To Save the Great Barrier Reef, We May Have to Selectively Breed it

New research from Melbourne-based scientists may provide a way to redesign the Great Barrier Reef around stress-tolerant corals to withstand warm ocean waters.

The study, published in the journal Science Advances, has identified the unique sections of coral DNA that can indicate a higher tolerance to environmental stress factors like unusually warmer water, excess sunlight, poor water quality, and ocean acidification.

This year excessively high temperatures combined with still, clear conditions literally cooked large sections of the reef's coral, with only seven percent unaffected by bleaching. Bleaching occurs when the algae living within coral decides conditions are too warm and leave. The algae, known as zooxanthellae, are photosynthetic and provide the coral with chemical energy. Once this algae has left, corals are unable to grow and left vulnerable to damage.

Speaking to VICE, one of the leaders of the study Professor Madeleine van Oppen from the University of Melbourne explained how her team has discovered that some corals are better at withstanding harsh conditions than others.

"In this research we worked on colonies from the same species, where some were found to be hardier than others," she said. "And this was to a considerable extent related to the coral's genetic make-up."

The team's findings could act as a guide for futuristic reef restoration. Both selective breeding and assisted migration of genetically blessed stress-tolerant corals could help scientists completely redesign reefs to cope with dramatic weather events.

Potentially, reef managers could choose to move particular corals from one area to another, or breed certain strains of coral and release them into areas particularly affected by bleaching.

"The two markers we identified can be used for spatial mapping of relative bleaching tolerance across the reef, and they can also be used to identify relatively tolerant colonies which could be used for selective breeding or translocation of corals, if managers wished to implement such strategies," said van Oppen.

"We are developing what I call a biological tool box to try and make coral stock with enhanced environmental stress tolerance."

Is it depressing that we've come to this? A bit. So far the Australian Government's commitment to climate change policies has been non-committal at best, and Australia has reached a stage where, for now, damage control and a bit of biological creativity could be the only way forward.

And there is certainly something a bit tempting about redesigning a genetically advantaged reef that can withstand El Nino events. But while it looks like the technology might be there, actually implementing changes will still require government approval and funding.

"This work is in the early stages, so it's hard to say whether we will be able to achieve this on time," says van Oppen. "We have started a discussion about this with coral reef managers, and if we are successful, then of course we would need legislative approval to seed reefs with enhanced coral stock."

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