Cold-based glaciers and underlying permafrost: A possible new habitat for fungi

Recent studies have increasingly focused on cold-adapted microbial communities in polar and sub-polar habitats, including the effects of global warming. Among them, much research has concentrated on bacterial communities, while fungi, which are essential for carbon and nitrogen cycling, remain sometimes little considered. This study investigates how the structure of fungal communities (including yeast and filamentous life forms) in an Antarctic coastal cold-based glacier and in the underlying permafrost (which is an understudied habitat exhibiting challenging conditions for fungal life) is driven by both the key abiotic drivers and by the putative presence of ecological cooperation among dominant taxa. Results revealed a total of 337 fungal OTUs across the different layers (ice, brine, and permafrost): overall, yeasts dominated over filamentous life forms. Meyerozyma and Taphrina were found as the dominant genera in the deepest layers, suggesting the existence of a potential ecological cooperation finalized in a mutual support for survival in such extreme conditions. Beta-diversity analysis showed significant (P < 0.05) differences between fungal communities in glacier ice and permafrost, with brine as a transitional layer. Some abiotic parameters (i.e., Ca2+, Cl−, EC, K+, Mg2+, Na+, NO3−, SO42−, and total nitrogen) were the key factors affecting the structure of fungal communities in the permafrost samples. This research offers new insights into fungal biodiversity between Antarctic cold-based glaciers and underlying permafrost, suggesting ecological equilibria affected by abiotic parameters. The dominance of Meyerozyma and Taphrina OTUs provides evidence of relict fungal taxa capable of long-term survival under extreme conditions over time.