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Public Radio's Environmental News Magazine (follow us on Google News)

Coral Reefs on the Brink

Air Date: Week of

PART 1: The diversity and beauty of coral reefs have forever fascinated and enchanted us. Writer Osha Gray Davidson has explored reefs around the world and written a book called “The Enchanted Braid: Coming to Terms with Nature on the Coral Reef.” He talked with Living on Earth’s Steve Curwood about how much reefs have changed in the last decades and why he thinks they’re worth saving.
PART 2: Scientists at the University of Queensland in Australia say that warming temperatures could cause the demise of Australia’s Great Barrier Reef within the next 90 years. Ove Hoegh-Guldberg, the paper’s lead author, talked to host Steve Curwood about his most recent research, and his call for a cut in global emissions to save, what he thinks, is one of the world’s treasures.


CURWOOD: From the Jennifer and Ted Stanley Studios in Somerville, Massachusetts, this is Living on Earth. I’m Steve Curwood.

More than 30 years ago I went diving in the Virgin Islands into the wonderland known as coral reefs. But when I went back a few years ago, all had changed. There were still a few bright rainbows of fish and coral, but most of the area was ragged and bleak. It’s not just a problem in the Virgin Islands; pollution and exploitation have taken a heavy toll on coral reefs around the world, and climate change is threatening to make matters even worse. Indeed, according to a group of scientists in Australia, warming temperatures could cause the demise of the world’s largest coral formation: the Great Barrier Reef. We begin our program today with Osha Gray Davidson, author of “The Enchanted Braid: Coming to Terms with Nature on the Coral Reef.” His book chronicles the natural history of what he calls “the soul of the sea.” Osha, can you explain what you mean by that?

DAVIDSON: You have to understand about coral reefs that they only make up about two-tenths of one percent of the area of the global ocean, and yet one-third of all marine fish species are found there. And their estimated number of species of all kinds living there is somewhere between one and nine million.

So coral reefs are just this unbelievable tiny fraction of the sea, but that so much of the sea depends on. It’s a nursery for all sorts of fish. The small fish live in and around the coral reef, and then when they grow they leave the reef area and they go out into the ocean. And they affect the entire ocean. So by saying that they’re the soul of the sea, what I mean is they’re the very heart of it, and the sea would be a completely different thing if it weren’t for coral reefs.

CURWOOD: There’s a part in your book where you describe a snorkeling expedition that you make. And it has some, well, some wonderful descriptions in it. I’m wondering if you could read that for us now.

DAVIDSON: Sure. (READING) I must have approached the reef crust, for all at once living corals were everywhere in the amazing variety of color and form that I had read described. Leather-like greenish corals. The colony folded in on itself many times. Large tabletops of lacey coral structures, comprising perhaps a million individuals, their tiny tentacles still withdrawn and waiting for darkness. Blue-tipped corals, and others with a reddish tinge. And strewn among the bottom, like upside-down mushrooms, Fungia corals.

Fishes were everywhere too. An orange and white striped clown fish peered out from a tangle of purple-tipped stinging tentacles belonging to a sea anemone. Curiosity got the better of him, and as long as I remained immobile, the clown fish inched his way toward me. As soon as I moved, however, he tore back into the safety of the tentacles, like a base runner tagging up. A black-tipped reef shark swam lazily by. After moving out of range, the shark returned, eyed me for a moment, and then disappeared again.

Multicolored grasses poked in and out of holes. Angel fishes of many varieties nibbled bits of algae from rocks and coral. Large gaudily colored parrotfishes did more than nibble at the coral. They bit off entire chunks of coral, hard skeleton and all. One coral scientist has described the parrotfish’s unique ability this way: they’d eat a McDonald’s parking lot to get the grease out of it.

The clear, clean waters of the Bahamas include many healthy coral reefs such as this site at Sandy Cay Reef, Abaco, Bahamas. (Credit: Craig Quirolo)

CURWOOD: I’ve been under the waves in the Caribbean and seen some coral reefs, actually quite a long time ago -- probably in the late ‘60s, early ‘70s, I went diving there for the first time. And then in recent times I’ve been back and they look very different. Why is that?

DAVIDSON: You’re absolutely right. Reefs have declined dramatically. I mean, when I was in Florida in the very early ‘70s, comparing that to what I found when I started research for this book – and I spent a few weeks at the Mote Marine Laboratories in the Florida Keys – and it was amazing the difference. The large stands of elk horn coral were gone. And that was because of a disease that had gone through.

And that’s something that hasn’t gotten all that much attention, the role of disease. It’s not just coral bleaching, which is bad enough. But what we’re doing by putting nutrients into the water, by putting sediments into the water, and by raising the water temperature is we’re turning the coastlines into giant Petri dishes that allow pathogens to grow and destroy all sorts of marine life. So there was a massive die-off in the Caribbean of elk horn corals, and they’re no longer the dominant coral on many reefs. And that’s just in the blink of an eye that that’s changed.

CURWOOD: Help me a little bit please with the biology of coral. You look at a coral reef and it looks like plants, and yet these are animals.

DAVIDSON: It’s truly amazing – it’s one of the most amazing things about corals. And it’s one of the reasons I titled the book “The Enchanted Braid.” Coral is an animal, it’s classified as an animal, but it’s really a braid of the three primary groupings that the world was organized into in the 18th century when taxonomy was really invented, and that’s animal, mineral and vegetable.

Well they’re certainly animals because they don’t photosynthesize. Corals cannot produce their own food, so they have these little stinging darts that come out and they feed on things that drift by. But they only get a small amount of their nutrients from eating these other creatures, and for a long time ecologists had no idea where they were getting their energy. And they looked all around the corals in trying to see what was around them, which is natural enough to do, but they couldn’t account for a lot of the energy that the corals had.

Sunlight is essential to the healthy growth of corals because it enables photosynthetic activities to occur in the zooxanthellae, a symbiotic algae that lives within the host coral and processes it waste products. The clear waters at this reef allow the sunlight to reach the corals. Sandy Cay Reef, Abaco, Bahamas (Credit: Craig Quirolo)

And then they finally looked inside the corals, and they found that there’s a tiny algae living inside the tissues of corals in a symbiotic relationship where they’re each helping each other out. And that algae is photosynthetic, it converts sunlight into food. And the algae shares that food -- a large percentage of it, in fact – with the corals. So corals were at one point described as plant/animals, zoophytes, which is Greek for “plant animal.” And there’s some truth to that, because they are this braid of those two.

And then the final part of this braid is that corals build reefs by removing calcium from sea water. And they secrete it in these thin layers of calcium carbonate, which is a form of limestone, and that builds the reef. And so you’ve got animal, vegetable and mineral all combined in one single entity.

CURWOOD: What are some of the most spectacular coral reefs out there?

DAVIDSON: I was off the coast of northern Sulawesi in Indonesia, and as I went down, first at the top, there was coral – just hundreds of species, probably, it was just gorgeous, and multicolored fish -- truly just outlandish and amazing. And then as I went deeper, at about 65 feet, those hard corals – the reef building corals that depend on the light, with their algae in them, to survive – now there are very few of those, and that was beginning to have other species of coral, the soft corals. So that was really the most diverse area, as far as corals go.

And once you get down to 100 feet it’s almost all soft corals, these hard to describe but unbelievably beautiful swaying, gelatinous creatures and spiral wire corals. Which if Dr. Suess had invented a coral, that’s what he would have made, the spiral wire. And there were all these sponges, and they’re crinoids, which are these beautiful feathery-headed animals that look like plants. And that’s down at 100 feet. So that was one of my favorite dives -- getting to see, as you go down, the different zones of a reef.

CURWOOD: Now, coral reefs are closely intertwined with many local communities and economies. Tell me a story of how local people use the reefs, from anywhere in the world.

DAVIDSON: Well, let me go up to Indonesia because that’s one that comes to mind very quickly. When I was there I was on a very small island, and the community was a traditional fishing community. And a man there told me a story through the interpreter. He said that before, years ago, when he would to fish for the day, his wife would start the fire to cook dinner and that was his cue to go out and fish. And by the time she was ready with the water boiling he’d be back with a fish. And he said it now took him two days to get fish for dinner, and that has changed their lives on this island dramatically.

It’s had another consequence that boomerangs and ends up hurting the reef again. Because it’s so hard to get fish, they’ve taken in this area -- and many areas of the world -- dynamite fishing or blast fishing. They use – it’s generally, I think, pop bottles filled with gunpowder. And you go out to the coral reef area where there’s a lot of – there are some fish, anyway – you light the fuse and you throw it in the water. It blows up, if you’ve timed it right, so that it stuns a lot of fish and kills a lot of fish, and then you collect them.

Well, there are a number of problems there, and one is that you blast a hole in the coral reef itself. It’s enormously destructive. If you just do it once, well, it takes many many years for it to recover. If you just do it once, okay, it will eventually recover. But if you blast fish in one area over and over, what will happen is you’ve reduced the entire area to coral rubble, algae takes over and there’s no hope for it returning.

Another effect of this is on the people themselves, the blast fishermen. This is a devastating problem in these areas, and it’s in the Philippines, it’s in Indonesia and many other parts of the developing world. They throw the homemade bombs into the ocean, and when that happens, a certain number of times they misjudge the timing, and it explodes in their hand and they lose hands and arms. And in one village I was told that a quarter of the population of men have lost a limb to blast fishing. So the effects on the people of this desperation, not only does it destroy the reefs, but it destroys the people who are dependent on the reefs.

If reefs are to survive in many developing nations, the pressures on fishing must be relieved.In the waters near Bali, Indonesia, former fishermen have found a sustainable alternative livelihood by “farming” seaweed that is then sold to Japanese cosmetic and pharmaceutical firms. (Photo: Osha Gray Davidson)

CURWOOD: So what are the problems, what are some of the problems, associated with the loss of coral reefs?

DAVIDSON: If we destroy coral reefs we’re destroying the heart of biological diversity for the planet. And the awe that I felt when I was on the coral reef, you can read about that same awe in Darwin’s writings. And so many divers who have gone to reefs experience that same feeling of awe. And future generations deserve to have the opportunity to experience that also. Coral reefs are simply – they’re a large part of what makes this planet unique. They’re the jewel in the crown of the Blue Planet, and if we aren’t willing to save them, if we’re not willing to take the steps that are necessary to preserve them, I don’t know what in the natural world we could find that would be important enough to protect.

CURWOOD: Well I want to thank you for taking this time with me today. Osha Gray Davidson is author of “The Enchanted Braid – Coming to Terms with Nature on the Coral Reef.”

DAVIDSON: Thank you very much, Steve. It’s been a joy talking with you.

CURWOOD: Coming up after a short break, we’ll be joined by professor Ove Hoegh-Guldberg, who is the director of the Center of Marine Studies at the University of Queensland in Australia and is co-author of a study on climate change and the threat to Australia’s Great Barrier Reef. Stay tuned to NPR’s Living on Earth.


CURWOOD: Welcome back to Living on Earth, I’m Steve Curwood. Today we’re talking about coral reefs, and for the next part of our program we turn to Ove Hoegh-Guldberg. He’s the director of the Center of Marine Studies at the University of Queensland and co-author of a study on climate change and the threat it poses to Australia’s Great Barrier Reef. Professor Hoegh-Guldberg’s research indicates that the reef could die off entirely in the next 90 years. Some conservationists have labeled that possibility a global crisis and a nightmare for the planet. And Australians could expect to lose more than $2 billion a year that the Great Barrier Reef currently adds to their economy from tourism. Professor Hoegh-Guldberg is on the line now from Brisbane. Thanks for joining us.

HOEGH-GULDBERG: Hi, nice to be with you.

CURWOOD: Tell me, how did you get interested in coral reefs anyway?

HOEGH-GULDBERG: Well, I can trace my interest in coral reefs back to a trip I made with my Danish grandfather, who went to the Great Barrier Reef as a tourist and as a butterfly collector. We went for a snorkel, and this was 1969 when, I guess, men were on the moon, and I got to the reef. And it was really, ah, I can still remember sort of entering the water and seeing my first butterfly fish, you know, which had significance for my grandfather. Yeah, from thereafter I hungered after getting up to the reef, or going below the water in Sydney and imagining I was on a coral reef.

CURWOOD: Now, who’s your co-author on this project?

HOEGH-GULDBERG: Hans Hoegh-Guldberg, who is actually my father. And he’s an economic forecaster, has written many, many reports on things like, what is tourism going to do in the future and so on. And so it was a natural partnership for us to try to ponder the future of a very complex economic and social phenomenon, which is the Great Barrier Reef.

CURWOOD: If you had to describe a coral reef, how would you describe it?

HOEGH-GULDBERG: I suppose it is very much like the most amazing metropolis, full of, you know, clowns and artisans that are doing things in ways which sort of defy almost what you’ve been taught about in terms of evolution. And so when you see parrotfish going across the reef that are painted pink and bright green -- and that’s the result of natural selection -- you have to go, “Wow! You know, what function does that have?”

And it’s only when you delve into it do you realize that all of these sort of signals, and the things we’re picking up on, are actually very finely tuned adaptations. You know, the parrotfish is trying to show off how dominant he is over his band of females that he rules over. So, it’s a funny place, because at first it seems impossible, but then when you get to know the million species – and it may be as much as nine million species living on coral reefs around the planet – each has a special and finely crafted position within that ecosystem.

CURWOOD: And how is it that you came to decide you wanted to do a study about climate change and coral reefs?

HOEGH-GULDBERG: Well, my interest in climate change was quite accidental. I did my Ph.D. at UCLA in Los Angeles, and I started studying a phenomenon known as coral bleaching. This was in the early to mid ‘80s, and at that point we didn’t really know what this phenomenon was. All we knew was that reefs off Florida and the Caribbean had been going white over large areas. And in studying that I, by the end of my Ph.D., had sort of come to the conclusion that, like some early authors in the ‘70s, a small change in temperature can cause this phenomenon. And in fact, by that time satellite experts at NOAA and Washington and so on were reporting a great correlation between bleaching and sea temperature rise, and what we were seeing was the first signs of climate change.

CURWOOD: Now you’ve just finished a report on the impact of climate change on Australia’s Great Barrier Reef. Can you tell us about what’s in your study and what you found?

HOEGH-GULDBERG: Well one of the most important aspects of climate change -- you know, the large scale mass destruction, for example, that we saw in 1998 when we lost 16 percent of the world’s corals -- we get to the point where we say, well so what? Are corals important? And so what we tried to do with this report was to take the perspective on what’s happening to reefs to that very important level of the socioeconomic ramifications. What does it mean for Australia if the Great Barrier Reef no longer has coral on it? And to do that you really need to evaluate the importance of coral, and when you do that you actually come up with some surprising sort of facts about how dependent a lot of the local economies in Australia are to the Great Barrier Reef.

CURWOOD: Now, Australia is one of a very few industrialized countries that have yet to ratify the Kyoto Protocol. Russia hasn’t, although recently Mr. Putin in Russia said he would. The United States hasn’t, and Mr. Bush has said pointedly he will not. And Australia hasn’t. Do you think that your report is going to change any minds there in Australia about the Kyoto Accord?

HOEGH-GULDBERG: Well, I think it’s part of a fabric that we have to build up. Because I think up until probably the last couple of years, I think politicians have been able to avoid the idea that there are great costs of not responding to climate change. And I should say that the various ministers that are involved with looking after the Great Barrier Reef have actually been quite responsive to the report. And there is a sea change I think happening within the Australian political scene where people are starting to realize that isolationism, which is essentially what not signing Kyoto amounts to, will not work in the long run.

And so I think that when people are actually told that well, it could be an $8 billion cost over 19 years, and that’s just the real minimum part of this cost in terms of the effect of climate change on the Great Barrier Reef alone. And you start to add up the effect on rainforests and you start to look at the impacts on agriculture and water availability, you start to see that the costs of not responding are much, much larger than the costs of responding.

CURWOOD: Now professor Hoegh-Guldberg, let me ask you this. In your report you state that only if global average temperature change is kept to below two degrees Celsius can the Great Barrier Reef have any chance of recovering from the damage that’s being predicted here. And I’m wondering how likely you think it is that, in fact, we can keep temperatures from rising more than that here on earth?

HOEGH-GULDBERG: That’s one of the more tricky scenarios, unfortunately, trying to keep the temperature from rising more than two degrees. That’s the lower end of the intergovernmental panel on climate change, which is that huge body of scientific credibility that have come up with future scenarios. That two degrees is at the bottom range. I mean, the more likely range that we’re going to hit by the end of this century is about four degrees. And so you’re right, it’s a very tricky thing that we have to achieve here.

But I think unless we understand what the goal is, I mean we can’t – science has to deliver the truth to society, I think, about what the state of opinion is, and what we think is where we need to go in terms of this. If we don’t, of course, then we’re kidding ourselves. So I think we’ve got to really call it as it is, and then I think we’ve got to look at what we can do socioeconomically. I mean, we are an amazing species, to put it bluntly. What technologies we may dream up in the next few decades may totally change the perspective on what we can actually achieve.

CURWOOD: In your report you talked about the importance of the reef having ecological resilience in order to survive the impacts of climate change. And just recently your environment minister there in Australia – David Kemp is his name, I have that right?

HOEGH-GULDBERG: That’s right.

CURWOOD: I believe he announced that he’s going to increase the protective zones on marine sanctuaries in the Great Barrier Reef from four percent to something like 30 percent or a third, something like that?

HOEGH-GULDBERG: Well, the good news is that that’s been passed, so the Great Barrier Reef, which only had 4.6 percent in no-take zones, now has 32.5 percent of the reef protected from any sort of extraction. So that process that we went through last year was really one of the, I think, one of the great success stories of conservation. And it came about using the sort of societal pressures – I mean everyone loves the Great Barrier Reef in Australia and I think people were quite shocked when they found out that only 4.6 percent was actually in no-take zones, you know, complete protection zones. Because everyone had assumed that if it’s the Great Barrier Reef Marine Park that must certainly mean that it’s all protected. Um, I was just going to go back to that question of reef resilience –


HOEGH-GULDBERG: That question is a very interesting because one of the outcomes early in the piece -- and it was sort of almost sort of, you know, a tragic debate, if you like. People would say well look, if reefs are all stuffed because of climate then why are we bothering to, you know, reduce the impact of industry on coastlines that have coral reefs? And why are we trying to solve sediment problems in rivers and agricultural run-off? And the answer actually is that those other issues are even more important now because of the following issue, and that is that we know that reefs that get affected by this phenomenon of coral bleaching will recover faster if we’re not impacting them with all these other issues. If we’re not hitting them with huge amounts of sediment when they’re bleached they’ve got a good chance of bouncing back. And that’s what reef resilience is all about. It’s about how quickly you can get up after you’ve been knocked down.

Now, of course, if you are being beleaguered by a whole series of other stresses then your ability to get back up off the ground after a climate event, of course, is small. So reef resilience, conservation of reefs, is even more important than it was before the realization of the climate threat. I mean, now we really should be looking at these large no-take zones, because we’ve got to leave reefs with as many options, if you like, for bouncing back from bleaching events. Let’s go back to the parrotfish, the garish parrotfish walking--swimming across the reef. They actually play an important role in keeping the algae at bay, right? They eat algae, so they’re cropping coral reefs all the time. And when you have a bleaching event and you have parrotfish then the parrotfish essentially keep the bottom of the ocean open for the settlement of corals and so on. Now if you don’t have the coral—if you don’t have those parrotfish you don’t have the gardeners, and you have a bleaching event. Then the algae have been observed to go wild, you know: Corals die off, the algae settle onto the dead corals, the parrotfish aren’t there to eat them, and essentially what happens is the reef changes to an algal-reef. And of course that’s a very graphic example of why you need MPAs and these large no-take zones, you know, time of climate. We need as many options, many components of coral reefs to make sure that they can bounce back after periodic periods of stress.

CURWOOD: Ove, I wonder if you thought when you got into science that you would have to do so much politics?

HOEGH-GULDBERG: That is a very good question. I had no idea (laughs) and it came down to…I think—you know I saw my grandfather, this lepidopterous butterfly collector, and you know he would spend his days sort of looking at his collections and writing papers on, you know, what was going on with the butterflies and so on. And I used to look at the historic figures like McClay, who was a guy who operated out of Australia in the 1800s which were academics and they would literally be pondering on biology by the day and probably taking tea at the regular hour and so on. But the way biology’s gone now is that we’ve been linked into these incredibly important debates. When you are talking about, you know, the prospect of a massive decline in these beautiful ecosystems – which, when you put a number on them in terms of tourism and fisheries, that’s really overlooking the fact that it’s really an art treasure which you can’t cost – and when you’re faced by this you find that you’re compelled into having to provide scientific opinion. And in some ways to enter into the game of politics because it becomes so important. That’s where the action is. Yeah, no, I had no idea.

CURWOOD: We need to go, but tell me – I’ve actually never been to the Great Barrier Reef -- how much time do I have--

HOEGH-GULDBERG: That’s sinful!

CURWOOD: How much time do I have to get down there to see it the way it should be seen?

HOEGH-GULDBERG: Well, I think we’ve got a good few decades left, and it really depends on what your and my country do in terms of controlling greenhouse gas emissions, but I’d say you’ve got a good decade or two. It depends on, obviously—look, this is so beautiful I can’t believe you haven’t come down here and seen it! I mean it really is one of the most spectacular treasures, and Osha did a very good job I think of describing going over the reef crest. And I mean that’s just the beginning of the journey. I mean when you get down to 30 meters and you see these soft coral gardens that are really like some Lewis Carroll manifestation – you know the pinks and greens and strange fish that sort of poke out, you know they poke their faces out and then disappear and then strange shellfish try to sort of catch your eye – it really is—look, you’ll have to come down to Heron Island and I’ll host you, ok? There’s an offer on radio.

CURWOOD: Well, how can I turn that down?

HOEGH-GULDBERG: Well, I hope you won’t.

CURWOOD: Ove Hoegh-Guldberg is co-author of “The Implications of Climate Change for Australia’s Great Barrier Reef” and he’s the director of the Center for Marine Studies at the University of Queensland in Australia. Thanks for taking so much time with me today.

HOEGH-GULDBERG: Oh, it was very much a pleasure. Thank you.


CURWOOD: You can hear our program anytime on our website. The address is Living on Earth dot org. That’s Living on Earth dot org. You can reach us at comments at loe dot org. Once again, comments at loe dot org. Our postal address is 20 Holland Street, Somerville, Massachusetts, 02144, and you can call our listener line at 800-218-9988. That’s 800-218-9988. CDs, tapes and transcripts are $15.



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