<span>First researches of the underwater ecosystem communities of an underground channel built in 1950s (Balaklava bay, Sevastopol)</span>

Abstract

The results of the first studies of the ecosystem state of the underwater part of the channel, artificially created in the middle of the 20th century on the western shore of the Balaklava Bay (Sevastopol) as a naval base of the Black Sea Fleet for the submarines repair, are presented. Channel's ecosystem is determined by uniqueness of anthropogenic formation and considered as analogue of natural Black Sea cave. Hydrospelological survey of the channel and biological studies allowed assessing its current state, the nature of biofouling of its walls and anthropogenic and technical pollution of the bottom. Macrofauna of the channel wall biofouling is represented by the Mytilaster lineatus community, which has a high level of species abundance (about 80 species have been registered) and quantitative development. Both in taxonomic diversity and in quantitative terms, this community is comparable to the rocky substrate community near open Crimean coasts, but with a smaller share of crustacean group development. Due to weakened hydrodynamics, well developed fauna of bryozoans forming plurannual crusty structures and single sponges is observed on the channel's walls. In contrast to the channel walls biofouling, its bottom macrofauna has relatively lower quantitative and qualitative composition. Meiobenthos in the channel’s wall biofouling is represented by 18 higher taxa (type, class, order) of Protozoa and Metazoa with predominance of harpacticoids by abundance. Meiobenthos of the soft bottom of underground channel is represented by 15 higher taxa with predominance of free-living nematodes and harpacticoids by abundance. Average density of meiobenthos in the channel’s bottom sediments is comparable with similar parameters of its development in open water areas and Sevastopol bays.

First finds of sessile ciliates (Ciliophora) in artificial and natural caverns on the Crimean coast of the Black Sea

“…Moreover, most of the available biological studies on this topic are not systemic but situational. For this reason, there is very little information on the biodiversity of bottom communities of underwater in coastal caves (Vorobyova et al, 2012;Sergeeva et al, 2021).…”

“…The uniqueness of the Balaklava underground canal is determined by the fact that it is an analogue of the natural Black Sea cave, but of anthropogenic formation. A detailed description, physical, chemical and hydrodynamic characteristics of the underground canal, general description of biological diversity are given in the article (Sergeeva et al, 2021).…”