TAXONOMIC ANALYSIS OF THE ALGOFLORA OF THE AKDARYA RESERVOIR IN THE MIDDLE REACHES OF THE ZARAFSHAN RIVER
Authors: Alimjanova Kholiskhon A. , Rajabova Mamura S. 
Published: July 2023

As a result of flora-systematic studies of the Akdarya reservoir, 71 species and varieties (63 species, 16 variations, 1 form) were identified, which belong to 4 departments, 10 orders, 14 families, 24 genera. The species composition is dominated by diatoms (Bacillariophyta), consisting of 56 species of varieties, followed by detached green (Cyanophyta) - 9 (8 species, 1 form), yellowish (Xanthophyta) - 4, green (Chlorophyta) - 2 species of algae. Hormogoniophyceae, Pennatae and Heterotrycho phyceae are the most diverse classes, representing 65 species and varieties (91.54%), consisting of 6 families, generalized by 62 different species (87.95%), and 7 genera, generalized by 53 (74, 64%) species and varieties. The flora-systematic analysis shows that the species composition of the Akdarya Reservoir’s algophore has a peculiar feature, where the data obtained in the Far East can be used in the study of the ecosystem of the Akdarya Reservoir, as biodiversity of primary producers.
Background. The reservoir plays a major role in the formation of ecosystems of certain geographical areas. The comprehensive study of biodiversity in a reservoir makes it possible to study and monitor environmental and biological changes in environmental factors. For this purpose, a preliminary inventory of the state of the aquatic environment and its organisms is carried out. In this regard, the objective of our research is the taxonomic analysis of the Akdarya Reservoir’s algophore.
Materials and Methods. In 2014-2022 from Akdarya reservoir-More than 150 alhologic samples have been collected and processed according to the generally accepted methods of alhology and hydrobiology [5, 6]. In the laboratory, preparations were prepared from algological samples, species compositions of algae were identified by determinants and frequency of occurrence in one lens field of view was determined. The experiments were carried out using a Carl Zeiss type light microscope, eyepiece +7 micrometer, and dyes. Species composition of algae, systematics and their taxonomy have been identified with the help of the determinant [4-11, 16] and the monograph [12, 17, 18]. The chemical composition of water is analyzed by the data of UzGMNII (Uzbek Hydrometeorological Research Institute).
Results. Based on taxonomic analysis, 71 species and varieties of algae (63 species, 16 variations and 2 shapes) were identified in alhologic samples from the Akdarya reservoir. They belong to 4 divisions (Cyanophyta, Bacillariophyta, Xanthophyta, Chlorophyta), 8 classes, 10 orders, 14 families and 23 genera, which are given in table 1.2.
Conclusion. The Akdarya reservoir in the middle of the Zarafshan River has a large amount of suspended substances and relatively high mineralization. This factor favourably influences the development, formation and intensive distribution of the algae division of Bacillariophyta (56), Cyanophyta (9), Xantophyta (4), Chlorophyta (2) in the ecosystem of the Akdarya reservoir. The obtained data can be used in the distant biodiversity of the primary producer of the ecosystem of the reservoir.