The sounds of our earth - Acoustic Ecology
Aktualisiert: 16. Nov. 2021
Hearing is like breathing. Never before have our ears been flooded with so many sounds.
We need sounds for our health. Our bodies are not made for absolute silence. But too much noise is harmful...
It all began with an accident in 1992, when a speedboat collided with a whale between the islands of Gran Canaria and Tenerife, killing one passenger. However, it did not remain with this one incident. The collisions became more frequent - mostly with fatal outcome for the whales.
Why did the whales not take evasive action?
The shipping company Trasmediterránea commissioned a study. The project was supposed to take two years, but ended up taking twelve.
It turned out that underwater noise had deafened the whales, which is why they were unable to avoid even the loud speedboats.
An acoustic trauma had cost the animals their lives. Exactly between Gran Canaria and Tenerife, where sea depths of up to 6,000 meters offer the animals a food-rich habitat full of microscopic organisms, also runs the region's busiest shipping route.
The ocean - a man-made "discotheque"?
For more than 80 years, man has been "polluting" the sea with noise without knowing it. The life of whales depends on the information that sound carries underwater.
The sperm whale, for example, prefers to hunt fish or squid that do not swim in the densest "sound thicket" but in calmer water areas where there are few false echoes. Once it has targeted a prey, it sonicates it with rapid clicks. In the darkness of the ocean depths, their calls and clicks function like acoustic feelers.
The sound tells the whale what its prey is like, where it is swimming, where it is moving. Because the large animals are not as agile, they must emit their clicking sounds from relatively far away, from a distance about three times their body length. This is the only way they have enough time to plan their movements ahead and catch their prey.
Water is not only the animals' life element, it is also their only communication channel. With their songs, the marine mammals maintain contact with conspecifics halfway across the ocean, and within the group itself, complex vocal communication helps maintain familial relationships.
But the noise of ship engines, wind turbines, icebreakers, oil and gas production facilities, military sonar equipment, and underwater blasts sonicates the ocean in unprecedented ways. The deafening soundscape overlays the communication of whales and seals and that of the entire underwater world.
None of our senses connect living things on the planet more than hearing. All living things share the sense of hearing, including invertebrates and plant life that respond to vibrations. If we disrupt this channel, not only will marine mammals die, but the entire ecosystem will be thrown out of balance.
The importance of soundscapes
Even without humans, the ocean would not be silent. Nature itself generates sounds. Fish grunt, knock, crustaceans rattle or scratch, and the sound of wind and waves interacts with structures on the ocean floor.
Thus, all ecosystems create their own soundscapes, their particular mix of noises, sounds, and tones. The enormous importance that underwater sound has on underwater life is still relatively new to humans.
A wide variety of creatures participate in the sound of a coral reef. Even corals produce sounds during photosynthesis.
Whales and coral reefs are closely connected. The vast soundscapes of coral reefs help marine mammals orient themselves and navigate safely. In return, the whales "fertilize" the reef with nutrients from the deep ocean.
"Singing" icebergs
It was only 30 years ago that researchers became aware that man-made sound permeates the entire underwater world. Only slowly is it becoming clear how much it damages ecosystems. In the last ten years, 66 percent of the oceans have been subjected to increasing multiple exposures.
Only three percent of the ocean is considered free of human pressure today.
If you want to know what the oceans once sounded like, you have to sink your microphones into the polar seas. There, the ice still protects against acoustic contamination.
There, there is still an incredible variety of sounds and singing icebergs. But in five to ten years, the polar ice caps will have melted to such an extent that the noise from ships and industry will also reach there.
Stephan Vincent Nölke
Geschäftsführer | CEO
"Above all, acoustic sustainability and healthy sounds are the name of the game these days.
Our daily incentive is to strive for a healthy sound ecology for all people. Your brand should sound sustainable. Quiet euphony is simply good for us."
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