Endoliths in Terrestrial Arid Environments: Implications for Astrobiology

Abstract

Roberto Barbieri served as industrial micropaleontologist for 12 years in Italy and north Africa with companies of the oil and gas group ENI. He joined the University of Bologna (where he got his laurea in 1979) as associate professor in 1993. Since 2005 he is professor of Paleontology. As a micropaleontologist and geomicrobiologist he investigates modern and ancient ecosystems from stressful conditions and the way for their recognition in rock deposits. Presently, he is investigating the role of the microbial communities from potential terrestrial analogues of Martian environments. Abstract Microbial life in hot and cold desert environments inhabits endolithic niches. The endolithic microorganisms include bacteria, fungi and lichens. To protect themselves from the inhospitable conditions, such as high UV radiation, dryness, and rapid temperature variations, microorganisms migrate into fractures or in pore spaces where the necessary nutrient, moisture, and light are sufficient for survival. Examples of endolithic communities are well documented from the Negev Desert, Antarctica and the Artic regions, and the Atacama Desert. The most common substrates are porous, crystalline sandstones with calcium carbonate cements and sulfate (gypsum) and other evaporite mineral crusts. The detection of sulfate on the Martian surface has sparked off considerable interest in the astrobiological potential of the evaporite deposits of continental environments, which may potentially host (or may have hosted) endolithic microorganisms.