Assessing the environmental status of the Zeya River by the state of aquatic communities at the construction site of the Amur Gas Chemical Complex

Environmental engineering survey performed at the construction site of the Amur Gas Chemical Complex in 2018 in order to assess the state of aquatic communities of the Zeya River revealed 37 taxa of planktonic algae (below genus rank), 32 species of zooplankton, and 37 species of benthic organisms. In May, phytoplankton was mainly represented by diatoms; in July, it was more diverse, when green algae, golden algae and cyanobacteria all played a significant role. In May, zooplankton included mainly rotifers; in July, crustaceans dominated by biomass at most stations. Zoobenthos was represented in May mainly by oligochaetes and bivalves, while insects dominated in July. The abundance and biomass of phytoplankton, zooplankton, and benthos were low. The Goodnight–Whitley, Parele, Woodiwiss, and Mayer indices testified to relatively favorable environmental conditions in the studied sections of the Zeya River. According to the indicators of phyto- and zooplankton, and zoobenthos, the waters of the river are classified as oligosaprobic