sounds revive coral reef
Dead coral reefs have become one of the major horrors resulting from human impact, with thousands of miles of coral ecosystem across the globe being transformed into bleached-out graveyards due to the devastating impact of fast-heating ocean temperatures, rising sea levels, pollution, and overfishing.

And for years, the Great Barrier Reef off Australia's coast — the largest living structure on the entire planet — has faced a slow death, with massive amounts of the corals simply dying while the rest of the once-dazzling coral transforms into bleached, lifeless matter.

But now, scientists have discovered an ingenious way to restore life to the dead patches of the Great Barrier Reef: by playing the ambient sounds of nature through loudspeakers to lure fish to the area. The fish would then help to clean up the reef, allowing for the growth of fresh corals necessary to recover reef ecosystems.

Scientists had long been concerned about the deadly quiet surrounding damaged coral reefs, which once teemed with the sound of healthy marine life, creating a sort of oceanic orchestra of sounds from fish, shrimp, and various other reef denizens. But without the sound of such traffic, many fish simply avoid the dead zones.

So a team of researchers led by marine biologists at the University of Exeter set up a system of submarine loudspeakers to play recordings of healthy reefs in a bid to attract the attention of fish to the dead coral patches around Lizard Island on the Great Barrier Reef.

The results, which were published in the peer-reviewed scientific journal Nature Communications, were astounding.

According to a Friday press release by the University of Exeter:
The study found that broadcasting healthy reef sound doubled the total number of fish arriving onto experimental patches of reef habitat, as well as increasing the number of species present by 50 percent.
The study's lead author, marine biologist Tim Gordon, said:
Fish are crucial for coral reefs to function as healthy ecosystems ... Boosting fish populations in this way could help to kick-start natural recovery processes, counteracting the damage we're seeing on many coral reefs around the world.
Steve Simpson, a fellow marine biologist at the University of Exeter and co-author of the study, added:
Healthy coral reefs are remarkably noisy places — the crackle of snapping shrimp and the whoops and grunts of fish combine to form a dazzling biological soundscape. Juvenile fish home in on these sounds when they're looking for a place to settle.

Reefs become ghostly quiet when they are degraded, as the shrimps and fish disappear, but by using loudspeakers to restore this lost soundscape, we can attract young fish back again.
The loudspeaker experiment, which lasted about six weeks, could provide one more tool in the ongoing fight to restore and protect the world's dying coral reefs.

However, the broadcasting of healthy reef sounds won't necessarily allow the dead patches to miraculously swing back to life. Continued restoration efforts and moves to mitigate or halt climate change remain crucial in saving the Great Barrier Reef.

Andy Radford, a co-author from the University of Bristol, noted:
Acoustic enrichment is a promising technique for management on a local basis.

If combined with habitat restoration and other conservation measures, rebuilding fish communities in this manner might accelerate ecosystem recovery.

However, we still need to tackle a host of other threats including climate change, overfishing and water pollution in order to protect these fragile ecosystems.