Humans and animals have evolved in environments that have a lot of noise.

We have noise from rain, we have noise from thunder, we have noise from other animals like

birdsong, or crickets chirping, but human industrial activities also have introduced a lot of

noise that are quite different from the sounds that we and other animals have evolved to live with.

Peter Tyak, TYAC, is a behavioral ecologist at the University of St. Andrews in Scotland.

And I've studied the sounds of mainly marine mammals, and that's given me an entry point

to understanding how sound travels in the ocean, which is quite different from what we used to on land.

Different how?

We as terrestrial mammals are used to vision being the great distance sense.

We can see things from very far away much further than we can hear, but if you've snorkeled in the ocean,

you know you can only see about ten meters, something like that, but you can hear much further away.

So the key difference between life on land and life underwater is that for a mammal that wants to understand what's far away,

they really need to rely on sound in the ocean.

Sound in the ocean therefore exerts a lot of leverage.

Sometimes this is good news. Consider a recent experiment by scientists working at the Great Barrier Reef off of Australia.

When a coral reef is healthy, it is quite noisy with the sound of marine activity, and that noise attracts more activity.

But a patch of coral reef that is dead or dying is quiet.

So the scientists went to these quiet patches and placed speakers underwater to play the sounds of a noisy reef.

It seems to have worked, attracting lots of fish who stayed on.

Here's how the researchers put it.

Acoustic enrichment shows promise as a novel tool for the active management of degraded coral reefs.

So there are beneficial ocean sounds and the opposite.

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