Environment

Off color: 93% of Great Barrier Reef struck by mass coral bleaching event

Off color: 93% of Great Barrie...
Global warming spells bad news for Australia's Great Barrier Reef
Global warming spells bad news for Australia's Great Barrier Reef
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On 316 reefs, between 60 and 100 percent of corals are severely bleached
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On 316 reefs, between 60 and 100 percent of corals are severely bleached
The National Coral Bleaching Taskforce has performed an aerial survey of 911 individual reefs along the 2,300 km (1,429 mi) length of the Great Barrier Reef
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The National Coral Bleaching Taskforce has performed an aerial survey of 911 individual reefs along the 2,300 km (1,429 mi) length of the Great Barrier Reef
Global warming spells bad news for Australia's Great Barrier Reef
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Global warming spells bad news for Australia's Great Barrier Reef
The teams observations were corroborated by teams of underwater divers, confirming that only seven percent, 68 reefs of the 911, have gone unaffected by bleaching
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The teams observations were corroborated by teams of underwater divers, confirming that only seven percent, 68 reefs of the 911, have gone unaffected by bleaching
On 316 reefs, between 60 and 100 percent of corals are severely bleached
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On 316 reefs, between 60 and 100 percent of corals are severely bleached
33 percent of the 226 reefs in the central sector were also severely bleached
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33 percent of the 226 reefs in the central sector were also severely bleached

Last month, an aerial survey of the northern section of Australia's Great Barrier Reef returned some pretty grim results, revealing that the World Heritage Site had been hit with the worst coral bleaching event in its history. The researchers have now continued their work along this magnificent stretch of coastline and the news isn't getting any better. The results of their end-to-end study now reveal that 93 percent of the reef has been affected by bleaching as a result of warmer sea temperatures in the area.

Led by Professor Terry Hughes, the National Coral Bleaching Taskforce has performed an aerial survey of 911 individual reefs along the 2,300 km (1,429 mi) length of the Great Barrier Reef. Its observations were corroborated by teams of underwater divers, confirming that only seven percent (68 reefs of the 911) have gone unaffected by bleaching. On 316 reefs, between 60 and 100 percent of corals are severely bleached.

"We've never seen anything like this scale of bleaching before. In the northern Great Barrier Reef, it's like 10 cyclones have come ashore all at once," says Hughes. "Towards the southern end, most of the reefs have minor to moderate bleaching and should soon recover."

33 percent of the 226 reefs in the central sector were also severely bleached
33 percent of the 226 reefs in the central sector were also severely bleached

Of the 522 reefs surveyed in the northern section of the reef, 81 percent have suffered severe bleaching, while 33 percent of the 226 in the central sector were also severely bleached. Traditionally, the northern parts of the reef have been the most easily preserved due to the lack of human presence, but scientists worry that this is changing.

"Tragically, this is the most remote part of the Reef, and its remoteness has protected it from most human pressures: but not climate change," says Professor Andrew Baird from the ARC Centre of Excellence for Coral Reef Studies. "North of Port Douglas, we're already measuring an average of close to 50 percent mortality of bleached corals. At some reefs, the final death toll is likely to exceed 90 percent. When bleaching is this severe it affects almost all coral species, including old, slow-growing corals that once lost will take decades or longer to return."

On 316 reefs, between 60 and 100 percent of corals are severely bleached
On 316 reefs, between 60 and 100 percent of corals are severely bleached

The Great Barrier Reef has suffered through two mass bleaching events before, in 1998 and 2002. These are triggered when sea temperatures venture out of their normal range, causing stress on the algae inside the coral which they rely on for sustenance. These abnormal conditions cause the coral to expel the colorful algae from their tissue, leaving them to turn white and, in some cases, die.

A number of factors can bring about natural changes in sea temperatures, such as El Niño patterns, but rising global temperatures are expected to increase both the frequency and severity of mass bleaching events.

On the upside, the serious damage does seem to be mostly limited to the northern sections. The team says that reefs in the southern section have have not suffered damaging levels of bleaching, while it's expected that most of the moderately bleached coral in the central section will survive and return to normal color as temperatures lower over the next few months.

Source: ARC Centre of Excellence for Coral Reef Studies

3 comments
Rann Xeroxx
The Earth has been warmer and colder, even in recent history. If this is caused by man, warming more than likely is not the reason, I would guess more to do with pollution. http://iceagenow.info/wp-content/uploads/2011/06/Easterbrook-Natural_global_warming.jpg
Lbrewer42
Politics is the only thing behind global warming. Simple proof - warming temps are blamed on (supposedly) too much man-made CO2 b/c - as everyone is programmed to think - CO2 is a greenhouse gas. Fact: Ask any greenhouse owner - they do NOT have to PUMP EXTRA CO2 into the greenhouse to make it WARMER! The ONLY CO2 in the greenhouse is from the air around it. The plants all use the CO2 present in the natural air around them during photosynthesis. The CO2 is broken apart and the plant gives off O2 and water vapor (we DO remember simple high school photosynthesis lessons... right...?). There is an EXCESS of WATER VAPOR in a greenhouse - and the water vapor is what HOLDS in THE HEAT holds in the heat. There is no excess CO2 in a greenhouse b/c the plants use it! But the ones making so much money off of programming us to thinking CO2 will make the earth warmer could not very well pull off their scam by saying water vapor was bad for the environment now could they? They realized that (at least some) people would never fall for paying a fee for a forced "water vapor emissions" testing for your car. Can you imagien how much trouble they would be in if the truth was ever widespread? They could be sued by everyone who has been coerced and lost money over this political fantasy. Remember this the next time you enter a greenhouse: Ask them how much excess CO2 they pump into their greenhouse to make it warmer. Watch them respond to how ignorant a statement this is. The data showing global warming as "fact" is ALWAYS altered. Look into the actual data yourself for the facts of this. Remember this the next time you enter a greenhouse: Ask them how much excess CO2 they pump into their greenhouse to make it warmer. Watch them respond to how ignorant a statement this is. Quit being suckered.
Stephen Colbourne
Assuming that the water temperature on the Barrier reef is warmer in the north and cooler in the south, I propose moving the algae from living northern reefs to the south so that they are already adapted to the warm water. We could find algae in place like Thailand and Indonesia to repopulate the northern Barrier reef. Could the whole reef possibly end up moving south to adapt to the warming water temperature.