Heavy Metal Co‐tolerance in a Copper‐tolerant Population of the Marine Fouling Alga, Ectocarpus Siliculosus (Dillw.) Lyngbye

SUMMARY The growth of individuals from a copper‐tolerant and a non‐tolerant population of Ectocarpus siliculosus (Dillw.) Lyngbye, in media containing copper (0.10 mg 1‐1), cobalt (0.10 mg 1‐1), zinc (0.25 mg 1‐1) or cadmium (1.50 mg 1‐1) was measured using a wet wt method. The copper‐tolerant population was found to have an increased tolerance to cobalt and zinc, in addition to a high tolerance to copper. It is believed that the copper tolerance mechanisms, or other physiological processes, typical of the fouling population, are the basis of this co‐tolerance. The importance of a general tolerance to heavy metals in a major fouling alga is noted.