Cryptic fungal diversity revealed by DNA metabarcoding in historic wooden structures at Whalers Bay, Deception Island, maritime Antarctic.

We provide the first assessment of fungal diversity associated with historic wooden structures at Whalers Bay (Heritage Monument 71), Deception Island, maritime Antarctic, using DNA metabarcoding. We detected a total of 177 fungal amplicon sequence variants (ASVs) dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota, Chytridiomycota, Monoblepharomycota, Rozellomycota, and Zoopagomycota. The assemblages were dominated by Helotiales sp. 1 and Herpotrichiellaceae sp. 1. Functional assignments indicated that the taxa detected were dominated by saprotrophic, plant and animal pathogenic, and symbiotic taxa. Metabarcoding revealed the presence of a rich and complex fungal community, which may be due to the wooden structures acting as baits attracting taxa to niches sheltered against extreme conditions, generating a hotspot for fungi in Antarctica. The sequences assigned included both cosmopolitan and endemic taxa, as well as potentially unreported diversity. The detection of DNA assigned to taxa of human and animal opportunistic pathogens raises a potential concern as Whalers Bay is one of the most popular visitor sites in Antarctica. The use of metabarcoding to detect DNA present in environmental samples does not confirm the presence of viable or metabolically active fungi and further studies using different culturing conditions and media, different growth temperatures and incubation periods, in combination with further molecular approaches such as shotgun sequencing are now required to clarify the functional ecology of these fungi.