Bacterial Communities in Pigmented Biofilms Formed on the Sandstone Bas-Relief Walls of the Bayon Temple, Angkor Thom, Cambodia

Research at the Bayon Temple in Angkor Thom, Cambodia, reveals that pigmented biofilms on sandstone bas-reliefs harbor distinct bacterial communities that differ from those in surrounding air and exhibit low sequence similarity to known database entries. Non-destructive sampling identified novel bacterial groups associated with different biofilm colors: Rubrobacter in salmon pink biofilms, Cyanobacteria in chrome green biofilms, and a mix of Cyanobacteria and Chloroflexi in signal violet biofilms, among others. Stratified analysis showed that blue-green biofilms, linked to severe deterioration, were rich in Cyanobacteria near the surface and Chloroflexi deeper within, with high nitrate ion concentrations. These findings provide critical insights into biofilm formation processes and tropical sandstone weathering, offering potential strategies for mitigating damage to UNESCO World Heritage Sites like Angkor.

Kusumi, A., Li, X., Osuga, Y., Kawashima, A., Gu, J.-D., Nasu, M., & Katayama, Y. (2013). Bacterial Communities in Pigmented Biofilms Formed on the Sandstone Bas-Relief Walls of the Bayon Temple, Angkor Thom, Cambodia. Microbes and Environments, 28(4), 422–431. https://doi.org/10.1264/jsme2.me13033