| Chaetoceros radicans was selected to test the effect of copper concentrations of 0.001, 0.005, 0.01, 0.05, 0.1 and 0.5 ppm for 6 days on the photosynthetic activity and chlorophyll-a content under laboratory conditions. The photosynthetic activity decreased with time of exposure and copper concentration. The control photosynthetic activity reached a maximum value at 120 hours and chlorophyll-a at 72 hours. Chaetoceros radicans cultures treated by copper showed a slight decrease in its photosynthetic activity and chlorophyll-a at levels 0.001 and 0.005 ppm, while they rapidly decreased at higher copper concentrations. |
