Diversity, distribution and ecology of fungal communities present in Antarctic lake sediments uncovered by DNA metabarcoding

Abstract

We assessed fungal diversity in sediments obtained from four lakes in the South Shetland Islands and James Ross Island, Antarctica, using DNA metabarcoding. We detected 218 amplicon sequence variants (ASVs) dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota and Chytridiomycota. In addition, the rare phyla Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Monoblepharomycota, Rozellomycota and Zoopagomycota as well as fungal-like Straminopila belonging to the phyla Bacillariophyta and Oomycota were detected. The fungal assemblages were dominated by unknown fungal taxa (Fungal sp. 1 and Fungal sp. 2), followed by Talaromyces rubicundus and Dactylonectria anthuriicola. In general, they displayed high diversity, richness and moderate dominance. Sequences representing saprophytic, pathogenic and symbiotic fungi were detected, including the phytopathogenic fungus D. anthuriicola that was abundant, in the relatively young Soto Lake on Deception Island. The lake sediments studied contained the DNA of rich, diverse and complex fungal communities, including both fungi commonly reported in Antarctica and other taxa considered to be rare. However, as the study was based on the use of environmental DNA, which does not unequivocally confirm the presence of active or viable organisms, further studies using other approaches such as shotgun sequencing are required to elucidate the ecology of fungi in these Antarctic lake sediments.

Fungal and fungal-like diversity in marine sediments from the maritime Antarctic assessed using DNA metabarcoding

“…In addition, recognized plant and animal pathogens were detected with different abundances, including Aspergillus , Candida , Cryptococcus , Cutaneotrichosporon , Fusarium , Malassezia and Rhodotorula . The same functional ecological profile detected for fungi present in marine sediments here have also been reported in studies sampling fungi in soil 12 , air 31 , lake sediment 43 and rocks 49 in Antarctica. However, we recognize that, as this study detected environmental DNA, further functional ecological studies are required to better understand the role and importance of fungi in these Antarctic marine sediments.…”

“…Ciliophora is a genus of Ascomycota reported to be saprophytic and recovered from tropical environments of Central America 42 , with currently only two known species, C. cryptica and C. quercus ( www.mycobank.org ). In Antarctica, sequences assigned to Ciliophora have been detected with low and medium relative abundance in DNA metabarcoding studies of lake sediments 43 , 44 and soils 45 from James Ross Island, and in wood samples from historic anthropogenic structures on Deception Island 46 . The fungal-like Straminopila genus Chaetoceros was described by C. Ehrenberg in 1844 based on Antarctic material containing the type species C. dichaeta , and also occurs in other oceans including in the Arctic 47 .…”

Endolithic Fungal Diversity in Antarctic Oligocene Rock Samples Explored Using DNA Metabarcoding

“…The ecological functional group assignments in the current study are similar to our recent metabarcoding studies of fungal communities in various Antarctic habitats [26,28,29,72,74,86,87]. Our ASV assignments suggest the presence of a diverse fungal community associated with the Oligocene rock samples analysed.…”

Fine-scale phylogenetic diversity gradients support the Antarctic geothermal refugia hypothesis

“…Deception Island also experiences high levels of tourism (Dibbern 2010) and is the subject of considerable anthropogenic pressure (Carvalho-Silva et al 2021). Studies have been examining biodiversity across the island using metabarcoding approaches (Rosa et al 2020, Carvalho-Silva et al 2021, de Souza et al 2022 but have not tested the influence of thermal gradients around fumaroles. We explore the role of soil temperature in structuring eukaryotic communities on Deception Island to test the geothermal refugia hypothesis using DNA metabarcoding of eukaryotes on small spatial scales (metres).…”