There’s some really bad news for the world’s largest living ecosystem – more than 50 percent of the Great Barrier Reef has already died or is in the process of dying. Things will get even worse and the chances of survival for the rest of the reef are looking extremely unhopeful at the moment.

Why is This Happening
When corals are faced with adverse environmental conditions such as high level of pollution, disease or warmer water temperatures their symbiotic micro-algae (zooxanthellae) tends to leave them behind in search of a better habitat. It’s the job of the micro-algae to provide corals with essential nutrients and their fabulous colours. So, when they leave the corals, the corals start dying. Initially, they lose their colours and become bright white hoping to attract new micro-algae, but when that doesn’t happen, they start to perish. This process of corals losing their colours is known as coral bleaching. Recently a team of scientists revealed that 93 percent of the reef has been struck by bleaching.

El Niño has played a major role in coral bleaching this year, not just in Australia, but in Hawaii and Fiji as well. El Niño is the phenomenon in which ocean temperatures rise in the Pacific as a result of a pulse of warm water flowing around the ocean. Add to this chaos, a generous dose of global warming caused by man-made greenhouse gas emissions and there, you’ve got yourself some coral bleaching!

Areas Affected
According to Professor Ove Hoegh-Guldberg from the University of Queensland who has studied coral bleaching over the last 3 decades, this is the worst case of coral bleaching in the history of Australia. In a statement, Professor Ove revealed, “From the tip of the Cape York to the Whitsundays, the Great Barrier Reef in the east to the Kimberleys in the west and SydneyHarbour in the south, Australia’s corals are bleaching like never before.” He further added that corals are even dying in places that they thought would not be affected by rising sea temperatures.

Andrew Baird from the ARC Centre said that the bleaching is extreme in the 1,000 km region north of Port Douglas all the way up to the northern Torres Strait between Australia and Papua New Guinea.

The Impact of Bleaching
The Great Barrier Reef generates tourism business worth $5 billion (Australian dollar) every year. More than 70,000 people are associated with these kinds of tourist activities in Australia. Coral bleaching is affecting the lives of these people, the most.

Also, when bleaching is this severe, it affects almost all the coral species, which includes the old, slow-growing corals as well. Once bleached, these old corals could take decades to return to their normal shape. It’s more likely that they won’t return at all.

Coral reefs are important for the sustenance of the ocean ecosystem. If they’ll perish they’ll hugely affect the lives of reef-based fishes and other sea-animals.

Indrasish Banerjee

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