Ocean Noise Increases with Greenhouse Gas Emissions

HELON ALTONN, Honolulu Star Bulletin, December 27, 2009

The ocean is becoming a noisier place due to increased greenhouse gas emissions, California and Hawaii scientists report.

Rising atmospheric carbon dioxide absorbed by the oceans not only has increased seawater acidity but has affected its acoustics—making it more transparent to low-frequency sound, the scientists said in a study published in the journal Nature Geoscience.

Scientists said seawater sound absorption will drop by up to 70% this century.

“It was surprising to us,” said Richard Zeebe, an associate professor of oceanography at the University of Hawaii School of Ocean and Earth Science and Technology.

Increased atmospheric carbon dioxide dissolved in the oceans increases acidity, or hydrogen ion concentration, and as the acidity rises, it lowers the seawater pH (a measure of acidity), researchers said.

“Certain chemical compounds in the ocean absorb sound and affect sound propagation,” Zeebe said. “Frequencies can get louder and more intense, depending on the chemistry.”

Not all frequencies will be affected, he said, explaining pH changes mostly affect sounds in the lower frequency range.

SOEST researcher Tatiana Ilyina said the pH of surface seawater will drop by 0.6 units by the year 2100 at the current rate of carbon dioxide emissions, with a one-unit drop of pH representing a tenfold increase of acidity.

“As a result, the absorption of 200 Hz sound would decrease by up to 70%,” she said, noting the middle C of the piano is tuned to 261.6 Hz. Sound around that frequency is produced by natural phenomena such as rain, wind and waves, and marine mammals and manmade activities, she said.

Naval, commercial and scientific activities use low-frequency sound and marine mammals rely on low-frequency sound to find food and mates, the scientists said.

“As a result, ocean acidification may not only affect organisms at the bottom of the food chain by reducing calcification in plankton and corals, but also higher tropic-level species, such as marine mammals, by lowering sound absorption in the ocean,” they said.

Zeebe said: “The consequences of these changes on marine mammals is not well known at the moment. There is a lot of background noise in the ocean generated by humans—ship noise, construction, seismic surveys and sonar—and this noise will essentially increase in volume in the ocean in the future.

“If the noise level increases, it can distract species,” he said. “If they’re trying to identify certain sounds in the ocean important for them for reproduction, feeding or something, and if the background noise is increasing, it could essentially cover certain sounds they depend on. This is a possibility.”

Another possibility is that marine mammals may be able to communicate over larger distances in the lower frequency range if sound absorption is decreased because underwater sounds can travel farther than at the surface, he said.

“Also, there are commercial and scientific applications, seismic surveys, that probably will have to take into account that future sound propagation in the ocean will slowly change,” Zeebe said, adding that more study is needed to determine the effects of the ocean acoustics changes.

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Whale Strandings Sounding Alarms in NZ & Italy

Fire Earth, December 28, 2009

Image by Sally & Doug Morrison

About 30 pilot whales died after they became stranded on Coromandel peninsula yesterday and will be buried by the local Maori.

Meanwhile, up to 120 long-finned pilot whales, both calves and adults, were found dead  at the Farewell Spit on Boxing Day.

“More offshore wells have been drilled in the last two years than the rest of the decade combined: 35 on and offshore wells were drilled between January 2008 and July 2009 alone,” said a report.

Each year about 2.5 million tourists visit New Zealand, straining its fragile ecosystems to the breaking point, creating a massive litany of different types of pollution, including noise.

Mendo Coast Current wrote: “Studies show that these cetaceans, which once communicated over thousands of miles to forage and mate, are losing touch with each other, the experts said at a U.N. wildlife conference in Rome.”

“The sound of a seismic test, used to locate hydrocarbons beneath the seabed, can spread 1,800 miles under water, said Veronica Frank, an official with the International Fund for Animal Welfare. A study by her group found that the blue whale, which used to communicate across entire oceans, has lost 90% of its range over the past 40 years.”

Environmental experts are studying numerous cases of beached whales and dolphins that are believed to have been caused by sound pollution, according to Simmonds.

Just two weeks ago at least five whales died after nine were beached in Mediterranean off the southern coast off Italy, an unusual place for whales to beach themselves.

‘A massive beaching is extremely rare in the Mediterranean,’ biologist Maurizio Wurtz at the University of Genoa said.

Noise pollution from seismic surveys for oil and gas as well as naval activities are believed to have confused whales by interfering  with their communication, thus leaving them stranded and ultimately dead,  many  Conservationists and biologists say.

The International Fund for Animal Welfare (IFAW) says man-made ocean noise inhibits cetaceans’ communication and disrupts their feeding.

The level of ocean noise in some regions is doubling each decade, according to IFAW.  “Humanity is literally drowning out marine mammals.”

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Whale Songs Drowned Out by Human Noise Pollution

Endangered species’ communication critical to survival

ARIEL DAVID, Seattle Post Intelligence, December 8, 2008

The songs that whales and dolphins use to communicate, orient themselves and find mates are being drowned out by human-made noises in the world’s oceans, U.N. officials and environmental groups said Wednesday.

That sound pollution — everything from increasing commercial shipping and seismic surveys to a new generation of military sonar — is not only confounding the mammals, it also is further threatening the survival of these endangered animals.

Studies show that these cetaceans, which once communicated over thousands of miles to forage and mate, are losing touch with each other, the experts said at a U.N. wildlife conference in Rome.

“Call it a cocktail-party effect,” said Mark Simmonds, director of the Whale and Dolphin Conservation Society, a Britain-based NGO. “You have to speak louder and louder until no one can hear each other anymore.”

An indirect source of noise pollution may also be coming from climate change, which is altering the chemistry of the oceans and making sound travel farther through sea water, the experts said.

Representatives of more than 100 governments are gathered in Rome for a meeting of the U.N.-backed Convention on the Conservation of Migratory Species of Wild Animals.

The agenda of the conference, which ends Friday, includes ways to increase protection for endangered species, including measures to mitigate underwater noise.

Environmental groups also are increasingly finding cases of beached whales and dolphins that can be linked to sound pollution, Simmonds said.

Marine mammals are turning up on the world’s beaches with tissue damage similar to that found in divers suffering from decompression sickness. The condition, known as the bends, causes gas bubbles to form in the bloodstream upon surfacing too quickly.

Scientists say the use of military sonar or seismic testing may have scared the animals into diving and surfacing beyond their physical limits, Simmonds said.

Several species of cetaceans are already listed as endangered or critically endangered from other causes, including hunting, chemical pollution, collisions with boats and entanglements with fishing equipment. Though it is not yet known precisely how many animals are affected, sound pollution is increasingly being recognized as a serious factor, the experts said.

As an example, Simmonds offered two incidents this year that, though still under study, could be linked to noise pollution: the beaching of more than 100 melon-headed whales in Madagascar and that of two dozen common dolphins on the southern British coast.

The sound of a seismic test, used to locate hydrocarbons beneath the seabed, can spread 1,800 miles under water, said Veronica Frank, an official with the International Fund for Animal Welfare. A study by her group found that the blue whale, which used to communicate across entire oceans, has lost 90 percent of its range over the past 40 years.

Despite being the largest mammal ever to inhabit Earth, the endangered blue whale still holds mysteries for scientists.

“We don’t even know where their breeding grounds are,” Simmonds said. “But what’s most important is that they need to know where they are.”

Other research suggests that rising levels of carbon dioxide are increasing the acidity of the Earth’s oceans, making sound travel farther through sea water.

The study by the Monterey Bay Aquarium Research Institute in the United States shows the changes may mean some sound frequencies are traveling 10% farther than a few centuries ago. That could increase to 70% by 2050 if greenhouse gases are not cut.

However, governments seem ready to take action, said Nick Nutall, a spokesman for the U.N. Environment Program, which administers the convention being discussed in Rome. The conference is discussing a resolution that would oblige countries to reduce sound pollution, he said.

Measures suggested include rerouting shipping and installing quieter engines as well as cutting speed and banning tests and sonar use in areas known to be inhabited by the animals.

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Noise Pollution Forcing Blue Whales to Cope & Compete

MendoCoastCurrent, October 27, 2009

Editor’s Note: Over the past few weeks there have been numerous Blue Whales showing up dead on the coast of California and a cause of the recent Blue Whale washing up on the Mendocino coast has been the topic of great discussion and mystery here. Actual cause of death has been identified by propeller of a NOAA research ship. Additionally, here’s a new theory based on noise pollution and new research: Blue whales are forced to make more noise to compete with man-made noise pollution like ship sounds and sonar. More specifically: Blue whales increase their ‘singing’ to cope with noise pollution. And: Man-made noise such as ships’ engines has caused hearing loss in whales.

LOUISE GRAY, Telegraph UK, September 23, 2009

It has also caused other behavioural changes, including forcing the creatures to strand on beaches because they are unable to navigate.

The endangered blue whale uses sonar to navigate, locate prey, avoid predators and communicate.

However in recent years the increasing use of hi-tech sonar by ships, the noise of propellers, seismic surveys, sea-floor drilling, and low-frequency radio transmissions have made oceans noisier.

New research has shown that the whales are having to ‘chatter’ more often and for longer periods to communicate the location of prey and to mate.

Zoologist Lucia Di Iorio, of the University of Zurich, analysed the song of blue whales recorded by microphones during seismic explorations in the St Lawrence estuary off Canada’s north east coast over an eleven day period in August 2004.

“We found that blue whales called consistently more on seismic exploration days than on non-exploration days as well as during periods within a seismic survey day when the sparker was operating,” she said.

“This increase was observed for the discrete, audible calls that are emitted during social encounters and feeding.”

The study, published in Biology Letters, provides the first evidence that blue whales change their calling behaviour when exposed to sounds from seismic surveys.

“This study suggests careful reconsideration of the potential behavioural impacts of even low source level seismic survey sounds on large whales. This is particularly relevant when the species is at high risk of extinction as is the blue whale,” added Dr Di Iorio.

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