Sublethal response of barnacles to chlorine: An experimental study for power plant biofouling control

Results of the study on sublethal responses of Megabalanus tintinnabulum, an acorn barnacle exposed to different levels of chlorine, is presented. In control, juvenile barnacles showed increased filtration rates, cirral activity and oxygen consumption per unit body weight as compared to larger barnacles. When both the size groups were exposed to chlorine levels, filtration rates and cirral activity declined. In larger barnacles the decline in filtration and cirral activity was less prominent. A decline in oxygen consumption observed in larger barnacles appears to be due to anaerobic metabolism under chlorinated conditions, when shell valves close. Juveniles appear to have normal oxygen consumption rates and thus may be more prone to stress.