Unearthing lights-induced epilithic bacteria community assembly and associated function potentials in historical relics

Microbial biodeterioration causes a considerable loss of authenticity and aesthetic value of historical relics worldwide. However, we know very little about the ecology of the environmental microbiomes of these fragile ecosystems, impeding their long-term conservation. Towards an essential understanding, we explored the highly interactive triangle among community assembly process, composition and biodeterioration functional potentials of dominant epilithic bacteria community in a 1060-year stone relics-the Two Mausoleums of the Southern Tang Dynasty in China. Microbial assembly processes were evaluated using statistical null models and then associated with taxonomic and biodeterioration functional diversities along successional chronosequences. Results showed that stochasticity was a persistent force structuring the assembly of the epilithic bacterial community, creating a succession characterized with diverse heterotrophic colonizers but with reduced prevalence of Cyanobacteria. Along with the succession, potential functional diversity significantly increased, which may in turn induce severe biodeterioration to historical relics. To benefit reservation management, we speculate that it is critical for a scheme to interfere with the ongoing stochasticity. In total, a systematic perspective linking community assembly, taxonomic and functional compositions is key to understanding ecological mechanisms underlying microbial biodeterioration of cultural relics and supporting preventive conservation for future generations.