Zinc tolerance and zinc removal ability of living and dried biomass of Desmodesmus communis

Abstract

Effects of zinc on growth, cell morphology, oxidative stress, and zinc removal ability of the common phytoplankton species Desmodesmus communis were investigated at a concentration range of 0.25-160 mg L -1 zinc. Cell densities and chlorophyll content decreased in treated cultures, changes in coenobia morphology and elevated lipid peroxidation levels appeared above 2.5 mg L -1 zinc. The most effective zinc removal was observed at 5 mg L -1 zinc concentration, while maximal amount of removed zinc appeared in 15 mg L -1 zinc treated culture. Removed zinc is mainly bound on the cell surface. Dead biomass adsorbed more zinc than living biomass relative to unit of dry mass, but living biomass was more effective, relative to initial zinc content. This study comprehensively examines the zinc tolerance and removal ability of D. communis and demonstrates, in comparison with published literature, that these characteristics of different isolates of the same species can vary within a wide range.