Biodiversity of photosynthetic micro-organisms dwelling on stone monuments

A critical survey of literature data for the biodeteriogens acting on stone monuments was combined with the results of our investigations performed by traditional and biomolecular (ARDRA) methods. It was showed that the photo synthetic micro-organisms dwelling on stone monuments have a rather ample b iodiversity, and this was also confirmed by our data on axenic cyanobacteri al strains isolated from Italian monuments. The correlation between the lit erature data reporting the presence of photosynthetic micro-organisms, and the nature of the stone substrate showed that the cyanobacteria Chroococcus , Myxosarcina, Pleurocapsa and Scytonema, and the chlorophyta Apatococcus a nd Stichococcus were associated with calcareous substrates, while Nostoc sp p. were more frequently associated with artificial substrates. We also demo nstrated that Lyngbya B2 and Apatococcus B4, previously isolated from monum ents, when inoculated on stone slabs differing in porosity and surface roug hness, had a preference for calcareous lithotypes with high values of rough ness and porosity. (C) 2000 Elsevier Science Ltd. All rights reserved.