Cell Number Dynamics, Chlorophyll <i>а</i> Fluorescence Intensity, and Photosynthetic Pigment Content in <i>Thalassiosira nordenskioeldii</i> Cleve 1873 (Bacillariophyta) Exposed to Environmental Copper Pollution

The effect of copper at concentrations of 10, 20, and 50 µg/L on population growth, chlorophyll a fluorescence, and content of photosynthetic pigments (chlorophyll a and carotenoids) of the diatom Thalassiosira nordenskioeldii was studied. It was shown that at metal concentrations of 10 and 20 µg/L, the cell number started to increase from the first days of the experiment and, by the end of the experiment, exceeded that in the control group 5.8- and 5.6-fold, respectively. The intensity of chlorophyll a fluorescence and the content of photosynthetic pigments under these conditions were higher than in control throughout the experiment. At a metal concentration of 50 µg/L, the growth of the cell population was inhibited at the beginning of the experiment; by the end of the experiment, the cell number exceeded that in control. The same pattern was recorded for the other parameter, too. Based on the obtained data, it is hypothesized that copper at the studied concentrations may contribute to the proliferation of T. nordenskioeldii in the natural environment.3