Quantitative characteristics of zooplankton in the rivers of the Upper Amur Basin, exposed to the effects of placer gold mining

Abstract

Research conducted in June and September 2020 showed that the species composition of rotifers and lower crustaceans in 17 water courses of the Upper Amur Basin, exposed to the effects of placer gold mining, included 43 species. Most of the water courses were researched for the first time. Based on the environmental and geographic assessment, the prevalent species were widespread and eurytopic. Most parts of the rivers were characterised by low quantitative characteristics (0.01–3.77 × 103 ind. m-3 and 0.06–54.64 mg m-3), which was explained by the hygrological conditions and long-term effects of mining in the river beds. A better productivity (up to 39 × 103 ind. m-3 and 228 mg m-3) was registered in the areas of former excavations in the river beds, with slower water exchange and better conditions for the development of zooplankton.