Climate change: Great Barrier Reef has lost more than HALF its corals in the ...

More than half of the corals on the Great Barrier Reef have been lost to 'bleaching' due to climate change over the last 25 years, a study has found.

Experts studying the state of the Australian reef system — one of the seven natural wonders of the world — reported that it is disappearing faster than thought. 

Human-induced climate change is speeding up so-called bleaching episodes, in which corals lose their vital symbiotic algae, turn white and can ultimate die off.

More than half of the corals on the Great Barrier Reef have been lost to 'bleaching' due to climate change over the last 25 years, a study has found Pictured, a coral on the reef

More than half of the corals on the Great Barrier Reef have been lost to 'bleaching' due to climate change over the last 25 years, a study has found Pictured, a coral on the reef

'The decline occurred in both shallow and deeper water and across virtually all species — but especially in branching and table-shaped corals,' said marine biologist Terry Hughes

 'The decline occurred in both shallow and deeper water and across virtually all species — but especially in branching and table-shaped corals,' said marine biologist Terry Hughes

VIRUS AIDS CORAL BLEACHING EVENTS

Researchers from the Oregon State University in the US have found that an infection aids coral bleaching.

The team compared the viral metagenomes of coral colonies in Mo'orea, in French Polynesia, during a minor bleaching event in 2016.

'After analysing the viral metagenomes of each pair, we found that bleached corals had a higher abundance of eukaryotic viral sequences,' said paper author and Adriana Messyasz. 

'Non-bleached corals had a higher abundance of bacteriophage sequences,' he added. 

'This gave us the first quantitative evidence of a shift in viral assemblages between states.'

Eukaryotic viruses are those that affect animals, while Bacteriophages selectively infect bacteria.

The team also found that bleached corals had a greater abundance of a new type of 'giant' virus that may aid bleaching, they said.   

The full findings of the study were published in the journal Frontiers in Marine Science.

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'We found the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 per cent since the 1990s,' said paper author and marine biologist Terry Hughes of the University of Queensland, Australia.

'The decline occurred in both shallow and deeper water and across virtually all species — but especially in branching and table-shaped corals.'

'These were the worst affected by record-breaking temperatures that triggered mass bleaching in 2016 and 2017.'

Branching and table-shaped corals provide build structures on the reef that are important for other marine life, such as fish.

Their loss is serving to reduce population sizes and sea food productivity.

So vast that it can be seen from space, the reef off of Queensland's coastline  hosts Earth's largest collection of living organisms, including some 1,500 fish species.

The Great Barrier Reef is larger than the Great Wall of China and stretches for around 1,400 miles over an area of roughly 133,000 square miles.

When ocean temperatures are too high, corals expel their colourful symbiotic algae that provide them with food — turning them a bleached white.

If the ocean cools quickly enough, the ejected algae can return, but if it stays too hot for too long, the corals begin to starve. 

Studying changes in the coral populations can reveal valuable insights into how the reef has responded to past stresses and how it will likely fare in the future.

Researchers studying the state of the Australian reef system — one of the seven natural wonders of the world — concluded it is disappearing faster than thought. Human-induced climate change is speeding up so-called bleaching episodes , in which corals lose their vital symbiotic algae, turn white and can ultimate die off

Researchers studying the state of the Australian reef system — one of the seven natural wonders of the world — concluded it is disappearing faster than thought. Human-induced climate change is speeding up so-called bleaching episodes , in which corals lose their

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