The relative importance of different ciliate taxa in the pelagic food web of lake constance.

Abundance, biovolume, and species composition of pelagic ciliates in Lake Constance were recorded over two annual cycles (1987/88). Production was estimated from mean annual biovolumes and size-specific growth rates obtained from the literature. Cell concentrations and biovolumes ranged from 0.1 to 120 cells ml(-1) and from 3 to 1,200 mm(3) m(-3), respectively. Mean annual values were, respectively, 6.8 cells ml(-1) and 94 mm(3) m(-3) in 1987, and 12.0 cells ml(-1) and 130 mm(3) m(-3) in 1988. In both years, prostome nanociliates (<20μm) dominated numerically, while strobiliids in the size range 20-35μm contributed most significantly to ciliate production. Ciliate community production, according to a crude calculation, yielded approximately 10-15 g C m(-2) year(-1).