15 NOVEMBER 1999
EFFECTS OF HEAVY METALS (Ag, Cd, Cu) ON THE BIOCHEMICAL COMPOSITION AND OF THESE METALS IN 2 MICROALGAE SKELETONEMA COSTATUM AND TETRASELMIS SUECICA.
H. Perrein-Ettajani, J.C. Amiard, J. Haure, C. Renaud-1999
Canadian Journal of Fisheries and Aquatic Sciences, 56(10) : 1757-1765
Abstract :
Effects at sublethal silver, cadmium, and copper concentrations on growth and biochemical composition of two marine microalgae Tetraselmis suecica and Skeletonema costatum revealed that growth is by far the most sensitive factor, whereas cellular content of polysaccharides, proteins, lipids, and pigments are not significantly affected. This suggests that the first target of these metals is cell division and processes related to it. Heavy metal concentrations in algal cells were lower in S. costatum than in T. suecica, and the study of metal partitioning showed that for both algal species, Cd was easily released after treatment by the chelating agent. However, in both algal species, Cd and Cu were predominantly present in the insoluble fraction, and in the cytosol, thermoresistant metal-chelating polypeptids are involved. For this study, the major metal detoxification process in algae exposed to sublethal concentrations is therefore their binding to insoluble components. The strong stability of the latter suggests less bioavailability and maybe a limited transfer of these metals to higher trophic levels.