The southern Great Barrier Reef is suffering from extensive coral bleaching due to heat stress, the reef’s managers said, raising fears that a seventh mass bleaching event could be unfolding across the vast, ecologically important site.
Aerial surveys conducted by the Great Barrier Reef Marine Park Authority and Australian Institute of Marine Science found bleaching was ‘extensive and fairly uniform across all surveyed reefs.’
The teams flew over 27 inshore reefs in the Keppel Islands and Gladstone region and 21 offshore reefs in the Capricorn Bunkers off the coast of southern Queensland.
Dr. Mark Read, the authority’s director for reef health, said most coral surveyed ‘displayed some level of bleaching with white and fluorescent colonies observed in shallow reef areas.’
Covering nearly 133,000 square miles (345,000 square kilometers), the Great Barrier Reef is the world’s largest coral reef, home to more than 1,500 species of fish and 411 species of hard corals. It contributes billions of dollars to the
Australian economy each year and is promoted heavily to foreign tourists as one of the country’s – and the world’s – greatest natural wonders.
But soaring ocean temperatures are fueling destructive bleaching of the reef, as the world continues to burn planet-heating fossil fuels. Ocean temperatures are also becoming even hotter under the current El Niño – a natural climate pattern that brings warmer-than-average sea-surface temperatures – which is one of the strongest on record.
Bleaching occurs when stressed coral ejects algae from within its tissue, depriving it of a food source. If the water temperature remains higher than normal for too long, coral can starve and die, turning white as its carbonate skeleton is exposed.
The Great Barrier Reef’s managers plan to extend aerial and in-water surveys across the entire reef over the coming weeks.
While the southern part of the reef is the most affected, the reef authority has received reports of bleaching from all other regions of the marine park.
‘Aerial s
urveys are an ideal tool to assess the spatial extent of bleaching, but we need to go under the water to understand more about the severity of bleaching and how deep the bleaching extends,’ said Dr. Neal Cantin, senior research scientist with the Australian Institute of Marine Science.
And a separate report from a team at James Cook University reported areas of moderate to severe coral bleaching around the Keppel Islands, where water temperatures were well above the summer average.
‘I have been working on these reefs for nearly 20 years and I have never felt the water as warm as this,’ said Dr. Maya Srinivasan, a scientist at the university’s center for tropical water and aquatic ecosystem research, in a statement last week.
‘Once we were in the water, we could instantly see parts of the reef that were completely white from severe bleaching. Some corals were already dying.’
Source: Oman News Agency