Exploring Particle Motion Near a Wave Energy Converter

There is a growing expectation for the expansion of marine renewable energies (MRE), yet their impacts on marine fauna at both individual and array scales are not yet fully understood. Offshore marine energy installations represent emerging anthropogenic noise sources capable of propagating acoustic energy through the water column and substrate. MRE devices may cause acoustic disturbances, potentially affecting demersal and benthic species of fish and invertebrates. However, data on particle motion and substrate vibrations generated by floating structures moored to the seafloor remain scarce. This chapter provides an example of ongoing work involving direct measurements of acoustic particle motion and pressure data collected near ISWEC (Inertial Sea Wave Energy Converter), a wave energy device located off the coast of Pantelleria (Italy), Mediterranean Sea. Data were collected using an acoustic vector sensor equipped with a 3D accelerometer and omnidirectional hydrophone. An example of the acoustic signature of the ISWEC mooring is reported. Results indicate differences in behavior between pressure and particle motion, suggesting that their relationship is not straightforward. These findings highlight the importance of direct measurements for accurate underwater noise assessments and for improving understanding of particle motion behavior.