Biological Colonization of Carolei’s Nymphaeum (Calabria, Italy)

The nymphaeum originated as a monument dedicated to the nymphs and defined as a natural cave with a water source. Over time, it has been transformed into an artificial cave with the presence of fountains, statues and wall paintings. The nymphaeum is exposed to specific environmental conditions, leading to biodeterioration caused by vegetal organisms that find an ideal environment for their growth. This study aimed to document the vegetation present inside and outside the Carolei’s Nymphaeum, as well as the biofilm on the interior walls, particularly the painted walls. The biological work is part of a large-scale project involving building materials, thermo-hygrometric parameters, and partial pilot restoration work. Multiple approaches were used for biological analysis by combining microscopic, culture, and molecular techniques. We identified Pteridophytes, Angiosperms, and mosses, as well as fungal taxa, cyanobacteria, and chlorophytes in the biofilms. The results indicate that there is a very heterogeneous organism composition with significant biodeterioration potential. Biodeterioration is one of the major problems in the prevention, conservation, and restoration of cultural heritage, and the data gathered in this research may help to enhance the understanding of issues and develop suitable strategies for restoration, upkeep, and accessibility and usability.