Red sandstone surface microbiota: functional convergence despite taxonomic divergence under dispersal limitation and hetero selection

Understanding the role of microbiota on stone surfaces is essential for developing effective grottoes conservation strategies. However, ecological feature of microbial communities on stone surfaces remains underexplored. In this study, we explored diversity, ecological feature, and functional profiles of microbial communities on the red sandstone surface of the Leshan Giant Buddha from microbial ecology perspective. The results show that Proteobacteria, Actinobacteria, and Cyanobacteria are the dominant prokaryotic phyla, and Ascomycota is the most dominant eukaryotic phylum. Interestingly, despite taxonomic divergence, the functional profiles of different types of the microbial communities remain convergent across all samples. As indicated by the ecological modelling, the interplay of dispersal limitation and hetero selection might have contributed to such species divergence, while selective pressure from the harsh environment on the stone surface promoted functional convergence. The assembly of visually distinct microbial communities is linked to a narrower ecological niche, higher proportion of habitat specialists, elevated complexity, and increased resilience of the prokaryotic network to disturbances. Microbial-mediated ammonium assimilation and nitrogen mineralization might be the two prominent processes that contribute to stone biodeterioration. This study deepens our understanding of microbial community assembly mechanism on stone cultural heritage surfaces and functional potentials, which provides microbial ecological insights for the conservation of these cultural treasures.