It is well known that the oceans are suffering due to global warming. In addition to the oceans warming they are also becoming more acidic. Oceans are a main carbon sink for the planet, but the ability of them to absorb carbon is decreasing. However, the amount of carbon dioxide that continues to be absorbed by the ocean is impacting it in ways never expected.
In addition to warming oceans and acidification, the oceans are also expected to become louder. This is the topic of a recently published study in the journal Nature Geoscience. Three scientists worked on the study together, two from the University of Hawaii: Tatiana Ilyina and Richard E. Zeebe. Another contributor was Peter G. Brewer of the Monterey Bay Aquarium Research Institute.
The scientists used computer models to predict oceans’ ability to absorb sound with increasing carbon dioxide. Chemical compounds absorb sound in the oceans, including boric acid. However, the oceans becoming more acidic causes less of these sound-absorbing reactions to occur. Due to this, areas with greater acidity will be louder.
The scientists study found that some areas will experience a sixty percent decline in sound absorption by the year 2100. The areas most susceptible are those in high latitudes and in deeper waters. Such a drastic decline in sound absorption could signal a great deal of problems, especially for marine species.
Currently, the oceans absorb most sound that occurs between 1,000 to 5,000 hertz. This range of frequencies includes overall ship noises, propeller sounds and military and research sonar. This will cause locations with a large amount of ship activity to be louder with less absorption of sound.
A major concern for increasing sound would be the ability for marine mammals to communicate and echolocate. Whales, in particular, have been shown to be impacted by sonar even at current levels of sound absorption. The overall impact increased noise will have on such species is not completely clear. The scientists also pointed to a potential positive, the increased travel of noises which may help whales and other mammals communicate.
