photothermal Infrared (O-PTIR) spectroscopy to investigate both modern and subfossil lake’s microbialites. Our findings shed light on how hydrothermal inputs and volcanic lake chemistry shape microbial community dynamics, microbe–mineral interactions and pathways for organic matter fossilization. By providing detailed insights into biosignature formation and preservation in a Martian analogue environment, this research contributes to refining life-detection strategies for future Mars missions.

The HELENA project is funded by the Italian Space Agency (contract n. 2023-9-U.0).