The effect of vibration frequency and amplitude on biofouling deterrence

The use of vibration is proposed as a means of controlling the settlement of marine fouling organisms. In this study, panels with embedded lead zirconate titanate, known as PZT, were placed in the field over 3 months. The panels were vibrated at different velocity levels at frequencies between 70 and 445 Hz. It was found that barnacles (Amphibalanus variegatus Darwin and Elminius sp.) were the only fouling organisms affected by the applied vibration, and these organisms settled in significantly lower numbers when the plates were excited at specific frequencies and amplitudes. Panels vibrating at relatively higher frequencies, greater than 260 Hz, exhibited reduced barnacle settlement, whilst lower frequencies in the 70-100 Hz range had little or no effect. The settlement of other fouling organisms such as tubeworms, bryozoans, ascidians and algae did not appear to be affected by the applied excitation. The experimental results showed that increasing the velocity amplitude of vibration was a contributing factor in inhibiting barnacle settlement.