Shelyuk Y. Phytoplankton of diverse aquatic ecosystems within Polesye region

A total of 812 algal species (877 infraspecific taxa) from 15 classes, 43 orders, 99 families and 261 genera were identified in lakes and rivers within basins of the Prypiat River and the Teteriv River – the main rivers of Polesye. All types of waterbodies were predominated by green algae, diatoms and euglena algae. The share of dominant species and species with high occurrence rate (over 50%) decreases in the following sequence: rivers → water reservoirs → lakes → quarries. This is explained by increase in the ecological conditions uniformity from lotic environment to lentic environment. The vegetation period average phytoplankton biomass and gross primary production reduced in the following direction: water reservoirs → rivers → quarries → lakes. Phytoplankton diversity and growth intensity in lakes and rivers are determined by specifics of nutrient and light conditions. Photosynthesis intensity and production-destruction ratio to a great extent depend upon the nutrient content, hydrooptic conditions, morphometric parameters of lakes and rivers. High level of algae primary production is the most important mechanism supporting phytoplankton succession in artificial water-bodies, which causes new types of aquatic ecosystems to form. It has been proven experimentally, that production processes in the aquatic ecosystems under study play the environment-forming role, altering their light and gas conditions and shifting pH towards alkaline conditions.