Coral Reef Ocean Explorer - Meet the Expert | National Geographic

I'm Lizzy Daly, your host, and I am super thrilled to be back for yet another epic live! Today, if you're new around here, welcome, welcome, welcome! You are in for a treat. Today, if you've been following over the past few weeks, let me tell you—we have been on quite a journey across the world chatting to experts and scientists, learning all about fascinating science, natural world behaviors, and new sciences happening around the world.

We've met with Dr. Ray Ryan Grant, talking about how to be a bear biologist. Last week, we were in Hungary learning about the meadow viper and how venom—the world's deadliest venom—can be applied to us, our world, and medicine in the most mind-blowing ways.

Now, if you are new around here—hello! I'm a biologist and wildlife TV presenter. I'm so thrilled to be hosting today's live with our very special guest, who I'll introduce very shortly. But I can tell you that today we're going to be heading below the waves. This is probably a topic that I absolutely love. It's probably one of my favorites, to be honest.

I'm not a marine biologist, but I have an absolute love for the ocean. So if you do as well, this is your opportunity to get your questions into myself and our expert today, live, all about coral. I'm sure you have massive questions about coral. What is coral? How does coral reproduce? Where can you find coral on the planet? Pretty much anywhere!

But coral is a mind-blowing, incredible, incredible marine invertebrate that there is so much more to learn about. One of my favorite things to see on a dive is always the vibrant colors of coral. And yes, you get vibrant rock coral even here—rainy Wales, here in the UK, where I'm coming to you live. In fact, in the UK, I have a bit of a love for marine invertebrates in general.

This was me diving with the giant jellyfish just last year. And it was a real giant! Just a fascinating group that perhaps many of us have misconceptions about. As I said, many may not even know what coral is. So today is all about delving into the science and the information about some of the most widespread, diverse, and vibrant corals of our planet.

So who are we talking to today? Well, we are chatting to Dr. Erica Mosley, who is all about coral. She's a marine biologist; she's spent the past 15 years actually studying coral. She's a National Geographic explorer, and she about, well, a number of years ago, started a non-profit organization called The Hydras, because she herself has big questions about coral and so wanted to share information about this whole group with us and to you and I, to the wider public, to kids, and education kits and VR.

She basically is bringing coral to us in classrooms, in our living rooms, to our homes, so we can all learn more about coral and experience it. Now, very excitingly, at the end of today's live, we are going to show you how you yourself can go on a VR dive deep into the ocean to meet coral. But before we do that, we've got lots to learn.

I've got lots to learn, and Erica is actually with us here now live. Erica, hello!

"Hello, Lizzy! I am so excited to go diving with you today. Thanks so much for having me!"

Do you know I've been looking forward to this one, Erica, because I have a serious love for the ocean, but I actually have many, many questions about coral. So I guess an obvious place to start is you and your journey in the past 15 years. Incredible, incredible work—why coral?

"It's a great question! Corals are just absolutely fascinating animals, and as you mentioned, they're found all over the world. There are corals that are deep, corals that are in cold water, even up in Alaska. They exist from the equator to the poles and they are living animals but they also have characteristics of plants. So they have partnerships with types of algae to photosynthesize to gain energy, and they can turn sea water into rock! I mean, they're miraculous. And the rock that they build creates these amazing geological structures that provide habitat.

So the tropical shallower water coral reefs are the ones that I've been exploring for the last 15 to 20 years as a scientist and as a diver. The more I learn, the more enamored I become, because they're so beautiful and so fascinating."

Absolutely! And yeah, as I was reading about this before we went live, you know, over 6,000 different species of coral. But I know you specifically look at how changing oceans can impact corals and how they develop. And we'll talk about how they reproduce as well very shortly. But, um, you touched on it just then—actually, what is coral? I know our audience are really hot on this kind of thing and they're really knowledgeable, but if you could describe coral as an organism, what actually is it?

"Yeah, so corals are relatives of jellyfish and anemones, so they're soft-bodied and they're made up of lots of little polyps. So if you can imagine a central mouth surrounded by multiple tentacles. Those soft-bodied polyps are what secrete calcium carbonate structure, so the aragonite or limestone that builds the habitat.

So here we have a still image of our 360 film that sort of shows the structure, and they're colonial animals that can bud and clone and grow while laying down rock, essentially. And so even though they're made up of very small individual polyps, they can build massive structures that cover large areas."

Yeah, I mean, even just thinking about that, it is a fascinating organism to look at. But you spent a lot of time on the Great Barrier Reef, right? Tell us more about that. That must be the place for coral, surely!

"Absolutely! It's the largest reef system in the world. The Great Barrier Reef runs about 2,000 kilometers long and covers a large area. It's a marine protected area in Australia, and I've been so fortunate to spend so much time on islands and underwater and on boats exploring and diving in these amazing places. It's just been a joy and a privilege, and I've also seen these places change pretty rapidly over just, you know, the few years that I've been exploring them."

Wow! And yeah, I can't even imagine how much you've seen. If you—I'm just thinking of the general diver now. I mean, for anyone who isn't a coral expert like you, you may hold onto a reef and see just a load of colors. How many coral species can you get in one reef? Say, if you go on one dive.

"Absolutely! So the hard corals, so the reef-building corals, also known as scleractinians, there are about a thousand species around the world. At places on the Great Barrier Reef, you might see 400 or so. But if you go into places like Indonesia, where the species richness is the highest on earth, you'll get even more than that, and usually the further you go away from the equator, the fewer types of species there are, even if the abundance is high."

Wow, okay, that's interesting. Is there a reason behind that at all?

"Yes! So much of coral reefs and where they're successful has to do with suitable habitat and suitable parameters. So, for instance, the aragonite saturation in the water has to be right, so the water chemistry has to be conducive to coral growth. The temperatures have to be within a certain range that allows for them to grow, survive, and reproduce over many generations.

And for the coral reefs that I generally work with, you need relatively shallow water. So like on the Great Barrier Reef, you have this amazing continental shelf that goes out many miles, that doesn't go straight into deep water, so it allows for access to sunlight for those species that need sunlight to generate energy."

Absolutely fascinating! And we'll talk a little bit more about how that kind of fits into your really important research a little bit later on. I've got to ask, do you have a favorite coral? I know what mine is—the only local—you must have one, surely!

"I have a few favorites! I really like Stylophora pistillata because it's just really vibrant colors. It has sort of a fuzzy appearance because their tentacles are usually extended and it can be bright pink, bright blue, and it's just absolutely beautiful. I also really like Goniastria fabula, which exists usually at high latitudes and have unique ways of reproducing and surviving in really difficult places. So I like the spirit of that species."

Yeah, yeah! My favorite coral is not a scientific name here—it's cup coral—which is a lot easier to spell for the team in the chat—try to spell out those two species—but love cup corals! What's fabulous about coral is that they don't necessarily have to be in big colonies; they can be on their own fighting the elements and sort of singular polyps in cold and deep areas.

"Yeah, they're tough!"

They are! They're tough! And I mean, it's—here in the UK, we don't have the best diving spots but we've still got coral, which says a lot about how brilliant they really are!

Okay, so, I mean, that's kind of looking at the basis of what coral is. And silly question—what does coral eat? How does it work? What's their ecology like?

"Great question! So with these hard reef-building corals, most of the energy that they get to survive comes from their photosynthesizing algae partners, so a plant-like organism that actually lives in the soft tissues of those polyps. They generate energy from the sun, essentially, just like a plant on land would do.

And that energy leads to about 70% of what the coral needs to survive. And then the tentacles, to make up the remaining energy that they need, can capture small organisms from the water in what's called collection and sort of filter feeding of different particles that just happen to be floating by because corals can't really move around and hunt; they just stay in one place. They're basically cemented to the sea floor while the water current brings food."

I guess the more healthy the ocean, the larger the reef?

"Eventually it depends! It really just matters what the parameters are and how certain species are locally adapted to those environments. Although in recent years, especially in the Caribbean and on the Great Barrier Reef and other large reef systems, we have seen them declining pretty rapidly over recent years from the combined effects of a lot of things including overfishing, habitat destruction, pollution, and also rising ocean temperatures are making it pretty stressful for coral animals at the moment."

Yeah, absolutely! I'm sure many people watching have heard about the decline of coral, and I'm sure you'll tell us more about it shortly. So you've worked extensively on coral across the world, fascinating research, and your application with VR and connecting the world of coral is fabulous!

But before we go into that, I have a question for you, and it's really kind of an important one, right? In terms of how life is formed and continues, how does coral actually reproduce? It's a question that's been on my mind now for a wee while.

"Well, this is my area of expertise, and it's my favorite thing to talk about! So as I mentioned, coral that I generally study are hard corals as opposed to soft corals, which are sort of the sea fans that move with the water current. But the hard corals build the reef, and so when I study coral reproduction, I like to call it 'hard coral porn.'

What happens is, in order for these ecosystems to regenerate and persevere and continue, especially following disturbances like cyclones or bleaching events or any kind of habitat destruction, you need these amazing mechanisms to replenish themselves. So corals can reproduce asexually as well, so they can clone themselves, and that's how they actually build the reef. But the sexual reproduction is fascinating!

So imagine you're a coral. You're basically cemented to the seafloor; you can't move around. Yeah, you're doing a great job! How do you find a mate when it's time to breed? And it's not like a tree or a flower because there are no pollinators in the ocean, right? What's happened is corals have developed this amazing synchronicity where, cued by lunar cycles and water temperatures, they all spawn at the same time.

So over the course of a few nights following a full moon in the springtime, after the sun goes down, corals release these bundles that can be pink or red or orange, filled with egg and sperm. So these are the hermaphroditic species—the ones that have both male and female gametes—and those bundles are positively buoyant, so they float up to the surface and break apart from the water movement, and then can cross-fertilize with other genetically distinct colonies from other areas.

That fertilized egg, over the course of a few days, will develop into a coral larvae, which can then, when it's ready, settle back down on a reef and metamorphose into a new polyp, and then grow and grow, cloning itself to build the reef on top of its ancestors, essentially. And it's known as the most synchronized sex event in the whole animal kingdom, and it's just such a privilege to be diving during this. So that image you just saw—just imagine all of these orbs of colorful egg and sperm bundles floating around you!

It's like, oh yeah! Oh my gosh! Billions and billions and billions! Just a table coral or in a crop red this big can produce about a million eggs. So imagine that for many miles—it’s just a bonanza! And there are a lot of fish that are spawning around that time, giant clams are spawning around that time—I've been on island research stations that are also bird sanctuaries, and they're nesting, and the turtles are coming up on the beach to lay eggs. So it's a very sexy time on the reef! 'Sexy time on the reef! Hard coral porn!' I just—it's actually mind-blowing the way that animals have this way of kind of still being able to reproduce despite how they live. You know, you hear about sperm casting; it's kind of like an extreme version of that, isn’t it? Launching across the ocean? Honestly, that is mind-blowing!"

So, just that is fascinating. A particular species will release…we'll go into that spawning event, and that sperm for that species will fertilize the same species but perhaps in a completely different geographical region, is that right?

"Absolutely! And the currents can take that spawn and that larvae many, many miles—like thousands of kilometers—depending on the water motion because they're just passive drifters, and they're going where the ocean takes them, essentially."

Wow! Wow! You have the coolest job ever! So interesting! That is absolutely fascinating! And do you have some coral with you? Because we've talked about some species, and what I love about this is this actually isn't real coral; this is a reproduction of a real colony from Hawaii! So mike and I, we went diving and took lots and lots of pictures of this living coral on the reef, and we were able to stitch it together in a method of reality capture called photogrammetry, and we were able to turn that into a digital 3D model that is informative because it gives us things like volume and surface area to understand its ecology even better. And we could 3D print it!

So this coral we hope is still alive and well on the reef! So this is a non-destructive way to teach about coral, to show just how beautiful and interesting they are. We also painted this particular colony a certain way to visualize like for a coral to partially bleach, okay?

"We also have a pretty amazing ability to 3D print. Wow! This didn't require the painting. Yes, so this is a Pasta opera mandrina—okay, pretty small colony—of course, it's scale, so it's actually a lot smaller than it is in the ocean. But what was really cool is when we printed this, it printed as its natural colors, okay? So why don't you paint it?

So wow! So this would make amazing decoration! We're hoping to sort of replace the need to decorate with coral skeletons, which can be damaging especially for areas that are already affected. And we also have these special corals that we've painted with a special kind of paint to demonstrate that areas of the reef are turning white when you poke warm water. Bleaching!

"Hey, that's bleaching! Basically, you are showing what happens when bleaching occurs! Absolutely! So what's happening is when corals are experiencing higher than normal sea surface temperatures, they get kind of stressed out, and many corals are living at their upper thermal limits, and when they get stressed, they expel their algal symbionts—thezooxanthallae that live in their tissues and give them their energy. And without those, you can see through the coral polyp to their white calcium carbonate skeleton, and so it looks white. And that's why it's called bleaching! It's not because people are pouring bleach into the water; it's just a descriptive term! And when you see a white reef, it doesn't mean that it's dead, but it does mean that it's starving, usually!

Bleached reefs become overtaken by seaweed, and it's really hard for reefs to recover and grow back, and so any way that we can work on bringing color back to the reef has a shot of continuing and persevering. And corals can recover—they can! And we've seen that; we just have to let them and give them that space."

Absolutely! And talking about bringing coral back to the reef, you're bringing—sorry—color, not coral, or colorful coral, to be honest! You're bringing both to us as well through VR! So I mentioned the non-profit organization The Hydras. What a brilliant idea about using VR because so many of us—you know, I'm sat in my garden right now—you know, I'm not able to go however many feet down to see beautiful coral. So tell us more about that!

"I'm super excited about this! Well, Lizzy, one of my favorite things to do in the world is to take people diving! I just love being underwater, and even more, I love taking people underwater with me. I'm a dive master, so I've led dives for many years. I'm a kayak guide; I love taking people into the ocean in some way. However, I can't take everyone to the ocean, and so I'm really interested in using scalable technologies to bring the ocean to everybody because there's such a disconnect between living on land and life underwater.

For a lot of reasons, like for instance, we can't breathe underwater and not everyone can swim, and it's not always available for people to visit the ocean. And so what's so exciting is this medium of virtual reality, this electronic immersion, can generate presence and agency and make you feel like you're there. And so it's that emotional connection that can really bridge the disconnection between scientific discovery and public understanding. Plus, it's just so joyful!

So here's a picture of me diving in the Republic of Palau with our amazing underwater cameraman and a producer on our VR film, and he's holding this incredible camera called the Virtual 2. Essentially, it's 13 different individual cameras mounted together in an underwater housing and was able to shoot 60 frames per second in 4K, and they're mounted in pairs so that we can generate depth in the end. What an epic bit of kit! Look at that! That is absolutely fabulous!

And, um, that's what I mean—all the pictures shown here, most of them shown in this chat, by the way, everyone watching—this is what you'll be able to experience at the end when we share a little bit more about going on that VR dive! But I mean, for you, this must be a real opportunity to, as you say, create that connection!"

"Absolutely! And I love talking to people after they go virtually diving with me because, in the experience, I'm actually your dive guide! I get to signal to you. I point out turtles and signals. I get to feel so connected to people, and when they come out of the experience, often I get to hear really cool stories about their ocean journey and whether they've ever gone diving or tide-pooling or spent time at the beach. And I've been so overjoyed by how many people have their own connection to the ocean in a really specific and unique way.

And not only is the ocean beautiful and an amazing place to be, we also all rely on it—healthy oceans, healthy people!"

Yeah, absolutely! I do want to come on to that a little bit later and how we're very much connected to the ocean even if it's not right in front of us. But for you, in this VR, what has been, do you think, the most valuable thing for people going on these dives?

"I just love looking around and feeling submerged, because oceans and VR are such a match made in heaven! Because when you're floating, you can look up and down and all around you. When you're kind of walking on land, you don't look down as much, for instance. And just seeing a school of fish surrounding you and seeing the reef sort of building over you and these big cathedral-like structures is really incredible.

To feel like you're there rather than, you know, watching a video of a scientist or a diver exploring a reef, you get to become the scientist or the diver and explore yourself."

Absolutely fascinating! Now, the reef is only part of the picture, right? I'm sure you've seen so much on and around reefs. But let's talk a little bit about how it works its way up the food chain, if you like, up the system of bigger life. What's your—what's been your favorite moment in a reef?

"Oh my gosh! So coral reefs are like the rainforest of the ocean. They cover less than one percent of the whole seafloor but harbor about a quarter of all marine biodiversity! And so that includes the smallest colorful sea slug or nudibranch, crabs and mantis shrimps, up to fish and bigger fish, and then turtles and sharks and whales and dolphins and everything that comes through a reef uses it as habitat or as food and spends some portion of their life cycle on it.

So I've been so lucky! I could stare at just like a meter by meter area of reef for hours because there's so much going on. There's competition, there's predator-prey relationships. I can look very close and just get totally stuck there! But when you zoom out, you're like, oh, there's a shark behind me! And getting to swim with gray reef sharks or whale sharks is just a total joy! And there have even been times where I've been diving and hear humpback whales singing, and the way sound works underwater feels like it's all around me, and it feels like I'm swimming with them. It’s just that immersion and that experience of weightlessness and floating is absolutely magical!

And to be able to swim with and visit this biodiversity is such a privilege!"

Absolutely! Yeah, it really really is! Lovely picture of you there, by the way, with a manta! Oh, must be just absolutely awesome! And to make all those connections is super important! You know, I may be wrong in saying this, but I do feel like there's a bit of a misconception about a reef; you know, it's kind of just stuck to the bottom of the sea, and of course, they're very beautiful to look at.

But the power in which they kind of harness, as a food system, as a habitat for so many life forms on this earth, is very misunderstood. So have— I mean, what do you think is the biggest misconception about coral?

"Well, as you say, I think not everyone realizes that they're living animals! They kind of—we're just swimming by; they look like they're rocks or they might be plants because they seem to be still with our sort of perception of time and movement. But again, if you put a time-lapse camera, the reef is so big! Different coral colonies are fighting with each other; they're moving around; they're extending their polyps; they're moving with the water currents; they are reproducing; they're migrating because they have that life history stage where they can float through the water and settle somewhere else.

So they're incredibly dynamic; they're incredibly just lively, just not in the way that we generally perceive animals. Because when we think of animals, like they run around and chase each other and climb trees. But they are living things! And so that means that the way that we treat them and the way that we utilize them, especially for resources like fish and any other kind of food or pharmaceuticals, we really need to take care of them because they are living—so much depends on them including us!"

Absolutely! So let's talk about that! I mean, what for you have you found to be the main threats to our corals of the earth and across all our oceans?

"Well, if we talk very generally—and this includes deep corals and cold water corals—things like dredging and habitat destruction and pollution is really damaging. So off the coast of California, here in the colder deeper water, we have these amazing diverse coral communities that really rely on the local protection.

So luckily, a lot of that is really well cared for; that's not the case everywhere! And the issue with tropical shallow water coral reefs is we've lost about half of those reefs over the last 50 years, and that is due to just the combined effects—the cumulative effects of direct human disturbances—overfishing, because when you take too many things out of the food web, it sort of ripples down to the reef and vice versa. So if you destroy the reef or if the reef bleaches, the fish and the other invertebrates and everything else that goes up the food chain really relies on it!

So unfortunately, a lot of places in the world are sort of getting hit from all sides."

Yeah, yeah! And is there a particular reef? I mean, you spent so much time on the Great Barrier Reef, but is there a particular reef that's really facing bigger challenges than others? Because as you say, lots going on in our oceans right now; it's kind of hard to understand on a big scale.

"Well, unfortunately, there isn't just one reef that's under a lot of threat. The bleaching event from 2015 to 2017 was the largest, most widespread, severe event ever recorded, and it hit every ocean! So there are shallow water coral reefs in Eastern Africa, throughout the Indian Ocean, throughout Indonesia, Japan—the Great Barrier Reef is just—the Caribbean in Hawaii is just hit! Everywhere! And it's been very dramatic to see just in a few weeks a reef that's been there for hundreds and or thousands of years turn white and just die in a very short amount of time."

And that was just for those who may not know—what happened during that bleaching event? Could you break down some of the causes behind that?

"Yeah, so usually these bleaching events coincide with El Niño events, where temperatures are higher than normal. We have these warm water anomalies, and sometimes storms come through and prevent the sort of stagnant warm water from just kind of staying still and warm. And those elevated temperatures over a, you know, a couple of weeks cause corals to get stressed out, and the algae that live inside them are overoxidizing, and that's really not good for the coral.

So they expel their symbionts, and that—they need them to survive! And so it's really a matter of higher than normal temperatures with the fact that corals that are better protected on a local level have a better chance at recovering. Like I mentioned, corals can recover! I've seen a reef completely wiped out by a cyclone, and within about five to ten years it was growing back! It's amazing what corals can do!"

Thanks to those amazing reproductive mechanisms! So of course, that is absolutely incredible! How sensitive are our corals and coral reefs? We talk about changing oceans all the time, and as we're seeing that more and more—In fact, actually, let's talk about some of those changes and some of your research looking into that first, and then we can go a little bit more into how sensitive they are, because it's something I'm always thinking—I'm thinking of constantly, you know, how we can do our bit to help save coral. But it's hard to kind of truly get to the bottom of that exact issue.

"Absolutely! And so corals are often called sensitive, but I think that's a little unfair because we're putting a lot on them! And I've survived warmer periods in our earth history, and they've migrated to higher latitudes, and we have this amazing geological record right now. The issue is the rate of changing oceans—not only the water chemistry and the water temperature changing, but also all of the pollution, all of the overfishing, all of the habitat destruction that's piling onto that. It's just a lot for corals to overcome."

Okay, yeah! And I mean, that in itself is really interesting because you do read all the time about "sensitive corals, sensitive coral reefs..." and put them—there's so much to do! And are you positive about the future about corals? Please say yes!

"I have so much ocean optimism! And what I love seeing is the incredible work being done around the world by community leaders, by ocean advocates, by scientists, by educators who are taking a really amazing multidisciplinary approach to addressing these issues and addressing it from a human-centered lens because, in the end, it's all about our relationship to the ocean! Whether we can continue relying on these ecosystems that we need to survive!"

Yeah, and you must have seen how close our relationship, in some coastal communities, is with coral. Do you have any kind of stories about that, or any particular places that you've been where you’ve seen this kind of really intricate relationship between people and coral?

"Absolutely! I've met a number of artisanal fishermen or fishers that, you know, go out fishing every day. And thanks to healthy reefs, they have food to feed their family or sell, and they're also amazing tourism industries! So a number of people I've met know the reef far better than I ever could, and they've grown up on it, and they've explored it, and they've seen changes themselves.

And they also know that their livelihoods are impacted by tourism and the health of the reef, and so they're very driven to protect it and keep it healthy—not only because it's the right thing to do and it's important for the ecology and the beauty of the reef, but it's something that they directly depend on. You can have a close relationship alongside these ecosystems and these habitats sustainably, right, for the future?"

Absolutely! Love it! Love the ocean optimism as well. I'm going to use that; I think that's a really lovely one! And okay, we have questions flooding in and some really great ones! I'm not surprised by that at all! So let's actually head over to some of those questions.

We have one here: "How quickly do they grow, and how long can a coral live for?" Good question to set us off!

"Great question! And so that completely depends! So deep water cold corals are very slow growing, where, um, staghorn coral—so like these branching ones—or the genus Acropora are known as sort of the weedier species and they grow quickly and they’re known to be some of the first colonizers of a reef that's been damaged.

Whereas a boulder coral or a brain coral might grow more slowly. And of course, there are trade-offs to that. So the slower-growing species are generally more resistant to changing oceans as opposed to fast-growing acroporids or branching corals, which are generally the most vulnerable!"

Okay, so we're seeing that kind of across species then? We're seeing a faster decline in those species that are faster growing?

"That is exactly right! And with regards to the question of how long do they live—that's actually a complicated question, a complicated answer! Because corals are always cloning, and that genotype gets replicated in a way. They just keep going and going unless they're like completely stopped.

So in some way, you might see them as immortal if they're just growing on the ancestors. So if you look at a coral reef, the surface of it—the skin of it—is that soft-bodied living animal, and everything below is the calcium carbonate skeleton that has built up over generations and generations. And a single coral polyp can also be eaten by a fish, and so they have natural predators—it's all part of this ecosystem.

And they'll just keep living until you stop them, which we're doing! It's like a multi-layered cake of coral goodness!"

This is just—it's mind-blowing, everyone! This is incredible!

"Oh, great question! Kevin asks, 'Please discuss reproduction by cuttings to propagate new corals.' Nice, nice question there!"

"Great question! So there are a lot of amazing practitioners that are experimenting and trying coral gardening or coral planting! So if I were to take a little piece of this coral branch—well, not this because it's a 3D printed model—and gently place it or grow it in the lab or put it back on the reef and use special glue, it can keep growing, and it can have done this to create sort of coral gardens in areas that have been damaged. Of course, my big question is, will it get damaged again the same way the first reef was damaged?

And so there's a lot of interesting research into how to do these fragments of coral, and micro-fragging is what it's called, to increase the rates of growth and maybe even breed thermally tolerant species that allow the corals to withstand greater stress!"

Okay, that's fascinating! So that initial coral will still survive as a coral; just part of that will then be essentially sustainably taken elsewhere for regrowth?

"Absolutely awesome! And I have heard of that before, but you know, just the power of that, I guess, the future of our corals—those particularly in decline would just be awesome, you know, if they could take that forward!

How do corals contribute to the animal kingdom?" We've touched on this briefly! From large and small, could you sum that up?"

"It's a bit of a tricky one! I mean, the animal kingdom is so huge! If you specify to the ocean, I mean, from a scientist's point of view, they're just so unique and fascinating! And from the corals' point of view, they support so much! They are the ecosystem engineers of these habitats, and they build the three-dimensional structure that allow little fish or little crabs or shrimp to hide in them!

And that rugosity, as it's called, is what allows for so much life on the reef! I mentioned this before, but about 25% of all marine animals rely on coral reefs because they create this habitat!"

I mean, that is the fact, isn't it? That figure is 25%! That says it all! Incredibly important!

"Fabulous questions coming in! Okay, we've got another one here. Can coral animals die from man-made pollution in the sea? And how are we recycling microplastics in the ocean?"

"So let's start with the first one—'Great question,' I love that! And the answer is yes! Unfortunately, a lot of the things we put into the ocean are affecting it! It used to be thought that dilution was the solution to pollution, but we find out that, you know, even in a place as big as the entire ocean, it is still affected by us putting our waste into it! An example of that is fertilizer runoff or runoff from cities, so any kind of waste can create an overabundance of nutrients in the water that can cause algae blooms or phytoplankton blooms, and that can smother corals because they need that access to light!

And so you have these sort of ripple effects, the domino effects of putting extra stuff in the ocean that we might not have thought has these effects. And so, unfortunately, in a lot of places that don't have proper waste treatment or are stirring up sediment, the corals get covered by algae or by sediments and they just can't continue to survive!"

That's a really good point! You know, do you think we're fully aware of the impact we may be having on our corals?

"I don't think as much as we should! It's, you know, it's a very much-out-of-sight-out-of-mind problem. Quite often, we just see the surface of the ocean, and it looks calm and beautiful. But there's a lot going beneath the surface, and the things that we do on land truly impact what's happening underwater—and fast changes as well!

And of course, that question about microplastics and the impact of plastics in our ocean—that does plastic impact coral at all?"

"It does, unfortunately! My colleagues and co-founders of The Hydras—Nora—she discovered that coral animals are actually ingesting microplastics in the lab where she put microplastics in the water that the corals feed on because, as I mentioned, they also, you know, take the water with their tentacles, and they're ingesting microplastics. And that can really be disruptive to their ability to feed and survive!"

Yeah, sure! And I know there's a number of cleanup operations for microplastics, but microplastics is one of the biggest social problems in that ocean, whether they're primary or secondary. And it's a really kind of hard-to-grasp issue that our oceans are facing! And unfortunately, it's sad to hear that our corals are facing those issues as well!

Is the damage to our reefs really reversible? And taking CO2 actively out of the air is nearly impossible, they're a physicist, they say! And what can—Oh, there's lots of questions here! So let's start with those fears. I mean, ocean optimism—you've talked about that! I'm an ocean optimist now, definitely! But can we reverse some of that damage, really?

"Yeah, well, I really want to thank that physicist for that question because it really does come down to that in a lot of ways! So when it comes to addressing the warming oceans, we really need to address the fact that there's an excess amount of CO2 in our atmosphere, which also gets absorbed into our ocean and changes the chemistry! And the ocean is warming!

And so I would want both mitigation and adaptation, and so when it comes to sequestration, as our physicist friend points out, it is very difficult. In terms of taking CO2 out of the atmosphere or out of the ocean, and there's a lot of really fascinating research that's going into that, and I'm excited to see how that evolves!

Oh yeah! I think we should address the root of the problem and, as an international community of people, really take a stand in preventing excess CO2 being released into the atmosphere! I think it's really up to us to use our powers as citizens and consumers to prevent that from getting worse. And corals can recover again! If we tackle these problems, we have a really good chance of keeping corals and people healthy!"

It's a good question! I think largely because many of us want to do our bit, but it's hard to actually make that positive impact! But the initial thing is to slow down the way that we are consuming, the way that we live.

So you know, it's a question which I think we should be—not asking yet! We should first be asking the question, you know, what can I do every day to really, as a consumer, make those changes to slow down that process? But nevertheless, good to have a physicist on—that's great!

What can young people do to help protect our oceans? Great question! I love that question! And I'm just hearing a bunch of new solutions and ideas every day! And I want to preface this by saying that we all need to decide on our own what works for us! I feel like a lot of people, including myself, sometimes get overwhelmed with not being able to do everything all the time, but there are so many small ways that we can each protect our ocean every day!

And one of my favorite sayings is, 'Don't let perfect be the enemy of good!' So what I'm about to say—you don't have to do it all! I'm just giving options! One of the best ways that you can protect the health of our oceans and the health of people that rely on them is to think about how you source your seafood! So sustainably sourced seafood means better jobs, more jobs, and healthier fish and more fish!

So a really great resource that I highly recommend is the Monterey Bay Aquarium Seafood Watch program, and they have a free app! So if you're ordering food or buying food, you can enter the sort of fish that you're interested in, where it comes from, and learn more about whether it's a quote-unquote green choice—which I think should be a blue choice—or a red choice, which may be something you want to avoid because it can be caught through damaging methods that affect reefs or other parts of the ocean!

Another thing is to really think about your waste and how much marine waste you're producing, whether it's related to your community's recycling programs or waste treatment, or you as an individual. And then finding ways to reduce your carbon footprint! And like I said, it's a little bit hard to go completely carbon neutral, but there are ways you can reduce! There are ways that you can offset! And all of the choices really, really add up!

And like I mentioned before, use your power as a consumer! Support businesses that are ocean-minded or sustainably-minded, and use your power as a citizen! Vote for ways to protect the ocean!"

Absolutely super important! One just at the end there! And I would also add on to that actually go to The Hydras and learn more about and get—learn about them and about their dives! Go on a VR dive and just get to know the ocean! Get to know the nitty-gritty science behind it! If you're interested in it, you will learn everything there is to know with Erica herself!

And one last question before we go! Do you think it is possible to use artificial intelligence technologies like machine learning and deep learning to help save coral reefs? Good question!

"And there are so many brilliant people working on that right now! And so for instance, Dr. Grace Young is working on machine learning to help track ocean health and help identify fish species! And we have so much amazing data, and big data is such a great way to monitor and understand and study our ocean so that we know how to better protect it! And absolutely, there are so many great examples of machine learning and AI!

The first thing that comes to mind actually is you might have seen that photo of me diving with the manta ray and you could see that there were markings on its belly, and those markings are unique for each individual like a fingerprint or a QR code! And so for scientists to track these animals, they don't need to put a physical tagging device on them; they just need to use their photos—and all of these photos together—thousands and thousands collected around the world can use machine learning algorithms to identify and track these individuals so that we can better understand this threatens an endangered species."

Fantastic! The power of technology, see! Slowly learning more about our oceans and learning how to protect them, and cause it—you have been absolutely fantastic! It's been so good to chat to you and to learn more about your work, your research.

Before we go, really exciting! I'm hoping everyone is clinging on with excitement because how can people go on a VR dive? Tell us! And I'm pretty sure we've got a code or something for them, right?

"Yes! So I just made that reference to the QR codes on the manta bellies! And in a moment, we're going to show a graphic of a manta ray with a QR code! So what you can do is take your smartphone and open your camera app, and when you see the QR code, the link should just pop up and you can open it!

Make sure you open it in the YouTube app and you'll be able to see our 360 dive, which is called Immersed, that my amazing team at The Hydras has developed! And you can watch it on your phone in a few different ways! You can move your phone around and see the reef around you as you move it—love it! Or you can drag with your finger, or if you happen to have a cardboard viewer like this—I put a little mask sticker on it! You can press the special VR icon in the app! It will then turn into a split-screen, which you can turn sideways and put into your VR viewer like this! Total immersion going—piping! It’s a real-life dive!"

Absolutely fantastic! Um, Erica, thank you ever so much for coming on live! I can't wait to see what you're up to next! I'll be going on a VR dive right after this! Anything else you'd like to add before we sign off?

"Just thank you so much for coming diving with me!"

Yeah, it's been absolutely wonderful! And you do fantastic work, and I'm sure everyone on here has enjoyed it and has enjoyed listening to you! So thank you!

"And thank you all for tuning in! You can see that QR code right now—go, go, go! We hope you've enjoyed it! From spawning mass, incredible coral spawning events to learning about the intricate cup corals that you may have on your reefs on your doorstep, and going on a VR dive with Erica herself—I mean, what an incredible live this has been! My mind has been blown about these incredible marine invertebrates, and it seems we have lots and lots to do to help conserve them! So if you're passionate about the ocean, coral reefs, or anything that Erica has talked about today, please go on that QR code now, go on a VR dive, and we'll see you again here on the channel next week, same time! Bye!"