It’s the positive environmental news we all need to hear: efforts to heal the natural world can be successful. Why? A project led by scientists in the UK and Indonesia has successfully regrown damaged coral reefs in just four years.
Most of the world’s coral reefs are now under threat, with some even damaged beyond repair. But, amidst plenty of bad news about the state of the planet’s natural world, this new research brings hope.
Published in the journal Current Biology, the study reveals a method that can increase coral cover and even restore vital ecosystem functions – and fast.
“The speed of recovery that we saw was incredible,” said study author Dr Ines Lange from the University of Exeter. “We did not expect a full recovery of reef framework production after only four years.”
Coral reefs are vital habitats for marine life, and also protect coastal areas from storms and erosion. One such coastal area is South Sulawesi in Indonesia, where one of the largest coral reef restoration projects in the world is taking place.
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Known as the Mars Coral Reef Restoration Programme, the project builds hexagonal ‘Reef Stars’ (sand-coated steel structures) and attaches young corals to them. They then place them in reefs damaged by blast fishing: a practice that uses explosives to trap fish. In these areas, loose rubble stops young coral from growing – meaning there are no signs of recovery without human intervention.
The team observed corals growing onto the structure. When corals grow, they add calcium carbonate to the frames, while some fish and sea urchins erode the carbon away. This was an important measure to the scientists: whether the reefs had a positive or negative ‘carbonate budget’ told the scientists whether the reef was growing or shrinking.
But they found that, in just four years, the carbonate budgets of the damaged reefs had tripled – bringing them in line with the carbonate budgets of healthy reefs.
The scientists plan to continue observing the recovering reefs to see how they respond to stress, such as warming oceans during climate change. Restoration doesn't necessarily mean full recovery, as the restored reefs have not yet recovered their full diversity.
In fact, the team only transplanted one type of corals known as branched corals – and these corals are more sensitive to bleaching (when warmer seas cause the corals to die). However, the researchers hope they will 'recruit' other coral species to form a more diverse reef.
Lange said: “As is so often the case, there is no one-size-fits-all solution, but we hope that this positive example can be used as inspiration for other reef restoration projects around the world”.
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