Oceans becoming noisier thanks to pollution -- report

Dec 20, 2009
A dolphin swims off the coast of Rangiroa, or "Rangi", the most populated of the Tuamotu islands in French Polynesia. The world's oceans are becoming noisier thanks to pollution, with potentially harmful effects for whales, dolphins and other marine life, US scientists said in a study published Sunday.

The world's oceans are becoming noisier thanks to pollution, with potentially harmful effects for whales, dolphins and other marine life, US scientists said in a study published Sunday.

Low-frequency sound in the ocean is produced by such as rain, waves and , and by human activities such as sonar systems, shipping and construction.

The sound is absorbed mainly through the viscosity of the water and the presence of certain dissolved chemicals, said the report published in the science journal Nature.

But the concentration of chemicals that absorb sound in the oceans has declined as a result of , in turn caused by rising concentrations of carbon dioxide.

Rising levels of carbon dioxide come from human activity such as shipping, with the number of ships roughly doubling over the past 40 years, the scientists said.

This was in turn increasing the acidity of the ocean, shown by a lowering of its pH levels, they said.

Using model simulations, the scientists found that increases in acidity could reduce seawater sound absorption by as much as 60 percent by 2100 in high latitude oceans.

Concern about the negative effect of the sea's increased acidity had previously been concentrated on the reduced rate of calcification, such as in .

"However, a less anticipated consequence of ocean acidification is its effect on underwater sound absorption," the authors said.

"A decrease in pH lowers sound absorption in the low-frequency range and, as a result, leads to increasing sound transmission."

Future global warming due to an accumulation of greenhouse gases may further decrease the ocean's sound absorption capacity at certain frequencies, the study said.

"High levels of low-frequency sound have a number of behavioural and biological effects on marine life," it added.

This included tissue damage, mass stranding of mammals such as whales and temporary loss of hearing in dolphins associated with military tests using intense mid-frequency sonar, the report said.

Marine species had adapted to varying levels of noise but the consequences of the sea's decreased ability to absorb sound were uncertain and required further research, the scientists said.

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User comments : 5

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Hoodoo
not rated yet Dec 20, 2009
Oceans becoming nosier eh? As in "on the nose" / stinkier? Or a plethora of unnecessary noses are finding finding their way into the ocean from unregulated nose landfills? Perhaps the oceans are becoming unduly curious and inquisitive? Nobody knows.

**Sorry, I'll shut up now. Good article, disturbing consequences**
Ve1anarris
2.6 / 5 (5) Dec 21, 2009
Why don't we just shoot the whales and other cetacions, then we can be as noisy as we want?
Velanarris
2.3 / 5 (3) Dec 21, 2009
Why don't we just shoot the whales and other cetacions, then we can be as noisy as we want?

You're an idiot, MikeyK/Noein.

This is an actual problem, and can be solved through better irrigation and ballast dumping regulations as well as multiple minor cultural practice changes.

Unfortunately sonar is invasive and should be replaced by a less harmful alternative as soon as is possible.

From what I understand the world's navies are looking into other ultra high and ultra low frequency sonar systems to alleviate the noise pollution undersea that's killing off ocean based mammals.
GrayMouser
not rated yet Dec 24, 2009
This is an actual problem, and can be solved through better irrigation and ballast dumping regulations as well as multiple minor cultural practice changes.

Unfortunately sonar is invasive and should be replaced by a less harmful alternative as soon as is possible.

From what I understand the world's navies are looking into other ultra high and ultra low frequency sonar systems to alleviate the noise pollution undersea that's killing off ocean based mammals.

My understanding is that the link between sonar and strandings has been partially (if not completely) discredited. There appear to be many causes.
http://www.scient...emselves
Ongelover
not rated yet Dec 30, 2009
"Using model simulations, scientist found..."

So there is NO empirical data. It is all by conjecture.
The ocean is alkaline. Ice-core investigations have shown the atmosphere to have had much more CO2 than today. There stil are dolphins around. Hence we see a postulated effect without causality.

I have a model too.

This is the scientist income model:
If {
Keywords in funding request contains "Global Warming'| 'CO2'|"caused by man'
THEN {"Wahoo, you get free money'}
ELSE {'Sorry bro, you gotta work for your dough'}
}

This model predicts that we as a tax payer will be paying more and more hard earned money to freeloaders like these.

I really object to using the term scientist by every hobo that jumps on the climate scam train.

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