Coral bleaching

The founder of SECORE, an international coral reef conservation non-profit organisation, Dirk Petersen said in 2016 30 percent of coral in the Great Barrier Reef, off north-eastern Australia, died from coral bleaching.

Dr Petersen said with the rapid decline, existing technology for restoring coral was slow and labour intensive.

However, he said the new method could pave the way for large-scale coral reef restoration.

The bleaching - or loss of algae - affects a 1,500km (932 miles) area of the reef, according to scientists.

The latest damage is concentrated in the middle section, whereas last year's bleaching hit mainly the north.

Experts fear the proximity of the two events will give damaged coral little chance to recover.

Prof Terry Hughes, from James Cook University, said governments must urgently address climate change.

Attempting to stop coral bleaching through any other method will not be sufficient, according to scientists.

The research, published in the journal Nature, said bleaching events should no longer be studied individually, but as threats to the reef's survival.

The bleaching - or loss of algae - in 2016 was the worst on record.

Some 67% of corals died in the reef's worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.

The situation was better in the central section, where 6% perished, while the southern reef is in good health.

But scientists warn recovery could be difficult if climate change continues.

Coral bleaching happens when water temperatures rise for a sustained period of time.