Characteristics of phytoplankton functioning in urban water reservoires (based on the example of Basivkut Reservoir, Ukraine)

Abstract

The study states fundamental patterns of development for species and taxonomic composition, structure and seasonal population dynamics, biomass and informational diversity of phytoplankton in Basivkut Reservoir. During the research (June–October, 2022) it has been identified 121 algae species represented with 125 intraspecific taxa that belong to 84 genera, 43 families, 29 orders, 12 classes and 8 divisions. Floristic aspect of plankton algae is presented with Chlorophyta (40.1% of the total species number), Bacillariophyta (26.4%), Euglenozoa (13.2%) and Cyanobacteria (12.4%). The population of phytoplankton in Basivkut water storage was ranging from 4654 thous. cells/dm3 to 14212 thous. cells/dm3 (August), and the population of biomass was changing from 0.8732 mg/dm3 (July) to 9.4828 mg/dm3 (October). Shannon index has changed within 0.62–5.07 bit/mg according to biomass, 2.13–4.50 bit/sp. according to the population. The average values of the saprobic index have ranged from 1.74 to 2.14 that correspond to the third class of water quality (poorly polluted). The author highlights the increasing of Cyanobacteria development whose population and biomass reached 86.1% and 33.2% that caused intensive algal blooms in all summer months and is the impact of algal groups on the anthropogenic factors effect and climate changes. Aphanizomenon flos-aquae (10.5–32.2% and 10.6–12.4%) and Cuspidothrix issatschenkoi (11.6–31.2% and 10.2–14.5%) have dominated according to their population and biomass. Bacillariophyta impacted on population (39.5–74.0%) and biomass (88.7–98.4%) in autumn. Small cell type Stephanodiscus hantzschii has been characterized with significant population (16.9–65.4%) and biomass (51.1–92.9%) that focuses on increasing degree of trophic level in the Basivkut water storage.