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Effects of low level chlorination on the recruitment, behaviour and shell growth of Mytilus edulis Linnaeus in power station cooling water
I.S. Thompson, R. Seed, C.A. Richardson, L. Hui and G. Walker

Chlorination procedures are widely used to control biofouling in the cooling water systems of coastal power stations. However, relatively little is known about the ways in which these procedures affect the ecology of major fouling organisms such as the mussel, Mytilus edulis. High concentrations of chlorine (8 mg l-1), as sodium hypochlorite (NaOCl), lead to mortality of all planktonic larval stages, while lower concentrations (1 mg l-1), produce changes in the swimming and crawling behaviour of larvae in experiments conducted in non-flow through systems. The age and growth history of individual mussels collected from power station culverts were determined from the growth lines present in acetate peels of polished and etched shell sections. During periods of chlorination shell growth is severely reduced resulting in marked changes in shell structure and deposition. Consequently, growth rates of naturally occurring mussels were substantially greater than those occurring within the culverts. The information provided by this study, together with an ongoing monitoring programme of the natural periods of mussel settlement on artificial substrata, is currently being used to develop an appropriate chlorination protocol at Wylfa Nuclear Power Station, North Wales, UK. The use of mussels to evaluate the long-term effects of low level chlorination is briefly discussed.

Contents of this volume Sci. Mar. 61(Suppl.2) : 77-85 Back PDF
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