Bottom diatom taxocenes of the sublittoral zone of Lake Issyk-Kul

In July 2018, the bottom sublittoral taxocens of diatoms of Issyk-Kul Lake (Kyrgyzstan) were studied: composition, structure, diversity, equiability and vertical distribution of these characteristics in depth. It was considered not only the ratio between the abundance of species, but also the size-ecological groups of diatoms in the structure and composition of communities. At 9 stations in the western, northern, and northeastern parts of the lake, at depths of 8.4–558 m, a total of 155 taxa of diatoms were found, adapted to dwelling on the bottom (48–89 taxa per station, an average of 66.56). With increasing of the depth, a general decline in species wealth was noted. At a depth of 558 m, the number of species was 49 (48 per 145.5 m). The average qualitative similarity of communities made 60,11%, while the set of species from site to site did not varied extremely. The structural diversity of taxocenes was everywhere high (H` = 3.052–3.782, on average 3.473), and the role of dominants was rather weak (PIE = 0.898–0.966, on average 0.938). Amphora species dominated at almost all stations (at a depth of 8.4 m — Achnanthidium affine).