Hydroids in biotest : clava multicornis exposed to cadmium

The influence of different temperatures and salinities on the toxicity of cadmium has been studied in short- and long-term experiments, using the colonial hydroid Clava multicornis as test organism. Clones were subcultured under prospective T/S-test conditions, applying 12 l recirculating seawater systems with biological water conditioning, glass plates for substratum, and Artemia nauplii for food. The inability of C. multicornis to catch and swallow prey induced by heavy metals was chosen as lethal criterion. - High temperature and low salinity within the ecological range of the species increased the acute toxicity of cadmium, while low temperature and high salinity enabled C. multicornic to resist higher metal concentrations in the water or delayed the appearance of reactions on pollution, respectively. The long-term sublethal threshold concentration of some 200 μg Cd · 1-1 was not affected by combinations of temperature from 5 to 20°C and salinity from 10 to 25‰