Zooplankton of Lake Pyasino and the rivers flowing into it after the diesel spill in 2020
O. P. Dubovskaya1,2, O. E. YOLGINA1, I. I. MOROZOVA2
1Institute of Biophysics of Federal Research Center “Krasnoyarsk Science Center of Siberian Branch of Russian Academy of Sciences”, Krasnoyarsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
Keywords: zooplankton, Lake Pyasino, species composition, abundance, biomass, production, fish productivity, oil spills, water quality
Abstract
The large Norilsk expedition of the SB RAS at the beginning of August, 2 months after the spill of 20 thousand tons of diesel fuel into the Bezymyanny stream, which took it out to the Daldykan and Ambarnaya rivers, took samples of net zooplankton at 13 stations, located in both sections of these rivers and Lake Pyasino with the outflow of the Pyasina River. Comparative analysis of the species composition, abundance, biomass and saprobity index of zooplankton at these stations has been carried out. The productions of rotifer and crustacean zooplankton and potential production of planktivorous fish in Lake Pyasino have been calculated. Based on the state of zooplankton, a gradual improvement in water quality has been observed from river areas exposed to the oil products to the northern part of the lake and the River Pyasina outflow. The low abundance and biomass of zooplankton in the lake (43800 ± 17550 ind./m3, 112.8 ± 26.2 mg/m3, on average) due to the dominance of rotifers ( Ploesoma truncatum (Levander), Bipalpus hudsoni (Imhof), Conochilus unicornis Rousselet) resulted in low values of zooplankton production and potential production of planktivorous fish (0.85 kg/ha per season).
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