Australia’s Great Barrier Reef suffers ‘extensive’ coral bleaching, as scientists fear seventh mass bleaching event

CNN
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The southern Nice Barrier Reef is affected by in depth coral bleaching as a consequence of warmth stress, the reef’s managers mentioned Wednesday, elevating fears {that a} seventh mass bleaching event could possibly be unfolding throughout the huge, ecologically vital web site.

Aerial surveys performed final weekend by the Nice Barrier Reef Marine Park Authority and Australian Institute of Marine Science discovered bleaching was “in depth and pretty uniform throughout all surveyed reefs.”

The groups flew over 27 inshore reefs within the Keppel Islands and Gladstone area and 21 offshore reefs within the Capricorn Bunkers off the coast of southern Queensland final weekend.

Dr. Mark Learn, the authority’s director for reef well being, mentioned most coral surveyed “displayed some stage of bleaching with white and fluorescent colonies noticed in shallow reef areas.”

Protecting practically 133,000 sq. miles (345,000 sq. kilometers), the Nice Barrier Reef is the world’s largest coral reef, house to greater than 1,500 species of fish and 411 species of arduous corals. It contributes billions of {dollars} to the Australian economic system annually and is promoted closely to international vacationers as one of many nation’s – and the world’s – best pure wonders.

However hovering ocean temperatures are fueling damaging bleaching of the reef, because the world continues to burn planet-heating fossil fuels. Ocean temperatures are additionally changing into even hotter underneath the present El Niño — a pure local weather sample that brings warmer-than-average sea-surface temperatures — which is one of the strongest on record.

Bleaching happens when pressured coral ejects algae from inside its tissue, depriving it of a meals supply. If the water temperature stays increased than regular for too lengthy, coral can starve and die, turning white as its carbonate skeleton is uncovered.

The Nice Barrier Reef’s managers plan to increase aerial and in-water surveys throughout all the reef over the approaching weeks. Whereas the southern a part of the reef is probably the most affected, the reef authority has acquired reviews of bleaching from all different areas of the marine park.

“Aerial surveys are a really perfect device to evaluate the spatial extent of bleaching, however we have to go underneath the water to know extra in regards to the severity of bleaching and the way deep the bleaching extends,” mentioned Dr. Neal Cantin, senior analysis scientist with the Australian Institute of Marine Science.

A CNN group that visited the Nice Barrier Reef two weeks in the past noticed bleaching on the southern-most coral cay, Woman Elliot Island and on 4 totally different outer reefs off Cairns, within the center part of the reef.

And a separate report from a group at James Cook dinner College reported areas of reasonable to extreme coral bleaching across the Keppel Islands, the place water temperatures have been effectively above the summer time common.

“I’ve been engaged on these reefs for practically 20 years and I’ve by no means felt the water as heat as this,” mentioned Dr. Maya Srinivasan, a scientist on the college’s heart for tropical water and aquatic ecosystem analysis, in a statement final week.

“As soon as we have been within the water, we may immediately see components of the reef that have been fully white from extreme bleaching. Some corals have been already dying.”

Scientists say corals can get better if ocean temperatures stabilize.

“We’ve seen fish abundance decline as coral cowl declines on this area following previous impacts like this. However we’ve got additionally seen the restoration of coral and fish communities on many areas of reef – there simply must be sufficient time between impacts to permit this restoration to happen,” Srinivasan mentioned.

Hotter ocean temperatures brought on extreme mass bleaching on the Nice Barrier Reef in 2016, 2017 and 2020. Earlier bleaching occurred in 1998 and 2002.

Another bleaching event in 2022 – the primary throughout a La Niña occasion, El Niño’s counterpart, which tends to have a cooling affect – raised severe considerations in regards to the reef’s outlook.

There are considerations that 2024 will see a seventh mass bleaching occasion.

“Whereas we should look ahead to official affirmation from the Marine Park Authority, it definitely seems to be just like the seventh mass bleaching occasion is unfolding on the Nice Barrier Reef, with reviews of extreme bleaching occurring alongside its size,” David Ritter, CEO of Greenpeace Australia Pacific, informed CNN.

“We all know that the local weather disaster is driving marine heatwaves and main to those bleaching occasions, however the frequency and scale at which they’re now occurring is horrifying — each summer time we’re holding our breath.”

A record marine warmth wave “decimated” coral populations round Florida and the Caribbean final 12 months and observers in Australia concern an identical destiny could possibly be in retailer for the nation’s reefs.

“What we’re seeing in Florida and the broader Caribbean is a lesson of what’s going to occur within the subsequent 12 months as we see this factor rolling via now,” Ove Hoegh-Guldberg, climatologist and chief scientist on the Nice Barrier Reef Basis, lately informed CNN.

Final 12 months, the warmest year since international information started in 1850, in response to the US Nationwide Oceanic and Atmospheric Administration’s (NOAA) annual local weather report, noticed ocean temperatures surge to 100 levels Fahrenheit (37 levels Celsius) in some regions and the bleaching of entire reefs.

With water temperatures climbing to unprecedented heights, NOAA earlier this month added three new levels to its alert system to account for more and more extreme coral bleaching and better mortality charges.

Alert Stage 5, the brand new highest stage categorized as “close to full mortality,” means larger than 80% of corals within the highlighted space are liable to dying as a consequence of excessive, long-lasting water temperatures.

Final 12 months, the UNESCO World Heritage Committee determined to not add the Nice Barrier Reef to its list of sites “in peril,” regardless of scientific proof suggesting the danger of one other mass bleaching occasion.

Greenpeace’s Ritter mentioned that following the choice, “the Australian authorities promised to do every little thing it may possibly to guard the Nice Barrier Reef. This has to incorporate addressing local weather change as an existential risk to the reef, and making certain our emissions reductions plans are aligned with a 1.5 diploma pathway.”

He added that “claims that Australia is taking the well being of the Nice Barrier Reef critically ring hole once we proceed to develop and subsidize the coal and gasoline business to the tune of billions yearly.”

In line with the Australia Institute’s Coal Mine Tracker, the Labor authorities has authorized 4 new coal mines or expansions since coming to energy in Could 2022.