This phenomenon was reported by Danihelka et al. (1997) as well. Probably due to intoxication, algal cells have partially lost their binding capacity and small amount of metal was subsequently released back into solution. But after a few hours, a strong intoxication likely caused the death of some cells, and because of that, the ratio between the living and dead cells changed. Since dead cells have shown higher absorption capacity, part of the released copper was rebound at the end of the experiment