Metabolic Response of the Two Marine Unicellular Algae &i&Chlorella salina&/i& and &i&Dunaliella bardawil&/i& to Toxicity of the Antifouling Agent Irgarol 1051

摘要

Toxic pollutants are metabolic poisons that can seriously injure or destroy the photosynthetic organisms upon which the food chain depends. Since microalgae play a key role in marine ecosystems, marine microalgae are proposed as excellent bio-indicators of pollution due to their high sensitivity, which can give warning of the toxic effects of chemicals sooner than any other species. The aim of this work concentrated on the effect of different concentrations of the antifouling biocide (Irgarol 1051) on growth and chlorophylls content (as an essential metabolite) of the two marine unicellular green algae Chlorella salina and Dunaliella bardawil that usually used in fish feeding. The growth of the wall-less Dunaliella bardawil was more sensitive to Irgarol 1051 than the walled cells Chlorella salina , although the concentrations used were greatly different. The product of photosynthesis in the two algal species greatly affected since in the presence of Irgarol 1051, a serious destructive effect was observed. The cell wall appeared to play a significant role in protecting the organism against toxicity of the antifouling agent either by adsorption or degradation. The strength of toxicity depends mainly on the concentration of the antifouling agent, the length of culturing period and the type of organism tested.