FIGURE 4.

Proportions of CL500-11 in percentage of total prokaryotes (FISH-positive vs. DAPI-stained cells) (left; %) and their absolute abundances (right; 10⁵ cells mL^-1) generated by multiplying relative proportions with total prokaryotic abundances (Figure 2). The vertical axes indicate water depth. For Lake Zurich and Maggiore, spatio-temporal measurements are shown by contours. Dots indicate sampling depths and dates, shaded areas missing measurements. In Lake Maggiore, since total prokaryotic abundances were determined in the integrated epilimnetic (0–20 m) and hypolimnetic (20–350 m) samples (Figure 2), the averaged percentage for each layer was used to generate average CL500-11 abundances for epi- and hypolimnion.