Calculations were based on factors established for 89 water samples across Lake Baikal in July 2001 (see text). The traps were deployed for about 16 months and the core top spanned c. 7 years (see text).According to the contribution to the chlorophyll a-model shown in Eq. (1), the chlorophyll a content in the water of the south basin in July 2001 was composed of 30% Bacillariophyceae plus Chrysophyceae, 44% Chlorophyta, and 26% cyanobacterial picoplankton. In the 40-m trap, in contrast, 87% of the chlorophyll a originated from Bacillariophyceae plus Chrysophyceae, 11% from Chlorophyta, and 2% from cyanobacterial picoplankton (Fig. 5). The percentage contribution did not change with the water depth, as the same composition was found in the deepest traps (Fig. 5).