Microfungal colonisation in some Bratislava-old town historical objects (Slovak Republic). A preliminary study

Abstract We conducted a mycological study on selected historical monuments found in the historical centre of Bratislava (Slovakia). These were the Gothic Ossuary of St. James (thirteenth century), a two-chamber potter’s kiln from the late La Tène period (a Celtic kiln) used for firing ceramics (first century BCE), Fisherman’s Gate (fourteenth century), a Celtic mint (end of the third century BCE), and the remains of a Celtic settlement (first century BCE) and a Roman corridor (fifteenth century) located in Bratislava Castle. From the listed objects, only the Celtic mint is accessible to regular museum visitors; the other objects are not accessible to visitors or are accessible in only limited numbers. We identified 20 genera and 36 species of microscopic filamentous fungi, including a light-coloured sterile mycelium, from the surfaces of the mentioned objects and from the air. The genus Aspergillus (7 species) and the genera Acremonium and Cladosporium (5 species) were the most numerous. We most often (8 times) isolated the species Cladosporium cladosporioides. We recorded the greatest diversity of microscopic filamentous fungi in the Gothic Ossuary of St. James (sample 1a), on the surface of the Celtic kiln (sample 2a) and on the perimeter walls of the Celtic settlement (sample 5a). Since no temperature and humidity sensors are found in the mentioned objects, our results point to the necessity of installing such devices for the protection and maintaining of historical objects in good condition.