sydney, March 24 (IANS) Environmental organisation Greenpeace on Friday released a video showing the "silent and high-speed destruction" of the Great Barrier Reef, caused by coral bleaching that has occurred for two years in a row.
The images were captured by short-range drones on March 17 above the central zone of the 2,300-km-long Great Barrier Reef, a marine ecosystem stretching along the Queensland coast, Efe news reported.
"Almost all of the coral we saw was dead or bleached," a Greenpeace Australia official said in a statement.
"I've seen previous bleaching on the Reef but nothing could have prepared me to see the reality of the destruction up close," he said.
When facing an increase in water temperature, corals eject the zooxanthallae algae which provide the host corals with oxygen and a portion of the organic compounds produced through its photosynthesis process.
The coral polyps are then left without pigmentation, which is a phenomenon known as coral-bleaching.
The increase in seawater temperatures recorded between 2015 and 2016 has worsened the effects of the cyclical natural phenomenon El Nino, which caused 93 per cent of the Great Barrier coral to bleach, 22 per cent of which has died.
Scientists and activists point out that the Great Barrier Reef, an ecosystem which was declared a World Heritage Site by Unesco, has suffered from coral bleaching for two consecutive years without having time to recover.
The recent coral deterioration is considered more severe than cases in 1998 and 2002.
"What is most heartbreaking about this footage is that it shows a lot of the coral that managed to survive last year is now totally bleached and on its way to dying," the spokesman added.
Unesco placed the Great Barrier Reef under observation in 2015 due to the improper management of the ecosystem by the Australian government.
However, Greenpeace criticised Australian Government's plans to invest $760 million in developing a huge coal mine in the area, demanding that the project be abandoned.
The Great Barrier Reef began to deteriorate in the 1990s as a result of the double impact of the increase in water temperature and in water acidity caused by carbon dioxide in the atmosphere.