Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ocean Noise Has Increased Considerably Since 1960s, According to New Scripps Analysis

22.08.2006
Declassified Navy documents allow comparison that points to global shipping as the likely reason behind increase in undersea noise pollution Scripps Institution of Oceanography/UC San Diego

With populations increasing around the globe in recent decades, no one would be surprised by an increase in the amount of noise produced in terrestrial environments. Now, a unique study involving researchers at Scripps Institution of Oceanography at the University of California, San Diego, has shown that the underwater world also is becoming a noisier place, with unknown effects on marine life.

New research published in the August issue of the Journal of the Acoustical Society of America (JASA) has shown a tenfold increase in underwater ocean noise off Southern California's coast as compared with the 1960s. Mark McDonald of WhaleAcoustics in Bellvue, Colo., and John Hildebrand and Sean Wiggins of Scripps Oceanography accessed acoustic data recorded in 1964-1966 through declassified U.S. Navy documents and compared them against acoustic recordings made in 2003-2004 in the same area off San Nicolas Island, one of the Channel Islands more than 160 miles west of San Diego.

The results showed that noise levels in 2003-2004 were 10 to 12 decibels higher than in 1964-1966, an average noise increase rate of three decibels per decade. The culprit behind the increase, according to Hildebrand, appears to be a byproduct of the vast increase in the global shipping trade, the number of ships plying the world's oceans and the higher speeds and propulsion power for individual ships. The noise detected off Southern California originates from ships traveling across the entire North Pacific Ocean. According to Lloyd's Register figures quoted in the JASA paper, the world's commercial fleet more than doubled in the past 38 years, from 41,865 in 1965 to 89,899 in 2003.

"We've demonstrated that the ocean is a lot noisier now than it was 40 years ago. The noise is more powerful by a factor of 10," said Hildebrand, a professor of oceanography in the Marine Physical Laboratory at Scripps. "If we've doubled the number of ships and we've documented 10 times more noise, then the noise increase is due to both more ships and noisier individual ships than in the '60s. And that may be because the ships are now bigger, faster and have more propulsion power. The next step is to understand what aspect of modern shipping has resulted in more noise per ship," said Hildebrand.

Several years ago, while searching for information about noise levels off Southern California, Hildebrand obtained declassified documents that described a U.S. Navy sound surveillance system that used cabled hydrophones to measure ambient ocean noise in the 1960s. A detailed analysis of the recordings was reported in 1968.

Hildebrand's group sought to obtain similar readings in the same location using advanced listening devices called acoustic recording packages, or ARPs, developed in Hildebrand's laboratory. Hildebrand and members of his group regularly deploy ARPs at various locations around the world to obtain and analyze acoustic signals emitted by whales, dolphins and other marine animals.

Sean Wiggins examines data disk drives inside an acoustic recording instrument.
The authors of the study argue that the increase in noise documented off San Nicolas Island may be representative of the entire Northeast Pacific Ocean. To understand what impacts such noise might have on sound-dependent marine mammals and other sea life, the authors argue that repeated acoustic measurements at multiple sites are needed.

"The impact of the increased noise on marine animals is unknown," said Hildebrand. "If impacts are shown to exist, what can be done to protect marine animals? For instance, it may be appropriate to move shipping lanes away from areas where there are concentrations of marine animals. The impact of ocean noise pollution may be minimized by diminishing the noise source or by separating the noise from things that are sensitive to it."

The research was supported by the U.S. Navy and the Office of Naval Research.

Mario Aguilera | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>