Didinium nasutum
[ref. ID; 1072]
Test system
Effect of copper the interaction between Didinium (predator) - Paramecium (prey)
Strains
Escherichia coli, Paramecium caudatum (Ward's Biological Company) and Didinium nasutum (Ward's Biological Company).
Toxicants/concentrations
CuSO4/5H2O, Cu concentrations 0, 150, 300, 600, 900, 1200 and 1500 ug/L.
Test design
pH 6.8-7.0. 24-hr dark photoperiod at 25+/-0.2 degrees C. Paramecium or Didinium were added to a 50-mL glass beaker containing Cerophyl medium.
- Intrinsic rates of natural increase:
- Isocline analysis: Determination of the equilibrium point of the predatory-prey interaction under control (0 ug/L Cu).
- Acute lethality tests:
Measurements/observations
At 4 intervals, over a 24-hr period, a 2.0-mL was taken from each beaker and all animals were counted.