Sediments Microfungi Diversity in the Demänovská Ice Cave: A Combined Morpho-Molecular Approach with Edaphic N, P, K, C and pH Factors.

Subterranean environments represent extreme oligotrophic ecosystems where microclimatic and edaphic factors restrict microbial life. This study evaluated culturable fungal communities in the soil and sediment samples of the Demänovská Ice Cave to determine their spatial diversity and abundance across psychrophilic (5 °C) and mesophilic (24 °C) incubation temperatures in relation to soil and sediment chemistry. Using a combined morpho-molecular approach, 19 distinct fungal species were identified, with a strong taxonomic dominance of Ascomycota and the genus Penicillium. Culturing temperatures acted as a primary selective filter. At 5 °C, specialized cold-adapted fungi (Cladosporium cladosporioides and Pseudogymnoascus) were more abundant in subterranean sediments than in surface samples. Conversely, incubation at 24 °C reduced fungal abundance and diversity in subterranean samples, with most fungal growth observed in surface samples from the outdoor control site. Statistical analysis revealed that at 24 °C, fungal abundance correlated significantly with total nitrogen (r = 0.909), available potassium (r = 0.878), and total organic matter (r = 0.757). However, under psychrophilic conditions, these nutrient-driven relationships were no longer observed, yielding non-significant interactions inside the cave. These findings demonstrate that subterranean microclimatic stability, rather than localized nutrient abundance, determines the ecological and distribution dynamics of ice cave mycobiota. In addition, cave sediments and soils can harbor opportunistic and toxigenic pathogens, including genera typically associated with azole resistance.