Opportunistic fungi in urban soil and bottom sediments of largest polar city (Murmansk)

The relevance of studying Arctic regions is growing rapidly due to the sensitive response of fragile ecosystems under climate change and increasing anthropogenic pressures. Under the urbanization impact, there is a significant transformation of abiotic and biotic properties of ecosystems, which affects the ecosystem services provided and can lead to disservices such as the emergence and accumulation of microbial species hazardous to health, including microfungi. Pathogenic and opportunistic fungal species are becoming increasingly important with the growing recognition of chronic diseases and the number of patients with severe immunodeficiencies. However, studies of opportunistic microfungi in Arctic cities are sporadic. In this case, the opportunistic microfungi of Murmansk, the largest Arctic city in the world, was studied in comparison with a background area of natural forest tundra. Mycological analysis was carried out for different components of urban ecosystems: soil cover, atmospheric air, water and lake bottom sediments.In urban soil and bottom sediments of urban lakes there was an increase in the diversity and number of opportunistic species of microfungi from 30% in background soil/lake to 50-60% in urban soil and 50-100% in bottom sediments of urban lakes. In the air and water, the content of species harmful to human health did not differ from the background level. This emphasizes the high indicative value of buffer components of ecosystems - soil and bottom sediments, as compared to transit components - air and water, in determining the level of long-term anthropogenic load on ecosystems. The most dangerous identified species were fungi Paecilomyces variotii, Aspergillus flavus and Aspergillus fumigatus, capable of causing pulmonary infections, otitis, sinusitis, endocarditis, osteomyelitis, keratitis, traumatic mycoses, peritonitis, onychomycosis. The fact of Paecilomyces variotii dominance in water and bottom sediments of lakes used for recreational purposes is alarming.