A commercially available adenosine triphosphate (ATP) detection system, supported by cultivable microbial indicators, was optimized to estimate bioburden in different habitats in and outside show caves. Mass cave tourism and the presence of allochthonous organic matter result in high levels of airborne, and total biomass. Underground habitats play an important role in the preservation and concentration of microbial biomass using air and water as transport mechanisms.
COBISS.SI-ID: 40106541
Airborne microorganisms are an integral part of a cave ecosystem. The impacts of tourists, and natural river aerosolization on the cave air quality were estimated in large cave spaces of the Škocjan Caves. A diverse mix of bacteria typically associated with human microbiome, and with other natural habitats was found in the cave air. A strong positive correlation between tourist numbers and the rise in the concentration of airborne bacteria during tourist visit was indicated. Concentration of airborne bacteria rises particularly high close to the underground river during periods of high discharge.
COBISS.SI-ID: 41852973
Sulphate minerals in caves in Slovenia are not very often reported and analysed. In Črna Jama, near Kočevje the presence of sulphate minerals was detected by SEM/EDS analysis of speleothems. The cave is characterised by dark colour coatings on cave walls, floor and speleothems. The analysis of the black coated speleothems reveals the presence of calcium sulphate, confirmed by XRD as gypsum. Gypsum crystals are around 50 µm in size and they occur in thin crusts. Additionally, some rare authigenic baryte crystals a few µm in size were detected. The sulphates ?34S value is +10.4‰ VCDT. The very likely source of sulphate ions is biomass burning. Bedrock and/or biomass ash are a very probable source of calcium and barium. The highly probable pyrogeneous origin of sulphates draws attention to human impact on cave mineralogy. This cave is paralleled with similar dark coatings in Postojna Cave.
COBISS.SI-ID: 1368670
Črna Jama is the coldest section of cave within the Postojna Cave System. It exhibits winter and summer temperature regimes. During warm periods (T-cave(T-out) it acts as a cold air-trap, exchanging no air with the outside atmosphere. Cave-air temperature is significantly stable and affected only by elevation of the groundwater table, which is associated with precipitation. During cold periods (T-cave)T-out) ventilation takes place and dense, cold, outside air sinks into Črna Jama because of the favourable cave entrance morphology. Recent Črna Jama air temperature data (2014–2019) indicate a (0.5°C higher temperature than that recorded in historical data since 1933. Črna Jama is the most appropriate place within the Postojna Cave System to study long-term climatic changes. There are hardly any tourist visits to the cave, and human impacts on the cave climate are essentially reduced.
COBISS.SI-ID: 42090285
World-wide there are at least 12 ILTER (International Long Term Ecological Research) sites with an emphasis on karst, but the study of cave ecosystems has been largely neglected. Only two ILTER sites, both in Slovenia, are primarily caves. Caves are under-represented for several reasons, but especially because of the overall difficulty of access and the lack of a clear research agenda for cave ecosystem studies. We review several aspects of long-term studies in Postojna Planina Cave System (PPCS), proposing our approach as a model for ILTER research in caves. Five factors (temperature, drip rate, river discharge, epikarst copepod fauna, and organic carbon) were analyzed in detail and found out that are the appropriate variables for capturing the essential long-term trends in cave ecosystems.
COBISS.SI-ID: 42929197