Structural and Quantitative Features of Phytoperiphyton Communities in Watercourses of the Zeya River Basin, Amur Oblast

The results of a study of periphyton algae in the Zeya River and nine watercourses of its drainage basin (Amur Oblast) are presented. The composition of dominant species is determined, the structural features of algal communities are considered, and quantitative characteristics of some of their components are obtained. The total abundance of phytoperiphyton in the Zeya River is 583 billion cells/m(2); biomass is 102-1106 g/m(2). In medium-sized watercourses, the total abundance of algae ranges from 16.2 to 100 billion cells/m(2); biomass is from 2.0 to 18.3 g/m(2). Most of the biomass is formed by diatoms (Encyonema silesiacum, Hannaea arcus, Ulnaria ulna, Gomphoneis olivaceum, and large-celled species of the genus Gomphonema); most of the abundance is formed by cyanobacteria and diatoms from the genera Achnanthes, Fragilaria, Gomphonema, and the species Encyonema minutum.