Laboratory stimulation of oil-spill effects on marine phytoplankton

Continuous culture conditions designed to achieve a dynamic equilibrium between phytoplankton growth and nutrient input were established for Phaeodactylum tricornutum, Isochrysis galbana and Chlorella salina. The technique was used to determine the no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) for algae after spiking with diesel oil. P. tricornutum (NOEC = 0.25 mg/l, LOEC = 0.3 mg/l) was more sensitive than I. galbana (NOEC = 2.5 mg/l, LOEC = 2.6 mg/l), while C. salina (NOEC = 16.0 mg/l, LOEC = 17.0 mg/l) was the most tolerant. Continuous renewal of medium ensured that experimental conditions remained stable throughout the test period and is a more environmentally relevant method for assessing the effects of many contaminants.