Aquatic Microfungi of the Greenland Sea in the Vicinity of Barentsburg Settlement (Svalbard)

Polar ecosystems are extremely sensitive to anthropogenic impact, which is particularly evident near Arctic settlements with high economic activity. Samples for analysis were collected in 2018–2019 in Grønfjorden (Greenland Sea, Svalbard Archipelago). A comparative study of the diversity of secondary aquatic microscopic fungi included samples from (a) the central part of the fjord, (b) the pollution-free coastal zone, and (c) the coastal zone near the Barentsburg settlement. The study revealed 42 species of microscopic fungi, mainly belonging to the phylum Ascomycota. The diversity and occurrence of representatives of the phyla Basidiomycota and Mucoromycota were comparatively low. The abundance and species composition of microscopic fungi depended on the presence of anthropogenic discharges, seasonality (snowmelt), and tidal dynamics. Species of the genera Cadophora, Pseudogymnoascus, and Cladosporium were reported in the largest number of examined samples. All isolated secondary aquatic fungi can be provisionally divided into the following groups: (1) typical marine species, such as Metschnikowia bicuspidata, a known parasite of aquatic animals; (2) secondary aquatic species representing the largest group of microscopic fungi, formed mainly by typical inhabitants of Arctic soils; and (3) fungi whose entry into the aquatic environment is associated with human activity (mainly Aspergillus species). The anthropogenic impact is shown to cause changes in the species composition and abundance of fungi in the aquatic environment, as well as the appearance of facultative pathogenic species, which are not typical for Arctic ecosystems.