Abstract
Volcanic activity has a great impact on terrestrial ecosystems, including soil algae in general and diatoms in particular. To understand the influence of volcanoes on the biodiversity of diatoms, it is necessary to explore the flora of these microorganisms in regions with high volcanic activity, which includes the Kamchatka peninsula. During the study on diatoms in the soils of Mutnovsky and Gorely volcanoes of Kamchatka, 38 taxa were found. The Mutnovsky volcano diatom flora was more diverse and accounted for 35 taxa. Eunotia curtagrunowii, Humidophila contenta, and Pinnularia borealis were the dominant species. In the Gorely volcano, only 9 species were identified, with Caloneis bacillum and Pinnularia borealis prevailing in the samples. Overall, the genera Pinnularia and Eunotia were the most diverse in the studied area. The diatom flora of the studied volcanoes comprises mostly cosmopolitan small-sized taxa with a wide range of ecological plasticity. Our data confirm the high adaptive potential of diatom algae and add new knowledge about the ecology and biogeography of this group of microorganisms.