The Infinite Monkey Cage - Coral Reefs

Episode Date: January 27, 2020

The Magic of CoralBrian Cox and Robin Ince are joined on stage by comedian Marcus Brigstocke and marine biologists Professor Callum Roberts and Dr Heather Koldewey as they look at the amazing creatures that create and colonise coral reefs. Just two microscopic organisms are responsible for the creation of these incredible structures, structures so huge that they can be seen from outer-space. Brian, Robin and the panel talk about the vital yet delicate relationship between the coral polyp and and its tiny plant lodger, how they evolved to be so co-dependent, and how this unique partnership has lead to some of the most diverse ecosystems on the planet. They also look at the very real threat to our planet's reefs as our oceans warm, and what, if anything can be done.Producer: Alexandra Feachem

This is the first radio ad you can smell. The new Cinnabon pull-apart only at Wendy's. It's ooey, gooey and just five bucks for the small coffee all day long. Taxes extra at participating Wendy's until May 5th. Terms and conditions apply. BBC Sounds. Music, radio, podcasts. Hello, welcome to the infinite. I did a very special hello, by the way. That was what we call the podcast hello, which means that because slightly younger people often listen to BBC Sounds for their podcasts, I go, hello, there we are.

Can I just explain who that is? That's Robin Ince, I'm Brian Cox, and you are listening to the BBC Infinite Monkey Cage podcast on BBC Sounds, which you know because presumably you've downloaded it. My wife's family used to own a mermaid. This is entirely true. They owned a mermaid,

and eventually they sold it to a hair salon in North Shields. And it turned out it was basically an embalmed cod body with a monkey's head stuck to it. And I have no idea why a hair salon would want that, as if that was going to be kind of one of the tips. I was going to ask for a perm, but I think instead instead could you make me look like a decaying macaque head what are you talking about well the trouble is that most of this show is it's about coral and it's about the ocean and i've not had any oceanic adventures because you've had loads on the telly

and in real life whereas uh i have a kind of like, well, I suppose really, I'm allergic to both seawater and jeopardy. Richard Feynman once said, the imagination of nature is far greater than the imagination of man and the oceans offer many examples of the eccentric creations of natural selection from the blobfish to the blue whale. But it's not merely the great and grotesque that should fascinate. What of the microscopic organisms that create great reefs?

Today we have a distinguished panel to discuss the magic and wonder of coral, and they are... I'm Callum Roberts, Professor of Marine Conservation at the University of York and author of Reef Life, an Underwater Memoir. And I think the greatest mystery in the ocean is how really rare creatures find each other to reproduce the ocean is just so incredibly vast and yet the rarities in it are often vanishingly small and they have a really limited range of movement so it's entirely possible they spend their entire lifetimes never seeing another creature like themselves. In fact, for most of

them, that's probably what happens. But enough of them do find each other that the species are able to persist. And I think that's just an incredible mystery and a wonder. My name's Heather Coldway. I'm a marine conservationist with the Zoological Society of London an honorary professor at the University of Exeter. My mysterious fact about the ocean is that over 90% of species in the ocean have yet to be described. And that's in a world where we tend to think we have so much knowledge and information and facts and we know quite a lot about life. The fact that you can go exploring parts of the ocean and just discover new species even entirely new ecosystems is a magical fact that keeps me engaged in the ocean i'm marcus brigstock and i once genuinely accidentally swam with a polar bear and i agree very much with callum about rare and extraordinary

creatures finding each other for sex. Having been a goth, I can attest to how difficult that is. And this is our panel. Can I just say, Marcus, the image of a goth swimming with a polar bear is a delight. It's beautiful, isn't it? It was a very confused polar bear, I can tell you that much. I was sailing. I sailed from Svalbard to Greenland

with a group of climate scientists and artists. And one of the filmmakers on the boat said, I'd really like to get footage of one of us floating between icebergs, a sort of man and the ice thing, and I was nominated. It had been a very traumatic journey. The crossing was horrendous. I was very sick and I think I actually didn't eat

for three hours on one occasion. But you can hear this filmmaker, it was great footage, me climbing down the side of the boat, and he says, oh, there's a seal in the water. And I thought, oh, brilliant, there's a seal. That'll make the footage even better. So I then pushed away from the boat, wearing this very stiff survival suit.

And as I push away, you can hear him say, oh, no, no, it's a bear. Which then changed its direction, in the direction of the boat, and I was back on board mighty quick. How do we get rid of the bloke who keeps being sick everywhere? I have a plan! We were filming once, we were filming Great Whites, just off the South Australia, the South Neptune Islands.

And so my director dropped his camera over the side of the boat and then jumped in after it when we were filming The Great White Sharks. Wow. Which was a genuinely stupid thing to do. And the film was in his memory. We put it at the end. It was all right.

Anyway. First of all, I'd like to know, Callum, we should really start with a definition because I think a lot of people are still not really aware what coral is. So corals have fascinated us for a very long time. Since the 16th, 17th century, people have been wondering what this stuff is

that's washed up on the beach of tropical shores. And it was the typical question question animal vegetable or mineral so the things that were dried out on the beach were very definitely mineral they were made of the same substance as chalk calcium carbonate but when they were fresh and they'd washed up and they were covered in this kind of fishy film which was very animal in its origin but people looking over the side of boats through glass-bottomed buckets would look at them and they'd see this kind of garden underwater. And they thought, well, they must be plants.

We resolved that question by figuring out that they're all three at once. They're animal, vegetable, and mineral. And the vegetable bit is that the animal, the coral animal, which is a little bit like a whole colony of sea anemones, contains within its tissues these tiny microbes called zooxanthellae, and they are able to photosynthesize, and the coral has hijacked them

to produce 85% or 95% of its food. So they have to live like plants because they need sunshine, so they're out in the open. And that's the secret of their success because once they had got this plant working for them the corals were then able to produce calcium carbonate far faster than anything else in evolutionary history which means that coral reefs could be formed as geological edifices that can be seen from space and these are produced

by little microscopic animals often you know things that you need a magnifying glass to see properly are they named after susan thalley who discovered them zoos zoos and thalley zoos and thalley yes that's a lot of people not go into marine biology because they go do you know what these pronunciate i'm going to go into physics it's a lot easier muons and gluons and everything where zooxanthellae took you about two hours with that this afternoon didn't it no yes it did yes it did so so the calcium carbonate i suppose the thing that we think of as the coral reef that we can see is really a a by-product or has the the animal now sort of evolved in almost to use that structure?

I mean, it's part of what makes the coral, it's providing it with its home and its place to live. And these multiple millions of small creatures, these polyps, together are forming these giant reef structures. And we also mustn't forget, although we have these incredible tropical reefs, which is the first thing that come to mind, but we also find corals living in the deep seas we find them in cold waters and indeed i think the oldest corals have been found in the deep which have been recorded up to 4 000 years old

are those ones in the deep not dependent on light then that's right yeah so that they have a obviously a different strategy of life and they don't have the zooxanthellae so maybe that's another option for marine biologists with pronunciation challenges so they're best seen as a colony essentially a large colony absolutely billions of organisms absolutely yes and as callum said the well the largest living structure on Earth is the Great Barrier Reef, and that's 2,300 kilometres of reef that's in a mixture of islands and this huge, enormous structure that you can see from space. And that comes from these microscopic animals that are there together. So it is very much the basis of the coral is the animal, but completely dependent on this plant as well.

When did they emerge in evolutionary time? How long have they been on earth? So the coral that builds today's reefs got together with the zooxanthellae about 100 million years ago and so we are living within the greatest era of reef construction that earth has ever seen in geological history and that's that's quite a remarkable point to be at particularly when as we will find out later we are pushing coral reefs towards the end of that era very rapidly and of course within within the reefs you've got this huge diversity of species so it's it's not just one thing you think that's what's so incredible about reefs is they cover less than one percent of the ocean and yet they host 25 percent of all species in the ocean so you think of the the huge array of of life you probably think of the fish the sharks

the rays the turtles um and then the corals which sometimes could be seen as the wallpaper but actually those are the fundamental part of the um the life and hosting this incredible diversity that's a remarkable statistic so 25 of known marine species are associated with reefs can you give us a i mean i was going to say can you give us an overview can't it gives an overview of 25 of all marine species. Yes, I'll give you a list. I'll start for the rest of the show. A description of what does a food chain look like on a reef?

How does that build up from the base to the predators? Well, I think it begins with the coral itself. And I think one of the cool things, and coming to this evening full of cold, I was thinking, you know, one of the great things and coming to this evening full of cold i was thinking um you know one of the great things about corals is their mucus um and the vast amounts of mucus they produce so they take some of the carbon that they there's captured through the algae and then they spit that out as mucus but that mucus then captures all the other nutrients in

in the in the water and then sticks it down back down on the sediment and on the reef so that's keeping the nutrients within the reef itself so it's sort of part of that whole feeding cycle so it starts right at the bottom of the chain then obviously the complexity of the reef habitat starts to provide homes for tiny many tiny invertebrates, and that's where your discovery of new species is going to be, then those are starting to provide the food chain through to the fish. You've got the fish that feed on the algae, you've got fish that feed on the corals themselves, you've got the fish that feed on other fish,

and then you work your way up the food chain. When you talk about new species, do we see... Because people often talk about the fact, I know this is not not true but that you cannot observe uh actually in in real time you cannot observe uh evolution but in something on this scale do we see within that are we able to see the patterns of how these very small creatures are evolving and changing in an environment like this well we do know that uh things are evolving quickly on the reef. And one of the things which is incredibly potent as a selective force is predation.

So reefs look like they're really benign places to live and everything's bobbing around. You know, if you've watched Finding Nemo, everyone's getting along incredibly well, even the predators and the prey. And that's true. If you look at the reef um there will be tiny little fish just dancing around within inches of the mouth of a huge grouper and the group is sitting there in its hole eyeing it but not really bothered to move and you think

well why is that why doesn't this fish uh snap up these these insolent little prey items? And the answer is that because the prey items know that the grouper is there, the grouper knows there's no point in it actually trying to catch them because they will lose. The prey will win. So what you see is this kind of illusion of a benign place, a happy place. But in fact, acts of predation are incredibly quick and and fleeting so you can be down there for hours i've seen exactly that happen in a nightclub

in cardiff same system i'll stop there i'm fascinated by that and and by the some of the stuff you see on reeve i mean look i know it wasn't made for my benefit but boxfish that how was there an evolutionary advantage to effectively becoming a slow-moving cube that's bright yellow that everything everything can see that doesn't really function like a fish does because it can't move its body properly. It can only do its tail and side fit. I mean, it can do jazz hands like you wouldn't believe. But I cannot imagine when I look at them, what was the evolutionary advantage of turning out like that?

And also for the audience listening on the radio, that was a superb... Thank you. I did jazz hands down by my hips and did a bit of a shimmy and look yeah tried to look as cubic as possible yeah that i can pull off pretty easily but i think i mean that is what has to happen on a reef is that things have to get specialized into niches that you wouldn't have quite imagined that they could exist i think marcus is asking what is the niche the niche is firstly they would get stuck in your throat because they're solid and they're square

and they're not that tasty and they're saying by being unusually shaped and brightly colored that that's a warning that you're not that good to eat so it is the colors and the patterns and then you get the complexity of the things that are saying that because they're genuinely not good to eat or they're um you know they've got toxins or spines or whatever and then the things that pretend they're like that but aren't really um and then you know in my first foray of research and coral reefs was on the seahorses and that is as crazy um that would involve a different set of jazz hands but you know that is a an extraordinary as people have said to me alongside our corals rocks or plants is you know seahorses are far too cute to be a fish

which is that same thing is becoming adapted to actually be very good at camouflage changing color hanging on to a piece of coral or a sponge or something on the reef and being perfectly camouflaged waiting for that moment with your independent eyes moving just like a chameleon until a little shrimp swims past innocently and then sucking it up with your straw-like mouth so there's all these incredible behaviors specializations that if you're going to cram in that many species into that small an area with that much life you have to do that and that applies right to the smallest level so you know brand new coral larvae arriving on the reef settling down and working out where it's going to start growing

is quite a big challenge if you think about how full a reef already is through to the species that depend on it yeah and callum your your introduction was was fascinating this idea that there are animals on the reef that appear never to meet another of the same species. So, I mean, you said it was a great mystery, so my question is almost redundant, but you speculate. I mean, what is happening? It seems completely counter to what you would expect.

It can't breed, basically, because it never meets anyone else. The thing is that if you go out and you sieve every little piece of sand on a reef if you turn over every rock if you take things apart as some scientists have done in in places and looked intensively then you can find pretty much all the species that are there and this group of scientists went to a reef in new caledonia for a period of about 10 days and they they did nothing other than search for snails and clams and they found thousands of species of snails and clams different ones and about half of them were only represented in their sample by a single individual and so they were they were exhaustively looking for everything that was there and if they could only

find one well what could that poor animal find in the way of a mate they would just never have a chance it would be like stepping out of your front door in london and thinking will i find a soul mate today but not with the the option of hundreds or thousands of people that are all the same as you but just will I find any creature that is the same as me at all and the answer for most of them has to be no but there's there's this little quirk of reproduction which means that a few individuals that find each other may be responsible for the great majority of the reproduction from one generation to the next. And geneticists found out that when they sampled the genetic makeup of newly settling clams from the plankton, they have a planktonic larval stage, so the eggs float off, then they hatch into larvae,

and the larvae eventually settle onto the bottom. When they sampled those, the effective population size was a few dozen individuals across the whole of this huge area of coast. And so you literally might have your entire reproductive output dependent just on these chance meetings. See, I think it's a rather beautiful vision because the state of humanity at the moment, and I woke up and I couldn't find any of the same species as me.

It was lovely. I had the library all to myself. Marcus, I want to ask you, you've become very interested in the environment, really, and quite active in the last decade or so. Do you remember, what was it for you where that story really begins? Well, I got tipped over into it by mistake, really.

I mean, I suppose like a lot of people, I just didn't know very much about it. And I think the thing that turned me on to climate science actually was the resistance to it. That's probably the mindset of a comedian, really. was the resistance to it. That's probably the mindset of a comedian, really. But I was reading unbelievably stupid stuff by people who were willing to put a photograph next to their name. So then I started broadcasting a bit about my very shallow understanding of it,

and I got scooped up by climate scientists going, you'll do. And then I did this sailing trip from norway to greenland and then the year later up the west coast of greenland so that was what what threw me in i'm a level one cheese judge i mean i am genuinely i am i'm a level one master of cheese so you, you know, in terms of the climate, it's my fault. At least we got to the bottom of that. Yeah, yeah, yeah, yeah. It's me. It's me that's done it. How many levels are there?

How many levels of cheese? Two. Oh. So I'm halfway there. One's where you start, so two's better. Two is better. Two's much better, yeah. Two, you love two. Two's all about the molecular bonding process of how milk becomes cheese.

I don't need to know that, but I can tell you an excellent Stilton when I see one. Heather, you can have a choice of answers now. You can either... I will ask you a question on your favourite cheese, or we can talk about the mysteries of reproduction in coral. Which would you prefer? Probably to stick with the corals, if that's OK. That's fine.

Do you want to give us the favourite cheese or not? My favourite cheese? Yeah, you don't have to, though. There's no pressure on that. Cornish yarg. Ah, delicious. That's over and done with now. Let's go on to the reproduction.

Right, excellent. Thank you. Wrapped in nettles, of course, and named after them. We're really going to have to get you off the cheese now. To bring it back to the subject, the question is, how do coral reproduce? So corals have a couple of different strategies and one of the most spectacular, I think, features of them is the broadcast spawning.

And that's basically if you're stuck on a reef and unable to get to a Cardiff nightclub, then you have to think of something else. And so at that point, it's a case of releasing your packets of eggs and sperm into the water. And what's particularly spectacular is that you can pretty much set your watch by when that's going to be in for a certain species in a certain location at a certain time so it usually happens at night time so there's a combination of of lunar cycles of the sea temperature cycles and then the the time of day or night and at that point you you have a certain species will release these bundles they float up to the surface and then they will slowly break down and if every colony of that species in the area is releasing

at exactly the same time and then all accumulating into this particular area area of water when they break down then they start mixing up and that's where you're getting your um your sexual reproduction um and so this is an extraordinary sight to see as a scientist is when you actually get in the water and it's um this spontaneous um emergence of these packets that you suddenly see starting to pop off colonies floating a bit like in a in a snow globe but heading to the surface to form these great slicks of reproduction and is this just on a on a snow globe but heading to the surface to form these great slicks of reproduction and is this just on a on a particular day or a particular time of day once a year essentially yes exactly for for some species it is a once a year um happening and obviously scientists are

slowly growing their knowledge of the different species in different locations about when that happens and that's particularly critical in understanding about how reefs can persist going forwards into the future the other way that's that reefs corals can reproduce is i guess more plant-like in terms of asexual reproduction and and that's basically through a storm damage or being knocked or whatever that a bit breaks off and if it lands somewhere suitable then it can grow again or if a colony gets big enough then it starts budding off new corals that are exactly the same as the as the parent colony this is a remarkable idea because you're talking about reefs now that may be and a hundreds of kilometers or more across but there's a synchronization absolutely which can be to the almost as you described it to the to the hour yes yeah to the

minute yeah i mean people you know the scientists who are studying those particular mass spawning events, are planning around the particular time on that particular date and getting everything organised and ready to be there at that particular point in time. How does that synchronisation occur? Do we have any idea? It is that combination of the changes, the natural cycles that you get in temperature, the lunar cycles that you get in temperature um then the the lunar cycles that you get and then and then the the the daily cycle that you you also happen so these things are coming together to cause that synchronization and timing and it's a perfect strategy to enable that sexual reproduction and that's really going to um ensure the evolution of of corals over

time how's a lunar cycle i mean what's the mechanism is it moonlight is it well that's a very good question and i'm now bubbling out of my depth as as to what exactly it is about the lunar cycle because that's all also turned uh you know mixed up with the tidal cycle which the the corals can sense very strongly. But what's curious about this mass spawning is that when you're there, it's not just the corals that are going off, it's all sorts of other things. So there are these little starfish that are crawling their way up onto the tops of corals and then bursting out with the bright red caviar droplet eggs. And then polychaetes, these worms, are rushing out of all the interstices of the reef

and and you know flying past your mask and uh and as they do so they're literally ripping themselves apart and releasing a body full of eggs in this kind of final act of self-sacrifice that they do and they often self-sacrifice themselves into your ears as well which is extremely unpleasant but but the whole of the water in front of you is just full of reproducing organisms and things eating reproducing organisms as well okay question yeah i'm just gonna say i mean this is right back at cardiff it's we should say if you want to be the sacrificial element of it just literally ripping themselves apart in order to find a mate i've seen that take place well i know that you own that big yellow jacket with shoulder pads and that makes you a lot safer doesn't it

when you're boxier and yellow everyone leaves you alone in that nightclub i don't know who he is but i'm not going near him i've done some i did a bit of um coral planting you know you were talking about how some of them like break off and you can there was like um a metal frame it looked very much like an umbrella and then we like really carefully underwater attached pieces of coral to it and the the project's been really successful in the maldives and it's it's it's one of one of a few ways in which tourism has been turned slightly eco is you can plant your own reef and then they'll film it for you and send you an update so you can see the reef growing which i have to say does happen fairly slowly we We've talked about the wonder of these ecosystems,

but it's also been, as many people will know, widely reported that the reefs are under threat. I suppose the Great Barrier Reef is the most worrying example. So what is the extent of that danger now and what is causing it? I mean, corals are one of the most vulnerable ecosystems on the planet and they are definitely the canary in the coal mine for what's happening to the ocean more generally. We have lost 20% of coral reefs in the last 20 years,

and we are on a very dark trajectory of losing all the coral reefs by 2050, if things don't change. We're talking about shallow coral reefs in tropical climates, living this really delicate balance that's dependent on things like temperature. And as that changes, the whole relationship between that beautiful thing called the zooxanthellae and the animal also changes. And it goes from a beautiful symbiosis to a kind of anxious hate relationship where the coral polyps spits out zooxanthellae algae and we get this event called bleaching where literally the colour disappears from the coral and they look physically white. If the temperature doesn't

change quickly then the coral then dies and that's been the major cause of loss of coral lives and is the major challenge going going forwards for them yes i'd read callum that uh that in the 97 98 in the el nino 95 of the reefs in the indian ocean were lost 70 to 95 of the coral so that's the the thing we're often coral and reef are conflated uh in these sorts of things the reefs will still be there uh the corals may not be alive on them and so the the structure that has been built over 10 000 years is going to persist for a lot longer than the the coral so we're losing a lot of coral from reefs in each of these warm water events. The thing is that the oceans are very, very good

at absorbing heat. And of the heat trapped by greenhouse gas emissions since the onset of the Industrial Revolution, 93% of it has been taken up by the oceans. Now that's incredibly lucky for us because if it hadn't been, the temperature on land would not be a degree centigrade warmer than it has been in the historical past. It would be 36 degrees warmer. And if you measure the amount of heat which is being trapped by the

oceans every day, it's equivalent to something like three to six Hiroshima-sized bombs being exploded in the ocean every second. So that is about a quarter of a million nuclear bombs exploded on the Earth every day. That's roughly the extra heat being added. So all the climate change deniers out there, try and get your heads around that one and yet if you swim off scarborough it's still incredibly fresh the other thing i learned

about this when i went to the arctic is that the uh the function of the the sea ice serves with with huge levels of salinity and cold water that's sinking rapidly to the bottom and drawing warm water across the surface and that as the sea ice disappears that process becomes warped and it's very hard to predict exactly what that will look like. I remember being told though that Edinburgh is on the same latitude as Anchorage in Alaska, which people will have seen pictures of or perhaps even been to. Edinburgh and Anchorage are on the same latitude and Edinburgh is kept as temperate as it is by the top of the North Atlantic Drift, right?

Yeah, that's what keeps it temperate. And as soon as you start changing that system, it's very hard to predict what will happen then. But it's happened in the past what will happen then you know it's happened in the past so you can see what happened and that is it got a lot colder in the in the north atlantic and there was a a period when there was a big uh ice dam broke from north america which uh led to a flood of fresh water into the north atlantic which reduced the rate of sinking which reduced the pull of warm water to the the north and it caused this

little ice age the younger dryas and and this is a period where you know the earth cooled right down again in the north atlantic region at least that's often thrown about by climate change deniers we've had ice ages before and i always think yeah we weren't here then i mean i don't want to be here for that it sounds awful i like skiing as much as the next man let's be honest i like skiing as much as i like cheese which is a lot more than the next man but i think it'd be very cheese rolling on a sled that's your favorite thing of all isn't it literally is nothing better than that um i wondered about talking about the actual apart from coral obviously being a very clear marker of dangerous change but when you actually also see this dying

those around what effect does that then have the ramifications for the ecosystem as a whole i mean i'm sure that the loss of that therefore those other things around it as well the ramifications it must go on and on absolutely um you know we when you've got that dependency on the corals at the base of that system um then obviously if those corals die there's a huge consequence um for for the life that lives lives on them so you'll see some you know species that eat corals obviously we're going to be the first to be affected but over time it's going to run through that food chain. So you see lag effects after coral reefs, or the corals in a reef system are killed by a bleaching event.

Then you'll see the immediate impacts on some species and then slower impacts on others. But obviously, when you've got that degree of dependency for all of that biodiversity, the ramifications are huge. And we also mustn't forget how incredibly important coral reefs are for billions of people around the world as well, in terms of a massive source of food security. That reef structure is providing protection

in terms of stopping waves from smashing into the shore um and you know we've got this incredibly important system for a wide variety of reasons that this is is at risk and you know a dead reef erodes far quicker than a growing um a reef that's that's still got its structure and function have um any types of coral proved to be more resilient to the change yes um and i think this is you know moving forwards in in a more positive way firstly we really need to protect our coral reefs and we know that if we protect them we're buying time we're not solving the problem of climate change but we're taking the pressure off those really important

systems and that's absolutely critical and we know in places like the the chagos archipelago where i work that um where you have a fully protected system uh where it doesn't have other threats from overfishing or coastal development or you know population pressures that it can bounce back quickly um from and when i say quickly i'm talking about a decade of recovery um but it still can fully recover but what's happening now is we're seeing these warming events and the consequent impact on corals happening um over you know more severely over shorter time periods so it's instead of being something that happens you know once every you know decades it's happening every few years and so there's no chance then for the reefs to recover so we've just been through yet another global

bleaching event 2014 to 2017 and we're still understanding the ramifications of that now so how are things you know how are the the corals going to recover and that's where we've been so devastated by the news of the great barrier reef where half of it's dead so kind of i mean that's the real battle isn't it which is it's not changed at this speed before that's that's exactly it and uh if if you look at the the great extinction events in planetary history they most of those were associated with a large scale release of carbon dioxide into the atmosphere which led to runaway global warming, which led to acidifying oceans and too much heat, etc. And so there were a lot of extinctions that happened as a result of those. Now, the present rate at which we're releasing greenhouse gases into the atmosphere

is about 8 gigatons per year, the uh the big mass extinction event the uh n permian mass extinction was about 0.6 gigatons per year so we we're looking at a very intense spike in release of greenhouse gases into the atmosphere which is driving climate change at a far more rapid pace than before now we it will take us a very long time to get to the total amount of carbon released at the end-permium mass extinction. So we do have time to change course and we do have the opportunity to mend our ways

in time to save many ecosystems. It looks like coral reefs will struggle, regardless of what we do, that there is no easy win to to saving them now and I think that's one of the lessons here is that coral reefs may already be too far gone for us to rescue them in the state to which we inherited them from previous generations and the the wonderful movies that Jacques Cousteau made which look incredible today, but are increasingly scarce. You'd have to go further afield to more remote places

to find bits of reef that look like the ones in Jacques Cousteau's films. And in 80 years' time, it will be much, much more difficult to do that. That's not to say there's no hope. I mean, you were asking about evolution earlier, and evolution is happening on the reef. We know from experiments in Hawaii about 40 years apart, people stressing corals with warm water. And in the 70s, they did it in order to find out what the effects of power station effluent, cooling water effluence would have on coral reefs. Today, they're doing it to find out whether there's been any evolution of those corals

to the warming of the ocean. And there has been. The corals bleach less quickly and at higher temperatures now than they did in the 1970s. So there is some resistance building in there, but the bad news is they're not doing it as fast as the temperatures are changing. So we've got evolution underway. Now there are other slight glimmers of hope, which is, one of which is that we do find corals in places with really hot water right now, in places like the Arabian Gulf, for example, or in tide pools on Pacific islands.

And these are extreme environments that some corals have adapted to well. And there is a whole kind of subfield of science now looking at what it is about those corals that makes them resistant to these temperatures. it is about those corals that makes them resistant to these temperatures and can we somehow engineer or you know assist evolution to promote these characteristics in other corals in other places at the moment i think it's it's science that's really worth doing we're going to find out a lot of stuff along the way but i don't think it's a cure for the problems that ale reefs that the number one thing we have to do is to transition to a carbon neutral economy marcus you you how do you find your optimism or or hope because sometimes

it can seem so so bleak and i understand that people have to face a reality of it as well but also to have that ammunition of thinking right what do we need to do now well it's sort of it's sort of what's in awful actually and what's in awful is that the evidence is becoming more and more difficult to ignore i mean if you if you look in terms of evolution at david attenborough's commentaries on the programs he makes from the first blue planet where he he said and it's all under terrible pressure and blue planet two he went you're doing this and the new series he's like seriously pack it in i mean he's really he's really gone for it on seven kingdoms and there seems to me to be a little less pushback it's no

good going well we've passed a point and there's no point trying now. I do think young people get it. Not the ones who are gluing themselves to the train I want to be on, but the other ones. In terms of the oceans now, beyond the reefs, the ecosystems that you know about in the oceans, if we achieve the climate goals that have been set, so still that we're there with this attempt to limit

the temperature rise to two degrees or so, is that sufficient? Or, as you said, perhaps for the reefs, we're already locked in. That statistic you gave, Heather, was stunning that perhaps by 2050, or frightening, by 2050, there may be no living coral left or very few areas where the coral is there yeah i mean i think it will be changed dramatically

beyond all recognition and i certainly certain reefs are like that today i mean you know any talk to any scientist who's worked on the great barrier reef for any period of time and and certainly working in the chagos archipelago i know that in 1998 it got hammered 90 of corals dead and then it bounced back and it was a happy ending i've watched it personally this time go through that and see you know what was this incredibly rich perfect coral reef and this amazing ocean wilderness area straight out of blue planet turn into you know these gray you know horrible rocky broken you know like moonscapes they look completely different um and it's heartbreaking and i don't know if there's going to be a happy ending this time

gloomy though no no there is there is a glimmer of hope from the Waldies, just north of the Chagos. Gone through much the same bleaching events. So, 97, 98, some areas of reef were completely devastated. And today, you can swim over some of those areas and see almost no coral recovery from that die-off. For one reason or another, some bits haven't come back. The bones of the corals are strewn across the bottom like some sort of elephant's graveyard. But if those areas are protected well from other sorts of human pressures, like fishing, for instance, then they're able to thrive in a different way. And I've dived in sites which have

got, you know, maybe 3% of the bottom is covered in living coral, but they've been protected from fishing. And you can hardly see any of the bottom for fish. It's just these huge schools swirling around you. They're almost like rivers flowing across the seabed. And every hole and ledge is filled with fish and turtles and moray eels of all sorts. So it is possible to see that coral reefs can still be beautiful and wonderful.

They're not going to be the same as they are. But with the right kind of nurturing and protection, we can make them the best that they can be out of a bad deal, really. And there's a lot of animals and plants on reefs that are not coral, that are not impacted by this warm water temperature in the same way. I mean, there's huge numbers of ways in which warming affects species. But, you know, there are winners and there are losers out of any change. You know, there are winners and there are losers out of any change. And so we really need to, you know, focus on making the reef as good as it can be. And that way it will support fisheries.

It will support people from, you know, tourism livelihoods. It will still be a wonderful place for people to go on holiday. The water will be even warmer, if anything, than it is today. And the sea level will be a bit higher so uh you know those those stilt houses set out across the the coral reef will be a even more beneficial than they are at the moment right we're gonna stop there no no no no we're on a moment of optimism anyway so uh we asked the audience a question and we asked them uh what would you most like to find washed up on the shore? Again, we didn't realise how dark that could be, and most of these won't get read out. So, what have you got, Brian?

It says, the Tory party. But then, no, that would spoil the environment. At the end, it gets very dark. So, we'll leave that one. What would you most like to find washed up on the shore? A treasure chest full of Brian's CDs. You absolute creep. CDs?

Imagine that. Both albums in there. A wonderful treasure chest. A message in a bottle sharing the secrets of Brian Cox's eternal youth. Brian Cox. We're beginning to get a pattern here, aren't we? This one's quite surreal. Lasagna.

From Ben Garfield. I've got the Loch Ness Monster, brackets, who now lives in the Atlantic Ocean cos climate change. So, thank you very much to Callum Roberts, to Heather Calderway and Marcus Brigstock. Next week, our producer has booked Ed Byrne, and because she booked Ed Byrne, she said, because we've booked Ed Byrne, we're going to do fire.

What worries me is the week after, she's booked William Shatner. So I have no idea what that's going to be. Goodbye. Turned that nice again thanks very much for listening we hope you enjoyed the podcast we hope you understood it they will have enjoyed it

well they might not have done there might have been a point where you said something that was confounding or one of our guests said something which made them go this is much harder

than I thought well why would they have listened all the way to the end if they didn't enjoy it just to impress their friends alright well anyway if you did enjoy it then there are lots of other Infinite Moon Cage podcasts you can download on BBC Sounds if you didn't enjoy it. Just to impress their friends. All right. Well, anyway, if you did enjoy it,

then there are lots of other Infinite Mooncage podcasts you can download on BBC Sounds. If you didn't enjoy it, you can download somebody else's podcast on BBC Sounds. We leave the choice to you. I say we leave the choice to you, but as I've told everyone before, free will's an illusion.

You think you've got choice. Go on, choose something else you're not really choosing. Anyway, enjoy the podcast you believe you've chosen next. This is the first radio believe you've chosen next. you