"The presence of a previously undescribed endolithic microbial community that is different than the surface community has important implications for the conservation of Maya ruins as well as other stone objects and structures," says Christopher McNamara, a researcher on the study.
McNamara and his colleagues collected stone samples from a Maya archaeological site and separated it into surface and interior portions, which were then broken down into tiny particles. They extracted DNA from the samples and identified and compared bacterial communities on the inside and outside surfaces of the stone. Photosynthetic microorganisms, mainly proteobacteria, were found to populate the surface whereas Actinobacteria was the dominate population on the interior where no photosynthetic organisms were detected. Additional tests on the interior bacterial communities suggest that they break down limestone as they grow.
"Surface analysis of microbial growth and disinfection of stone objects and buildings can no longer be considered sufficient," says McNamara. "Furthermore, treatments designed to penetrate stone objects must consider the presence of a microbial community that may be substantially different than that visible on the surface."