Composition, biomass, and photosynthetic activity of the benthic algal communities in a littoral zone of Lake Baikal in summer

Abstract

The composition, biomass, and photosynthetic activity of benthic algal communities were investigated in a littoral zone of the south basin of Lake Baikal in July 1998. A transect survey revealed a vertical transition of the dominant taxonomic groups: Ulothrix and diatoms dominated in the shallowest station (depth, 0.5 m), whereas only diatoms were found in a station with a depth of 1 m. In deeper stations (depth, 2–3 m), an endemic filamentous green alga, Draparnaldioides baicalensis, was the predominant form, but in addition to this species, Tetraspora and diatoms were also abundant in algal communities collected in the deepest stations (depth, 5–6 m). Biomass expressed as chlorophyll a (Chl a) varied in the range of 8 mg Chl a · m−2 (at a depth of 1 m) and 300 mg Chl a · m−2 (at a depth of 3 m). The maximum photosynthetic rate (of carbon, C) of the community dominated by Ulothrix was 0.24 mg C · mg Chl a−1 · h−1, whereas the corresponding rate of the community dominated by Draparnaldioides was 1.51 mg C · mg Chl a−1 · h−1.