EN
A medium modified by 4-fold (Zn) or 2.5-fold (Mn) decreased/increased content of these metals did not influence the growth of the green microalga Desmodesmus armatus cultured for 24 h at ambient and elevated (2%) CO2, as compared with original BBM medium (Zn2+ = 2 mg/L, Mn2+ = 0.4 mg/L). The 4-fold increased content of Zn in the medium markedly enhanced the toxicity of CdCl2 applied at a concentration (16.8 mg/L) corresponding to EC50/24h. The 2.5-fold increase of Mn content reduced the inhibitory effect of Cd on the oxygen evolution rate and FV/FM. At low CO2, Cd did not affect the oxygen evolution but markedly stimulated the activity of carbonic anhydrase (CA). At elevated CO2, the rate of oxygen evolution was reduced by Cd, whereas CA activity remained unaffected.