Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Whales Hear Us More Than We Realize

05.05.2014

Sonar signal “leaks” likely audible to some marine mammals

Killer whales and other marine mammals likely hear sonar signals more than we’ve known.


Photo taken under NMFS permit #14534; credit A. Friedlaender

A sperm whale off the coast of southern California

That’s because commercially available sonar systems, which are designed to create signals beyond the range of hearing of such animals, also emit signals known to be within their hearing range, scientists have discovered.

The sound is likely very soft and audible only when the animals are within a few hundred meters of the source, say the authors of a new study. The signals would not cause any actual tissue damage, but it’s possible that they affect the behavior of some marine mammals, which rely heavily on sound to communicate, navigate, and find food.

The findings come from a team of researchers at the Department of Energy’s Pacific Northwest National Laboratory, working together with marine mammal expert Brandon Southall of Southall Environmental Associates. The findings were published April 15 in the journal PLOS ONE.

A team led by Zhiqun (Daniel) Deng, a chief scientist at PNNL, evaluated the signals from three commercially available sonar systems designed to transmit signals at 200 kilohertz. The impact of such systems on marine mammals is not typically analyzed because signals at 200 kilohertz can’t be heard by the animals.

The team found that while most of the energy is transmitted near the intended frequency of 200 kilohertz, some of the sound leaks out to lower frequencies within the hearing range of killer whales and other animals such as harbor porpoises, dolphins and beluga whales. The three systems studied produced signals as low as 90, 105 and 130 kilohertz.

At the levels measured, the sounds would be quieter than many other sounds in the ocean, including the sounds the animals themselves make, and they wouldn’t be heard at all by the animals beyond a few hundred meters.

“These signals are quiet, but they are audible to the animals, and they would be relatively novel since marine mammals don’t encounter many sounds in this range,” said Southall, who is the former director of the Ocean Acoustics Program of the National Oceanic and Atmospheric Administration.

“These sounds have the potential to affect animal behavior, even though the main frequency is above what they primarily hear. It may be that environmental assessments should include the effects of these systems. This may not be a major issue, but it deserves further exploration,” added Southall.

The new findings have their roots in a project to track marine mammals in Puget Sound, which was part of a broader effort to provide information on the environmental impact of a planned tidal energy project there near Seattle. Researchers had planned to use sonar to help locate killer whales, but some marine mammal experts had observed that the animals might actually be hearing the sonar. Those observations led to the study, which was funded by the Department of Energy’s Office of Energy Efficiency and Renewable Energy.

How do the sonar signals actually sound to marine mammals like killer whales? Since high-frequency sonar pings several times per second, it’s possible that it sounds like one continuous, high-pitched hum or ping.

“If you think of a keyboard on a piano, the ships would be hitting the low notes quite hard, the middle keys would be most of the sounds of the animals themselves, and the sonar systems we studied would be relatively quieter sounds in the top few octaves on the right of the keyboard,” said Southall.

The authors of the paper did not directly study the hearing capability of whales and other marine mammals. Instead, the study focused on the sounds produced by sonar systems, discovering that commercial sonar systems are emitting signals within the animals’ known hearing range. Deng and colleagues are currently considering ways to limit signal leakage to reduce the amount of sound from high-frequency sonar systems that would be audible to marine mammals.

# # #

Reference: Z. Daniel Deng, Brandon L. Southall, Thomas J. Carlson, Jinshan Xu, Jayson J. Martinez, Mark A. Weiland, and John M. Ingraham, 200 kHz commercial sonar systems generate lower frequency side lobes audible to some marine mammals, PLOS ONE, April 2014, http://dx.plos.org/10.1371/journal.pone.0095315.

Contact Information

Tom Rickey
tom.rickey@pnnl.gov
509-375-3732

Tom Rickey | newswise
Further information:
http://www.pnnl.gov

Further reports about: Energy Laboratory animals hearing killer whales mammals signals sonar sperm whale whales

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Solar Collectors from Ultra-High Performance Concrete Combine Energy Efficiency and Aesthetics

16.01.2017 | Trade Fair News

3D scans for the automotive industry

16.01.2017 | Automotive Engineering

Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs

16.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>