Increased Ocean Acidification May Alter The Acoustics of Seawater

Increased ocean acidification over the next century could alter the acoustic properties of seawater, giving the planet’s oceans the same hi-fi sound they had during the age of the dinosaurs. In an analysis of ocean acidity over 300 million years, U.S. researchers David G. Browning and Peter M. Scheifele calculated that increased ocean acidity as a result of global warming will have a negative effect on the absorption of low-frequency sounds. By 2100, they predict, sounds near the oceans surface, such as whale songs or sounds created by ships, will travel perhaps twice as far as they do today. The scientists based their calculations on historic levels of boron in seafloor sediments and an analysis of its sound-absorption traits and impacts on low-frequency transmission. “[This knowledge] impacts the design and performance prediction of sonar systems,” said Browning, who will present the findings at the annual meeting of the Acoustical Society of America. “It affects estimation of low frequency ambient noise levels in the ocean. And it’s something we have to consider to improve our understanding of the sound environment of marine mammals and the effects of human activity on that environment.”