Sensitivity of marine microalgae to copper: The effect of biotic factors on copper adsorption and toxicity

• Published in: The Science of the total environment Vol. 387; no. 1; pp. 141 - 154
• Main Authors: Levy, Jacqueline L., Stauber, Jennifer L., Jolley, Dianne F.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 15-11-2007; Elsevier Science
• Subjects: Adsorption; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Copper; Copper - metabolism; Copper - toxicity; Dunaliella tertiolecta; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Eukaryota - chemistry; Eukaryota - cytology; Eukaryota - drug effects; Eukaryota - physiology; Fundamental and applied biological sciences. Psychology; Marine; Microalgae; Polymorphus; Species Specificity; Toxicity; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Microalgae; Marine; Adsorption; Copper; Toxicity; Sensitivity analysis; Ecotoxicology; Algae; Environmental factor; Heavy metal; Biotic factor
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2007.07.016

Microalgae are sensitive indicators of environmental change and, as the basis of most freshwater and marine ecosystems, are widely used in the assessment of risk and development of environmental regulations for metals. However, interspecies differences in sensitivity to metals are not well understood. The relationship between metal-algal cell binding and copper sensitivity of marine microalgae was investigated using a series of 72-h growth-rate inhibition bioassays and short-term (1-h) uptake studies. A range of marine algae from different taxonomic groups were screened to determine whether copper adsorption to the cell membrane was influenced by biotic factors, such as the ultrastructure of cell walls and cell size.
Minutocellus polymorphus was the most sensitive species to copper and
Dunaliella tertiolecta the least sensitive, with 72-h IC50 values (concentration to inhibit growth-rate by 50%) of 0.6 and 530 μg Cu/L, respectively. Copper solution-cell partition coefficients at equilibrium (
K
d) were calculated for six species of algae on a per cell and surface area basis. The largest and smallest cells had the lowest and highest
K
d values, respectively (on a surface area basis), with a general (non-linear) trend of decreasing
K
d with increasing cell surface area (
p
=
0.026), however, no relationship was found between
K
d and copper sensitivity, nor cell size and copper sensitivity. Interspecies differences in copper sensitivity were not related to cell size, cell wall type, taxonomic group or
K
d values. The differences in sensitivity may be due to differences in uptake rates across the plasma membrane, in internal binding mechanisms and/or detoxification mechanisms between the different microalgal species.