Abstract EANA2025-70

The search for life beyond Earth remains a central objective in astrobiology. Terrestrial analog environments, such as volcanic lava tubes, offer crucial insights by mimicking the conditions of early Earth and present-day Mars. These subsurface habitats, protected from radiation and marked by geochemical extremes, are ideal natural laboratories for developing and testing life-detection strategies for extraterrestrial life exploration. In particular, siliceous speleothems within these environments are capable of preserving organic matter, making them valuable targets for biomarker identification as part of extraterrestrial biosignature studies.

Detecting potential biomarkers in extreme environments demands highly sensitive, minimally invasive analytical methods. Pyrolysis-based techniques are among the most promising, having already been deployed in planetary missions such as the Mars Organic Molecule Analyzer (MOMA) aboard the ExoMars rover. MOMA’s ability to detect low-molecular-weight biomarkers under Mars-analog conditions highlights the robustness of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) approaches (Reinhardt et al., 2020). Yet, standard flight instruments are constrained by limited resolution. Recent advances in analytical pyrolysis techniques, namely ultra-high-resolution pyrolysis gas chromatography coupled with quadrupole time-of-flight mass spectrometry (UH-Py-GC-Q/TOF-MS), and Pyrolysis-Compound-Specific Isotope Analysis (Py-CSIA), now offer exceptional molecular and isotope precision. These techniques can detect organic compounds at parts-per-billion levels, provide exact mass measurements to four decimal places, and yield δ¹³C and δ2H isotope values from microgram-scale samples without requiring sample pre-treatment. Such capabilities are critical for identifying delicate or rare biomarkers and for differentiating biogenic from abiotic organic matter. However, interpreting the resulting data remains a significant challenge. The analysis of a single sample may release over 3000 distinct organic compounds, making data analysis complex and time-consuming. Addressing this requires the development of advanced mathematical algorithms and integrated graphical-statistical tools (e.g., 3D van Krevelen diagrams) to extract meaningful insights from high-dimensional datasets. The integration of analytical pyrolysis with chemometric analysis is thus essential for: 1) the rapid identification of microbial biomarkers; 2) revealing microbial adaptations to extreme environments, and 3) tracing ecological disturbances that shape microbial communities.

In this study, we depict the applicability of the UH-Py-GC-Q/TOF-MS and Py-CSIA techniques to molecular and isotope characterization of organic matter preserved in siliceous speleothems from volcanic Mars analog sites (such as Lanzarote and La Palma (Spain), Selvagens Islands (Portugal), and Easter Island (Chile). By integrating these techniques with multivariate statistical and chemometric tools, we classify compound families, detect potential biomarkers, and reconstruct paleoenvironmental and anthropogenic signals. This analytical framework not only deepens our understanding of biosignature preservation in extreme environments but also strengthens our ability to detect traces of life on Mars and other planetary bodies—bringing us closer to answering the profound question of whether we are alone in the universe.

 

Acknowledgments: The Spanish Ministry of Science and Innovation from the Spanish State Agency (AEI) is acknowledged for funding projects TUBOLAN (PID2019-108672RJ-I00) and EQC2019-005772-P. This work was also supported by Junta de Andalucía and the Portuguese Foundation for Science and Technology (FCT) through the MICROLAVA (PROYEXCEL_00185) and MICROCENO (PTDC/CTA-AMB/0608/2020) projects, respectively. The Spanish National Research Council (CSIC) is also acknowledged for the intramural project PIE_20214AT021. N.T.J-M. thanks the Ramón y Cajal research contract (RyC2021-031253-I).

 

Reference:

Reinhardt, M., Goetz, W., Thiel, V. (2020). Testing Flight-Like Pyrolysis Gas Chromatography–Mass Spectrometry as Performed by the Mars Organic Molecule Analyzer Onboard the ExoMars 2020 Rover on Oxia Planum Analog Samples. Astrobiology 20, 415-428. https://doi.org/10.1089/ast.2019.2143