Seasonal dynamics of amino acids in two small Siberian reservoirs dominated by prokaryotic and eukaryotic phytoplankton

The comparison of the dynamics of phytoplankton biomass and total amino acid composition was made for two water bodies: in one the phytoplankton were dominated by prokaryotes (i.e., there was a bloom of cyanobacteria) and by eukaryotic microalgae in the other. The dynamics of phytoplankton biomass and of total amino acid composition of water were investigated during the vegetation season. It was found that the only factor that significantly changed the percentages of amino acids in water was the bloom of cyanobacteria in the blooming water body. During the bloom of cyanobacteria, the absolute and relative content of the Leu-Glu group increased, while the contents of other acids generally dropped. Before and after the bloom, no significant variations in the total amino acid composition were recorded. In the reservoir where eukaryotic microalgae dominated, no significant variations in amino acid composition were recorded during the season.