As a turbine operates, vibrations inside the nacelle (the housing that contains the generator, gearbox, and other parts) are transmitted down the main shaft of the wind turbine and into its foundation. These vibrations then propagate into the water column and seafloor. Mechanical noise generated by offshore turbines is concentrated at low frequencies below 1kHz, generally below 700 Hz. Bockstigen-Valar, Sweden Underwater recording taken less than 50 m from a 500 kW turbine operating at the Bockstigen-Valar offshore wind farm (Baltic Sea, . . .
https://www.wind-watch.org/documents/underwater-noise-of-operating-wind-turbines/
