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.