Ornella Salvadori

Biology in the conservation of works of art

Reports on the problem of biodeterioration of works of art. This didactic text is intended for conservators without specialization in biology and for biologist lacking experience in conservation. The book comprises six chapters: environmental factors in biodeterioration (general principles of ecology, atmospheric factors, pollution effects); mechanisms and phenomenology of biodeterioration (physical processes, chemical processes, aesthetic damage, phenomenology of biological alterations); biodeterioration of organic materials (wood, paper, textiles, leather, parchment, paintings); biodeterioration of inorganic materials (stone and related materials, glass, metals - fungi, bacteria, lichens, lower and higher plants); methods of prevention (indoor and outdoor environments); control measures (mechanical, physical, biological and chemical methods (biocides, insecticides, pesticides), biochemical methods. The work is completed by a glossary of biological terms and an appendix covering elements of general biology, systematics of biodeteriogens, and analysis techniques.

The Role of Fungi and Lichens in the Biodeterioration of Stone Monuments

This review elucidates current knowledge on the significant role of fungi and lichens in the biodeterioration of stone monuments. The effect caused by many epilithic lichen species in the deterioration of different types of stone has been extensively investigated and demonstrated. Nonetheless, many aspects of the deterioration mechanisms of microcolonial fungi (MFC) and endolithic lichens are still to be proved. An interesting hypothesis has recently been put forward involving the secretion of siderophores like compounds. Lichens can provide bioprotection for stone surfaces, acting as a barrier against weathering, retaining moisture, increasing waterproofing, reducing thermal stress and erosion, and absorbing pollutants. Nevertheless, the evaluation of biodeterioration vs. bioprotection cannot be generalised, since it can vary according to the behaviour of different species, as well as being affected by both the lithotype and the environment. In addition to the laboratory studies, more field studies of biological communities are required, to analyse their establishment and succession in natural conditions and after conservation treatments. In order to guarantee the best decision for stone conservation, cleaning operations should not be based on a generalised approach, but should rather be based on a careful evaluation of different aspects concerning biodeterioration and bioprotection.

Ecological Mapping for the Preventive Conservation of Prehistoric Mural Paintings in Rock Habitats: the Site of Filiano (Basilicata, Italy).

Biodeterioration phenomena are of great relevance in rock settlements, due to favourable environmental conditions, such as the infiltration of rainwaters, condensation phenomena and abundance of salts and organic nutrients. Rinaldi’s rock shelter in Filiano, which is located in a natural forest of mixed oaks is of great value due to the important traces of prehistoric paintings. It is an emblematic case of the delicate balance, achieved throughout the centuries, between the environment and artwork. During the plurimillenarian history of the site, a portion of the ceiling that covered the shelter collapsed, leaving signs that are still visible today, together with traces of blackening left by the fires of ancient settlements. Several of the biodeteriogens typical of rocky habitats have already been detected and include algae, cyanobacteria, mosses, lichens, vascular plants and fungi, which form macroscopic communities. Each community has an ecological preference and the mapping of their distribution is a suitable tool for understanding variations in the environmental factors that most affect them. Relating ecological data to the taxonomical characterization of the species and to the spatial distribution of each community, a site map of the humidity and of the nutrients was obtained. Among the various communities, microcolonial fungi (MCF), which appear as little black spots, here, represent the most critical risk factor, due to their low water needs. An evaluation of the biological risk for the possible future attack of such a biological community was made, suggesting indirect mitigation measures, through modification of the microclimatic and local ventilation conditions.