(21-10-10) A team of scientists has created a listening network in the Mediterranean and the Atlantic ocean that allow us to listen to sounds at depths. Now, from a web site, we can listen to those recordings live and enjoy “the cetaceans’ radio”.

    Thanks to a web site we can listen to what is happening in the depths worldwide. What was happening on October, 8, at 4 pm in the Spanish Mediterranean coast? What, at the same time, in the Azores? We can discover it just on one click on the computer. Now, it is possible to enjoy the sounds of the oceans live and from home.

    Through the 12 hydrophones distributed in the European seas and the three in Canada, the LIDO web (Listening to the Deep Ocean Environment) offers transmission at real time. The system allows us to register and file underwater noise in the long term for the investigators to study the effects of human activity on whales and dolphins.

    Connecting to “the cetaceans’ radio” and enjoying their singing is possible thanks to Michel André, a bioacoustics expert in sounds of marine animals at the Politécnica University of Barcelona. He and his colleagues have been spending the last 10 years placing hydrophones in the seabed, in the research platforms used to watch earthquakes and tsunamis.

    “There were wires that connected the European observatories offshore to get control of geophysics and astrophysics data. We have taking advantage of the network to install hydrophones that receive sounds at real time” says André. “The system is connected to land and the currents of audio data are connected to a server in which the signals are analyzed and published directly on the Internet”, he adds.

SOURCES OF SOUND: DANGER TO MARINE ENVIRONMENT

    In the last hundred years, sources of artificial sound have increased very much, becoming a threat to the marine environment balance. Whales, sperm whales and dolphins have not been able yet to adapt their listening system to these new sounds, which caused very negative effects in the functioning of their life systems (it is estimated that they are one of the elements disorienting whales and causing massive stranding).

    We don’t know exactly the impact of the acoustic pollution on cetaceans, but this system “is going to let us know the exact effects according to global data”, says the expert.

    Before, there were campaigns in some places with very scarce data. However, it is a general problem that needs to act on a large scale that could begin with this new system.

    An algorithm developed by André’s laboratory filtered the different frequencies of the signal to identify specific sounds, including the songs of 26 species of whales and dolphins, the noise of human activities such as marine transport, offshore wind, oil rigs and seismic tests.

    “It is the first time we are able to control the acoustic sources on a large, temporal and space scale”, says André. So far, most of the experiments to control underwater noise used temporary hydrophones installations during just a few weeks.

MORE INFORMATION WITH A WIDE HYDROPHONES NETWORK

    With more hydrophones in the network, the new system could show the effects of acoustic pollution on whales. “It is a system that offers a more complex vision of acoustic interactions taking place underwater” says André.

    Hydrophones can get the sound of whales taking place hundreds km away, so the installations in different places could be used to locate the position of an animal and follow it. This way it would be possible to determine if animals change their course as a response to the noise, or alter their favourite routes due to new acoustic sources such as maritime routes or ports.

    The system is prepared to place hydrophones in buoys around underwater industrial platforms to integrate them to the network. This mechanism could alert in real time to the presence of whales and dolphins. “As we know the exact position of the animal we can prevent these acoustic impacts from happening by restraining the activity until the specimens go away”, explains André.

    Having access to these data on a large scale has a very important scientific and informative value. As André thinks in global terms and uses modern technology, he has been able to make oceans and marine mammals be some more familiar and accessible for all of us, trying a work of social awareness on the problem whales are suffering.

Text: Guadalupe Romero / LIDO