It’s a September morning off the coast of northern Sicily in Italy.
A boat owned by environmentalists is carrying Laura Abbriano and her associates along the chain of offshore islands.
The warm waters here are beloved by dolphins and whales – but growing tourism and industrial developments can cause the creatures harm.
Laura is worried about this because she sees the harm to mammals as a symptom of a bigger threat.
Laura Abbriano, founder, Aeolian Dolphin Research: ”We study whales and dolphins mainly because these animals are on the top of the food chain, and their behaviour allows us to determine the overall condition of our marine surroundings.”
It’s all about balance.
Like every natural environment, the underwater ecosystem is managed by the equilibrium between the various organisms that live in it.
Any break in the food chain could have serious consequences for many species.
And the threats are plenty – particularly one kind of man-caused pollution which is dangerous and poorly understood: contamination of the seas with artificial noise.
Here, at the Barcelona Aquarium, in Spain, marine life is well protected behind the thick glass of their tank.
In the open seas animals can’t escape from ever-mounting human intervention into their lives.
Michel André, LIDO mission coordinator, Director of the Laboratory of Applied Bioacoustics (UPC): ”What has to be understood is that some of the marine organisms, who have been living in this environment for millions of years, have adapted to it. They’ve developed through the information they receive through sound underwater. In particular sea mammals – especially whales and dolphins – who use sound for all their activities. If man’s sources of noise contaminate the area the mammals live in, preventing them from correctly receiving the information, it will put all their lives in danger.”
For whales and dophins, sound is the primary means of learning about their immediate environment.
They can’t rely on their other senses, as the other senses’ effectiveness, like sight, is limited in water.
Loud man-made noises – such as industrial and military sonars, experimental acoustic devices and maritime transport like propeller noise – can traumatise and incapacitate whales and dolphins.
So much so, they can’t hear sounds that are essential for their survival.
Michel André: ”I think we can compare the process to human vision: if our vision is limited, we’re incapable of living without assistance. For those animals, daily activities become difficult with reduced capacity to capture prey and orientate themselves through sound.”
Some of the sounds made by sea mammals can be heard underwater from a distance of many kilometers.
Back off Sicily , the ecologists are looking for local whales and dophins using an electronical listening device.
Laura Abbriano: ”This is a hydrophone – a special microphone which allows us to capture sound underwater, particularly all the sounds made by whales and dolphins.”
No luck: this passing motor boat makes a deafening noise under water.
Whales and dolphins, with their delicate hearing, try to avoid it by swimming away or diving to dangerous depths.
The negative effect of noise pollution is becoming clear, though scientific data is still very scarce.
To assist with more research, scientists use hydrophones submerged in deep waters – thousands of meters below the surface.
Banks of such devices can collect enough data to accurately locate any sound source nearby.
Deployed on the sea bed, an acoustic observatory doesn’t disturb the underwater life.
This method is more environmentally friendly than using ordinary listening devices aboard ships and has the great advantage to allow a continuous access to data.
Such observatories can send the sound data to shore instantly.
One such is at the Sicilian port of Catania, at the laboratory taking part in a European demonstration mission called LIDO.
Giorgio Riccobene, Research assistant, Laboratori Nazionali del Sud, INFN: ”A hydrophone can be either lowered into the sea from a ship for a local recording, or, like in case of LIDO, installed under water and connected by optical fiber to computers at a land station. This allows us to listen in real time to the sounds made by whales and dolphins from a distance of many kilometres away from the sea.”
LIDO – which stands for “Listening to the Deep Ocean Environment” – is being coordinated at the Laboratory of Applied Bio acoustics in Vilanova i la Geltrú, not far from Barcelona.
It’s the centre where all sound data is processed from the European Sea-Floor Observatories Network – or ESONET, which links eleven observatories all over Europe.
Mike van der Schaar, Research assistant, Laboratory of Applied Bioacoustics, UPC: “We first filter the data to see if there are interesting acoustic events – this can be whistles, or this can be sonar signals from whales and dolphions or noise from human activities. After the detection stage we classify them, and then transmit the data to the general public. Everyone can download the analysis results, that are showed directly online.”
This scientific base should enable computers to automatically identify and classify different sounds whether animal or artificial.
Serge Zaugg, Research assistant, Laboratory of Applied Bioacoustics, UPC: “The vertical bars we see here are the clicks of a sperm whale – the clicks it uses, for instance, to find squids – one of its preys. This is one example of sound that can be recorded under the sea… And here is a noise produced by a ship. Distinguishing the sound of sperm whale from the sound of ship is an easy task for a human being, but quite a difficult one for a machine. So the challenge is to develop an automatic method to make such identification.”
The system is being designed to constantly monitor European populations of marine animals, providing knowledge of their migration patterns and reaction to man-made noise.
All this information will be publicly available on the Internet.
Michel André: ”We have developed a web site which will allow users to connect and listen in real-time to the sound sources coming from all the observatories and to visualise it as a sonogram. A sonogram is a – a real-time image of the sound that indicates the presence of a sperm whale, a dolphin or a boat. It also shows how they interact.”
There is so much we don’t know about the role of sound plays in the lives of whales and dolphins.
Man is making is lot of noise these days.
The only way to know more is listening to the deep.
