Composition and quantitative indicators of meiobenthos in springs of Kazan and its environs

Data are presented on the hydrochemical parameters and taxonomic composition of invertebrates from nine springs located on the territory of Kazan and the Vysokogorsky district of the Republic of Tatarstan, based on studies carried out in 2018 and 2020. Representatives of 10 groups of invertebrates were found in the spring communities of meiobenthos: Nematoda (38 species and taxa of supraspecific rank), Platyhelminthes (4), Harpacticoida (4), Ostracoda (4), Cyclopoida (1), Rotifera (1), Tardigrada (1) (eumeiobenthos), and also Inseсta (4), Oligochaeta (2) and Aphanoneura (1) (pseudomeiobenthos). On sandy and silty-sandy substrates, the abundance of spring communities varies widely, from 239 to 7942 ind./dm2 in density and from 0,41 to 65,40 mg/dm2 in biomass. The leading group of meiobenthos in springs, both in terms of abundance and diversity of species, are nematodes. In rheocrene springs, chironomid larvae are also dominant in the density of organisms. A feature of the meiobenthos of geocrene springs is the absence of crustacean hydrobiont groups in its composition and the dominance of phytoparasitic and soil forms of nematodes of the order Rhabditida.