‏מה לחיידקים ולקיומן של חרותות סלע בנגב?

Throughout the Negev Desert Highlands, thousands of petroglyphs carved into the natural rocks tell us the story of the desert inhabitants’ culture throughout the years. These petroglyphs are susceptible to deterioration processes, that may result in the loss of this unique rock-art. Hence, the overarching goal of our study was to characterize the composition, diversity and biodeterioration effects of the microbial lithobionts colonizing the rocks. Molecular methods )e.g., DNA sequencing( revealed a complex microbial community representing various taxa from the archaea, bacteria as well as some eukaryotes. In addition, the metagenomic analyses exhibit specific genes coding sequences )CDS(, which may be involved in the rock’s elemental geochemical cycles and elements uptake processes. Scanning electron microscopy observations revealed the spatial organization of these colonizers, and in particular their close association to the rock minerals. These associations indicated that the microbial–mineral interactions may contribute to rock weathering and potentially to the deterioration process. In laboratory experimental model, our cyanobacteria isolates presented attachment, growth and boring abilities when inoculated on stone slabs. Whole genome mapping of our local isolated cyanobacteria, Trichocoleus Desertorum, revealed coding sequences of genes involved in environmental resistance, carbon fixation processes, nitrogen cycle and cations )e.g., calcium, ferrous( uptake. Thus, our results provide evidence of the potential participation of the microorganisms in weathering of rocks. Moreover, we demonstrate an effective strategy to elucidate the complexity of bio weathering processes occurring at the ancient engravings analyzed.