Cultural heritage is an important indicator of the past creations of individual peoples and needs to be protected, especially today, when it is exposed to various factors of deterioration. One of the most important factors is biodegradation, i.e. the colonisation of microorganisms that cause further damage to the surface and subsurface of rocks through their growth.
In the master's thesis, we examined 5 carbonate rocks that are most commonly found in cultural heritage buildings, namely the Škofja Loka conglomerate, the grey Lesnobrdo limestone, the uniform Lipica limestone, the Lithotamnian limestone and the Sedovec sandstone. The petrographic composition, porosity and specific surface area of the rocks were determined. These rocks were colonized by 5 fungi – Aspergillus niger, Aureobasidium pullulans, Cladosporium neolangeronii, Exophiala sp. and Penicillium chrysogenum. These fungi were selected because they are among the most common fungi found on cultural heritage sites. The growth of the fungi was monitored at 4 time intervals, namely after 7, 14, 28 and 90 days of colonisation, to investigate the biodiversity of the individual rocks. The rock samples with fungi were first examined macroscopically with a stereoloupe microscope and then with an electron microscope. The strongest growth of all five fungi was observed on the grey Lesnobrdo limestone, which has the lowest porosity and a medium specific surface area among the selected rocks. The lowest growth was observed on the Lithotamnion limestone, which has a relatively high porosity and specific surface area. For all fungi on the rocks considered, growth was observed within a certain time frame. The most successful fungi for growth on the rocks were Exophiala sp. and Cladosporium neolangeronii. For all fungi, hyphae, sporulating structures and also large aggregations of hyphae were observed after three months of colonization. Bioreceptivity od rock to the growth of fungi depends on mineral composition and availability of carbon ions. Fungi growth is better if there is more sparite and calcite cement available than micrite in the structure of rocks. The topic of biodegradation in the field of cultural heritage in general is very important and certainly worthy of further study, especially to determine the appropriate protection of cultural heritage from deterioration by microorganisms.
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