Role of the microboring marine organisms in the deterioration of archaeological submerged lapideous artifacts (Baia, Naples, Italy)

Endolithic microorganisms responsible for micro-erosion of submerged archaeological artifacts, found in the Underwater Archaeological Park of Baia (Naples) were analyzed. SEM observations show that the process of bioerosion involves carbonate substrates related to endolithic activity by chemotrophic and phototrophic microflorabiota. Embedding casting procedure with polyester resins permitted the identification of five different micro-borer traces, corresponding to two species of cyanobacteria, one species of green algae, one species of fungi and to a clionaid sponge (ichnogenus Entobia). Traces of the green alga Ostreobium quekettii were found to dominate in all samples. The data confirm that endolithic cyanobacteria, chlorophytes and fungi together with macroboring organisms due to the growth of clionaids and bivalves play a significant role in biodeterioration processes of submerged calcareous artifacts.