The Unusual Dominance of the Yeast Genus Glaciozyma in the Deeper Layer in an Antarctic Permafrost Core (Adelie Cove, Northern Victoria Land) Is Driven by Elemental Composition

Rock glaciers are relatively common in Antarctic permafrost areas and could be considered postglacial cryogenic landforms. Although the extensive presence of rock glaciers, their chemical-physical and biotic composition remain scarce. Chemical-physical parameters and fungal community (by sequencing the ITS2 rDNA, Illumina MiSeq) parameters of a permafrost core were studied. The permafrost core, reaching a depth of 6.10 m, was divided into five units based on ice content. The five units (U1-U5) of the permafrost core exhibited several significant (p < 0.05) differences in terms of chemical and physical characteristics, and significant (p < 0.05) higher values of Ca, K, Li, Mg, Mn, S, and Sr were found in U5. Yeasts dominated on filamentous fungi in all the units of the permafrost core; additionally, Ascomycota was the prevalent phylum among filamentous forms, while Basidiomycota was the dominant phylum among yeasts. Surprisingly, in U5 the amplicon sequence variants (ASVs) assigned to the yeast genus Glaciozyma represented about two-thirds of the total reads. This result may be considered extremely rare in Antarctic yeast diversity, especially in permafrost habitats. Based on of the chemical-physical composition of the units, the dominance of Glaciozyma in the deepest unit was correlated with the elemental composition of the core.

Automated summary

Rock glaciers in Antarctic permafrost areas are postglacial cryogenic landforms, but their chemical-physical and biotic composition is understudied. In this study, a permafrost core was analyzed for chemical-physical parameters and fungal community. The core showed significant differences in chemical and physical characteristics among its five units, with higher values of certain elements found in the deepest unit. Yeasts dominated over filamentous fungi, and Glaciozyma was the predominant yeast genus, especially in the deepest unit. This dominance was correlated with the elemental composition of the core.