A new algal assay procedure for the determination of the toxicity of copper species in seawater

Abstract

Algal assays using the marine diatom Nitzschia closterium were carried out in raw, unenriched seawater to avoid the complexlng of copper by silicate, colloidal ferric hydroxide and other compounds which occurs in standard culture media. The algae remained in logarithmic growth for at least 72 h in unenriched seawater. The advantages of using this simple medium for the study of the effect of copper speciation on toxicity are outlined. Copper ions inhibit the growth of Nitzschia, but not the photosynthesis; possible reasons for this decoupling of cell division and the photosynthesis apparatus are discussed.