The paper presents data on the diversity of algal flora of thermokarst lakes located in the Tatta River basin (Lena-Aldan interfluve) in Central Yakutia. A total of 384 species (401 intraspecies taxa) were identified. They belong to nine divisions: Bacillariophyta – 100 (105), Chlorophyta – 90 (96), and Cyanobacteria – 86 (89) lead in species diversity. Heterokontophyta – 47 (55) and Charophyta (40) were less diverse, followed by Euglenozoa (10) and Myzozoa (7). Cryptophyta and Raphidophyta were represented by two species each. Bacillariophyta dominated in species diversity, while cyanobacteria had the highest quantitative indicators. Its representatives, Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault and Microcystis aeruginosa (Kützing) Kützing, caused water bloom in the studied lakes. It was found that with an increase in the algal number and biomass, indicators of biological pollution of water increase, and its quality deteriorates. In all studied lakes we recorded species-indicators of water saprobity related to β-α-mesosaprobes; the saprobity index ranged from 1.6–2.8. Based on biological analysis, taking into account the chemical parameters, the water of the lakes can be considered eutrophic and moderately polluted. Among taxa identified in thermokarst lakes of the Tatta River basin, four species and two infraspecies taxa are first cited for the algal flora of Yakutia. They include representatives of Cyanobacteria (Anabaena jonssonnii B.-Peters, Gomphosphaeria cordiformis (Wille) Hansgirg), Raphidophyta (Gonyostomum intermedia Skuja), Bacillariophyta (Surirella elegans f. constricta A. Mayer, Stauroneis phoenicenteron var. brevis (Dipp.) Hustedt), and Charophyta (Elakatothrix lacustris Korschik.).
Full text: PDF (Rus) 723K