Pigment composition of phytoplankton and its long-term dynamics in reservoirs of the Upper Volga

Abstract

According to field observations during 1995–2005 and 2012–2016, the pigment composition of phytoplankton in the Upper Volga reservoirs is given. With an average Chl a content of 13,1±1,4 to 52,5±2,7 μg/L in the Ivankovo reservoir and from 4,1±0,9 to 27,5±2,5 μg/L in the Uglich reservoir, an increase in Chl a was noted after an abnormally hot 2010. The content of Chl a in the Ivankovo reservoir retaining eutrophic status does not go beyond the limits of long-term fluctuations. In the Uglich reservoir, an increase in the absolute and relative amount of Chl a was revealed, indicating the transition of the reservoir to the eutrophic category.