Saturday, April 27, 2013
Amid all the flim-flam below there is only one solid fact: Corals can survive higher temperatures -- as has often been shown elsewhere
Experts say that more than half of the world's coral reefs could disappear in the next 50 years, in large part because of higher ocean temperatures caused by climate change. But now Stanford University scientists have found evidence that some coral reefs are adapting and may actually survive global warming.
"Corals are certainly threatened by environmental change, but this research has really sparked the notion that corals may be tougher than we thought," said Stephen Palumbi, a professor of biology and a senior fellow at Stanford's Woods Institute for the Environment.
Palumbi and his Stanford colleagues began studying the resiliency of coral reefs in the Pacific Ocean in 2006 with the support of a Woods Institute Environmental Venture Project grant. The project has expanded and is now being funded by Conservation International and the Bio-X program at Stanford.
"The most exciting thing was discovering live, healthy corals on reefs already as hot as the ocean is likely to get 100 years from now," said Palumbi, director of Stanford's Hopkins Marine Station. "How do they do that?"
Coral reefs form the basis for thriving, healthy ecosystems throughout the tropics. They provide homes and nourishment for thousands of species, including massive schools of fish, which in turn feed millions of people across the globe.
Corals rely on partnerships with tiny, single-celled algae called zooxanthellae. The corals provide the algae a home, and, in turn, the algae provide nourishment, forming a symbiotic relationship. But when rising temperatures stress the algae, they stop producing food, and the corals spit them out. Without their algae symbionts, the reefs die and turn stark white, an event referred to as "coral bleaching."
During particularly warm years, bleaching has accounted for the deaths of large numbers of corals. In the Caribbean in 2005, a heat surge caused more than 50 percent of corals to bleach, and many still have not recovered, according to the Global Coral Reef Monitoring Network, an international collaboration of government officials, policymakers and marine scientists, including Palumbi.
Havens of healthy reefs
In recent years, scientists discovered that some corals resist bleaching by hosting types of algae that can handle the heat, while others swap out the heat-stressed algae for tougher, heat-resistant strains. Palumbi's team set out to investigate how widely dispersed these heat-tolerant coral reefs are across the globe and to learn more about the biological processes that allow them to adapt to higher temperatures.
In 2006, Palumbi and graduate student Tom Oliver, now a postdoctoral researcher at Stanford, traveled to Ofu Island in American Samoa. Ofu, a tropical coral reef marine reserve, has remained healthy despite gradually warming waters.
The island offered the perfect laboratory setting, Oliver said, with numerous corals hosting the most common heat-sensitive and heat-resistant algae symbionts. Ofu also has pools of varying temperatures that allowed the research team to test under what conditions the symbionts formed associations with corals.
In cooler lagoons, Oliver found only a handful of corals that host heat-resistant algae exclusively. But in hotter pools, he observed a direct increase in the proportion of heat-resistant symbionts, suggesting that some corals had swapped out the heat-sensitive algae for more robust types. These results, combined with regional data from other sites in the tropical Pacific, were published in the journal Marine Ecology Progress Series in March 2009.
To see if this pattern exists on a global scale, the researchers turned to Kevin Arrigo, an associate professor of environmental Earth system science at Stanford and an expert on remote satellite sensing of marine microalgae. Arrigo gathered worldwide oceanographic data on a variety of environmental variables, including ocean acidity, the frequency of weather events and sea-surface temperature.
Oliver then compiled dozens of coral reef studies from across the tropics and compared them to Arrigo's environmental data. The results revealed the same pattern: In regions where annual maximum ocean temperatures were above 84 to 88 degrees Fahrenheit (29 to 31 degrees Celsius), corals were avoiding bleaching by hosting higher proportions of the heat-resistant symbionts.
Most corals bleach when temperatures rise 1.8 F (1 C) above the long-term normal highs. But heat-tolerant symbionts might allow a reef to handle temperatures up to 2.6 F (1.5 C) beyond the bleaching threshold. That might be enough to help get them through the end of the century, Oliver said, depending on the severity of global warming.
A 2007 report by the United Nations International Panel on Climate Change concluded that the average surface temperature of the Earth is likely to increase 3.6 to 8.1 F (2 to 4.5 C) by 2100. In this scenario, the symbiont switch alone may not be enough to help corals survive through the end of the century. But with the help of other adaptive mechanisms, including natural selection for heat-tolerant corals, there is still hope, Oliver said.
"These findings show that, given enough time, many corals can match hotter environments by hosting heat-resistant symbionts," he explained. "While hopeful, the work also suggests that modern environments are changing so rapidly that corals may not be able to keep up. It comes down to a calculation of the rates of environmental change versus the rates of adaptation."
Heat-resistant corals also turn out to be more tolerant of increases in ocean acidity, which occurs when the ocean absorbs excess carbon dioxide from the atmosphere--another potential threat to coral reefs. This finding suggests that corals worldwide are adapting to increases in acidity as well as heat, Oliver said, and that across the tropics, corals with the ability to switch symbionts will do so to survive.
The problem of coral bleaching comes down to a collapse of the algae at the cellular level, Oliver explained. But the molecular biology of corals and their zooxanthellae under stress is shockingly understudied, he added.
To examine the corals and their symbionts at the molecular level, the researchers are collaborating with John Pringle, a professor of genetics at Stanford. Pringle and his lab have set up tanks where anemones, corals and their algae are exposed to a variety of treatments, including changes in temperature, acidity and light. That research is ongoing.
"What I hope is that we will learn some really deep and interesting things about the cellular and genetic mechanisms that allow this symbiosis to function, and about the mechanisms that come into play when the symbiosis is breaking down under stress," Pringle said. "The longer-range hope is that having that understanding will contribute to efforts in coral conservation."
The ultimate goal is to find protein biomarkers that indicate signs of heat stress and potential heat resistance, Oliver explained. Then coral reef managers could go to a reef, take small coral samples and test for the presence of the biomarkers to see how resilient the reef will be to higher temperatures.
"With this tool, managers could identify existing populations that may be more resistant to climate change and potentially prioritize their protection from everything else that kills coral reefs, like fishing and [agricultural] runoff," Oliver said.
"Although we are doing things to the planet we have never done before, it's hard to imagine that these corals, which have existed for a quarter of a billion years, only have 50 years left," Palumbi said. "And part of our job might be to figure out where the tougher ones live and protect those places."
Thursday, April 18, 2013
And the experiment makes it look like coral reefs will be in trouble if the much-foretold global warming ever arrives. Would Warmists ever get any other result?
In real-life, however, corals survive well in a whole range of temperatures. Australia's Great Barrier reef stretches over 1600 miles roughly North to South, including temperate zones and near-equatorial zones. It is one vast natural experiment on the effect of temperature variation on coral growth. And guess where in those 1600 miles corals grow best? The warmest part!
So the Warmists on the reef fiddle around with fishtanks and ignore the reality out the window. What a joke! But reality never has suited the Green/Left
Scientists have been worried about coral reefs for years, since realizing that rising temperatures and rising ocean acidity are hard on organisms that build their skeletons from calcium carbonate. Researchers on Australia's Great Barrier Reef are conducting an experiment that demonstrates just how much corals could suffer in the coming decades.
As we burn fossil fuels - we're talking about oil, gas and coal - carbon dioxide builds up in the atmosphere. Now, there are debates about how quickly that is changing the global climate, but there is no question that billions of tons of carbon dioxide have soaked into the ocean. That's making waters more acidic, which puts some ocean ecosystems at risk, particularly coral reefs. We sent NPR science correspondent Richard Harris to Australia's Great Barrier Reef to look into these consequences. His first stop was a research station on Heron Island.
RICHARD HARRIS, BYLINE: Heron Island is surrounded by a reef that is home to sea turtles, sharks, rays, brilliantly colored fish, and hundreds of other species. The spectacular scenery draws snorkelers from around the world. The island also hosts one of the world's major coral reef labs, run by the University of Queensland, and research there shows that the reefs are in trouble. Scientist Sophie Dove plunges her arms into a tank the size of a kettle drum.
SOPHIE DOVE: OK. We'll start with the plates. Uh-huh.
HARRIS: She and research assistant Annamieke van den Heuvel are weighing chunks of coral.
ANNAMIEKE VAN DEN HEUVEL: Two hundred and forty-six point nine.
DOVE: Do you want to just check the zero when I take this away?
HARRIS: Dove has recreated a simplified version of the coral ecosystem in a dozen large tanks.
DOVE: And so in each tank here we basically - I can lift up the lid - this is one of our - this is our present-day tank, if you like.
HARRIS: The water temperature and the carbon dioxide levels match the conditions on the present-day reef.
DOVE: We've got little mushroom corals, fungia, brain corals, stylophera pistolata there. It's a very common coral around the world. We've got these corals that look like bunches of flowers. They're called lobophelia.
HARRIS: The corals in this tank look healthy. And as she weighs them, she seems that they've been growing since she transplanted them here nearly a year ago. Then she opens the next tank.
DOVE: We'll hop from present day, and the next one along here is the worst of the future with a thing we call business as usual or do nothing tank.
HARRIS: Dove is pumping much warmer water with lots of added carbon dioxide into this tank. This is what the world's oceans are likely to look like later in this century when the schoolchildren visiting this island today reach middle age.
DOVE: And as you look into here, it looks quite different, as you will see.
HARRIS: Oh yeah.
DOVE: OK. So there's lot of this slimy, yucky mess(ph) of cynobacteria.
HARRIS: Clumps of black gunk swirl along the surface of the tank.
DOVE: We find that cynobacterial (unintelligible) tend to do really well in the future. The slippery slope to slime seems to be the way to go.
HARRIS: Not so for the coral. Most of it has either died or turned white, which means the organisms that live inside the coral have moved out.
DOVE: So as you see, the future is not a great place. Here's - the needle(ph) coral is underneath here. It's gone. And there's really not very much left alive.
HARRIS: In all there are four sets of tanks here: the healthiest coral are in a tank that simulates pre-industrial conditions. The present day tank looks almost as good, but the coral looks progressively worse in tanks with increasing carbon dioxide and temperature.
DOVE: We can make this a little bit (unintelligible)...
HARRIS: Now, plenty of small-scale experiments in the lab have shown that corals suffer in hotter waters and in more acidic conditions. This experiment puts those two threats together, since that's what the reefs of the future will face. Dove tries to be dispassionate about her findings, but the site touches the human chord.
DOVE: I feel pretty sad when I look into this. You know, I look at the others, the control tank, and I think, well, that would be nice if we could at least stay like that.
HARRIS: But doing so would mean civilization would have to stop burning fossil fuels immediately. That's not going to happen. Instead, once the carbon dioxide concentrations get high enough in the ocean, the stony structure of the reef actually starts to dissolve. That's bad news for the vibrant life that lives on the reef.
DOVE: There's no reef building going on here. It's reef dismantling that's going on here. Maybe some fish can survive in this type of environment, but I think we're going to lose a lot of the fish capabilities, you know, for fishing and everything. So people who are trying to live off what the reef offers them, this is going to be much harder. From a tourist's point of view, I don't imagine this is something that tourists would feel that attracted to come and see.
HARRIS: And as the reefs erode, they will offer less protection from the storm surges generated by the typhoons that sweep ashore here in Australia and throughout the South Pacific.
ANDREAS ANDERSON: Millions of humans are dependent on the reefs today.
HARRIS: Andreas Anderson is a reef scientist at the Scripps Institution of Oceanography in San Diego. He says increasing ocean acidity is a big threat to the millions of people who depend on the fish that in turn depend on the reef. He says experiments like the one on Heron Island suggest the reefs face bad times ahead later in this century, but the weakness of studies like this is that they change conditions for the corals in one sudden shock.
ANDERSON: So what we don't really understand is, you know, how quickly will this happen, to what extent will it happen. Will organisms be able to acclimatize or adapt to this over a longer time scale?
HARRIS: The best case is that the change will be slow.
ANDERSON: If it breaks down very rapidly, we are definitely in big problems. But if it takes thousands of years, then, you know, perhaps it's not so bad.
HARRIS: Sophie Dove knows no experiment is perfect, but hers is designed to look for hints that corals can adapt to their new circumstances, and she doesn't see any sign of that. We will have more definitive answers soon enough because this experiment isn't simply confined to tanks at research stations - it's playing out on every coral reef in the world.
Sunday, April 7, 2013
The reef that regenerated: Researchers find corals in Northern Australia healed themselves in just 12 years
Greenies are always talking about things that they think will "damage" reefs but reefs turn out to be pretty good at looking after themselves
A coral reef in Northern Australia severely damaged by warming seas has managed to completely heal itself in just 12 years, stunned researchers have found.
The team found that being left alone to breed on its own was key.
The discovery raises hope that other damaged reefs could 'regenerate'.
The new research shows that an isolated reef off the northwest coast of Australia that was severely damaged by a period of warming in 1998.
It was hit by coral bleaching, caused by higher water temperatures that break down the coral's symbiotic relationship with algae that provide food for coral growth.
However, the team found Scott reef has regenerated in a very short time to become nearly as healthy as it was before.
What surprises scientists, though, is that the reef regenerated by itself, found a study published Thursday in the journal Science.
James Gilmour and colleagues studied the Scott system of reefs on the edge of Western Australia’s continental shelf, which lost 70 to 90 percent of its corals to a climate-induced bleaching event back in 1998.
The researchers found that, although the corals’ reproductive abilities were reduced by the bleaching, coral cover still increased from 9 percent to 44 percent across the entire system in just 12 years.
The team say the finding is surprising because researchers have assumed that recovery from such bleaching events depends upon the delivery of larvae from other, nearby reef systems.
But, the Scott system of reefs is located 155 miles (250 kilometers) from the mainland or any other reefs.
So, Gilmour and his team suggest that herbivorous fish, which remained abundant in the undisturbed Scott system, even after the bleaching, kept microalgae in check and allowed coralline algae to thrive.
This set of conditions in turn provided a suitable substratum upon which young corals could establish and grow., they claim.
The study suggests that reef systems can recover using local sources of larvae, especially when fish are plentiful and human activities, which have been shown to slow coral recovery in the past, are limited.
At first, the reef grew slowly, mostly through the enlargement of existing coral colonies. But to really recover, the coral needs to sexually reproduce, creating sperm and egg that form embryos that then land on the ocean floor and grow into adult corals, if all goes well.
These larvae can survive for hundreds of miles, swept along by ocean currents, and colonize new areas under the right circumstances.
Larvae floating in from other reefs could have helped the reef, had it not been so isolated.
But amazingly, after about six years, the surviving corals matured and began to reproduce, creating even more new colonies than before the bleaching. 'They recovered, and the larvae they produced settled and survived, at much higher rates than is often reported,' Gilmour said. By 2012, the reef was basically back to its old self.
Thursday, April 4, 2013
The "threat" posed by coal mining is entirely imaginary. Coal has been mined for decades with no link to the reef established. Greenpeace just like mucking around in boats
THE new Rainbow Warrior docked in Brisbane's today, for the first time in 30 years, as Greenpeace prepares to launch its Queensland tour.
Berthed at Portside Wharf, the ship will be open to the public for tours later this week, as the environmental group readies for a new Great Barrier Reef campaign.
Greenpeace CEO David Ritter said its arrival has come at an important time as coal expansion threatens to destroy Queensland's reef and waterways. "If we want to stop coal barons destroying the Great Barrier Reef and all the jobs associated with it, we need to act now," he said.
Mr Ritter invited Federal Environment Minister Tony Burke and Premier Campbell Newman to come aboard and discuss concerns for the sustainability of the reef. "We are down here on the boat if Campbell Newman or Tony Burke would like to come down for a chat," he said. "They need to know it is simply not okay to destroy and industrialise the Great Barrier Reef."
Greenpeace has expressed anger at the Queensland government's support of a revised expansion of the controversial New Acland coal mine in the state's southwest, after previously announcing the mine's third stage would not go ahead.
But despite renewed plans for coal expansion, Mr Ritter said it was never too late for action. "I can't look my children in the eyes and say it's too late," he said.
"It's never too late. The decision is in the state and federal government's hands to say it's not too late to save the world, it's not too late to act."
Mr Ritter was tight lipped about plans to actively stop coal expansion in North Queensland but did not rule out any direct action as long as it was done so peacefully.
"Greenpeace always tries to directly prevent environmental harm. We don't shy away from that, but it is always done peacefully. It's hard wired into our team, peace is in our name," he said.
The Queensland campaign will kick off in Townsville on Friday when they rally support among local community members to put a stop to coal mining.