INSIGHTS INTO MICROBIAL COMMUNITIES ASSOCIATED WITH PETROGLYPH SITES FROM THE NEGEV DESERT, ISRAEL

Rock art sites in the form of petroglyphs are found in the Negev Desert in southern Israel. These petroglyph sites include thousands of images depicting the life and culture of prehistoric peoples in the region. As they are part of the desert environment, these petroglyphs are exposed to natural and anthropogenic weathering processes. Of these processes, natural weathering by microorganisms was found to accelerate the deterioration of these rocks surfaces. Thus in order to develop tools for preservation and remediation, it is imperative to ascertain the role of these surface-inhabiting microorganisms in rock degradation. We therefore, undertook to identify the microorganisms in these sites and to try to clarify their roles in the weathering of Negev rock surfaces and in petroglyphs panels. Next Generation Sequencing technologies (NGS) were implemented on rock surface samples to identify the microbial communities found on and in them. Results showed that the most common microbiota components of rocks at the sites studied included Actinobacteria (33%), cyanobacteria (30%), proteobacteria (15%) and bacteriodetes (7%). From this we hypothesized that cyanobacteria play an important role in the deterioration of the rocks surface. We subsequently undertook to isolate and identify rock-inhabiting cyanobacteria as a first step in ascertaining their role in rock deterioration. Our study revealed three major cyanobacteria strains in our site. These strains, related to the Leptolyngbyaceae, Microcoleaceae, and Pseudanabaenaceae families, were prominent in our samples indicating their importance in this environment. This study provides a first step in understanding the dynamic communities of microorganisms associated to the petroglyphs.