Great Barrier Reef Suffers Its Most Widespread Mass Bleaching Event On Record (washingtonpost.com) 46
An anonymous reader quotes a report from The Washington Post: Surveys conducted by scientists at Australia's James Cook University and the Great Barrier Reef Marine Park Authority show that a summer of extreme heat has caused the reef, which is a World Heritage Site, to suffer a mass bleaching of unprecedented scale. Corals from the far north to the southern tip of the 1,400 mile-long ecosystem are experiencing severe impacts. It was also one of the reef's worst mass bleaching episodes in terms of intensity, second only to 2016, which killed half of all shallow-water corals on the northern Great Barrier Reef. Unlike the summer of 2016, when an intense marine heat wave coincided with one of the strongest El Nino events on record, this past summer brought a bleaching event without any assistance from the Pacific climate oscillation.
As heat built across the reef in February, the Great Barrier Reef Marine Park Authority began reporting pockets of bleaching in the far north toward the end of the month. By early March, vast swaths of the ecosystem had accumulated eight or more "degree heating weeks," a metric scientists use to describe recent cumulative heat exposure. At this threshold, reef scientists expect to see widespread bleaching and mortality from thermal stress, according to NOAA. Researchers decided to conduct aerial and waterborne surveys to assess the extent of the damage. The surveys, which took place during the last two weeks of March, quickly confirmed the reef has undergone its third mass bleaching event in the past five years. "This year, some 35 percent of the 1,036 reefs the scientists surveyed experienced moderate bleaching, while a quarter were severely bleached," the report adds. "Scientists saw severe bleaching on coastal reefs from Torres Strait in the far north to the southern border of the Great Barrier Reef Marine Park, at levels only eclipsed during 2016."
What's troubling to see is bleaching in the south, which has managed to escape the previous two events. "In the northern and central Great Barrier Reef, these corals were largely annihilated by bleaching in 2016-17, transforming vast swaths of the reef into a 'highly altered, degraded system,'" reports The Washington Post, citing a 2018 paper in the journal Nature. "Now the south seems poised to slide into a similar ecological disrepair."
As heat built across the reef in February, the Great Barrier Reef Marine Park Authority began reporting pockets of bleaching in the far north toward the end of the month. By early March, vast swaths of the ecosystem had accumulated eight or more "degree heating weeks," a metric scientists use to describe recent cumulative heat exposure. At this threshold, reef scientists expect to see widespread bleaching and mortality from thermal stress, according to NOAA. Researchers decided to conduct aerial and waterborne surveys to assess the extent of the damage. The surveys, which took place during the last two weeks of March, quickly confirmed the reef has undergone its third mass bleaching event in the past five years. "This year, some 35 percent of the 1,036 reefs the scientists surveyed experienced moderate bleaching, while a quarter were severely bleached," the report adds. "Scientists saw severe bleaching on coastal reefs from Torres Strait in the far north to the southern border of the Great Barrier Reef Marine Park, at levels only eclipsed during 2016."
What's troubling to see is bleaching in the south, which has managed to escape the previous two events. "In the northern and central Great Barrier Reef, these corals were largely annihilated by bleaching in 2016-17, transforming vast swaths of the reef into a 'highly altered, degraded system,'" reports The Washington Post, citing a 2018 paper in the journal Nature. "Now the south seems poised to slide into a similar ecological disrepair."
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Water is the great moderator. Large bodies of it store summer heat into the cold season and take a similar time to warm up when the heat returns. So far we can see reduced air pollution, but a few weeks of lockdown is not going to change anything that is actually submerged in the ocean.
My last visit to the region (earlier this year) (Score:4, Interesting)
Re:My last visit to the region (earlier this year) (Score:5, Interesting)
Those reliant on the Reef for a living may not have noticed anything, not around Cairns/Port Douglas anyway. From TFA:
Major tourism areas of the Reef mostly experienced no, negligible or moderate bleaching only - the exception is one area in the southern part of the Marine Park with severe bleaching.
BTW the aerial surveys are verified [theconversation.com] with direct underwater observation as well (see the paper here [nature.com]). While 40% of the Reef was largely unaffected this event, 25% experienced Severe bleaching with >60% of corals affected, much in the south that was largely unaffected on previous events.
As this is shaping up to be a regular event, I shudder to think how much worse it could get on the next strong El Nino year.
Re: My last visit to the region (earlier this year (Score:1)
Re: My last visit to the region (earlier this year (Score:4, Informative)
How long has this been going on?
Localised bleaching is not new, but these mass-bleaching events are new, and due to warmer oceans.
https://www.abc.net.au/news/20... [abc.net.au]
It is the third mass bleaching event on the reef in five years — a phenomenon primarily caused by greenhouse gas emissions, and one that had never been recorded before 1997.
Re: My last visit to the region (earlier this yea (Score:1)
Re: My last visit to the region (earlier this yea (Score:4, Informative)
We've recorded mass bleaching since at least the 1970s [wikipedia.org], though they have of course happened before (as far back as the Late Devonian). However, they're happening five times as often [sciencenews.org] even just in the last 40 years.
Re: My last visit to the region (earlier this yea (Score:1)
Re:My last visit to the region (earlier this year) (Score:4, Informative)
There's been occasions (year before last) when it was touted that most of the reef was dead
Don't know who was claiming that. The bleaching certainly covered "most" of the Reef in 2016 & 2017 (over 60% [aims.gov.au] in both years) - but nobody suggested all of those would die. Many of the moderately-bleached reefs recovered almost entirely - but not so much with severe bleaching.
As it was we lost over 22% of the entire Reef in 2016, and similar amounts in 2017, causing catastrophic [nature.com] changes to the Reef's ecosystem.
Look on the bright side. (Score:5, Funny)
These are troubling times with a lot of bad news out there, so let's try to be optimistic about this, and find the bright side.
Sure, this might be the worst shape the reef has been in for all of recorded history, but it's also the best shape the reef will be in for the rest of recorded history.
Re: Look on the bright side. (Score:1)
Could the reef be reinforced by towing all the cruise ships to the area to be sunk? Burned to the waterline first. And after reimbursing the cruise ship lines so they can reimburse sick customers with the money, of course.
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I really don't care if it uses Clorox or an off brand. Not really my largest concern these days.
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Somewhere in that brain there must have been the glimmer of rational thought. But then you started typing.
Re: UNPOSSIBLE (Score:1)
Its global warming all the way down.
Re:Im old enough to remember (Score:4, Insightful)
No. The story was it would be the end of reef life. And that is very much the case if you actually visit a bleached reef.
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No. The story was it would be the end of reef life. And that is very much the case if you actually visit a bleached reef.
Not really the end, though left to nature it will likely take a very long time for the corals to recover. There is hope that we can accelerate the process by transplanting coral larvae from warmer regions. Of course, we also need to reduce greenhouse emissions and stop making it worse, but even if we were able to stop all emissions right now, the planet would continue warming for most of a century. The corals are going to have a very hard time of it without help.
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30% dead [theguardian.com] in 2016. 50% dead [nationalgeographic.com] in 2018. That 50% includes the previous 30%, so no chance of breaching 100%, but we're quickly working on hitting it.
A 2019 study found that replenishment rates diminished by 89% [theguardian.com] after those events.
Now we have another back to back event occurring without even an El Nino to provoke it.
This is not good.
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For those that aren't just trolling: Much of the Reef does recover from bleaching, when the water cools off again. It's not permanent, except where the high temperatures are sustained long enough that the coral dies. That's why "only" 30% of the Reef's coral died in 2016, despite bleaching of more than twice that.
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I know you're trolling (and that you didn't actually read the links from my other post), but:
a) the first recorded mass bleaching in the Great Barrier Reef was 1997, not the 1970s, and
b) it's not fairly regular, that's the point - or at least it wasn't until 2016.
Can we have more nuclear power now? (Score:2)
Yet another story about global warming where no solutions are offered. Here's an idea, let's make a list. We'll list all the energy sources we have available to us then rate them on vital metrics. Metrics like CO2 emissions, safety, cost, abundance, labor needs, raw material needs, and land area requirements. This isn't that hard to do, it should only take a few minutes of searching the internet to find at least good order of magnitude numbers. Here's what you will find at the top of this list, separat
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If nuclear power plants are so great, we'll let you fund one and then you can have all the profit that results from it.
Re: Can we have more nuclear power now? (Score:2)
If you had government approval to build one, funding would be easy to secure.
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I'm sorry the joke went over your head. Nuclear power plants are heavily funded by governments, and if you take into account, it turns out they're never profitable. https://reneweconomy.com.au/nu... [reneweconomy.com.au]
Re: Can we have more nuclear power now? (Score:2)
I'm sorry facts went over your head. There are several countries operating profitable nuclear power. France and South Korea come to mind. There are probably others.
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If nuclear power plants are so great, we'll let you fund one and then you can have all the profit that results from it.
There's people standing in line waiting for the federal government to issue licenses to build. Some of them have been there for 40 years.
The only thing holding back new nuclear power right now in the USA is the federal government. I suspect that one good way for the government to get a lot of people to work in short order is to issue permits for nuclear power. This doesn't mean taking shortcuts on safety. This doesn't mean handing out government money. All this means is to give investors the confidence
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There's people standing in line waiting for the federal government to issue licenses to build. Some of them have been there for 40 years.
It turns out they're also standing in line waiting for the federal government to hand them money. Nuclear power plants are heavily government-subsidized and are never actually profitable. https://www.diw.de/de/diw_01.c... [www.diw.de]
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It turns out they're also standing in line waiting for the federal government to hand them money. Nuclear power plants are heavily government-subsidized and are never actually profitable. https://www.diw.de/de/diw_01.c [www.diw.de]...
The 1980s called, they want their anti-nuclear bullshit back. Let's take a few points from the abstract.
The findings show that nuclear energy can by no means be called âoecleanâ due to radioactive emissions, which will endanger humans and the natural environment for over one million years.
An isotope that is radioactive for over a million years is not a radiation hazard. The candle that burns twice as bright burns half as long. Depleted uranium is radioactive, it's primary constituent element is uranium-238. What is the half life of U-238? Over four billion years. https://en.wikipedia.org/wiki/... [wikipedia.org]
What do people use depleted uranium for? Well, for one it's used as protection against r
Clorox? (Score:2)
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The zooxanthella on which corals depend to survive, and which also help give corals their colour leave when coral becomes sick (such as from being too hot). That makes them go white and unable to feed, sometimes the zooxanthella returns, but more often it doesn't and they just die. All you're left with are white coral skeletons that eventually get overwhelmed by algae growth which typically prevents new coral from establishing.
This isn't necessarily permanently fatal to a reef, if you have healthy parrotfis