Comparison of Cd, Cu, and Zn toxic effects on four marine phytoplankton by pulse-amplitude-modulated fluorometry

• Published in: Environmental toxicology and chemistry 2005-10, Vol.24 (10), p.2603-2611
• Main Authors: Miao, Ai-Jun, Wang, Wen-Xiong, Juneau, Philippe
• Format: Article
• Language: English
• Subjects: Algae; Animal, plant and microbial ecology; Applied ecology; Bioaccumulation; Biological and medical sciences; Biomarkers; Biomarkers - analysis; Cadmium; Cadmium - pharmacokinetics; Cadmium - toxicity; Cell-specific growth rate; Cells; Comparative studies; Copper; Copper - pharmacokinetics; Copper - toxicity; Dunaliella tertiolecta; Ecotoxicology, biological effects of pollution; Fluorometry; Fundamental and applied biological sciences. Psychology; General aspects; Metal concentrations; Metals; Phytoplankton; Plankton; Prorocentrum minimum; Pulse-amplitude-modulated fluorometry; Synechococcus; Temperature; Thalassiosira weissflogii; Toxicity; Trace metals; Water Pollutants - pharmacokinetics; Water Pollutants - toxicity; Zinc; Zinc - pharmacokinetics; Zinc - toxicity
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1897/05-009R.1

The toxic effects of Cd, Cu, and Zn on four different marine phytoplankton, Dunaliella tertiolecta, Prorocentrum minimum, Synechococcus sp., and Thalassiosira weissflogii, were examined by comparing the cell‐specific growth rate, pulse‐amplitude‐modulated (PAM) parameters (maximum photosystem II quantum yield ϕM and operational quantum yield ϕ'M), chlorophyll a content, and cellular metal concentration, over a 96‐h period. The calculated no‐observed‐effect concentration (NOEC) based on both cell‐specific growth rate and two PAM parameters (ϕM and ϕ'M) were mostly identical. Thus, these PAM parameters and cell‐specific growth rate were comparable in their sensitivities as the biomarkers for trace metal toxicity to marine phytoplankton. The cyanobacteria Synechococcus sp. was the most sensitive species among the four algal species tested because of its higher cell surface to volume ratio. The toxicity of the three tested metals followed the order of Cd > Cu > Zn based on the cellular metal concentration of the four algae at the NOEC. The cellular metal bioaccumulation followed the same Freundlich isotherm for each metal regardless of the algal species, indicating that the metal accumulation was a nonmetabolic process under high ambient metal concentrations and that the cell surface metal binding was comparable among the different species. For all the algae examined in our study, the bioaccumulation potentials of Cu and Zn were similar to each other, while the Cd bioaccumulation was much lower under environmentally realistic metal concentration.