Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound
As the ocean becomes more acidic, low-frequency (~ 1–3 kHz and below) sound travels much farther due to changes in the amounts of pH-dependent species such as dissolved borate and carbonate ions, which absorb acoustic waves. The effect is quite large; a decline in pH of only 0.3 causes a 40% decreas...
Main Authors: | , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
The Oceanography Society
2009
|
Subjects: | |
Online Access: | https://doaj.org/article/32af6d59774246f29dce4a14f68dc84e |
id |
ftdoajarticles:oai:doaj.org/article:32af6d59774246f29dce4a14f68dc84e |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:32af6d59774246f29dce4a14f68dc84e 2023-05-15T17:50:44+02:00 Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound Peter G. Brewer Keith Hester 2009-12-01T00:00:00Z https://doaj.org/article/32af6d59774246f29dce4a14f68dc84e EN eng The Oceanography Society http://tos.org/oceanography/issues/issue_archive/issue_pdfs/22_4/22-4_brewer.pdf https://doaj.org/toc/1042-8275 1042-8275 https://doaj.org/article/32af6d59774246f29dce4a14f68dc84e Oceanography, Vol 22, Iss 4, Pp 86-93 (2009) ocean acidification borate low-frequency sound sound absorption pH Oceanography GC1-1581 article 2009 ftdoajarticles 2022-12-31T00:03:27Z As the ocean becomes more acidic, low-frequency (~ 1–3 kHz and below) sound travels much farther due to changes in the amounts of pH-dependent species such as dissolved borate and carbonate ions, which absorb acoustic waves. The effect is quite large; a decline in pH of only 0.3 causes a 40% decrease in the intrinsic sound absorption properties of surface seawater. Because acoustic properties are measured on a logarithmic scale, and neglecting other losses, sound at frequencies important for marine mammals and for naval and industrial interests will travel some 70% farther with the ocean pH change expected from a doubling of CO2. This change will occur in surface ocean waters by mid century. The military and environmental consequences of these changes have yet to be fully evaluated. The physical basis for this effect is well known: if a sound wave encounters a charged molecule such as a borate ion that can be “squeezed” into a lower-volume state, a resonance can occur so that sound energy is lost, after which the molecule returns to its normal state. Ocean acousticians recognized this pH-sound linkage in the early 1970s, but the connection to global change and environmental science is in its infancy. Changes in pH in the deep sound channel will be large, and very-low-frequency sound originating there can travel far. In practice, it is the frequency range of ~ 300 Hz–10 kHz and the distance range of ~ 200–900 km that are of interest here. Article in Journal/Newspaper Ocean acidification Directory of Open Access Journals: DOAJ Articles |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
ocean acidification borate low-frequency sound sound absorption pH Oceanography GC1-1581 |
spellingShingle |
ocean acidification borate low-frequency sound sound absorption pH Oceanography GC1-1581 Peter G. Brewer Keith Hester Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
topic_facet |
ocean acidification borate low-frequency sound sound absorption pH Oceanography GC1-1581 |
description |
As the ocean becomes more acidic, low-frequency (~ 1–3 kHz and below) sound travels much farther due to changes in the amounts of pH-dependent species such as dissolved borate and carbonate ions, which absorb acoustic waves. The effect is quite large; a decline in pH of only 0.3 causes a 40% decrease in the intrinsic sound absorption properties of surface seawater. Because acoustic properties are measured on a logarithmic scale, and neglecting other losses, sound at frequencies important for marine mammals and for naval and industrial interests will travel some 70% farther with the ocean pH change expected from a doubling of CO2. This change will occur in surface ocean waters by mid century. The military and environmental consequences of these changes have yet to be fully evaluated. The physical basis for this effect is well known: if a sound wave encounters a charged molecule such as a borate ion that can be “squeezed” into a lower-volume state, a resonance can occur so that sound energy is lost, after which the molecule returns to its normal state. Ocean acousticians recognized this pH-sound linkage in the early 1970s, but the connection to global change and environmental science is in its infancy. Changes in pH in the deep sound channel will be large, and very-low-frequency sound originating there can travel far. In practice, it is the frequency range of ~ 300 Hz–10 kHz and the distance range of ~ 200–900 km that are of interest here. |
format |
Article in Journal/Newspaper |
author |
Peter G. Brewer Keith Hester |
author_facet |
Peter G. Brewer Keith Hester |
author_sort |
Peter G. Brewer |
title |
Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
title_short |
Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
title_full |
Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
title_fullStr |
Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
title_full_unstemmed |
Ocean Acidification and the Increasing Transparency of the Ocean to Low-Frequency Sound |
title_sort |
ocean acidification and the increasing transparency of the ocean to low-frequency sound |
publisher |
The Oceanography Society |
publishDate |
2009 |
url |
https://doaj.org/article/32af6d59774246f29dce4a14f68dc84e |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
Oceanography, Vol 22, Iss 4, Pp 86-93 (2009) |
op_relation |
http://tos.org/oceanography/issues/issue_archive/issue_pdfs/22_4/22-4_brewer.pdf https://doaj.org/toc/1042-8275 1042-8275 https://doaj.org/article/32af6d59774246f29dce4a14f68dc84e |
_version_ |
1766157624385994752 |