Influence of the heavy metals copper and cadmium on the behaviour of Semibalanus balanoides and Balanus crenatus

Abstract

The effect of the heavy metals copper and cadmium on the behaviour of the sessile barnacles Semibalanus balanoides and Balanus crenatus over periods of 24 hours to 15 days has been studied using a photoelectric system to monitor cirral activity. In unstressed barnacles the amount of cirral movement remained fairly constant for several days although there was a marked decrease in the level of activity in animals kept in the laboratory for extended periods of time. In contrast to the response exhibited by bivalve molluscs, exposure to copper or cadmium did not elicit a rapid closure response in the barnacle. However, sublethal (80 ppb Cu, 100 ppb Cd) as well as lethal (500 ppb Cu, 500 and 1000 ppb Cd) levels resulted in a significant (P<0.05) overall reduction (averaging 30%) in the amount of cirral movement although at lethal levels there was often a period of increased activity prior to the onset of morbidity. Cirral beat frequency and duration were not often affected by exposure to 80 ppb of copper or 10...