Investigating the diversity contained in an established moss carpet in Admiralty Bay, King George Island (maritime Antarctic), using DNA metabarcoding

Moss carpets are a common feature in the maritime Antarctic. They provide habitats for a diverse community of organisms, including microbial groups, micro-invertebrates, and micro-arthropods, all of which depend on the moss for their survival. Despite recognition of this important role, studies of the moss-associated biodiversity to date have rarely involved the application of modern molecular tools. This study focused on an extensive and long-established moss carpet primarily comprising the moss Saniona uncinata, located adjacent to a reconstructed whale skeleton on a coastal beach and of historical importance, located near the Brazilian Antarctic Station (Admiralty Bay, King George Island), and is a popular attraction for tourists and scientists alike. We employed DNA metabarcoding to investigate the biodiversity of organisms potentially associated with the moss carpet, employing three well-established genetic markers, 16S, ITS2, and COX1. The marker generating the greatest number of amplicon sequence variants (ASVs, a proxy for taxon diversity) was 16S with 199 assigned ASVs, followed by COX1 (121) and ITS2 (26). In total, 346 ASVs were assigned, representing two Domains, five Kingdoms, and 38 phyla. As well as representing a diverse range of likely native taxa, a proportion of the assignments were exotic taxa not forming part of Antarctica’s native biodiversity. These assignments, while they cannot be proven to represent the presence of living organisms or established populations, may be an important indication of otherwise invisible human influence on the Antarctic environment, such as the introduction of DNA originating in human food and associated microbes, pests, and parasites.