Pozdnyakov D.V., Filatov N.N.
Reported and analyzed the results of satellite observations of Lake Ladoga water quality parameters (WQPs) primarily in spring 2016 and 2017. Our retrievals indicate that even in March, soon after the inception of ice cover melting, the concentration of chlorophyll a (Cchl) is non-zero (but yet very low) not only in the lateral but also pelagic waters of the lake. Arguably, the non- zero chl concentrations arise from the phytoplankton that vegetated under ice and then moved up to the surface as the ice sheets began melting. Spring-time concentrations of inorganic suspended matter (Csm) are year-specific and range between 0.1 and 3.5 mg/l with the elevated values inherent in lateral waters, especially in the vicinity of river outflows. Similar spatial patterns are found for the distributions of colored dissolved organic matter concentrations (Cdom). The lowest values of Cdom (<4.5 mgC/l) occurred in the pelagic waters, whereas the highest ones (12–15 mgC/l) resided in the lateral zone, in particular, within/adjacent to the Volkhovskaya Gouba. With the beginning of summer, the above concentrations, Cchl, Csm, and Cdom, start growing, remaining however less than they are in July.
