The importance of ciliates for interstitial solute transport in benthic communities

By 3 different approaches we demonstrate the ability of filter feeding ciliates (Euplotes spp. and Uronema mannum) to enhance interstitial solute transports. By a simple diffusion analogy we quantify the effect as a function of cell densities. Ciliate densities often encountered in biofilnis, microbial mats or estuanne sediments may enhance the transport coefficients of biogeochemical important solutes like, for instance, O2 by a factor of 1.1 to 10 above the diffusive coefficient. In less productive environn~ents (coastal or shelf sediments) ciliate densities are usuaiiy too low to cause any significant effect on the diffusive mediated solute transport, at least in the case of small fast-diffusing molecules such as 02.