On the Occasion of the "International Conference on the Molecular Biology and Biotechnology of Ciliates and Anaerobic Protozoa in connection with the 22nd Annual meeting of the German Society for Protozoology" (March 4-8, 2003, Nijmegen, The Netherlands)

Weisse, Thomas

154-163

This article discusses the current uncertainty in the assessment of the biodiversity of aquatic protists. By comparison with prokaryotes (bacteria) and asexually reproducing metazoans such as Daphnia (water fleas) it is illustrated that morphological and some genetic species demarcations may be too conservative to identify functionally different ecotypes. Intraspecific variation is extensive and has been demonstrated by ecophysiological experiments, in particular, for ciliates. The significance of the clonal differences for the biodiversity of aquatic protists needs to be addressed in a conceptual framework.