Spatial distribution of phytoplankton in Lake Baikal, Spring 1991

Abstract

SUMMARY Studies carried out in Lake Baikal in late spring (late May‐early June) 1991 showed marked differences in the species composition and abundance of phytoplankton in different regions of the lake. The south and north basins were characterized by small forms of algae. The middle basin, Maloe More and the shallow waters of the Selenga had species with large cells including Aulacoseira islandica subsp. helvetica, Dinobryon cylindricum and D. divergens. Areas of high biomass were correlated with shallow waters and river inputs. This was especially apparent in the region of the Selenga delta. The vertical distribution of phytoplankton indicated the non‐synchronous start of the spring homothermy throughout the lake. Phytoplankton were concentrated in the upper 100 m layer with subsurface maxima resulting from the sinking of large algae. The concentration of phytoplankton biomass in general at this time characterized the lake as moderately productive.