Protozoa (Unicellular Zooplankton): Ciliates and Flagellates

Heterotrophic and mixotrophic protozoa have been recognized as important constituents of aquatic microbial food webs since the 1990s. Much less is known about the ecosystem roles of these organisms than about bacteria and archaea. Several pioneering studies in Lake Kinneret made in the 1980s clearly indicated that heterotrophic and mixotrophic ciliates and flagellates were of great significance in the mineralization of organic matter and cycling of carbon, nitrogen, and phosphorus. Modeling studies suggested that the protozoa, especially ciliates, appeared to be a critical food source for copepods. However, only after many years there was renewed research on protozoa as drivers of carbon flux and nutrient cycling. Routine monitoring of the lake ciliate populations was begun in 2006.