Protozoans and Biofilms

The role of protozoans in both pelagic and benthic aquatic food webs has received increasing attention by scientists within the last two decades (e.g. Azam et al. 1983, Alongi 1991, Sherr and Sherr 2000). Protozoans are part of a complex food web, in which they conduct several important functions, such as the control of the bacteria (e.g. Berninger et al. 1991, Arndt et al. 2000) and the enhancement of remineralisation processes (Sherr and Sherr 1984). As main bacterial consumers, protozoans can have a high impact on both the taxonomic and morphologic composition of bacterial communities (e.g. Jurgens and Gude 1994, Jurgens et al. 1997). One defence strategy against protozoan predation is the formation of bacterial colonies and filaments (e.g. Jurgens and Gude 1994, Hahn et al. 2001) possibly also forcing the formation of biofilms.