Modes of copper toxicity in marine microalgae: an intracellular investigation

Toxicity of metals to aquatic organisms is dependent on both external factors, such as exposure concentration and water quality parameters, and intracellular processes including specific metal-binding sites and detoxification. Current models used to predict copper toxicity in microalgae do not adequately consider these intracellular processes. This thesis examines the toxicity of copper towards microalgae by investigating intracellular copper-binding ligands, including proteins, phytochelatins and glutathione from four species of marine microalgae, Dunaliella tertiolecta, Tetraselmis sp., Phaeodactylum tricornutum and Ceratoneis closterium, in controls (no added copper) and throughout a 72-h exposure to copper to their respective IC50 values (concentration of copper required to inhibit population growth by 50%). IC50 values were chosen to represent equal amount of cellular stress across the four species despite their differences in copper tolerance.