REARING EXPERIMENTS ON 2 MARINE FLAGELLATES (DINOPHYTA) AND THEIR APPLICATION TO A TOXICOLOGICAL WASTE WATER TEST

During rearing experiments with Prorocentrum micans and Ceratium furca (Dinophyta) under different conditions of temperature, light and nutrients, the role of industrial waste water of a titaniumdioxide factory has been examined. The waste water contains primarily H2SO4 and FeSO4 (for details consult Table 1); it is scheduled for discharge in early 1969 in quantities of some 1,200 tons per day into a North Sea area about 12 nautical miles north-west of Helgoland. The organisms were cultivated in bottles containing limited volumes of test liquid, and in chemostats, over periods of a few weeks. Growth rates of populations exposed to different waste water concentrations served as criterion of possible toxic effects of the industrial waste water. The experiments revealed distinct sublethal effects in dilutions (parts waste water : parts seawater of 32‰ S) down to 1 : 50,000 (Ceratium furca), and 1 : 32,000 (Prorocentrum micans). At 1 : 5,000 only a portion of the population (Prorocentrum micans) survives; the remaining cells stagnate reproduction at a given constant cell density. The specific toxic effects of the different components of the waste water are discussed. Further experiments are necessary to increase our knowledge on the biological consequences of the discharge of waste water into the North Sea, and to develop methods for the assessment of the effects of unknown toxic agents by means of culture experiments. © 1969 Biologischen Anstalt Helgoland.