Toxicity and Removal of Zinc in the Three Species (Acutodesmus obliquus, Desmodesmus subspicatus and Desmodesmus armatus) Belonging to the Family, Scenedesmaceae (Chlorophyta)

In this study, the effects of zinc upon growth of three green microalgal species, Acutodesmus obliquus (Turpin) Hegewald and Hanagata, Desmodesmus subspicatus (Chodat) Hegewald and Schmidt and Desmodesmus armatus (Chodat) Hegewald, and the capability of these green algae for removal of zinc were investigated. Growth inhibition of the microalgal cells was determined following exposure for 96 h to five initial concentrations of zinc. The growth of the alga decreased with increasing zinc concentrations. EC50 values were determined as 2257.824, 1922.049 and 1634.275 mu g L-1 for Zn in the case of D. subspicatus, A. obliquus and D. armatus, respectively. The highest zinc removal percentage from media was determined in D. subspicatus (40%), and followed by A. obliquus (30%) and D. armatus (18%). Phenotypic plasticity in Scenedesmus has been documented in response to a wide variety of conditions. The phenotypic plasticity was observed in A. obliquus and D. armatus in all tested zinc treatments.