Scientists’ experiment brings hope to coral reefs on the verge of global collapse

An underwater experiment using a combination of coral in vitro fertilization and fish noise recordings to restore coral reefs may offer hope to scientists who fear the fragile ecosystem is on the verge of collapse.

They claim the experiment, a global collaboration between two teams of scientists who have independently developed innovative coral rescue technology, has the potential to significantly increase the likelihood of corals repopulating degraded reefs.

BBC One drama to use integrated technology to repair damaged atoll in Maldives for first time our changing planet, co-hosted by naturalist Steve Backshall. It is hoped that this technology can be replicated on a large scale to help protect and revitalize dying coral reefs.

Professor Peter Harrison, a coral ecologist at Australia’s Southern Cross University, is a pioneer in coral in vitro fertilization. It involves capturing millions of coral eggs after heat-tolerant breeding corals float to the surface, or using cone nets to capture surrounding corals that have withstood a bleaching event. The net functions like a giant coral condom.

If you breed with heat-tolerant corals that can withstand thermal stress in the lab, the larvae of those corals will also be more heat-tolerant than the larvae of other corals, Harrison said.

The gametes (germ cells) then fuse together, fertilize and form coral larvae in floating nursery tanks, which protect them from predators and prevent them from getting lost at sea. If we don’t support the process of natural selection by focusing on survivors, we have everything to lose.

Harrison added that this technique could produce 100 times more coral colonies than would occur naturally on a reef with the same number of larvae: and research is underway on how to get this up to about 1,000.

To attract larvae to colonize degraded reefs, scientists are playing recordings of the sounds of fish caught near busy, healthy reefs. ‘We’ve already done this and restocked degraded coral reefs with fish,’ said Steve Simpson, professor of marine biology and global change at the University of Bristol.

Working with Peter was our first experience with coral. It maximizes the chances that the released coral larvae will find habitat, and they will then restore the reef habitat.

He found that coral larvae can detect sounds based on the movement of hairs on their bodies and can therefore be tricked into swimming toward and settling on normally quiet, unhealthy reefs. Simpson said it’s like sowing a piece of land and it will become a forest again.

In the lab, the larvae were particularly attracted to the low-frequency grunts, rattles and rumbles of territorial fish that protect Sandra growing on coral reefs. “We found that coral larvae can hear their way home as babies and then choose where to live for up to 1,000 years,” Simpson said.

They look simple, with no ears or brains, but corals may be among the first animals to enter their soundscape and dance to the beat.

Time is running out for the world’s coral reefs. Scientists recently announced that the world is experiencing its fourth global coral bleaching event since 1998, with 54% of coral reef areas in the world’s oceans experiencing heat stress high enough to cause colorful corals to turn white. Australia’s Great Barrier Reef has suffered its worst bleaching ever, with about 73% of the 1,429-mile (2,300-kilometer) reef affected.

Backshall’s original idea was to use the soundscape of a busy reef to attract tiny coral larvae to exposed areas with only bananas. “Seeing these gametes being brought out to sea, playing them the sounds of a healthy coral reef, and seeing them actively start swimming toward it, was probably the closest to a lightbulb moment I’ve ever experienced,” he said.

However, he worries that if global temperatures rise by 2.5 degrees Celsius or 3 degrees Celsius, coral reefs will face extinction regardless of these new technologies: If we continue with business as usual in terms of man-made climate change, I don’t think it will matter what measures we take .

Tropical coral reefs are on the front lines. But if we can limit global temperature rise to 1.5 degrees Celsius, then there’s a chance that these approaches will definitely be part of a better future.

Harrison said the world is gradually waking up to the seriousness of the global climate emergency. Meanwhile, he and Simpson were just trying to buy Coral time.

If we can keep the reefs alive enough to recover over the next two to three bumpy decades, Simpson said, we could secure the reefs for the future once the climate is brought under control. People say coral reefs are probably the first ecosystem we’re likely to lose, so I think they’re the first ecosystem we can save. If they are on the verge of collapse and we can save coral reefs, we can save everything. They become beacons of hope.