How does coral communicate?
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Coral is one of the coolest creatures in the ocean. It comes in all shapes, sizes and colors, from bright yellow stars to big round brains. Sometimes, coral looks like rocks or even plants – but did you know it’s actually an animal?
This week, your ears are in for a special treat: Brains On editor Shahla Farzan (a.k.a. world’s biggest coral fan) hosts the show! Join Shahla and co-host Eben as they go on an underwater adventure to learn about coral and the animals that call it home. We’ll also hear from a researcher about how coral might be able to hear and make sounds. All that, plus a rockin’ new mystery sound.
Featured Experts:
Camila Rimoldi Ibañez studied coral bioacoustics. Her research has been recognized internationally in scientific journals and at conferences like the International Science and Engineering Fair (ISEF).
Audio Transcript
Download transcript (PDF)
EBEN: You're listening to Brains On where we're serious about being curious.
CREW: Brains On is supported in part by a grant from the National Science Foundation.
MOLLY BLOOM: Oh, what a beautiful day. The sun is shining. The birds are singing. Time to sit in my big comfy chair and start learning about coral for our episode this week. Let's see.
SHAHLA FARZAN: Molly, thank goodness I found you.
MOLLY BLOOM: Brains On editor Shahla Farzan. What are you wearing on your head?
SHAHLA FARZAN: Oh, this? It's my coral hat. It's a perfect replica of my favorite sea creature, coral. That colorful, rocky-looking stuff on the ocean floor? Believe it or not, I made this hat myself out of papier-máché.
MOLLY BLOOM: Yeah, it's really eye-catching.
SHAHLA FARZAN: Plus, check this out. It's my membership card for the Coral of the Month Club. Every month they send you an autographed photo of a different kind of coral
MOLLY BLOOM: Oh, autographed by coral?
SHAHLA FARZAN: And I got a new bumper sticker for my bike. See, it says, "I brake for coral." You got to watch out for those little corals in the road, you know?
MOLLY BLOOM: Well, coral lives in the ocean.
SHAHLA FARZAN: I know.
MOLLY BLOOM: I can't help but notice that you're really into coral. Do you--
SHAHLA FARZAN: Desperately want to host the new Brains On episode on coral? Like the baddest I've ever wanted anything in my life. So I'm showing you all my cool coral stuff to help convince you I should get to do it.
MOLLY BLOOM: You want to host the Brains On episode about coral?
SHAHLA FARZAN: I thought you'd never ask. I'd love to. And great news, since you have the week off now, I got you tickets to that convention you were talking about.
MOLLY BLOOM: The Backward Pants Convention, where enthusiasts from around the world come together to discuss the latest developments in backwards, pants-wearing technology?
SHAHLA FARZAN: That's the one. Looks like somebody's going to be spending a lot of her time with her pants on backwards this week, if you know what I mean. Oh, and I almost forgot. I made you something. Just to say thanks for believing in me.
MOLLY BLOOM: A present? I love presents. You really shouldn't have. Oh, wow, Shahla it's--
SHAHLA FARZAN: Your very own papier-máché coral hat. You're listening to Brains On from APM Studios. I'm Shahla Farzan, and I'm filling in for Molly while she's away this week. Here with me is Eben from Aurora, Illinois. Hey, Eben.
EBEN: Hi, Shahla.
SHAHLA FARZAN: Today, we're talking all about coral, that hard, sometimes colorful stuff on the ocean floor that can form coral reefs. Eben, what do you picture when I say coral?
EBEN: I picture rocky-looking colorful guys that come in lots of shapes, sizes, and colors.
SHAHLA FARZAN: Yeah, that's actually pretty close to what I think of to. If I am picturing coral, I'm picturing something that's underwater, and usually something that's like it kind of looks like a big, bumpy, rough boulder with just like a bunch of fish around it. Coral is pretty amazing, and so is this question which inspired today's episode.
[AUDIO PLAYBACK]
- Hi, my name is Finnegan, and I'm from Ontario, Canada. And my question is, how does coral communicate?
[END PLAYBACK]
EBEN: Wow, that's a great question.
SHAHLA FARZAN: I know. Coral might look like a rock or a plant, but it's actually an animal.
EBEN: Right, it might not talk like we do, but maybe it has its own special way of sending signals to other creatures.
SHAHLA FARZAN: We'll talk more about that in a bit. But first I want to know, Eben, what do you think is cool about coral reefs?
EBEN: I think coral reefs are cool because it takes lots of corals to make a coral reef.
SHAHLA FARZAN: You mean a lot of corals all linked up together into one reef?
EBEN: Yeah.
SHAHLA FARZAN: That's cool. Do you have a favorite sea creature?
EBEN: My favorite sea creature is a sea turtle.
SHAHLA FARZAN: A sea turtle. What do you like about sea turtles?
EBEN: I like how when they go through the water, they just seem so calm.
SHAHLA FARZAN: I know. I love the way sea turtles move through the water where it almost looks like they're flying. Like, they move their flippers up and down in the water.
EBEN: Yeah, it kind of looks like they're gliding through it, the water.
SHAHLA FARZAN: Yeah, I know. It really does actually. Have you ever seen coral in real life, like out in the wild, or in an aquarium?
EBEN: Maybe once, but probably a long time ago, because I don't remember.
SHAHLA FARZAN: I have been really lucky to be able to see coral out in the wild. So cool fact about me, I actually used to live on the Marianas Islands, which is this tiny little group of islands way out in the Pacific Ocean by Japan. And I was working out there as a scientist studying the forests there on the islands. But after work, I got to go snorkeling pretty much every day around the coral reefs.
EBEN: OK, that's pretty awesome.
SHAHLA FARZAN: I know. It was awesome but I have to be honest with you, the first time that I actually jumped in the ocean to go snorkeling, I was really nervous. The water wasn't super deep, but I'm not a really strong swimmer and I've always felt scared in the water. But once I got in there and I relaxed, I realized that there were all of these just incredible sea creatures around me, just swimming all around the coral reef.
So things like these rainbow-colored parrotfish and really big fish called grouper. I even saw this giant barracuda once that was like 3 feet long. And I think the really cool thing for me was that swimming around the coral reefs just made the water feel a lot less scary to me, and it was fun. Do you think that's something that you'd ever want to do, Eben, go snorkeling in a coral reef?
EBEN: Yeah, I think that'd be really fun. I get to see all the fish and the coral. And, wait, are you able to touch the coral? Do you know what it feels like?
SHAHLA FARZAN: You're not technically supposed to touch the coral because it can be fragile, like, you can break it off by accident. But one time I was snorkeling and I was in big waves, and my leg touched the coral, and it was really rough.
EBEN: Oh.
SHAHLA FARZAN: So you can find coral in oceans all over the world, from the rocky coasts of California to the shores of Mozambique in Eastern Africa.
EBEN: It comes in all different shapes and sizes. Some coral is flat like a big pancake.
SHAHLA FARZAN: Some looks like bright yellow flowers, or stars.
EBEN: And some coral even looks like brains.
SHAHLA FARZAN: But those cool shapes aren't the living part of coral, they're more like its colorful, bony armor. More on that in a second. But first, in honor of today's coral-tastic episode, I've got a surprise for you, Eben.
EBEN: Is it a 100% unique hand-made papier-máché hat in the shape of my favorite kind of coral? Because I actually brought one with me. See, it looks like brain coral.
SHAHLA FARZAN: I was going to give you a 100% unique hand-made papier-máché coral hat. But yours, it's gorgeous.
EBEN: Hey, thanks.
SHAHLA FARZAN: And check it out, we match. I've got one that looks like fire coral. See, it's got little orangey branches all over it. Eben, I wish we were at a coral reef right now.
EBEN: Same.
SHAHLA FARZAN: Wait, Molly specifically said we can do whatever we want today.
EBEN: She did?
SHAHLA FARZAN: Oh, yes. Or at least I'm sure she would have said that if she thought of it. And that's good enough for me. And since we can do whatever we want, I think we should go to a coral reef, like right now.
EBEN: Road trip. I mean, reef trip.
SHAHLA FARZAN: To the ExPLORERR. Dibs on the back seat. Here, catch the keys.
EBEN: Shahla, I'm 10 years old, I can't drive.
SHAHLA FARZAN: Oh, right, I can take us. I forgot I totally know how to drive. Let's go. We're coming to you live from my favorite vehicle, the Extremely Practical Land and Ocean Rover Exploring Remote Realms.
EBEN: Or ExPLORERR for short.
SHAHLA FARZAN: And we just dove straight into the ocean to look at some coral reefs.
EBEN: Whoa, look at this reef. Looks like a bunch of big, colorful sea plants. But it's not a plant. It's an animal.
SHAHLA FARZAN: And it's stunning. So like we said earlier, the part of the coral we can see is like it's bony armor. That part is not alive.
EBEN: But the parts underneath that bony armor are alive.
SHAHLA FARZAN: These living parts are squishy animals called polyps. Coral polyps are usually only a couple millimeters wide.
EBEN: That's smaller than my pinky nail.
SHAHLA FARZAN: But some can get as big as a basketball.
EBEN: Sometimes coral polyps are so tiny, you need a magnifying glass, or a microscope to see them.
SHAHLA FARZAN: Speaking of, I could have sworn the ExPLORERR had a zoom ray button somewhere in here. Oops, that just made tacos fall from the ceiling. Mhm, I do love a ceiling taco, although I guess now it's a floor taco, whatever. We'll clean those up later, maybe with our hands, maybe with our mouths. JK, we're not going to eat off the floor, Eben. Or are we?
EBEN: Hey, Shahla, what about this button?
SHAHLA FARZAN: That's the disco party button, classic mix up. Oh, I know. What if we--
EBEN: Press the 1 with the magnifying glass on it?
SHAHLA FARZAN: Oh, I was actually going to suggest that we just press all of the buttons at once, like how I do any time I'm in an elevator. But you're totally right. That is the zoom ray button. It lets us see stuff way up close.
CREW: Zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
EBEN: Whoa, so magnified.
SHAHLA FARZAN: All the better to see coral. Amazing to think that big, colorful reefs all start with these teeny tiny polyps.
EBEN: Up close, the coral polyps look like squishy little trees.
SHAHLA FARZAN: The top of each polyp has little tentacles like an octopus. And when these baby polyps are first starting out, they float around in the ocean until they find a hard surface to stick to.
EBEN: Like rocks on the ocean floor.
SHAHLA FARZAN: Once a polyp finds a nice rock to settle down on, it starts to transform. Kind of how when I settle down on my couch, I start to transform into a human-shaped pile of blankets covered in chip crumbs.
EBEN: Same, so once that coral polyp settles on a rock, it starts absorbing minerals that are floating in the sea water.
SHAHLA FARZAN: And it uses these minerals to form hard, shell-like exoskeletons on the outside of its squishy body.
EBEN: It's like the polyp, is making its own body armor.
SHAHLA FARZAN: Awesome. It's this armor that you're looking at when you swim past a colorful coral reef.
EBEN: Another amazing thing about coral polyps is that they can make copies of themselves like clones.
SHAHLA FARZAN: One coral polyp can multiply into hundreds, even thousands of clones. And these clones make armor too.
EBEN: When lots of coral polyps link up next to each other, they make groups called colonies.
SHAHLA FARZAN: You can think of it like this. If each coral polyp with its hard armor is like its own little apartment unit, then a coral colony is like an apartment building made up of a bunch of individual units. Even though each coral polyp can be microscopic, their colonies can weigh up to several tons.
EBEN: About the same weight as an elephant.
SHAHLA FARZAN: When different coral colonies are built next to each other, they form coral reefs.
EBEN: Which is a bunch of different apartment buildings coming together to make up a whole city.
SHAHLA FARZAN: Yes, coral reefs are like cool coral cities. Here, let's zoom out again so we can marvel at them.
CREW: Zoom.
EBEN: Wow, it really is like a city.
SHAHLA FARZAN: Pretty neat, huh? Wow, look at the time.
EBEN: Oh, Shahla, that's a piece of taco stuck to your wrist, not a watch.
SHAHLA FARZAN: I totally knew that. Now, how does Molly always say it? Think, think, think, think. Come on, Shahla, think. Oh, right, Eben, it's time for the--
CREW: Mystery sound. Eben, are you ready to hear the mystery sound?
EBEN: Yes.
SHAHLA FARZAN: All right, let's hear it. Whoa, OK, Eben, what do you think? You got any guesses?
EBEN: OK, yeah. After a lot of water evaporates in the bathroom, it kind of makes a bunch of stuff on the mirror, and you can wipe it off with your finger, and sometimes it can make some squeaky noise. So I'm guessing that it's someone using their finger to squeak along the glass.
SHAHLA FARZAN: Oh, like wiping the steam off of a mirror?
EBEN: Yeah, except with their hands or finger.
SHAHLA FARZAN: Oh, that's such a good guess. OK, I was going to say it was like some sort of tiny animal, like a distressed tiny baby animal.
EBEN: Oh, yeah.
SHAHLA FARZAN: Your guess is so much better. I'm going to go with a tiny baby animal, cleaning steam off of a mirror with its finger. What do you think about that?
EBEN: Oh, that's a very good guess.
SHAHLA FARZAN: That's really nice of you to say that. OK, Eben, you're going to get a chance to guess again, and we're going to hear the answer after the credits.
EBEN: So stick around.
SHAHLA FARZAN: Hey, friends, we get so many awesome questions from you every day, and they make us so happy-- like, dance around with our pants on our heads, singing at the top of our lungs, kind of happy. But do you know what else we love? Fan art, drawings, paintings, popsicle stick art. We love all of it. Eben, have you ever been inspired to draw something, or make some kind of art based on a Brains On episode?
EBEN: It's not an art or anything, but it's a story about how I got inspired by Brains On Universe. So I decided, well, what if there are Brains On Universe, and then all the podcasts in Brains On universe like Forever Ago and Brains On Smash Boom Best, if each of those podcasts had a separate galaxy, like you could have adventures in them.
SHAHLA FARZAN: I love that idea. That is such a good idea. And you know what? I think a short story that's totally art. That's another form of art. Listeners, we want to see your fan art. Take a picture of it, and send it to us at brainson.org/contact. And while you're there, send us your mystery sounds, ideas, and questions.
EBEN: Like this one.
[AUDIO PLAYBACK]
- How do frogs tongues stretch so far?
[END PLAYBACK]
SHAHLA FARZAN: You can find answers to questions like these on the Moment of Um podcast, a short dose of facts and fun every weekday. Find Moment of Um and more at brainson.org
EBEN: And keep listening.
CREW: Brains On Universe is a family of podcasts for kids and their adults. Since you're a fan of Brains On, you'll love the other shows in our universe. Come on, let's explore.
[AUDIO PLAYBACK]
- Its alien laundry day. While I wash my nose mufflers and tummy togas, I'll listen to a new podcast. How about Forever Ago, my favorite history podcast?
- Whoa, I was not expecting that to work, or for it to sound this good.
- That's the DJ Dolo technique. DJ Dolo. When I say pizza, you say bagel. Pizza.
- Bagel.
- Zorp, signal down. Aargh, stay right there, tummy togas. Must find Forever Ago, now.
[END PLAYBACK]
CREW: Listen to Forever Ago, wherever you get your podcasts.
CREW: Ba ba ba ba ba ba ba ba, Brains On.
EBEN: You're listening to Brains On. I'm Eben.
SHAHLA FARZAN: And I'm Shahla.
EBEN: Today, we're talking all about coral, at a coral reef.
SHAHLA FARZAN: That's right. We're chilling in our go-anywhere, do-anything vehicle, the ExPLORERR, checking out this amazing reef. Before the break, we learned that coral comes in many different shapes, sizes, and colors. Sometimes coral looks like rocks or plants.
EBEN: But it's actually made up of animals called polyps. These polyps make hard exoskeletons around their soft bodies.
SHAHLA FARZAN: Groups of coral polyps are called colonies. And colonies can group together to form coral reefs.
EBEN: These coral reefs are home to all sorts of different fish, lobsters, shrimp, seahorses, sea sponges, and sea turtles.
ROCCO: Did somebody say turtle?
EBEN: We did, us, inside the underwater vehicle. Hi, I'm Eben, and this is Shahla.
CREW: What's up? I'm Rocco, the turtle, sweet coral hats.
SHAHLA FARZAN: Thanks, Rocco. We're huge fans of coral.
ROCCO: Oh, me too. I'm a bit of a nomad, so I like to travel a lot. But sometimes I call these coral reefs my home.
EBEN: They look busy.
ROCCO: Oh, they are. Coral reefs are home to thousands of different kinds of sea creatures all over the world.
SHAHLA FARZAN: It's true. Coral reefs take up less than 1% of the ocean floor, but they're home to about 25% of all marine life.
EBEN: Whoa, that means 1 in 4 marine animals live in a coral reef.
ROCCO: Right on, just like me and all of our other neighbors. Larissa, the lobster lives next door. Frederick, the seahorse is across the reef with his 700 kids. Oh, and Carl, the clownfish is about to sublet when I go up, see you next month. Gosh, I hope he remembers to water the plants.
EBEN: Aren't the plants always watered because we're in the ocean?
ROCCO: Excellent point, my friend. But he still has to check my mailbox. I'm expecting some very important sea snail mail, top secret stuff.
EBEN: Mhm, funny you should mention it, because coral also has a secret hidden it inside.
ROCCO: No way.
EBEN: Wait, there are tiny organisms living inside the coral polyps called algae.
SHAHLA FARZAN: You might have heard of algae before. The green scum that grows on top of ponds and lakes, that's algae.
EBEN: Seaweed is also a kind of algae. So is kelp.
ROCCO: Oh, I know all about algae. I'm a big fan of scum. I ate some for lunch today.
SHAHLA FARZAN: The algae that lives inside of coral is different from what you eat, though. It's also super tiny. You actually need a microscope to see it.
EBEN: You're probably wondering, why is there algae inside of coral?
ROCCO: I was wondering that.
SHAHLA FARZAN: Well, the algae use sunlight to make energy and sugar, like a plant does. The coral needs those nutrients to survive, but can't make it on its own.
EBEN: So the algae shares some of its nutrients with the coral.
SHAHLA FARZAN: And in return, it gets a safe place to live inside the coral like a house.
ROCCO: Whoa, algae and coral are like roommates.
SHAHLA FARZAN: Exactly, scientists think that coral and algae have been living together like this for more than 200 million years. In other words, this relationship started when dinosaurs were still walking the Earth. Pretty wild, huh?
EBEN: So wild. And did you know that algae is what gives coral all of its different colors?
ROCCO: Really? You're blowing my shell right now.
SHAHLA FARZAN: Yeah, the hard coral exoskeleton is actually white, but the algae inside can be red, pink, blue, or even purple, which makes the coral look colorful.
ROCCO: Algae rocks. Thanks for dropping this mad knowledge, human pals. All this algae talk has this turtle hankering for an algae smoothie. Catch you on the flip side.
SHAHLA FARZAN: Bye, Rocco.
EBEN: See you.
SHAHLA FARZAN: OK, let's head back to the studio. But first, sealing tacos with extra salsa. Confirmed coral is awesome. It's colorful, and complicated, and full of secret algae.
EBEN: Agreed, coral is super. But we still haven't answered the question that inspired this episode.
[AUDIO PLAYBACK]
- How does coral communicate?
[END PLAYBACK]
SHAHLA FARZAN: It's a great question. Scientists think that coral does in fact communicate. It sends messages.
EBEN: But there's a lot we don't understand about this communication.
SHAHLA FARZAN: Some scientists have found that coral can sometimes communicate by releasing chemicals. For example, one study looked at corals that were being attacked by toxic seaweed.
EBEN: They found that when the seaweed was taking over, corals would send out chemical signals into the water.
SHAHLA FARZAN: A certain kind of fish called goby fish, would smell this chemical signal and rush to the coral's defense.
EBEN: Like tiny bodyguards.
SHAHLA FARZAN: Yeah, they'd come over and start eating the seaweed off of the coral. Yay, gobies.
EBEN: Other studies have found coral might be able to send and receive sounds.
SHAHLA FARZAN: To learn more, we talked to Camila Rimoldi Ibanez. She's a marine biologist in Jupiter, Florida, and she studied this.
EBEN: Hi, Camila.
CAMILA IBANEZ: Hi, Eben. It's great to meet you.
EBEN: You too, with a couple of questions for you about coral. First, do we know how coral communicates?
CAMILA IBANEZ: That is an awesome question. So there's been a lot of really cool research that is trying to find how corals talk to each other, or how they communicate. And there's a few ways that we know corals already talk to each other. So one of the main ones is with chemicals.
So corals use these actually to fight each other in coral wars. They can use their tentacles and sting each other. It's like they're hitting each other with their arms. They can also use them to talk to fish.
SHAHLA FARZAN: Oh, yeah. We just talked about how they do that with gobies. It's so cool.
EBEN: You think coral might be able to hear and make sound? What got you thinking about that?
CAMILA IBANEZ: So there's a really, really cool study that showed that coral larvae, so the coral babies, when they're really, really tiny like so, so tiny, you can't even see it with your eye, they're just floating around in the ocean. And they're trying to find a coral reef to go and live and make their home.
And when they're trying to find their coral reef, they use a lot of different things to find that nice big coral reef. They use lights, they use currents. And this study found that the larvae actually used sound. So they're listening to the sounds of a healthy coral reef, which basically sounds like a big party because you have corals, you have fish, you have a lobsters, shrimp, all sorts of different animals making a lot of noise.
So it's been seen that coral larvae, so the coral babies, actually swim and use sounds to find their home in a big, nice coral reef. So I thought if coral babies can listen to sound, what about big coral? They probably have to talk to each other too.
EBEN: Whoa, what did your research find?
CAMILA IBANEZ: Oh, yeah. So in my research, that's what I did. I looked at big adult coral, so the ones that already have colonies, and I was trying to see if these corals are making sound. And I found that they do. I saw that corals are making ultrasonic sounds up to 30 kilohertz.
Ultrasonic sounds is a sound that is so, so high that you can't hear it. So corals are making these ultrasonic sounds that we can't hear, but maybe other animals in the ocean can. So I found that corals, they make these sounds whenever they're moving their tentacles. So whenever they're swaying them back and forth in their water, or when they [INAUDIBLE] pull them inside into their little cave home.
SHAHLA FARZAN: That's so cool, Camila. I'm also wondering, as I'm listening, how do you know that the coral are making these super, super high sounds? Like, did you put a microphone in to record them in the water?
CAMILA IBANEZ: Yeah, great question. So because there's so much sound in the ocean, I actually did this in a lab. So I was in a very special room where I could control everything, the temperature, the lights, all the different things which you have to do in an experiment. And in my little lab setting, I had one coral in a little tank, and I had a hydrophone. So a hydrophone is a microphone that can be used underwater.
So I used the hydrophone, and I also had a camera because I had to see what the coral was doing, what motions it was doing, so that I could later see whenever the coral talked, what kind of movement it did in the water.
SHAHLA FARZAN: That's so cool.
CAMILA IBANEZ: As I said, I love to talk about coral. I find them really, really amazing. And there's so much more we still have to learn about them. So there's a lot of coral bleaching going on right now. Have you heard that word before, coral bleaching?
EBEN: Yeah, when the coral gets overwhelmed, and they start to push out all the algae that gives them color like all their algae friends. And it's then because they're all overwhelmed. And sometimes when animals get overwhelmed, they can push out some of their friends. So they pushed out their algae, which makes them die.
CAMILA IBANEZ: You are quite the coral experts. Wow, that is an amazing way of saying it. Yeah, exactly. So coral bleaching is when they push out their little algae friends. But that doesn't mean they're dead yet.
EBEN: They're not?
CAMILA IBANEZ: No, I know. When I found that out, I was quite shocked too. Whenever they push out their little algae friends, they're very, very sick, but they can still come back and be healthy again. So there's a short window of time-- sometimes a few days, sometimes a few weeks-- when the coral is bleaching but is not dead yet.
So when they're in that little window is whenever we try to help the coral, so the algae friends can come back into the coral. So if the algae friends come back to live with the coral, then they can go out and be healthy and happy again.
EBEN: How do we help the coral?
CAMILA IBANEZ: A lot of the time, corals will push out their little algae friends, if the water is too hot. Or if they have plastic all around the coral and it's confused and it doesn't know how to get it off. So making sure that there's no plastic in the ocean, or if you see plastic on a coral reef, getting that out so the coral can feel healthy again.
SHAHLA FARZAN: Well, this has been so interesting, Camila. I just really appreciate you taking the time. We've learned so much.
CAMILA IBANEZ: Hey, I'm glad. I really enjoyed all of your questions and speaking to you guys.
EBEN: Thanks so much for talking with us, bye.
CAMILA IBANEZ: Bye.
CREW: Brains On the air.
MOLLY BLOOM: That was the best Backwards Pants Convention ever. I can't wait to start wearing my overalls backwards, and my sweatpants, and my-- hang on, why is the ExPLORERR sitting in the middle of the hallway? And why is it filled with ceiling tacos? Or are they floor tacos? And is this salsa on the seats? Shahla.
SHAHLA FARZAN: Oh, hey, Molly. Wow, oh, so much fun hosting today. Thanks so much for letting Eben and I do whatever we wanted today. Can't wait to host again sometime, bye.
EBEN: Coral is an animal, not a rock, or plant.
SHAHLA FARZAN: It's made up of tiny polyps that grow tough, little armor-like skeletons around themselves.
EBEN: Coral polyps group together to make colonies, which group together to form coral reefs.
SHAHLA FARZAN: About a quarter of all marine life lives in coral reefs. Coral has special algae living inside of it that help it get nutrients.
EBEN: Coral does send messages. We don't fully understand how.
SHAHLA FARZAN: Some can send chemical signals and others might be able to make and receive sounds.
EBEN: Scientists are studying coral to learn more.
SHAHLA FARZAN: That's it for this episode of Brains On.
EBEN: This episode was written by--
RUBY GUTHRIE: Ruby Guthrie.
EBEN: And--
SHAHLA FARZAN: Shahla Farzan.
EBEN: It was produced by--
MOLLY BLOOM: Molly Bloom.
EBEN: And--
ROSIE DUPONT: Rosie DuPont.
EBEN: Our editor is--
SANDEN TOTTEN: Sanden Totten.
EBEN: Fact checking by--
NICO WISLER: Nico Gonzalez Wisler.
SHAHLA FARZAN: Engineering help from Bryan Hartman, Josh Savageau, and David Tallaksen, with sound design by Rachel Brees. Original theme music by Marc Sanchez.
EBEN: We had production help from the rest of the Brains On Universe team.
ANNA GOLDFIELD: Anna Goldfield.
LAUREN HUMPERT: Lauren Humpert.
JOSHUA RAY: Joshua Ray.
REBECCA RAND: Rebecca Rand.
MARC SANCHEZ: Marc Sanchez.
CHARLOTTE TRAVER: Charlotte Traver.
ANNA WEGGEL: Anna Weggel.
EBEN: And--
ARON WOLDESLASSIE: Aron Woldeslassie.
SHAHLA FARZAN: Beth Pearlman is our executive producer. And the executives in charge of APM Studios are Chandra Kavati, and Joanne Griffith. Special thanks to Serene David and Mahalia Hudson, Diane and Levi Velasco, and Camila Grimaldi Ibanez.
EBEN: Brains On is a non-profit public radio program.
SHAHLA FARZAN: There are lots of ways to support the show. Sign up for the Brains On Universe newsletter for bonus activities, reading recommendations, and lots more. You can sign up at brainson.org.
EBEN: While you're there, you can send us mystery sounds, drawings, and questions.
SHAHLA FARZAN: OK, speaking of mystery sounds, Eben, are you ready to listen to that mystery sound one more time?
EBEN: Yes.
SHAHLA FARZAN: OK, let's hear it. OK, Eben, what do you think?
EBEN: I have some new guesses.
SHAHLA FARZAN: OK, let's hear them.
EBEN: It's kind of like your guess, except it's not an animal in distress. It's maybe a pet like a guinea pig, or maybe it's someone making a noise with their mouth.
SHAHLA FARZAN: Oh, I could totally imagine that because it's kind of like high-pitched and sort of squeaky sounding. I honestly am stumped. I have no idea what this is. Should we hear the answer?
EBEN: Yes.
[AUDIO PLAYBACK]
- Hi, my name is Cameron, and I live in Lethbridge, Alberta. And this was the sound of my baby pups drinking from their mom.
[END PLAYBACK]
SHAHLA FARZAN: What?
EBEN: Oh.
SHAHLA FARZAN: Oh, puppies. Oh, my gosh. What do you think, Eben? Is that surprising?
EBEN: Actually, now that I think of it, it's not very surprising, but I never thought of that.
SHAHLA FARZAN: I know. That was kind of hard. I would have never guessed it was puppies drinking milk from their mom. But you guessed pets, like maybe guinea pigs.
EBEN: I just said maybe some sort of pet, like maybe a guinea pig.
SHAHLA FARZAN: Oh, my gosh, so you totally got it then.
EBEN: Yay.
SHAHLA FARZAN: I'm giving us full credit for this. And now, it's time for the Brains Honor Roll. These are the awesome kids who keep this show going with questions, ideas, mystery sounds, drawings, and high fives.
[LISTING HONOR ROLL]
SHAHLA FARZAN: We'll be back next week with an episode all about asthma.
EBEN: Thanks for listening.
CREW: Brains On is supported in part by a grant from the National Science Foundation.
MOLLY BLOOM: Oh, what a beautiful day. The sun is shining. The birds are singing. Time to sit in my big comfy chair and start learning about coral for our episode this week. Let's see.
SHAHLA FARZAN: Molly, thank goodness I found you.
MOLLY BLOOM: Brains On editor Shahla Farzan. What are you wearing on your head?
SHAHLA FARZAN: Oh, this? It's my coral hat. It's a perfect replica of my favorite sea creature, coral. That colorful, rocky-looking stuff on the ocean floor? Believe it or not, I made this hat myself out of papier-máché.
MOLLY BLOOM: Yeah, it's really eye-catching.
SHAHLA FARZAN: Plus, check this out. It's my membership card for the Coral of the Month Club. Every month they send you an autographed photo of a different kind of coral
MOLLY BLOOM: Oh, autographed by coral?
SHAHLA FARZAN: And I got a new bumper sticker for my bike. See, it says, "I brake for coral." You got to watch out for those little corals in the road, you know?
MOLLY BLOOM: Well, coral lives in the ocean.
SHAHLA FARZAN: I know.
MOLLY BLOOM: I can't help but notice that you're really into coral. Do you--
SHAHLA FARZAN: Desperately want to host the new Brains On episode on coral? Like the baddest I've ever wanted anything in my life. So I'm showing you all my cool coral stuff to help convince you I should get to do it.
MOLLY BLOOM: You want to host the Brains On episode about coral?
SHAHLA FARZAN: I thought you'd never ask. I'd love to. And great news, since you have the week off now, I got you tickets to that convention you were talking about.
MOLLY BLOOM: The Backward Pants Convention, where enthusiasts from around the world come together to discuss the latest developments in backwards, pants-wearing technology?
SHAHLA FARZAN: That's the one. Looks like somebody's going to be spending a lot of her time with her pants on backwards this week, if you know what I mean. Oh, and I almost forgot. I made you something. Just to say thanks for believing in me.
MOLLY BLOOM: A present? I love presents. You really shouldn't have. Oh, wow, Shahla it's--
SHAHLA FARZAN: Your very own papier-máché coral hat. You're listening to Brains On from APM Studios. I'm Shahla Farzan, and I'm filling in for Molly while she's away this week. Here with me is Eben from Aurora, Illinois. Hey, Eben.
EBEN: Hi, Shahla.
SHAHLA FARZAN: Today, we're talking all about coral, that hard, sometimes colorful stuff on the ocean floor that can form coral reefs. Eben, what do you picture when I say coral?
EBEN: I picture rocky-looking colorful guys that come in lots of shapes, sizes, and colors.
SHAHLA FARZAN: Yeah, that's actually pretty close to what I think of to. If I am picturing coral, I'm picturing something that's underwater, and usually something that's like it kind of looks like a big, bumpy, rough boulder with just like a bunch of fish around it. Coral is pretty amazing, and so is this question which inspired today's episode.
[AUDIO PLAYBACK]
- Hi, my name is Finnegan, and I'm from Ontario, Canada. And my question is, how does coral communicate?
[END PLAYBACK]
EBEN: Wow, that's a great question.
SHAHLA FARZAN: I know. Coral might look like a rock or a plant, but it's actually an animal.
EBEN: Right, it might not talk like we do, but maybe it has its own special way of sending signals to other creatures.
SHAHLA FARZAN: We'll talk more about that in a bit. But first I want to know, Eben, what do you think is cool about coral reefs?
EBEN: I think coral reefs are cool because it takes lots of corals to make a coral reef.
SHAHLA FARZAN: You mean a lot of corals all linked up together into one reef?
EBEN: Yeah.
SHAHLA FARZAN: That's cool. Do you have a favorite sea creature?
EBEN: My favorite sea creature is a sea turtle.
SHAHLA FARZAN: A sea turtle. What do you like about sea turtles?
EBEN: I like how when they go through the water, they just seem so calm.
SHAHLA FARZAN: I know. I love the way sea turtles move through the water where it almost looks like they're flying. Like, they move their flippers up and down in the water.
EBEN: Yeah, it kind of looks like they're gliding through it, the water.
SHAHLA FARZAN: Yeah, I know. It really does actually. Have you ever seen coral in real life, like out in the wild, or in an aquarium?
EBEN: Maybe once, but probably a long time ago, because I don't remember.
SHAHLA FARZAN: I have been really lucky to be able to see coral out in the wild. So cool fact about me, I actually used to live on the Marianas Islands, which is this tiny little group of islands way out in the Pacific Ocean by Japan. And I was working out there as a scientist studying the forests there on the islands. But after work, I got to go snorkeling pretty much every day around the coral reefs.
EBEN: OK, that's pretty awesome.
SHAHLA FARZAN: I know. It was awesome but I have to be honest with you, the first time that I actually jumped in the ocean to go snorkeling, I was really nervous. The water wasn't super deep, but I'm not a really strong swimmer and I've always felt scared in the water. But once I got in there and I relaxed, I realized that there were all of these just incredible sea creatures around me, just swimming all around the coral reef.
So things like these rainbow-colored parrotfish and really big fish called grouper. I even saw this giant barracuda once that was like 3 feet long. And I think the really cool thing for me was that swimming around the coral reefs just made the water feel a lot less scary to me, and it was fun. Do you think that's something that you'd ever want to do, Eben, go snorkeling in a coral reef?
EBEN: Yeah, I think that'd be really fun. I get to see all the fish and the coral. And, wait, are you able to touch the coral? Do you know what it feels like?
SHAHLA FARZAN: You're not technically supposed to touch the coral because it can be fragile, like, you can break it off by accident. But one time I was snorkeling and I was in big waves, and my leg touched the coral, and it was really rough.
EBEN: Oh.
SHAHLA FARZAN: So you can find coral in oceans all over the world, from the rocky coasts of California to the shores of Mozambique in Eastern Africa.
EBEN: It comes in all different shapes and sizes. Some coral is flat like a big pancake.
SHAHLA FARZAN: Some looks like bright yellow flowers, or stars.
EBEN: And some coral even looks like brains.
SHAHLA FARZAN: But those cool shapes aren't the living part of coral, they're more like its colorful, bony armor. More on that in a second. But first, in honor of today's coral-tastic episode, I've got a surprise for you, Eben.
EBEN: Is it a 100% unique hand-made papier-máché hat in the shape of my favorite kind of coral? Because I actually brought one with me. See, it looks like brain coral.
SHAHLA FARZAN: I was going to give you a 100% unique hand-made papier-máché coral hat. But yours, it's gorgeous.
EBEN: Hey, thanks.
SHAHLA FARZAN: And check it out, we match. I've got one that looks like fire coral. See, it's got little orangey branches all over it. Eben, I wish we were at a coral reef right now.
EBEN: Same.
SHAHLA FARZAN: Wait, Molly specifically said we can do whatever we want today.
EBEN: She did?
SHAHLA FARZAN: Oh, yes. Or at least I'm sure she would have said that if she thought of it. And that's good enough for me. And since we can do whatever we want, I think we should go to a coral reef, like right now.
EBEN: Road trip. I mean, reef trip.
SHAHLA FARZAN: To the ExPLORERR. Dibs on the back seat. Here, catch the keys.
EBEN: Shahla, I'm 10 years old, I can't drive.
SHAHLA FARZAN: Oh, right, I can take us. I forgot I totally know how to drive. Let's go. We're coming to you live from my favorite vehicle, the Extremely Practical Land and Ocean Rover Exploring Remote Realms.
EBEN: Or ExPLORERR for short.
SHAHLA FARZAN: And we just dove straight into the ocean to look at some coral reefs.
EBEN: Whoa, look at this reef. Looks like a bunch of big, colorful sea plants. But it's not a plant. It's an animal.
SHAHLA FARZAN: And it's stunning. So like we said earlier, the part of the coral we can see is like it's bony armor. That part is not alive.
EBEN: But the parts underneath that bony armor are alive.
SHAHLA FARZAN: These living parts are squishy animals called polyps. Coral polyps are usually only a couple millimeters wide.
EBEN: That's smaller than my pinky nail.
SHAHLA FARZAN: But some can get as big as a basketball.
EBEN: Sometimes coral polyps are so tiny, you need a magnifying glass, or a microscope to see them.
SHAHLA FARZAN: Speaking of, I could have sworn the ExPLORERR had a zoom ray button somewhere in here. Oops, that just made tacos fall from the ceiling. Mhm, I do love a ceiling taco, although I guess now it's a floor taco, whatever. We'll clean those up later, maybe with our hands, maybe with our mouths. JK, we're not going to eat off the floor, Eben. Or are we?
EBEN: Hey, Shahla, what about this button?
SHAHLA FARZAN: That's the disco party button, classic mix up. Oh, I know. What if we--
EBEN: Press the 1 with the magnifying glass on it?
SHAHLA FARZAN: Oh, I was actually going to suggest that we just press all of the buttons at once, like how I do any time I'm in an elevator. But you're totally right. That is the zoom ray button. It lets us see stuff way up close.
CREW: Zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
EBEN: Whoa, so magnified.
SHAHLA FARZAN: All the better to see coral. Amazing to think that big, colorful reefs all start with these teeny tiny polyps.
EBEN: Up close, the coral polyps look like squishy little trees.
SHAHLA FARZAN: The top of each polyp has little tentacles like an octopus. And when these baby polyps are first starting out, they float around in the ocean until they find a hard surface to stick to.
EBEN: Like rocks on the ocean floor.
SHAHLA FARZAN: Once a polyp finds a nice rock to settle down on, it starts to transform. Kind of how when I settle down on my couch, I start to transform into a human-shaped pile of blankets covered in chip crumbs.
EBEN: Same, so once that coral polyp settles on a rock, it starts absorbing minerals that are floating in the sea water.
SHAHLA FARZAN: And it uses these minerals to form hard, shell-like exoskeletons on the outside of its squishy body.
EBEN: It's like the polyp, is making its own body armor.
SHAHLA FARZAN: Awesome. It's this armor that you're looking at when you swim past a colorful coral reef.
EBEN: Another amazing thing about coral polyps is that they can make copies of themselves like clones.
SHAHLA FARZAN: One coral polyp can multiply into hundreds, even thousands of clones. And these clones make armor too.
EBEN: When lots of coral polyps link up next to each other, they make groups called colonies.
SHAHLA FARZAN: You can think of it like this. If each coral polyp with its hard armor is like its own little apartment unit, then a coral colony is like an apartment building made up of a bunch of individual units. Even though each coral polyp can be microscopic, their colonies can weigh up to several tons.
EBEN: About the same weight as an elephant.
SHAHLA FARZAN: When different coral colonies are built next to each other, they form coral reefs.
EBEN: Which is a bunch of different apartment buildings coming together to make up a whole city.
SHAHLA FARZAN: Yes, coral reefs are like cool coral cities. Here, let's zoom out again so we can marvel at them.
CREW: Zoom.
EBEN: Wow, it really is like a city.
SHAHLA FARZAN: Pretty neat, huh? Wow, look at the time.
EBEN: Oh, Shahla, that's a piece of taco stuck to your wrist, not a watch.
SHAHLA FARZAN: I totally knew that. Now, how does Molly always say it? Think, think, think, think. Come on, Shahla, think. Oh, right, Eben, it's time for the--
CREW: Mystery sound. Eben, are you ready to hear the mystery sound?
EBEN: Yes.
SHAHLA FARZAN: All right, let's hear it. Whoa, OK, Eben, what do you think? You got any guesses?
EBEN: OK, yeah. After a lot of water evaporates in the bathroom, it kind of makes a bunch of stuff on the mirror, and you can wipe it off with your finger, and sometimes it can make some squeaky noise. So I'm guessing that it's someone using their finger to squeak along the glass.
SHAHLA FARZAN: Oh, like wiping the steam off of a mirror?
EBEN: Yeah, except with their hands or finger.
SHAHLA FARZAN: Oh, that's such a good guess. OK, I was going to say it was like some sort of tiny animal, like a distressed tiny baby animal.
EBEN: Oh, yeah.
SHAHLA FARZAN: Your guess is so much better. I'm going to go with a tiny baby animal, cleaning steam off of a mirror with its finger. What do you think about that?
EBEN: Oh, that's a very good guess.
SHAHLA FARZAN: That's really nice of you to say that. OK, Eben, you're going to get a chance to guess again, and we're going to hear the answer after the credits.
EBEN: So stick around.
SHAHLA FARZAN: Hey, friends, we get so many awesome questions from you every day, and they make us so happy-- like, dance around with our pants on our heads, singing at the top of our lungs, kind of happy. But do you know what else we love? Fan art, drawings, paintings, popsicle stick art. We love all of it. Eben, have you ever been inspired to draw something, or make some kind of art based on a Brains On episode?
EBEN: It's not an art or anything, but it's a story about how I got inspired by Brains On Universe. So I decided, well, what if there are Brains On Universe, and then all the podcasts in Brains On universe like Forever Ago and Brains On Smash Boom Best, if each of those podcasts had a separate galaxy, like you could have adventures in them.
SHAHLA FARZAN: I love that idea. That is such a good idea. And you know what? I think a short story that's totally art. That's another form of art. Listeners, we want to see your fan art. Take a picture of it, and send it to us at brainson.org/contact. And while you're there, send us your mystery sounds, ideas, and questions.
EBEN: Like this one.
[AUDIO PLAYBACK]
- How do frogs tongues stretch so far?
[END PLAYBACK]
SHAHLA FARZAN: You can find answers to questions like these on the Moment of Um podcast, a short dose of facts and fun every weekday. Find Moment of Um and more at brainson.org
EBEN: And keep listening.
CREW: Brains On Universe is a family of podcasts for kids and their adults. Since you're a fan of Brains On, you'll love the other shows in our universe. Come on, let's explore.
[AUDIO PLAYBACK]
- Its alien laundry day. While I wash my nose mufflers and tummy togas, I'll listen to a new podcast. How about Forever Ago, my favorite history podcast?
- Whoa, I was not expecting that to work, or for it to sound this good.
- That's the DJ Dolo technique. DJ Dolo. When I say pizza, you say bagel. Pizza.
- Bagel.
- Zorp, signal down. Aargh, stay right there, tummy togas. Must find Forever Ago, now.
[END PLAYBACK]
CREW: Listen to Forever Ago, wherever you get your podcasts.
CREW: Ba ba ba ba ba ba ba ba, Brains On.
EBEN: You're listening to Brains On. I'm Eben.
SHAHLA FARZAN: And I'm Shahla.
EBEN: Today, we're talking all about coral, at a coral reef.
SHAHLA FARZAN: That's right. We're chilling in our go-anywhere, do-anything vehicle, the ExPLORERR, checking out this amazing reef. Before the break, we learned that coral comes in many different shapes, sizes, and colors. Sometimes coral looks like rocks or plants.
EBEN: But it's actually made up of animals called polyps. These polyps make hard exoskeletons around their soft bodies.
SHAHLA FARZAN: Groups of coral polyps are called colonies. And colonies can group together to form coral reefs.
EBEN: These coral reefs are home to all sorts of different fish, lobsters, shrimp, seahorses, sea sponges, and sea turtles.
ROCCO: Did somebody say turtle?
EBEN: We did, us, inside the underwater vehicle. Hi, I'm Eben, and this is Shahla.
CREW: What's up? I'm Rocco, the turtle, sweet coral hats.
SHAHLA FARZAN: Thanks, Rocco. We're huge fans of coral.
ROCCO: Oh, me too. I'm a bit of a nomad, so I like to travel a lot. But sometimes I call these coral reefs my home.
EBEN: They look busy.
ROCCO: Oh, they are. Coral reefs are home to thousands of different kinds of sea creatures all over the world.
SHAHLA FARZAN: It's true. Coral reefs take up less than 1% of the ocean floor, but they're home to about 25% of all marine life.
EBEN: Whoa, that means 1 in 4 marine animals live in a coral reef.
ROCCO: Right on, just like me and all of our other neighbors. Larissa, the lobster lives next door. Frederick, the seahorse is across the reef with his 700 kids. Oh, and Carl, the clownfish is about to sublet when I go up, see you next month. Gosh, I hope he remembers to water the plants.
EBEN: Aren't the plants always watered because we're in the ocean?
ROCCO: Excellent point, my friend. But he still has to check my mailbox. I'm expecting some very important sea snail mail, top secret stuff.
EBEN: Mhm, funny you should mention it, because coral also has a secret hidden it inside.
ROCCO: No way.
EBEN: Wait, there are tiny organisms living inside the coral polyps called algae.
SHAHLA FARZAN: You might have heard of algae before. The green scum that grows on top of ponds and lakes, that's algae.
EBEN: Seaweed is also a kind of algae. So is kelp.
ROCCO: Oh, I know all about algae. I'm a big fan of scum. I ate some for lunch today.
SHAHLA FARZAN: The algae that lives inside of coral is different from what you eat, though. It's also super tiny. You actually need a microscope to see it.
EBEN: You're probably wondering, why is there algae inside of coral?
ROCCO: I was wondering that.
SHAHLA FARZAN: Well, the algae use sunlight to make energy and sugar, like a plant does. The coral needs those nutrients to survive, but can't make it on its own.
EBEN: So the algae shares some of its nutrients with the coral.
SHAHLA FARZAN: And in return, it gets a safe place to live inside the coral like a house.
ROCCO: Whoa, algae and coral are like roommates.
SHAHLA FARZAN: Exactly, scientists think that coral and algae have been living together like this for more than 200 million years. In other words, this relationship started when dinosaurs were still walking the Earth. Pretty wild, huh?
EBEN: So wild. And did you know that algae is what gives coral all of its different colors?
ROCCO: Really? You're blowing my shell right now.
SHAHLA FARZAN: Yeah, the hard coral exoskeleton is actually white, but the algae inside can be red, pink, blue, or even purple, which makes the coral look colorful.
ROCCO: Algae rocks. Thanks for dropping this mad knowledge, human pals. All this algae talk has this turtle hankering for an algae smoothie. Catch you on the flip side.
SHAHLA FARZAN: Bye, Rocco.
EBEN: See you.
SHAHLA FARZAN: OK, let's head back to the studio. But first, sealing tacos with extra salsa. Confirmed coral is awesome. It's colorful, and complicated, and full of secret algae.
EBEN: Agreed, coral is super. But we still haven't answered the question that inspired this episode.
[AUDIO PLAYBACK]
- How does coral communicate?
[END PLAYBACK]
SHAHLA FARZAN: It's a great question. Scientists think that coral does in fact communicate. It sends messages.
EBEN: But there's a lot we don't understand about this communication.
SHAHLA FARZAN: Some scientists have found that coral can sometimes communicate by releasing chemicals. For example, one study looked at corals that were being attacked by toxic seaweed.
EBEN: They found that when the seaweed was taking over, corals would send out chemical signals into the water.
SHAHLA FARZAN: A certain kind of fish called goby fish, would smell this chemical signal and rush to the coral's defense.
EBEN: Like tiny bodyguards.
SHAHLA FARZAN: Yeah, they'd come over and start eating the seaweed off of the coral. Yay, gobies.
EBEN: Other studies have found coral might be able to send and receive sounds.
SHAHLA FARZAN: To learn more, we talked to Camila Rimoldi Ibanez. She's a marine biologist in Jupiter, Florida, and she studied this.
EBEN: Hi, Camila.
CAMILA IBANEZ: Hi, Eben. It's great to meet you.
EBEN: You too, with a couple of questions for you about coral. First, do we know how coral communicates?
CAMILA IBANEZ: That is an awesome question. So there's been a lot of really cool research that is trying to find how corals talk to each other, or how they communicate. And there's a few ways that we know corals already talk to each other. So one of the main ones is with chemicals.
So corals use these actually to fight each other in coral wars. They can use their tentacles and sting each other. It's like they're hitting each other with their arms. They can also use them to talk to fish.
SHAHLA FARZAN: Oh, yeah. We just talked about how they do that with gobies. It's so cool.
EBEN: You think coral might be able to hear and make sound? What got you thinking about that?
CAMILA IBANEZ: So there's a really, really cool study that showed that coral larvae, so the coral babies, when they're really, really tiny like so, so tiny, you can't even see it with your eye, they're just floating around in the ocean. And they're trying to find a coral reef to go and live and make their home.
And when they're trying to find their coral reef, they use a lot of different things to find that nice big coral reef. They use lights, they use currents. And this study found that the larvae actually used sound. So they're listening to the sounds of a healthy coral reef, which basically sounds like a big party because you have corals, you have fish, you have a lobsters, shrimp, all sorts of different animals making a lot of noise.
So it's been seen that coral larvae, so the coral babies, actually swim and use sounds to find their home in a big, nice coral reef. So I thought if coral babies can listen to sound, what about big coral? They probably have to talk to each other too.
EBEN: Whoa, what did your research find?
CAMILA IBANEZ: Oh, yeah. So in my research, that's what I did. I looked at big adult coral, so the ones that already have colonies, and I was trying to see if these corals are making sound. And I found that they do. I saw that corals are making ultrasonic sounds up to 30 kilohertz.
Ultrasonic sounds is a sound that is so, so high that you can't hear it. So corals are making these ultrasonic sounds that we can't hear, but maybe other animals in the ocean can. So I found that corals, they make these sounds whenever they're moving their tentacles. So whenever they're swaying them back and forth in their water, or when they [INAUDIBLE] pull them inside into their little cave home.
SHAHLA FARZAN: That's so cool, Camila. I'm also wondering, as I'm listening, how do you know that the coral are making these super, super high sounds? Like, did you put a microphone in to record them in the water?
CAMILA IBANEZ: Yeah, great question. So because there's so much sound in the ocean, I actually did this in a lab. So I was in a very special room where I could control everything, the temperature, the lights, all the different things which you have to do in an experiment. And in my little lab setting, I had one coral in a little tank, and I had a hydrophone. So a hydrophone is a microphone that can be used underwater.
So I used the hydrophone, and I also had a camera because I had to see what the coral was doing, what motions it was doing, so that I could later see whenever the coral talked, what kind of movement it did in the water.
SHAHLA FARZAN: That's so cool.
CAMILA IBANEZ: As I said, I love to talk about coral. I find them really, really amazing. And there's so much more we still have to learn about them. So there's a lot of coral bleaching going on right now. Have you heard that word before, coral bleaching?
EBEN: Yeah, when the coral gets overwhelmed, and they start to push out all the algae that gives them color like all their algae friends. And it's then because they're all overwhelmed. And sometimes when animals get overwhelmed, they can push out some of their friends. So they pushed out their algae, which makes them die.
CAMILA IBANEZ: You are quite the coral experts. Wow, that is an amazing way of saying it. Yeah, exactly. So coral bleaching is when they push out their little algae friends. But that doesn't mean they're dead yet.
EBEN: They're not?
CAMILA IBANEZ: No, I know. When I found that out, I was quite shocked too. Whenever they push out their little algae friends, they're very, very sick, but they can still come back and be healthy again. So there's a short window of time-- sometimes a few days, sometimes a few weeks-- when the coral is bleaching but is not dead yet.
So when they're in that little window is whenever we try to help the coral, so the algae friends can come back into the coral. So if the algae friends come back to live with the coral, then they can go out and be healthy and happy again.
EBEN: How do we help the coral?
CAMILA IBANEZ: A lot of the time, corals will push out their little algae friends, if the water is too hot. Or if they have plastic all around the coral and it's confused and it doesn't know how to get it off. So making sure that there's no plastic in the ocean, or if you see plastic on a coral reef, getting that out so the coral can feel healthy again.
SHAHLA FARZAN: Well, this has been so interesting, Camila. I just really appreciate you taking the time. We've learned so much.
CAMILA IBANEZ: Hey, I'm glad. I really enjoyed all of your questions and speaking to you guys.
EBEN: Thanks so much for talking with us, bye.
CAMILA IBANEZ: Bye.
CREW: Brains On the air.
MOLLY BLOOM: That was the best Backwards Pants Convention ever. I can't wait to start wearing my overalls backwards, and my sweatpants, and my-- hang on, why is the ExPLORERR sitting in the middle of the hallway? And why is it filled with ceiling tacos? Or are they floor tacos? And is this salsa on the seats? Shahla.
SHAHLA FARZAN: Oh, hey, Molly. Wow, oh, so much fun hosting today. Thanks so much for letting Eben and I do whatever we wanted today. Can't wait to host again sometime, bye.
EBEN: Coral is an animal, not a rock, or plant.
SHAHLA FARZAN: It's made up of tiny polyps that grow tough, little armor-like skeletons around themselves.
EBEN: Coral polyps group together to make colonies, which group together to form coral reefs.
SHAHLA FARZAN: About a quarter of all marine life lives in coral reefs. Coral has special algae living inside of it that help it get nutrients.
EBEN: Coral does send messages. We don't fully understand how.
SHAHLA FARZAN: Some can send chemical signals and others might be able to make and receive sounds.
EBEN: Scientists are studying coral to learn more.
SHAHLA FARZAN: That's it for this episode of Brains On.
EBEN: This episode was written by--
RUBY GUTHRIE: Ruby Guthrie.
EBEN: And--
SHAHLA FARZAN: Shahla Farzan.
EBEN: It was produced by--
MOLLY BLOOM: Molly Bloom.
EBEN: And--
ROSIE DUPONT: Rosie DuPont.
EBEN: Our editor is--
SANDEN TOTTEN: Sanden Totten.
EBEN: Fact checking by--
NICO WISLER: Nico Gonzalez Wisler.
SHAHLA FARZAN: Engineering help from Bryan Hartman, Josh Savageau, and David Tallaksen, with sound design by Rachel Brees. Original theme music by Marc Sanchez.
EBEN: We had production help from the rest of the Brains On Universe team.
ANNA GOLDFIELD: Anna Goldfield.
LAUREN HUMPERT: Lauren Humpert.
JOSHUA RAY: Joshua Ray.
REBECCA RAND: Rebecca Rand.
MARC SANCHEZ: Marc Sanchez.
CHARLOTTE TRAVER: Charlotte Traver.
ANNA WEGGEL: Anna Weggel.
EBEN: And--
ARON WOLDESLASSIE: Aron Woldeslassie.
SHAHLA FARZAN: Beth Pearlman is our executive producer. And the executives in charge of APM Studios are Chandra Kavati, and Joanne Griffith. Special thanks to Serene David and Mahalia Hudson, Diane and Levi Velasco, and Camila Grimaldi Ibanez.
EBEN: Brains On is a non-profit public radio program.
SHAHLA FARZAN: There are lots of ways to support the show. Sign up for the Brains On Universe newsletter for bonus activities, reading recommendations, and lots more. You can sign up at brainson.org.
EBEN: While you're there, you can send us mystery sounds, drawings, and questions.
SHAHLA FARZAN: OK, speaking of mystery sounds, Eben, are you ready to listen to that mystery sound one more time?
EBEN: Yes.
SHAHLA FARZAN: OK, let's hear it. OK, Eben, what do you think?
EBEN: I have some new guesses.
SHAHLA FARZAN: OK, let's hear them.
EBEN: It's kind of like your guess, except it's not an animal in distress. It's maybe a pet like a guinea pig, or maybe it's someone making a noise with their mouth.
SHAHLA FARZAN: Oh, I could totally imagine that because it's kind of like high-pitched and sort of squeaky sounding. I honestly am stumped. I have no idea what this is. Should we hear the answer?
EBEN: Yes.
[AUDIO PLAYBACK]
- Hi, my name is Cameron, and I live in Lethbridge, Alberta. And this was the sound of my baby pups drinking from their mom.
[END PLAYBACK]
SHAHLA FARZAN: What?
EBEN: Oh.
SHAHLA FARZAN: Oh, puppies. Oh, my gosh. What do you think, Eben? Is that surprising?
EBEN: Actually, now that I think of it, it's not very surprising, but I never thought of that.
SHAHLA FARZAN: I know. That was kind of hard. I would have never guessed it was puppies drinking milk from their mom. But you guessed pets, like maybe guinea pigs.
EBEN: I just said maybe some sort of pet, like maybe a guinea pig.
SHAHLA FARZAN: Oh, my gosh, so you totally got it then.
EBEN: Yay.
SHAHLA FARZAN: I'm giving us full credit for this. And now, it's time for the Brains Honor Roll. These are the awesome kids who keep this show going with questions, ideas, mystery sounds, drawings, and high fives.
[LISTING HONOR ROLL]
SHAHLA FARZAN: We'll be back next week with an episode all about asthma.
EBEN: Thanks for listening.
Transcription services provided by 3Play Media.
