Effect of copper on growth and enzyme activities of marine diatom, Odontella mobiliensis.

The 72-h IC(50), 7-d no observable effect concentration (NOEC), low observable effect concentration (LOEC), Chronic values were derived for copper on the growth of marine diatom, Odontella mobiliensis. The effect of copper was also studied on cell morphology, size, nitrate reductase and antioxidant enzymes (Catalase, Superoxide dismutase and peroxidase). The 72-h IC(50) of 298.4 ± 28.3, NOEC of 15.6, LOEC of 29.6 and chronic value of 21.5 μg Cu L(-1) were found in the present study. The chlorophyll a was significantly decreased with increasing concentrations of copper. The length of the cell (apical axis) was extended from 30.14 ± 5.98 μm at control to 71.4 ± 6.29 μm at 574 μg Cu L(-1), the spines were absent at 574 μg L(-1) and the cell structure was entirely damaged at 926 μg Cu L(-1). The antioxidant enzymes viz. Catalase, Peroxidase activities and Melondialdehyde were increased whereas the Nitrate reductase and activity was reduced at 21.5 μg Cu L(-1) during 7 days exposure.