Kategorie: News
New study: Restored coral reefs can grow as fast as healthy reefs after just four years
Coral reefs are among the world's most beautiful, but also most endangered ecosystems. Acidic and excessively warm water severely affect the sensitive creatures. However, a research project on a large reef in Indonesia now shows that revitalisation is possible. Hope for damaged reef systems?
Just this week, the environmental organisation Coral Watch drew attention to the extensive coral bleaching off the coast of Australia. In some places, up to 80 per cent of the corals have already bleached. The Great Barrier Reef system is being severely affected by water temperatures of up to 30 degrees centigrade.
Revitalising a desert
Global warming is the biggest enemy of corals. However, if this development could be slowed down, coral reefs could be revitalised relatively quickly, as marine biologist Ines Lange and her colleagues have shown using the example of a reef off Indonesia. The results were published in a study in the scientific journal "Current Biology".
The Mars Coral Reef Restoration Programme off the Indonesian island of Sulawesi was the focus of scientific interest. A few years ago, the coral reef there was completely destroyed and resembled a desert - not due to climate change, but due to dynamite fishing up to 40 years ago. Explosives were thrown into the water to drive the fish to the surface. Although this extremely damaging fishing method is now banned, the coral reefs had already been completely destroyed. To revitalise them, marine biologists worked with star-shaped steel structures that were covered with sand and then populated with coral "babies".
Transplanting the corals
The Mars Coral Restoration Programme is one of the largest restoration projects in the world and has been running for more than a decade in collaboration with local communities. Healthy coral fragments are attached to hexagonal, sand-covered steel frames called "reef stars". These reef stars are attached to damaged reefs where they stabilise the loose rubble, promote the growth of new coral and provide habitat for reef animals to colonise.
The steel structures are attached to the seabed by divers: "After just four years, the restored reefs are growing just as fast as the healthy reefs nearby. This is an incredibly fast recovery that we didn't expect," says the marine biologist. With the right method and the right place, restoration can make a big difference.
The recovery took place in several phases: After one year, the coral fragments were already developing into colonies, after two years they branched out with their neighbours. "After four years, you often couldn't even tell that it wasn't a natural reef, but had been restored," explains Lange. Not only have the corals themselves grown back, but a fully functioning ecosystem with colonisation by numerous species of fish and snails has formed.
"We will definitely have to limit the rise in temperature and do something about climate change on a large scale," emphasises Lange. This challenge is huge. The good news is that, if successful, there are methods that can be used to rebuild reefs and restore them to a functioning and thriving system within a short space of time.
Further information:
Marine biologist Ines Lange
Website Mars Coral Reef Restoration Programme
Study in the scientific journal "Current Biology"
News item: Coral bleaching on the Great Barrier Reef