Toxicity of copper (Cu) on the growth and chlorophyll-a contents of marine microalgae Isochrysis sp.

The sensitivity of marine microalgae to metal contamination has been used for years and provide important information for predicting the impact of marine pollution. Toxicity testing was carried out in a laboratory to investigate copper toxicity on the growth and chlorophyll-a content of Isochrysis sp. Isochrysis sp. cultures were exposed for 96-h to copper ranging from 15 to 134 µgL−1. The results showed that copper significantly decreased the growth of Isochrysis sp. with IC50 value (the concentration caused 50% growth reduction) of 52.16 µg L−1. The cells number decreased drastically and increasing growth inhibition was observed by 65.24 % at 76 µg L−1 to 97.147 % at 134 µg L−1. A similar result was also observed for the chlorophyll-a content, which was decreased drastically after 96-h at the concentration of Cu above 76 µg L−1. Our results indicate that Isochrysis sp. is sensitive to copper and can be used as a good bio-indicator for metal contamination in the marine environment.