The Red Tide Organism Chaetoceros sp. Responding to Exposure to Oil and Dispersant

Laboratory experiments were conducted to study the effects of oil spills and dispersants on the growth of the red tide organism Chaetoceros sp. Crude oil produced from the Chinese Bohai Sea, diesel oil, and the chemical dispersant (GM-2) produced in China were added into Chaetoceros sp. cultures. The results showed that both crude oil and diesel oil could enhance the growth of Chaetoceros sp. Data were analyzed by one-way ANOVA, and the confidence interval was 95%. At a concentration of 20 mg L-1 crude oil and a concentration of 10 mu L L-1 diesel oil, Chaetoceros sp. bloomed to 1.57 x 10(5) cells mL(-1) (p < 0.01) at day 14 and 3.55 x 10(4) cells mL(-1) (p < 0.05) at day 10, respectively. A concentration of 10 mu L L-1 diesel oil stimulated the specific growth rate for Chaetoceros sp. of 0.49 d(-1) over 10 days. The specific growth rate of Chaetoceros sp. with 20 mg L-1 crude oil alone was 0.46 d(-1) over 14 days. However, the mixture of oil and dispersant did not enhance the growth of Chaetoceros sp. as significantly as oil alone. These results implied that oil spills in coastal waters can stimulate Chaetoceros sp., and the specific dispersant GM-2 applied following oil spills may be unlikely to further enhance the growth of Chaetoceros sp