Corals are 500 million years old. Starting off as simple, solitary organisms, they have come a long long way before evolving into the reefs we know today.

Over the years, corals formed colonies when conditions were favourable. They withered in mass extinctions, only to reappear after each event in a different shape and form. They have come and gone throughout the geological record. About 210 million years ago during the Triassic Period, things began to change. A massive worldwide coral-reef expansion was taking place and the hitherto lonely corals met algae.

And they struck a deal. Corals began to offer algae shelter, while in return, the latter offered nutrients from photosynthesis. Algae added colour to corals’ life. This symbiotic relationship has kept corals, algae and coral reefs alive all along. There have been tougher times. Many times corals have had to expel algae for various reasons, mostly due to ocean warming. And every time they expelled algae, the corals lost their colour (technically, bleached). The marine life that made the reefs their home have been left in the lurch. But they have always got back together, once the corals recovered.

They are dying

But the bleaching experienced in the recent past has been different. Scientists have predicted that the back-to-back severe bleaching events will leave little chance for recovery, especially in Australia’s Great Barrier Reef. This means two-thirds of the reef are dying. According to a recent study “Lethal Consequences: Climate Impacts on the Great Barrier Reef”, published by the Climate Council, it has been found that the Great Barrier Reef could suffer a bleaching event every two years by 2034 under the current level of greenhouse gas pollution. According to the study, 70 % of coral reefs will be at risk of long-term degradation by 2100 if the global temperature rises by 1.5 degrees Celsius above pre-industrial levels.


** The Great Barrier Reef is the largest reef system comprising more than 2,900 individual reefs. The reef is located in the Coral Sea, off the coast of Queensland, Australia. It is the world’s biggest single structure made by living organisms.

** The new Caledonia Barrier Reef, The Red Sea Coral Reef, Rainbow Reef (Fiji), Tubbataha Reefs (Cagayancillo, Philippines), Raja Ampat (Indonesia), Palancar Reef (Cozumel, Mexico), Wakatobi Islands (Indonesia) and the Maldives are some of the other systems around the world.


* Coral reefs provide habitats for one in four marine species.

* Reefs also form crucial barriers protecting coastlines from storms.

* They provide billions of dollars in revenue for countries from tourism and fishing.

* Many of the compounds are used in human medicines.

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