A new study shows that restoring coral reefs can bring ecosystems back to life — and with them, their sounds.

Transcript

MARY LOUISE KELLY, HOST:

A healthy coral reef is a spectacle for the eyes. It is also a chorus for the ears.

(SOUNDBITE OF CORAL REEF AMBIENCE)

TIM LAMONT: One of the sounds that we know quite well is that high-pitched whooping sound.

(SOUNDBITE OF DAMSELFISH CALL)

LAMONT: And that's made by a pretty little yellow fish called the damselfish.

AUDIE CORNISH, HOST:

Tim Lamont is a marine biologist at the University of Exeter in the U.K. His team used underwater microphones to record reefs in Indonesia. They're interested in what that soundtrack tells us about the health of a coral ecosystem.

KELLY: You see; some reefs in Indonesia have been destroyed by dynamite fishing.

LAMONT: Where people literally blow up the reef with a stick of dynamite in order to catch the fish. Obviously, that leaves the rest of the reef in total wreckage.

KELLY: The wreckage that remains resembles bleached, faded bones. And as life trickles away, so does all that vibrant sound.

CORNISH: But in recent years, the company Mars Inc. - yes, the one that makes Snickers bars - well, they've been working with local communities to restore those degraded reefs. Divers install metal frames underwater. They look like giant metal spiders. And they tie baby corals to the legs and let nature do the rest.

LAMONT: The corals grow very quickly. And then in the absence of the threat, they're able to recover the damaged area in two or three years.

KELLY: And as Lamont's team reports this week in the Journal of Applied Ecology, when the coral makes a comeback, so does the sound.

LAMONT: I think what we're hearing is an ecosystem coming back to life.

KELLY: Along with the whoop-whoops of those damselfish...

LAMONT: There's a sort of knocking sound.

(SOUNDBITE OF CLOWNFISH CLICKING)

LAMONT: It's a clownfish that makes the sound, and it actually makes the sound by biting together its teeth really, really quickly. And you hear that quite a lot as they talk to each other within the anemone.

CORNISH: Lamont says all that chatter is a beacon that attracts more life to the reef, though some of the new inhabitants remain a mystery.

LAMONT: One of them - the foghorn sound...

(SOUNDBITE OF FISH BELLOWING)

LAMONT: ...We kept hearing at sunset. But we couldn't work out what fish was making it.

CORNISH: He swam all over the reef, playing back the sound underwater in hopes of finding its maker.

LAMONT: I got the fish to reply, but I think it must be quite a shy fish that sits in a hole and hides away because loads of the fish do that. And so I never saw the thing. So the foghorn fish remains a mystery.

KELLY: Jennifer Miksis-Olds of the University of New Hampshire was not involved in the work. She says she was excited to see soundscapes being used to monitor reefs.

JENNIFER MIKSIS-OLDS: It's been used quite a bit in terrestrial landscapes and restoration, and it's great to see that now being done underwater.

CORNISH: Lamont points out that climate change still poses an existential threat to reefs worldwide. But if humanity can rein that in, he says the work proves corals can make a comeback and the fish will sing again.

(SOUNDBITE OF NITSUA SONG, "NEW TOMORROW (FEAT. SALEM AND TOPIX)") Transcript provided by NPR, Copyright NPR.