Expedition on board of R/V “Papanin” from June 15 till June 23, 2021
An expedition on board of R/V “Papanin” was performed from June 15 till June 23, 2021 along the eastern and western shores of central and southern basins of Lake Baikal.
The aim of the expedition was to study species composition and distribution of gastropods and bivalve mollusks, nematodes, hydras and bryozoans in Lake Baikal and adjacent water bodies. During the expeditions, the work was performed at 32 stations in open Baikal and in near-shore-sor zone at the depths of 0–45 m, 300–500 m. Benthic and meiobenthic organisms were sampled in the adjacent water bodies at the depths of 0–1.5.
An expedition on board of R/V “Papanin” was performed from June 15 till June 23, 2021 along the eastern and western shores of central and southern basins of Lake Baikal.
Among meiobenthic animals, a particular attention was paid to the group of free-living threadworms (Nematoda). All nematoda were divided under a binocular microscope in living state in the laboratory on board of the ship, and then fixed using a standard method for further preparations and studies of group taxonomic composition and abundance. Information on Nematoda fauna will be obtained first from Lakes Khankhoy, Zunduk, Zama, Kotokel’, a pond on the Krestovka River (Listvyanka). The samples collected in splash zone (above water edge) in the area of Listvyanka will give an opportunity to continue the previous studies on anthropogenic impact on the biodiversity of threadworms. Samples from Olkhon Island area (Saray beach) will allow assessing the ecological situation in this area basing on availability (or absence) of groups indicating an environmental pollution. Molecular genetic studies of some Baikal Nematoda species, such as Theristus psammophilus, Tobrilus elginus, Tobrilus undophilus will be performed for the first time.l.
Different representatives both of endemic (Baicaliidae, Benedictiidae) and Palearctic (Limnaeidae, Physidae) fauna of gastropods were sampled for studies of their species composition, trophic preferences, distribution peculiarities and molecular genetic analysis.
Bivalves were sampled at 22 stations. The preliminary analysis of morphological features allows revealing twenty-two species belonging to five genera of fingernail clams: Cyclocalix, Euglesa, Musculium, Pisidium и Sphaerium. Three latter ones are represented by single species: Musculium lacustre, Pisidium amnicum и Sphaerium corneum. Twelve species occur once; the most abundant were E. cassertana (40% of stations), E. globularis (32%) and S. corneum (27%). The subsequent genetic analysis will allow to specify the performed species identification and to obtain new data on genetic diversity of cosmopolite and Palearctic species of fingernail clams in Lake Baikal and adjacent water bodies.
Hydras were sampled in Lakes Ikhe-Nur and Kotokel, a preliminary morphological analysis allowed referring them to the species Hydra oligactis and H. circumcincta. Some hydras were fixed for future preparations and studies of the structure thread-cells, some organisms were placed in lysis solution for further DNA extraction and molecular genetics analysis.
