Deterioration-Associated Microbiome of Stone Monuments: Structure, Variation, and Assembly

Area of Science:

• Microbiology
• Geomicrobiology
• Conservation Science

Background:

• Stone monuments are susceptible to biodeterioration and microbe-induced carbonate precipitation.
• Understanding microbial communities is crucial for managing stone degradation and exploring conservation strategies.

Purpose of the Study:

• To investigate seasonal variations in microbial communities on stone monuments.
• To identify specific bacteria and fungi associated with stone deterioration and carbonate precipitation.
• To explore the potential of microbial carbonate precipitation for stone conservation.

Main Methods:

• 16S rRNA and internal transcribed spacer gene amplicon sequencing for bacterial and fungal composition.
• Alpha diversity analysis (Shannon, Simpson indices).
• Large-scale association analysis and functional prediction.
• Culture-dependent techniques and biomineralization assays.
• Imaging techniques (SEM-EDS, XRD, fluorescence imaging) for crystal identification.

Main Results:

• Cyanobacteria and Ascomycota were predominant bacterial and fungal phyla, respectively.
• No consistent temporal or spatial trends in species abundance were observed.
• Bacterial diversity changes correlated inversely with fungal community changes.
• Specific bacteria and fungi were associated with stone deterioration; CaCO3 crystals (calcite, vaterite) were identified.
• 64% of bacterial isolates induced carbonate precipitation.

Conclusions:

• Microbial communities play a significant role in stone biodeterioration and carbonate precipitation.
• While detrimental, bacterial CaCO3 precipitation offers a novel, eco-friendly approach for stone conservation.
• Further analysis of microbiomes can identify beneficial or detrimental microbes and their pathways for monument protection.