Abstract: | The effects of cadmium on a marine protozoan community were studied. After 96 h (0.5 mg/L cadmium) there was a reduction of biomass and a dissappearance of bacterivorous ciliates that were replaced by small flagellates. Other cadmium concentrations utilised affected abundance and biomass after 48 hours. A change of the community structure by the loss of Cd-sensible species and the appearance of Cd-resistant species occurred. The structure of community was simplified and the diversity and variety values decreased. The bacterivore-detritivore and photoautotroph groups, that were the main components in the control, were notably reduced in the presence of cadmium. The metal concentrations on the protozoan biomass increased during the experiment, indicating a certain bioassimilative role of these organisms. |