Characteristics of Lake Baikal summer phytoplankton and autotrophic picoplankton

This work deals with peculiarities of species diversity, number and biomass of phytoplankton and autotrophic picoplankton (APP) in different areas of Lake Baikal in summer 2005. It was revealed that complexes of phytoplankton dominant species are the same in all three depressions of lake except bays, shoals, and littoral areas where an increase of species composition of phytoplankton and higher values of number and biomass were recorded. The level of development of phytoplankton and picoplankton in the pelagic zone is medium-productive. The APP contribution into the total biomass of the water area varies from 3 to 71%; the chlorophyll α concentration is between 57% and 89%. A decrease of picophytoplankton contribution to the total biomass was observed both in the bays and littoral areas. The APP role in pelagial of the lake is high; it makes up 38−62% of biomass in the 0−50 m layer.