Insights into bacterial communities associated with petroglyph sites from the Negev Desert, Israel

Rock art sites containing petroglyphs are found throughout the Negev Desert of southern Israel. Recently, as more sites have been revealed, there has been an increasing awareness of their importance as a cultural heritage resource. However, the rocks on which the petroglyphs were engraved are exposed to natural and anthropogenic weathering processes. In order to characterize the bacterial communities that may play a role in the weathering of rock surfaces and petroglyphs panels, we undertook culture-independent (Next Generation Sequencing technologies) and culture-dependent methods to identify the bacterial communities on these rock surfaces. The Results reveal that the most common bacterial components at two petroglyphs sites studied were Actinobacteria (33%), Cyanobacteria (30%), Proteobacteria (15%) and Bacteriodetes (7%). Further study and isolation revealed several Cyanobacteria strains related to the Oscillatoriales and Synecococcales orders. This study provides an important first step in understanding the bacterial community structure that may be associated with the weathering of petroglyphs in this region.