STRUCTURAL AND FUNCTIONAL CHARACTERISTICS OF PHYTOPLANKTON OF LOWER DNIPRO WATERFLOWS

Abstract

The study of waterflows in the lower currents of the Dnipro in 2016–2020 showed that groups of plankton algae are quite rich in species composition and characterized by polydominant structure, and Chlorophyta, Bacillariophyta and Cyanophyta (in the amount of 82%) are the main structure-forming divisions.

145–261 WWs from 9 divisions were found in rivers and tributaries. The floristic spectrum of planktonic algae there is similar and formed mainly by green (32%), diatoms (30%) and blue-green (20%) algae; The river Viryovchyna is an exception, in which the third place in terms of the number of WWs is occupied by the Euglenophyta division (14%), and the indicators of phytoplankton development are 2.3 and 5.7 times higher than the following indicators in the rest of the studied water bodies: 2.7 million. cells / dm³ and 0.967 g / m³ against 6.2 million cells / dm³ and 5.537 g / m³ due to the inflow of allochthonous organic matter with wastewater from urban treatment facilities. The dominant phytoplankton complex of waterflows is formed mainly by diatoms.

The primary production of algae, during the research period, averaged 3.55 g O₂ / m³ × day and in different waterflows was 1.6–2.0 times higher than the destruction. Destructive processes, similarly to the productive ones, took place most intensively in the river Viryovchyna, where in all seasons the p / p was not less than 6.19 g O₂ / m³ × day. Gross p / p in the lower Dnipro waterflows averaged 3.55 g O₂ / m³ × day during the study period and was 1.6–2.0 times higher than destruction.

The destruction of organic matter (OM) in the studied water bodies averaged 2.06 g O₂ / m³ × day, net production - 1.49 g O₂ / m³ × day, which indicates the accumulation of organic matter in the studied waterflows of the lower Dnipro during 2016-2020. In the river Viryovchyna, during all the seasons, the gross p / p was not less than 6.19 g O₂ / m³ × day.