Shipping Noise (AUDIO) NOAA Headquarters Your browser does not support the audio element. Caption The steady, rhythmic sound of a ship propeller was captured by the NOAA hydrophone. Credit NOAA/ Bob Dziak Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.