Coral bleaching has affected more than 90 percent of the Great Barrier Reef. As a result of global warming, the colorful world natural heritage is slowly dying. But it’s still not too late.
June 8th is UN World Oceans Day. Since 2008, it has been intended to draw attention to the importance and threats to the oceans every year. Climate change, overfishing and littering have all hit the oceans in recent years. “The oceans have reached their load limit, in some cases it has already been exceeded,” warns biologist Ulrich Karlowski from the German Foundation for Marine Protection. The Great Barrier Reef, a natural world heritage site, is also under serious threat.
With its variety of fascinating creatures, the coral reef is one of the most breathtaking natural wonders on the planet: Schools of tropical fish, humpback and minke whales, sea turtles, sharks, rays, colorful corals or gently swaying sea anemones. But more and more corals are mutating into a kind of undersea ghost forest: instead of outdoing each other in their splendor of colour, the cnidarians suddenly lose their color and stand there pale and white.
The Great Barrier Reef can still be saved
The world’s largest reef, which can even be seen from space, is increasingly at risk from ocean warming – and increasingly affected by extreme coral bleaching. “The future of the Great Barrier Reef is on the brink, but it’s not too late to save it,” said Anna Marsden, director of the Great Barrier Reef Foundation, on World Oceans Day on June 8.
The earth is 70 percent covered with water. The seas are of immense importance for the survival of mankind: They not only produce a lot of oxygen, but are also a source of food, raw materials and energy. At the same time, they are suffering extremely from climate change, as the example of the Great Barrier Reef shows. “The oceans are victims of global warming and at the same time our greatest hope,” writes the German Nature Conservation Union (Nabu).
As early as March, experts warned of renewed severe coral bleaching on the Great Barrier Reef in view of warmer sea temperatures. Since May it has been clear: more than 90 percent of the reefs are already affected. It is the fourth massive bleaching since 2016. “Coral bleaching has been reported in all three regions of the reef, and the extent ranges from moderate to severe,” said Foundation Director Marsden of the German Press Agency. In difficult conditions, the corals shed the algae that cause the coloring and with which they otherwise live. Bleached corals are extremely stressed, but – and this is the good news – they are still alive. “If the cause of their stress is removed and it gets cooler, for example, then corals are able to recover.”
Climate change is the greatest threat to the Great Barrier Reef
Climate change is by far the greatest threat to the Great Barrier Reef and coral reefs worldwide. However, other factors often come into play – as is the case in Australia. “Poor water quality, coral-eating crown-of-thorns starfish, and hurricanes and severe weather are also part of a growing combination of threats,” Marsden said.
Experts are intensively searching for solutions. “We can save the Great Barrier Reef for generations to come, and we are bringing together the brightest minds and the best science to do just that,” Marsden said. Successes have already been achieved. Among other things, on ways to breed more heat-tolerant corals and prevent coral bleaching through cooling and shading. Studies also indicate that corals could be made more resilient to environmental stresses by administering probiotics.
The Great Barrier Reef has been badly affected, but is far from dead, emphasizes the Marine Parks Authority (GBRMPA). “Reports that focus on how much of the reef has died imply finality,” the website reads. But there are around 3,000 reefs spread over 14 degrees of latitude – and therefore not a single living being, but an enormous ecosystem. “The area is larger than Great Britain, Switzerland and the Netherlands combined.”
Sources: German Foundation for Marine Protection
