Characteristics Of Diatom Plankton During The Flood Season Across The Districts Of Andijan Region

Abstract

This study aimed to investigate the composition, species diversity, quantitative parameters, and ecological characteristics of diatom plankton (phylum Bacillariophyta) during the flood period across the 14 districts of Andijan Region. Methods: During the spring seasons (March–May) of 2022–2024, plankton samples were collected from 18 sampling stations, including the Andijan Reservoir, the Kara Darya River, the Khojaobod Canal, and lakes in Jalakuduk District, using plankton nets (No. 78 silk mesh). A total of 540 samples were analyzed. Results: The study identified 147 species and infraspecific taxa belonging to the phylum Bacillariophyta, of which 38 were dominant species characteristic of the flood period. The dominant genera were Navicula (27 species), Nitzschia (24 species), Cyclotella (12 species), Fragilaria (11 species), Aulacoseira (9 species), and Gomphonema (8 species). Cell density ranged from 12,400 to 189,600 cells/L. According to the Sládeček saprobity index, water quality corresponded to the β-mesosaprobic level (S = 1.8–2.3). The results indicate that the diatom plankton community during the flood period in Andijan Region is characterized by high biological diversity, with bioindicator species reflecting organic loading caused by agricultural activities predominating.