Can heat-resistant corals save the Great Barrier Reef?

It may seem like little more than a science project: a small robot deployed to disperse thousands of baby corals in a bit to revive dying reefs.

Yet it’s no mere whimsy. Scientists in Australia are scattering 100,000 tiny larvae from heat-resistant corals across badly damaged parts of the Great Barrier Reef by help of an underwater drone called LarvalBot. Millions more are set to follow in coming months if the first batch of larvae can manage to take hold in local waters.

The Great Barrier Reef is one of the world’s natural wonders but is in terminal decline as a result of warming water temperatures and increasing ocean acidification, which have caused repeated mass bleaching episodes. The hope is that heat-resistant corals that can tolerate warmer temperatures will help rejuvenate the reef, which is one of the world’s most biodiverse marine environments.

“This year represents a big step up for our larval restoration research and the first time we’ve been able to capture coral spawn on a bigger scale using large floating spawn catchers then rearing them into tiny coral larvae in our specially constructed larval pools and settling them on damaged reef areas,” explains Professor Peter Harrison from Southern Cross University.

Harrison is an originator of the project, which builds on the scientist’s earlier larval reseeding technique piloted on the southern Great Barrier Reef in 2016 and 2017.

“With further research and refinement, this technique has enormous potential to operate across large areas of reef and multiple sites in a way that hasn’t previously been possible,” Harrison adds. “We’ll be closely monitoring the progress of settled baby corals over coming months and working to refine both the technology and the technique to scale up further in 2019.”

It is widely believed by scientists that the Great Barrier Reef will likely be doomed unless large-scale conservation efforts, including larval seeding, can succeed in preserving larger parts of it in the face of relentless climate change. Planting hardy, heat-resistant corals from elsewhere to replace dead native species is increasingly seen as a possible solution to save the reef, or at least parts of it.

However, critics argue that there is no guarantee that replanted corals could successfully take the place of dying native species.