How can we save the Great Barrier Reef?

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1:05Caroline Steel:The water looks so nice. It's really clear. You're listening to CrowdScience from the BBC World Service. I'm Caroline Steele and I'm in the ocean in Australia, floating in a small boat above one of the natural wonders of the world, the Great Barrier Reef. and beneath me I can see the corals and also thousands of these weird white shapes that my shipmates have thrown overboard. What brought me here is a question from listener Felix in Sydney. I'm Felix and I'm from Australia. And what's your question for CrowdScience? I've seen TV shows that talk about protecting the coral reef but why is the reef so important?

1:52And how do you protect the reef? Would you like to see the Great Barrier Reef at some point? Yeah, it sounds cool. It sounds like it might be also a nice place to swim.

2:01Caroline Steel:Yeah, I reckon so. Do you like sort of going for a swim in the ocean and having a look at what's down there? Yeah, I haven't done it before, but it sounds fun. And how do you feel about the fact that we need to protect our reefs? Are you sort of worried about our reefs? I feel you should protect the reef because there are lots of lives in there that could be saved if you protect it.

2:30Caroline Steel:Australia is home to the world's largest and most famous coral ecosystem, the Great Barrier Reef. Learning about the Great Barrier Reef is an important part of any young Australian's education. From school to TV shows, the Great Barrier Reef is everywhere. And listener Felix wants to know why it needs protecting and how we should do it. Which brings us to Townsville on the eastern coast of Australia. After driving through a thick swamp, teeming with toads, snakes and crocodiles, we arrived at the Australian Institute of Marine Science, or AIMS. AIMS has dozens of projects looking at everything from the genetics of heat resistance in coral to how to grow more replacement corals.

3:16Caroline Steel:And we're lucky enough to be following one particular experiment throughout this show to answer Felix's question. But more on that later. For now, we're in a huge warehouse at Ames, teeming with tanks. Wow, OK, so in front of us is the biggest fish tank I've ever seen. Is it mean to call it a fish tank? That feels like I'm underselling it. I would call it a coral tank, but it does have fish as well. Yes, it's a coral tank that happens to have some fish as well. And it's beautiful. I mean, you've got orange coral, red coral, these huge green flat pieces of coral, which I've never seen before. This is Dr.

3:57Caroline Steel:Carly Randall, a senior research scientist at Ames. So let's start with the basics. What is coral? Yes, great question. And your listeners might be surprised to know that corals are actually living animals. Animals, not plants. That's correct. They're an animal. But some people think that they're plants, and that's quite interesting because they have an endosymbiotic algae, so a single-celled algae that actually lives inside their tissues that's a symbiotic partner to the coral. Okay, so it's an animal that depends on a plant to survive. Exactly. Is it kind of like how we humans have loads of different bacteria in our gut that we need to survive?

4:36It's quite similar in a lot of respects. So the algae do a lot of things for the coral, but the most important function is really to provide them with the energy that they get from photosynthesis. Really the structure and the function that coral reefs support is dependent on this really important symbiosis.

4:56Caroline Steel:Coral and algae work together. The algae turn sunlight into food, which is shared with the coral. And in return, the coral offers the algae a nice safe home. But why are these tiny animals and their plant tenants so important? Oh, coral reefs are critical ecosystems that feed billions of people, that protect shorelines, that offer recreation. They perform so many functions for people. They also have an intrinsic value, I think, in terms of the great biodiversity that they sustain. So they're just really important ecosystems. But they're struggling, aren't they? Indeed, they are struggling. They're one of the bellwethers of climate change.

5:38Because corals exist very close to their upper temperature limits already, warming oceans really threaten their persistence. And so we're seeing damage to coral reefs on a global scale because of marine heat waves and climate warming.

5:52Caroline Steel:So what kind of thing might scientists be able to do to help coral reefs? Well, really there are a number of interventions that are being studied around the world to try to help reefs. One of the key ones that we're working on here at the National Sea Simulator is spawning and breeding corals to try and enhance their resilience to heat in the future. And then we're putting those corals back out onto the reef. And this is a process that we call seeding. So very similar to the way you would seed plants or reforest, we actually re-seed reefs. It's really hard to keep coral alive outside of the ocean.

6:30Caroline Steel:But the National Sea Simulator, or SeaSim, does just that, with some of the most advanced research aquariums in the world. So what we can do here is actually manipulate the environment that the corals live in. We control the temperature, the salinity, the pH, to try to understand how corals are going to adapt or acclimatise under a changing climate. The Great Barrier Reef is 345 ,000 square kilometres, or about the size of Japan. It's home to thousands of species of fish and coral. And there's so much scientists don't really know about how the Great Barrier Reef reacts to warming waters. It's really impractical to study.

7:18Caroline Steel:It's at least a 90-minute boat ride from shore, and it's underwater. So CSIM offers a way to recreate it. so scientists can study corals. And one of those scientists is Dr Saskia Urians. My research is looking at reef reproduction ecology. If you look closely, you'll see that it looks a bit like an upside-down jellyfish. We call it a polyp. Coral is formed of many polyps living together as a colony, a coral colony. These polyps, they clone themselves and they produce a carbonate skeleton. So we're surrounded by tanks full of coral. Could you show me a polyp in one of these tanks? Yes. It's coral in different growth forms, different sizes, different species in here, which is really quite unique.

8:05Caroline Steel:If you had to pick your fave out of this tank, or is that like picking between your children? I'd like this folios coral like this. This flat green one? Yeah, I think that's beautiful as well. How is that coral? Because for me, that looks just sort of like a flat green sphere. Right. So if we look really closely, you can see little bubbles, like little bumps. Yes, the surface has kind of little dots on it. And each bump inside of it, the bump will be skeleton, it will be like when you touch it, it will be hard, but inside is a little coral polyp and you can see maybe a little bit tentacles coming out.

8:42At night when corals are more active, the tentacles will extend further and they're using their tentacles to grab prey and water particles and food particles and so each bump houses a little polyp and And together it forms this colony that we call coral.

8:57Caroline Steel:You often hear about coral bleaching, or it comes up in the news quite regularly, I think. What's going on? Right, so we call it bleaching because we see the corals turning white. And that's because this symbiosis that we talked about, where the coral lives with this plant cell. This plant cell gives them the pigments that gives them the colours. When the temperature gets too high and the corals experience a lot of heat stress, this symbiosis breaks down. and the coral expels the symbionts that they live with. Why is it that higher temperatures mean the algae disappear? We think that it becomes toxic for the coral to keep the algae inside of their tissue and so the coral expels the algae.

9:39Ah, OK. So the algae gets kicked out rather than leaves voluntarily.

9:44Caroline Steel:The reef can sometimes recover from bleaching events, but the heatwave last summer killed almost half of the monitored corals. Scaled up, that's thousands of square kilometres of bleached corals. Listener Felix wonders how you protect the reefs. And what if you could regrow new corals over the damaged areas? Which brings us back to that experiment we're following. Scientists at CSIM have recreated the conditions that keep corals happy. Now they just need them to reproduce and scatter their offspring over a vast area of ocean. Put it in gently. Drop the bucket in and then tip it out gently. Let's talk about reproduction.

10:29Caroline Steel:Corals don't just clone themselves. They also spawn every year. After dark, a couple of nights after a late November full moon, there's a coordinated effort from multiple species to try to reproduce. Every coral throws its eggs or sperm into the reef waters at the same time. And this is the sound of AIM scientists scooping up all those sex cells into buckets to bring back here. But the corals already established in CSIM tanks also go through the same coordinated spawning. Here's Saskia again. Most corals here at the Great Barrier Reef have an annual spawning cycle. there is these mass spawning events once a year where a lot of corals release their sperm and eggs in bundles and they do that it's it's amazing it's absolutely magic the species will do that almost to the minutes at the same time at the same time yeah how do they know it's it's one of the mysteries still that we're trying to find out and here aims what do you do with the sperm and eggs do you bring them together yourself is it kind of like coral ivf yeah that's it actually lately now we've been spawning them in what we call an auto spawner.

11:46It's a big tank where we put all the corals of the same species in together. Then when they release their bundles, these things flow to the surface. The eggs and sperm will mix and fertilization will happen. Then we have a culture and this culture we bring to another room. These grow out into larvae that takes a few days. We settle them on these tiles, on these sheets. Is that what those things are over there? All the whites. Can we go have a look at them? Yeah, absolutely.

12:14Caroline Steel:These tiny coral larvae settle on ceramic tiles, just rough enough to give the babies something to grab onto. So these are the sheets or tiles. Okay, so they're squares, 20 by 20. Yeah, and look on the other side, chocolate block. Oh, it does look like chocolate, yeah. We've been referring to these as chocolate tiles. Because the idea is that you can break them off. Like pieces of chocolate, yeah. And so each little piece will then slide into a device. Earlier I saw quite a few people sort of diligently sitting, breaking up these tiles. At the moment it's a very manual and labour-intensive process.

12:54Caroline Steel:About a dozen people are sat hunched over the trough-like long tanks, snapping these ceramic bars into individual squares or tabs. We break these tiles up in tabs and each tab will have a number of coral babies on it. And each tab will slide into a device. OK, so you put the tabs into, what's this device made of? Ceramic. Each device looks a bit like a star with three points. And each leg of the star has a space to slot in a square tile with any coral babies growing on it. And is the plan that these corals are going to grow and kind of engulf? Yeah, yeah, yeah. So the coral will start to grow on the tab, becomes part of the reef and stays there.

13:41Caroline Steel:It's the end of their time here for some of the coral and it's time to go back home. That's right. Yeah. These are the lucky ones that get to go up back on the reef. The baby corals have been loaded onto the devices and the devices are stacked on top of each other on a metal rod. to me when it all comes together it looks a bit like a human spine the plan is to take these baby corals back to the reef so Saskia and I are waiting on the arrival of a truck which is going to be loaded up with large plastic containers or bins full of water and the baby coral the truck is out there actually oh the truck's already arrived should we go have a look at the truck okay cool

14:24Caroline Steel:OK, so it's a huge truck with an open back and basically stacked next to each other. Lots and lots of these black kind of bathtubs. They sort of look a bit like a bathtub. Full of these devices stacked on top of each other, travelling up the main road to Cairns. As the truck pulls off into the distance, we head home. It's time to race the coral up the coast to the city of Cairns.

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16:01Caroline Steel:You're listening to CrowdScience from the BBC World Service. I'm Caroline Steele and we're answering a question from listener Felix in Sydney, Australia. Why and how do we protect our coral reefs? We've tackled the first part of Felix's question. Coral reefs support the whole ocean. They're home to vast numbers of important sea creatures, and they provide income and food for millions of people. To find out how we can protect them, we're following a science experiment that's growing baby coral in a lab and then reseeding them on the reef. We last saw our baby coral being driven off into the night.

16:40Caroline Steel:This part of the world is hot right now, averaging 30 degrees Celsius. And these are animals that dislike temperature change. So there's a real danger that if they're left in transit for too long, they could start to die off. So 350 kilometres up the coast at Cairns, we board a boat with a team of scientists at the crack of dawn, ready for the next stage of Operation Reseed the Reef. There's a button on the side and in that bucket of flares. There's all sorts of flares, parachute flares, rocket flares, orange flares, red flares, you name it. It's the 4th of July in there. If you find yourself in a position where you do have to deploy a player because you've got one in your hand My only recommendation is you point it away from you as you pull it and you don't look at it whilst you pull it Otherwise you'll make a bad day, a really really bad day because she's going to go off in your face Okay, in saying that you should not need to use any of that type of safety equipment Because you guys are going to operate nice and safe and so is my crew whilst we operate the vessel Cool, have a great day everyone.

17:45Caroline Steel:Thank you. Thanks for everything

17:50Caroline Steel:So we're just pulling out of the marina. We're heading out to meet a bigger boat. And on the bigger boat is the coral that's been grown. And then we're going to plant it. It's looking quite flat currently, but apparently it's going to be so wavy that we're guaranteed to get soaked through, which I can't really picture. We did, in fact, get soaked through. After 90 minutes of speeding away from land, we check in with our baby coral on a bigger boat. My name's Dr Kathy Page. I am an experimental scientist working at the Australian Institute of Marine Science, specifically in the coral aquaculture and restoration space.

18:34Caroline Steel:And what's your role on the boat today? My role on the boat is really kind of keeping an eye on the corals. So we have a lot of seeded devices here, so ceramic devices seeded with baby corals. my role is to keep an eye on them and just make sure that we're giving them the best chance to get out onto the reef in good condition. Okay so you're essentially the coral nanny? Yeah coral nanny that's a that's a great description so yeah we've actually done some quality control checks this morning so before the corals left Ames we did some checks to make sure that all the corals were healthy and alive ready to go out onto the reef and just this morning here with my colleague we've done some additional checks to make sure that they are still in good condition.

19:16What does checking a coral involve? Yeah it's visually looking at each tab that has been seeded with baby corals and just checking that there are still live healthy looking baby corals on that tab.

19:30Caroline Steel:And it's looking so good so far? Looking very good we have a very very small amount of mortality which is to be expected but you know very very high survival rates at this point which is fantastic so it's Pretty good going given these coral have come all the way from Townsville on the back of a truck, then have made it onto this boat, have spent, how long have they been on the boat for, 24 hours or so? Yeah, 24 hours so far, but some of them will spend another 24, 48 hours. So yeah, it is really important that we keep an eye on them out here. It's been months and months of work getting the corals from the reef, spawning them, and now getting them back out onto the reef.

20:04So it's super important that we continue to keep our eye on the game.

20:07Caroline Steel:The next step is carefully loading these corals onto our boat, while trying not to drop or break any of the devices, as so much hard work has gone into getting them this far. Once safely on board, a team of dedicated coral scientists spring into action. I'll be on the live view calling, deploy or not deploy. Nader's helping Tim prepare the spigot for deployment. Tim, you'll be on the deployment, so as I'm calling, you're letting devices in at an even rate. And then Chloe and Alexis, if you can do support. Sound good? Any questions? Two people move the devices across the deck from their nice cool bucket of water to a gap in the side of the boat.

21:01Caroline Steel:One person uses a camera to monitor the sea floor.

21:11Caroline Steel:Another looks at the camera and calls out when to deploy the coral. Which is a fancy way of saying, time to throw one of the devices gently overboard. And another person, Tim Henry, who's project and field operations officer at Ames, actually places the devices into the water. I'm trying my best to not get in the way.

21:38Stop.

21:39Caroline Steel:The coral are quite fiddly and fragile to sort of get off the stick that all these devices sit on like a caban. Also, we're having to be quite particular about where they are deployed. so there's a lot of seafloor underneath us that isn't good enough to drop the coral onto. And it seems like the buoys keep drifting, but I can't tell if I'm just getting really disorientated. Like a farmer planting seeds, we're kind of trying to go in a snake-like pattern, but we're also competing with currents and waves and moving buoys. It's like plowing a field with a tractor that moves when you don't want it to, a field that moves when you don't want it to, and you're wearing a blindfold.