Abstract EANA2025-22

Basaltic rocks, abundant on the lunar highlands, Martian crust, and Earth’s volcanic terrains, are pivotal to both astrobiological prospecting and in situ resource utilization (ISRU) strategies for sustained human presence on extraterrestrial bodies. Their intrinsic mineralogical and physicochemical heterogeneity, such as high porosity, vesicularity, and surface microtopography, renders them both mechanically suitable for construction and potentially hospitable to microbial colonization. Yet, their long-term functional performance, especially under exposure to biological activity, remains insufficiently characterized.

Here we present a multidisciplinary assessment of the bioreceptive potential of basaltic lithofacies from the 2021 Tajogaite eruption (La Palma, Canary Islands), integrating petrophysical characterization, high-throughput DNA sequencing, photosynthetic pigment quantification, and confocal laser scanning microscopy. Using standardized colonization assays (Guillitte 1995; Miller et al., 2010), we inoculated four distinct lava types with a natural photosynthetic microbial consortium, incubating them over 12 months under simulated terrestrial conditions. Taxonomic profiling of biofilms revealed dynamic microbial successions dominated by Alphaproteobacteria (e.g., Reyranella, Hyphomicrobium), Verrucomicrobia (Prosthecobacter), Cyanobacteria (Arthrospira), and green algae (Chlorella, Chlamydomonas), with significant shifts in community structure and functional gene abundance over time. Colonization dynamics revealed preferential biofilm formation on scoriaceous and vesicular basalts, with photosynthetic organisms (e.g., Chlorella, Chlamydomonas, Arthrospira) dominating the consortia. Functional prediction indicated enriched pathways for phototrophy, ureolysis, nitrification, manganese oxidation, and chemoheterotrophy, which are metabolisms relevant for primary production, mineral weathering, and nutrient cycling.

Basalt's near-ubiquity in extraterrestrial terrains,comprising ~99% of mare basalts on the Moon and forming the bulk of Martian volcanic plains, makes it the logical cornerstone for off-Earth construction. Also, the ability of microbial communities to colonize and modulate basaltic substrates supports the integration of microbial consortia into engineered systems for air revitalization, CO₂ sequestration, and enhanced soil formation from regolith analogs.

This research bridges planetary geology, microbial ecology, and space architecture, advancing basalt as both a functional construction material and a catalytic interface for life in off-Earth environments.

Acknowledgments: This work received support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under the research project HIRES-SOM (ref. TED2021-130683B-723 C21/C22) funded by MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR. The research project MICROLAVA (ref. 725 PROYEXCEL_00185) funded ´sby Junta de Andalucia is also acknowledged.