Corals Face Catastrophic Bleaching

[marchesarosa]

Chance coral can survive warmer ocean
Sydney Morning Herald April 1, 2012


Hope … some coral can withstand temperature change.

CORAL that has been exposed to fluctuating water temperatures in the past may be able to survive warmer ocean climates in the future, giving hope to the long-term wellbeing of the world's reefs.

A team of scientists from the Australian Nuclear Science and Technology Organisation (ANSTO), the University of British Columbia in Canada and the Scripps Institution of Oceanography in the US made the discovery after studying the health of coral in the remote Pacific island republic of Kiribati.

Their findings were published in the peer-reviewed online journal PLoS One yesterday.

Dr Jessica Carilli, a post-doctoral fellow in ANSTO's Institute for Environmental Research who took part in the research, said the findings suggest that some coral reefs will be able to withstand a predicted rise in sea temperature caused by climate change.

When water temperature rises, the algae that gives coral its colour and provides food is expelled in a phenomenon known as coral bleaching. However, in areas where temperatures fluctuate, the coral seems to have adapted for survival.

The world's largest best known reef, the Great Barrier Reef, covers such a large region, some areas have stable sea temperatures while others do not.

Dr Carilli said it would be hard to predict how the 2600-kilometre long reef would fare overall in rising sea temperatures.



Read more: www.smh.com.au/environment/climate-change/chance-coral-can-survive-warmer-ocean-20120331-1w518.html#ixzz1qn9SG93V

[StuartG]

MM,
I found this on another thread
Re: WWF again!
« Reply #6 on 21/3/2012 at 12:16 »

Scientists 'crying wolf' over coral
BY: JAMIE WALKER From: The Australian December 19, 2009

"Professor Ridd said scientists who predicted corals would be mostly extinct by mid-century had a credibility problem because the Great Barrier Reef was in "bloody brilliant shape". "

radio4scienceboards.proboards.com/index.cgi?action=display&board=politics&thread=260&page=1#16810

and there's this paper ...
www.ncbi.nlm.nih.gov/pmc/articles/PMC3053361/

...as usual, nobody's told the coral. "Backpedalling" ? I would say so, despite what they say, their own research suggests that the coral is tiggling along much like it's always done, such that 'win some, lose some'. On this forum somewhere there's a piece about the SE coast of Auz, despite the heat and extra ionising radiation [their #13 = v high] it is still OK.

ps. should read SW coast, only two Europe widths out, what a plonker!

[marchesarosa]

Thanks for those links, stu. I was looking for the "Crying Wolf" article but couldn't remember where I posted it. As you can see I try to keep stuff on the same subject together, not always successfully.

[StuartG]

Never mind we all have problems, see above!

[marchesarosa]

A new study confirms that the threat from CO2 is exaggerated


Matt Ridley writes:


A new study of the Great Barrier Reef will apparently confirm what I argued in The Rational Optimist that local pollution and over-fishing are a much greater threat to coral reefs than either climate change or changing alkalinity (sometimes wrongly called acidification).

The actual paper will appear in Current Biology, but this is from the press release from James Cook University (I hate it when scientists announce their results by press release before the journal article is available).

Update: here's the article in press, but behind a paywall. www.sciencedirect.com/science/article/pii/S0960982212002552

Quoting one of the authors, Terry Hughes:

"This study has given us a more detailed understanding of the sorts of changes that could take place as the world's oceans gradually warm and acidify.

"And it has increased our optimism about the ability of coral reef systems to respond to the sorts of changes they are likely to experience under foreseeable climate change."

The good news from the research, says Professor Hughes, is that complete reef wipeouts appear unlikely due to temperature and pH alone.

"However, in many parts of the world, coral reefs are also threatened by much more local impacts, especially by pollution and over-fishing. We need to address all of the threats, including climate change, to give coral reefs a fighting chance for the future."

The press release gives more details of the study:

They identified and measured a total of 35,428 coral colonies on 33 reefs from north to south. Studying corals on both the crests and slopes of the reef, they found that as one species decreases in abundance, another tends to increase, and that species wax and wane largely independently of each other.

And:

"We chose the iconic Great Barrier Reef because water temperature varies by 8-9 degrees along its full length from summer to winter, and because there are wide local variations in pH. In other words, its natural gradients encompass the sorts of conditions that will apply several decades from now under business-as-usual greenhouse gas emissions.'

This is a point that I have been emphasising recently: that natural variation in ocean pH is already greater than any future trend likely from carbon emissions.

www.rationaloptimist.com/blog/coral-reefs.aspx

[marchesarosa]

Scientists 'crying wolf' over coral
BY: JAMIE WALKER From: The Australian December 19, 2009

A SENIOR marine researcher has accused Australian scientists of "crying wolf" over the threat of climate change to the Great Barrier Reef, exposing deep division about its vulnerability.

Peter Ridd's rejection of the consensus position that the reef is doomed unless greenhouse emissions are checked comes as new research on the Keppel group, hugging Queensland's central coast, reveals its resilience after coral bleaching. Professor Ridd, a physicist with Townsville's James Cook University who has spent 25 years investigating the impact of coastal runoff and other problems for the reef, challenged the widely accepted notion that coral bleaching would wipe it out if climate change continued to increase sea surface temperatures. Instead of dying, the reef could expand south towards Brisbane as waters below it became warmer and more tolerable for corals, he said.

His suggestion is backed up by an Australian Institute of Marine Science research team headed by veteran reef scientist Ray Berkelmans, which has documented astonishing levels of recovery on the Keppel outcrops devastated by bleaching in 2006.


Professor Ridd said scientists who predicted corals would be mostly extinct by mid-century had a credibility problem because the Great Barrier Reef was in "bloody brilliant shape".

He said the reef had defied predictions that it would be overwhelmed by crown of thorns starfish, smothered in sediment from river runoff or poisoned by sediment and chemicals washed on to corals from the mainland. He accepted that ocean acidification associated with climate change was a genuine danger because it could impede the process of coral calcification, destroying the reef's building block. Scientists responsible for "crying wolf" over lesser threats had done the research community a disservice, he said.

"Ten years ago, I was told that the coral was going to die from sediment, and we have proved that is complete rubbish," Professor Ridd told The Weekend Australian.

"They are saying that pesticides are a problem, but when you look at the latest data, that is a load of rubbish. They are saying bleaching is the end of the world, but when you look into it, that is a highly dubious proposition.

"So when something comes along like the calcification problem, you are sort of left with this wolf story . . . they are crying wolf all the time.".........

www.theaustralian.com.au/national-affairs/climate/scientists-crying-wolf-over-coral/story-e6frg6xf-1225811910634

[marchesarosa]

Jennifer Morohasy

All the species of coral that occur in the Great Barrier Reef also grow in Papua New Guinea where the waters are 2 degrees warmer.

[marchesarosa]

One vulnerable coral type adapts to ocean acidification in just 6 months

We already know that pH varies naturally across the oceans of the world. In some sites, it varies more in a single day than global oceans are likely to face in a century.

But cold water corals live in deep water, are slow growing, and hard to study.

Six years ago, experts in cold water corals were telling us how they would be likely to fall victim to ocean acidification first, and that they believed this for good reasons but with little experimental data. But about a year ago data came out (by one of those same experts) showing that rather than being the badly affected, cold water corals adapted to effectively very high levels of CO2 and possibly even increased their calcification rates. Eight days after the pH was changed suddenly, the corals did worse. But when the experiment was continued for six months, the results turned right around. The researchers pointed out how useful longer studies are: “This is the first evidence of successful acclimation in a coral species to ocean acidification, emphasizing the general need for long-term incubations”.

The paper is called “Acclimation to ocean acidification during long-term CO2 exposure in the cold-water coral Lophelia pertusa.” The pH fell as low as 7.75 in the long term study (from the normal pH of about 8.1).

It’s highly unlikely the atmospheric levels of CO2 will reach 1,000 ppm in the next couple of centuries, but if they did, it appears that at least one major and widespread species of cold water coral can adapt within six months. Co2 feeds plant life above the water, and atmospheric levels were much higher during the time that corals evolved. That doesn’t guarantee anything, but suggests scientists could have been more cautious in predicting a disaster when they didn’t have the data.

more here
Jo Nova
joannenova.com.au/2012/10/one-vulnerable-coral-type-adapts-to-ocean-acidification-in-just-6-months/

[marchesarosa]

Remote reefs can be tougher than they look. They recover pretty fast


WA's Scott Reef has recovered from mass bleaching in 1998



Isolated coral reefs can recover from catastrophic damage as effectively as those with nearby undisturbed neighbours, a long-term study by marine biologists from the Australian Institute of Marine Science (AIMS) and the ARC Centre of Excellence for Coral Reef Studies (CoECRS) has shown.

Scott Reef, a remote coral system in the Indian Ocean, has largely recovered from a catastrophic mass bleaching event in 1998, according to the study published in Science today.

The study challenges conventional wisdom that suggested isolated reefs were more vulnerable to disturbance, because they were thought to depend on recolonisation from other reefs. Instead, the scientists found that the isolation of reefs allowed surviving corals to rapidly grow and propagate in the absence of human interference.

Australia's largest oceanic reef system, Scott Reef, is relatively isolated, sitting out in the Indian Ocean some 250 km from the remote coastline of north Western Australia (WA). Prospects for the reef looked gloomy when in 1998 it suffered catastrophic mass bleaching, losing around 80% of its coral cover. The study shows that it took just 12 years to recover.....

more links here
wattsupwiththat.com/2013/04/07/good-news-about-coral-reefs-they-recovered-from-warming/

[marchesarosa]

Just to remind you 1998 was the year after a peak El Nino event when the world's oceans hopped up a step in temperature.