Ocean acidification physically amplifies how far sound travels in seawater
Evidence
An increased merchant shipping activity has had a growing impact on the sea noise with an increase in the past four decades of 2.5β3 dB per decade in the frequency band 30β50 Hz. β¦ Ocean acidiο¬cation, from the reaction of CO2 with the water and the formation of carbonic acid (H2CO3), has the effect of propagating sound farther, increasing the noise level in the oceans. For instance, a noise of 3 kHz would increase by 30 % if the pH decreases from 8.0 to 7.4 (Etter 2012). β Almo Farina, Soundscape Ecology, 1332
Categorization
- QUESTION: Interesting counterintuitive mechanism β carbonic acid lowering pH propagates sound farther. Worth chasing the underlying physics (absorption coefficient drop with pH) for accuracy in teaching.
- SHARE: The 3 kHz / 30% / pH 8.0-to-7.4 figure is a nerdy, precise fact for someone working in ocean acoustics or climate communication.
- XREF: connects to: Each marine noise source occupies a characteristic frequency band at a measurable distance β Almo Farina, Soundscape Ecology: Principles,β¦, 1331; Temperature layers in the ocean duct sound and enable very long range propagation. β David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 339; Ocean depth creates a wave-guiding sound speed minimum around 800 meters β Eric J. Heller, Why You Hear What You Hear- Anβ¦, 219 (+2 more)
Broader Connections
- Ocean depth creates a wave-guiding sound speed minimum around 800 meters
#qualifies(0.78) β Eric J. Heller, Why You Hear What You Hear- Anβ¦, 219 - Deep-ocean pressure and temperature trade-offs create a sound-speed minimum waveguide
#qualifies(0.78) - Temperature layers in the ocean duct sound and enable very long range propagation.
#qualifies(0.75) β David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 339 - Climate shapes signal propagation through humidity and temperature-dependent sound absorption
#expands(0.72) β Almo Farina, Soundscape Ecology, 756