The sounds in the oceans are very different today compared to 200 years ago.

A new compilation of several research studies published in Science shows how the soundscape has changed.

It has become increasingly noisy below the water surface. 

One type of sound can be categorized as impulsive sounds.

They are sudden sounds with very high energy that can physically harm animals or scare them away for long distances.

This can be, for example, explosions.  

 - Animals can actually die from being exposed to loud noises such as underwater explosions.

It can also lead to some animals that whale, for example, being frightened and swimming into bays where they strand and die, says Mathias Andersson, researcher in marine biology at the Swedish Defense Research Agency, FOI. 

Noise mat creates stress 

Another category of noise is continuous noise from fishing boats, wind turbines and low-flying aircraft.

This type of noise can scare animals away from certain places, such as around wind turbines. 

 - The sound is there and grinds all the time and creates a noise carpet.

They may not create escape reactions, but they do create indirect effects such as stress.

It can also mask important information for the animals.

Animals use hearing for pretty much everything in their daily lives, says Mathias Andersson.  

Imbalance in technology development

There are techniques to attenuate the impulsive sound at the source.

When piling wind turbines down into the seabed, bubble curtains can be sent out to attenuate the radiated sound.

But the researchers in the study point out that there is a large imbalance in technological development. 

 - Good methods against piling have been developed, but there is hardly any technology at all against blasting, says Mathias Andersson.  

Noise in the marine environment is considered a pollution just like eutrophication and chemicals, and according to Mathias Andersson, noise can be the factor that causes the cup to overflow for the animals in an already sensitive ecosystem. 

- When you look at the cumulative impact - the more loads you put on - on an already stressed ecosystem, it can go bad.  

The study also indicates that it has become quieter in some places on earth.

Some sounds have disappeared.

Singing from whales has largely disappeared due to whaling and noise from ice as calves has decreased as a result of increased ice melting.