Hey, I'm Molly Webster. Hey, I'm Mono Montgomery. Mono and I just made a snail episode. It's called snail sex tape. And we have not stopped talking about snails for like months. We've become deeply obsessed with snails. I think we should all get snail tattoos. Ooh, snail tattoo could be cute. But you know what, you can get instead of a snail tattoo. What? You can get an enamel snail pin in honor of our snail sex tape episode. I've never been more honored in my life. I know. It is based on a real medieval snail miniature. I will be rocking it on my gene jacket all spring long. So to get one of these pins, you have to join the lab. And when you join the lab in addition to helping fund our show, you get access to sponsor free podcasts, plus monthly bonus content, plus invitations to events with the team. Including an AMA that we're going to be doing next month, you and me about the behind the scenes of making snail sex tape. Behind the shell, BTS, all you have to do is go to radiolab.org slash join. And if you use the code word snail, you get two months off the first year of an annual membership. Get your pin. And we can't wait to see you guys next month. Thanks, everyone. Oh, wait, you're listening. OK. Got it. OK. Got it. Door listening to radio lab. Radio from W and Y. See. See. This is radio lab. I'm Molly Webster. I'm going to open up the show today with Deepsea Explore and Oceanographer, Edie Whitter. I'm still here ready to go. Why don't you tell me how you bumped into our friend? Our friend, giant squid. No, our friend, the angler fish. Oh, the angler fish. I'm here for the small. I called Edie because I wanted to talk to her about the angler fish and this kind of weird thing I had heard about their immune systems and how they mate with each other. I wanted to be, but never. But then Edie wooed me with a story that had to do with none of that about being a grad student in the 80s, working on the back of a boat and pulling sea creatures out of the deep. I was going to see on ships with scientists who had developed a way to bring animals up from the deep sea alive. So they usually come up dead when you bring them up in the net because of temperature changes. They're basically cooked alive. So he had developed what was called a thermally insulated closing cod end that went on the end of a net. And so he'd bring them up and they'd still be alive. So they'd be swirling around in that tub and you'd have to plunge your hand into this icy cold water and your hand would go completely numb. And one of the first animals I pulled out was this bright red shrimp about the size of a hamster. And it was squirting neon blue light out of tubes on either side of its mouth. And it pulled in my hand and then dripped between my fingers back into the tub. Really? It was astonishing. What was it like to hold dripping light? I can't describe it any other way. I mean, it was cold light and it was brilliantly blue. If you're fully dark adapted by luminescence, it can look very bright. And it went on glowing in the water and then kind of swirled around and disappeared. Wow, I can't even... Because I didn't... I guess I always think of light or something that creates light as like in a container. You know, like almost like a light bulb has a border. I never think of it as like oozy. Oh, for me, it was revelatory. I just couldn't believe that all of this existed. And you know, at that time you could pick up a marine biology textbook and find no mention of bioluminescence. No way. Oh, really? Yes. It's not that they didn't know about it. It just didn't think it was very important. After that experience, E.D. spent the next 40 years and counting because she's still going, chasing the light, diving into the ocean over and over and over again in search of creatures that glowed like the shrimp. How many times have you gone down 3,000 feet in the ocean? I stopped counting after about 300. 300? I'm in the hundreds, definitely. Wow. Oh, yeah, so many things I've seen from submersibles that I'm pretty sure nobody's ever seen. E.D. has plunged into the unknown in a way that few people on the planet ever have. And so I very quickly abandoned my sort of angler fish interest and I just followed her into the deep, into a world of brilliance and color where light suddenly comes to life. My first open ocean dive was in the Santa Barbara channel. I was testing this diving suit called Wasps that was developed by the offshore oil industry for diving on oil rigs down to 2,000 feet. Is it like you're in an astronaut's suit that you can control? Yeah, it's exactly like an astronaut's suit. It's got a plexiglass bubble for the head, Michelin man arms, no legs for walking on the bottom just a pod with thrusters that are attached to it and you control the thrusters with foot switches on the bottom of the suit. It's like being in a fishbowl but the fish are on the outside and the people are on the inside. You're the fish. Yep. Wait, your first big dive was in this Marshmallow Man's suit? Yep. But that first dive was just to be to 800 feet to make sure I wasn't going to have a claustrophobic meltdown. Oh my God, you are so gutsy. Did you get nervous? Yeah, OK. I was nervous. It was an early evening dive and they lowered me off the back of the ship. And I'm just imagining kind of an ungainly splash when you hit the water. Yeah. It's about right. And they got down to 800 feet and I turned out the lights. And I was instantly in the center of this fireworks display. And I was just blown away by how much light there was all around me. Just sparkles and glows and squirts, squirts, squirts. All of it, different shades of brilliant, brilliant blue. Oh, blue. All blue. Oh, I was imagining yellow. No, blue is the color that travels farthest to sea water. And so most of it by far is blue. And is it pointalistic glowing? Like is it dots or is it like? Some of it's not dreaming things. Some of it's like a little smoke cloud or it can be a little cloud of particles. That's so cute. The weirdest thing for me, though, was that when I turned on the lights, there was almost nothing in the water column that I could identify as a potential source for all this luminescence that I was seeing. But you couldn't see it with the lights on. You have to turn the lights off to actually see what you want to see. Right. And could it all have been the same thing? Or do you think it was many different things? That first dive, it was many different things. But I was just overwhelmed by how much luminescence there was. And my brain was racing as they pulled me up because I just thought, you know, this is so important, but how the hell do you study it? If you turn on the lights and there's nothing there. And why did you think it was so important? Because it takes so much energy to produce light, to use that much energy, so critical to life, that I mean, there was no question, this had to be about life or death. There have been experiments that have been done that have found, for example, if you star by luminescent copepods, they will give up the ability to make eggs before they give up the ability to make light. Wow. Because they use their light for defense in that particular case. And so they can't live without their bioluminescence. Wait, so yeah, tell me about the different ways these animals use bioluminescence. So one way is to find food. So a lot of them have fish and squid and shrimp that have built in light organs next to their eyes that they use like flashlights to be able to see in the dark. There are animals that have oddly shaped light organs that allow the male to find this female of his species to mate with, so to attract a mate. There's animals that will use every light organ they've got, which may have many different functions, but they'll flash like crazy if they're caught in the clutches of a predator, because their luminescence is functioning as what's known as a bioluminescent burglar alarm. It's meant to attract the attention of larger predators that may attack their attacker, and therefore, for them an opportunity for escape. And then there is a huge amount of it that's used for camouflage, something that's called counter illumination. A lot of them will produce bioluminescence from their bellies that exactly matches the color and intensity of sunlight, filtering down from above to camouflage their silhouette. And if a cloud goes over the sun and dims the sunlight, they dim their bioluminescence. That quickly, they can respond that quickly. Absolutely. The cookie cutter shark, which is one of my favorites, produces bioluminescence from its belly. That's the most perfect counter illumination pattern you've ever seen, because the light organs are so small, that it just completely disappears. It's the perfect cloaking device. But like, if the sun is passing over and then a cloud passes over the sun, like, how does it sense like the right amount of light shift that must occur and then quickly adapt it? Well, that's like, how can it read the light? That's an excellent question. So some of them actually have a light organ above their eye that they can see. They can see that light organ relative to the background light to be able to adjust to exactly match. Some of the others were not sure how they do it, because they don't seem to have a sensor system, a feedback like that. Edie just kept going back again and again to how much we don't know about the deep sea, like how light is used, how light is made. And then she had so many cool, weird stories about like these convoluted, almost gothic light organs. There is one type of angler fish known as the bearded sea devil. Okay. It's got a luminescent lure on its forehead to attract food, the way most angler fish do, but it's got a chin barbell on its chin. And the absolutely insane thing about this is not only that it's got these two completely different light organs on its head, but the one coming out of its chin is intrinsic chemistry, Lucifer and Luciferase. But the one coming up out of its forehead is by luminescent bacteria. The angler fish literally has kind of a bobble that comes out over its forehead and has bioluminescent bacteria tucked inside of it. Right. Where does the bacteria come from? Like does it find the fish early in life or is it like birthed with the fish? Well, a lot of these bioluminescent bacteria are available in ocean water. And so it's thought that they picked the bacteria up from the environment. But the weird thing about bioluminescent bacteria is bacteria glow all the time because their light output is linked to their, what is basically their breathing, their respiratory chain. So as long as they've got enough oxygen, they just go on glowing. So some of these angler fish control the light output by just controlling the amount of oxygen. I mean, it's different in different fish. Some of them do it by having a mechanical shutter that just covers the light organ. Almost like an eyelid? Yes, there's some flashlight fish that have an eyelid that closes up over the light organ to be able to block out the glowing bacteria. There's others that roll the whole light organ back into their head, like the headlights on your Lamborghini. What? Yep. I really, this is so, I just think of light as like so passive in a way. Like the fact that it's so active and alive feeling? That's exactly right. I've always taken bioluminescence as an indicator of life. And I think it's got a lot to tell us about life in the ocean. Like what? Where it is? Yes. How the carbon pump is functioning. You know, it's... But like, those are, but even more than that, it feels like almost the idea of having another eye on my body that is searching around and reading the environment and then changing what I look like to match that environment. It feels like super intelligence. Well, it's super evolution. We'll be back in just a minute. Hey, Lulu here. And this episode is sponsored by BetterHelp. It is March in like a lion, out like a lamb, and somewhere in the middle, it's International Women's Day. And BetterHelp wants us all to just take a moment to consider the women in our lives, our personal lives, our society, and thank them for their strength and for all that they carry. That work matters. They matter. You matter. And therapy offers a space for all of us to take care of ourselves in the way we deserve. Think about the roles you play for the people you love. Think about how those roles, intentionally or not, way on you and in the worst moments, work to weigh you down. Therapy helps create perspective, set healthy boundaries and work toward balance. BetterHelp has loads of therapists, all of whom work according to a strict code of conduct and are fully licensed in the US. Why not give it a try? Fill out a short questionnaire and BetterHelp will use their 12 plus years of experience to match you with one. If you aren't happy with your match, switch to a different therapist at any time. Your emotional well-being matters. Find support and feel lighter in therapy. Sign up and get 10% off at betterhelp.com slash radio lab. That's betterhelp.com slash radio lab. From WQXR and Carnegie Hall comes Classical Music Happy Out. A new podcast hosted by me, ManiX. Each episode will speak with a special guest about their lives, listen to musical gems, answer your classical queries and take part in playful musical games. So grab a drink and press play on the new podcast celebrating our love for all things classical. Listen wherever you get your podcasts. I have one answer for a question you didn't ask. Oh, please tell me, I love those. Is how did bioluminescent bacteria come to be? This is radio lab. I'm Molly and we are back with Edie. Because this was a hotly contested topic when I was a graduate student because the conundrum was that a single bacterium does not produce enough light to be seen by any known organism. So how could there be a selective advantage to producing light? How could it ever be selected for? Well, there were some experiments done a few years back by some Polish scientists where they had light producing bioluminescent bacteria and a dark strain. And they mixed them together and when they grew them in a dish, the dark strain always overgrued the light strain because it takes energy to produce bioluminescent. So further questions about, you know, what could possibly be the selective advantage when it's energetically costly to produce light? But if they irradiated that dish then with UV light, then suddenly the thing flipped and now the light producing cells had the advantage and they overran the dish. And it turned out the reason was a enzyme called photolias that repairs DNA damage from UV light, which happens in the upper ocean. And so the light produced by a single-dynamic ligulate was enough to activate this light activated enzyme called photolias. And so the selective advantage had nothing to do with vision initially. It had to do with protection against UV light. So hundreds of millions of years ago, there were these tiny cells out in the ocean and they glowed. And even though no one could see it, it made a difference because it let them heal their DNA that was damaged by the sun. But as these creatures went deeper and deeper into the ocean, the sun started mattering less and the glow started mattering more. They could use it to lure and to lie to hunt or mate or survive. And it's into this world that Edie goes basically just to observe and study it until one day, almost by accident, she becomes a part of it. In 1985, I got to pilot a single person submersible call Deep Rover. And what I discovered with that, which was a major breakthrough in understanding the nature of the visual environment in the deep sea, was if I trimmed the sub out to neutral buoyancy and just made it as dark as I possibly could, I had black tapes so I blackened out any little indicator lights. And I waited. And I waited. And I waited. Nothing. Just as the black is black, you can imagine. But if I activated the thrusters, there would be these vortices of lights whirling up out of the thrusters and particles screaming back over the sphere and just light all around me. With later dives, I discovered that I could also stimulate it by turning the lights on and off. I think it was probably one of the pilots that alerted me to it originally, where you just flick the lights on and off. And everything surrounding you seems to come on in unison. And then fade out in unison. It's a phenomenon we call the flashback phenomenon. And how long is the flash that you put out? It'd be on off, on off, and on the second flash, you are surrounded by all of these things lighting up. We actually don't know what is flashing back at us, which makes it even more intriguing. But I think what I'm seeing with the flashback is bioluminescence in marine snow. Marine snow are all of these particulate organic matter that filters down through the ocean and is the base of the food web in the deep ocean. So plankton photosynthesizing at the surface, die, and as they sink through the ocean, they often are described as looking like marine snow, these flocculent white particles. And some marine snow is bioluminescent. And it seems to be bioluminescent because of bacteria. And so when you bump the particle, you're introducing oxygen into the marine snow environment. And you create light. I see. I think the reason that the light stimulus works is because there are cyanobacteria also in marine snow. And you're activating photosynthesis, which produces oxygen. And do you think it's all marine snow that's doing the flashback or there are other creatures that are also doing it? It's mostly the marine snow. We would occasionally see something identifiable like a tomoptorid worm that was particularly recognizable because it's yellow. It almost looks like gold. It's so beautiful. ED doesn't know for sure what's happening. But she thinks that the flashback is a natural phenomenon. That's actually something that's happening between the deep sea creatures when she's not there. So a thin brushes the water and mixes in oxygen and it gets bacteria to light up. Or a light on a fish's belly flashes. And it makes photosynthesis happen. And again, the world comes alive. And ED believes that this back and forth with light is not accidental, but that it's purposeful. The bacteria glow in order to be eaten. They want to be eaten, excuse the anthropomorphism. But it is to their advantage to be eaten because then they are reintroduced into the food-rich environment of a fish gut. And that when she does that flashback with the creatures in the deep sea, in a sense, she's become one of them. So her submarine thruster is like a fin. Or her flashlight is like a lure. And in those moments, she's become part of the dance. It's just such a remarkable feeling. I'm not a poet. But there's no question. I feel a tremendous sense of awe. Very often the feeling of, you know, I want to stay here. I want to understand this. I mean, that's key to who we are as human beings. You know, we were born as strangers in a strange land. We don't know anything when we were born. And our survival on the planet has been to explore the world around us and share that information. And I think that there's something very innate in us that responds to that. And the others that I have shared it with have had the same experience. That's, I don't have a ton of experience with bioluminescence, but I always have, but one story always ticks with me, which is, and I've never seen this happen before, but I grew up in kind of rural Ohio, in farm country, and we had a pond. And my parents sold the property that we grew up on. And my very last night at the property, I went out for a walk at night, like I loved walking around in like the woods and listening to night creatures and stuff. And so I went for a walk, and I walked down to the edge of the pond, and the whole edge where the water met the soil, was all lit up. Glow in. And yeah, it was like all bioluminescing. And I've been in that act. That had to be bacteria. And like, where would it suddenly come from? Well, something organic in the water, but it's still, it's surprising. You don't see that very often. Wow, that's an interesting story, actually. It was so beautiful, and I actually went back inside and woke my parents up, and they, we all marched down to the pond, and just stood there and like looked at this glowing. See, there's a mystery that needs to be solved. I can't tell you for sure what that was, but... It's so powerful. I think it's interesting that people that have had interactions with bioluminescence, sometimes, often rank them as their most meaningful lifetime experiences that they carry with them throughout their lives. It's interacting with life. It's life illuminated. And there's this interactivity to it, where you're making things happen. You're in a bioluminescent bay, and you run your hand up side your kayak, and off of every fingertip, you've got sparkles. It's like being merlin. Yeah, there is like a deep communicate. It almost feels like you're like saying something to each other. Yeah. It's a form of communication. I've somewhat provocatively tried to claim several times that it may be the most common form of communication on the planet, partly depends on how you can define communication. And what do you think you're communicating? And what do you think it is communicating back to you? I'm most focused on what it's communicating back to me. I have no idea. Okay. Actually, there have been a few times when I've communicated with luminescent animals. And in one case, there were some deep sea shrimp that I was getting a great response out of. And I had no idea what I was saying, but I was pretty sure it was something sexy. Why? Because that was the kind of response you'd expect from a crustacean that was responding to them. Tidilated. Yeah. It was putting out a string of dots in the water. A string of glowing pearls. Glowing pearls. Yeah. And that's what it does when it's turned on when it's like, hey, come hither. So you do believe that there's some sort of messaging in the light. Oh, there can be, yes. And definitely some of these animals have pretty elaborate displays. And I think they're communicating something important. But we have done so little actual observing that most of its guests work. And so you, when you're like down there flashing, you're like, I'm going to flash three times. And I don't know if in triple language, that means something. We'll just see what happens. Yep. Best job in the world. Best job in the world. Eh. This episode was produced by Maria Paz Gutierrez with original reporting and production help from me, Molly Webster. I want to thank Dr. Edie Witter, who is the CEO and senior scientist at the Ocean Research and Conservation Association. If you're interested in seeing more of Edie's work, it just so happens that there is a documentary that is soon to drop about her. It's currently making the rounds at festivals. It is called a life illuminated. It's by our friends over at Sandbox Films and director Tasha Van Zant. And Edie says it has some of the best underwater footage of bioluminescence ever recorded. But you know what? If you're too impatient to wait for that documentary, if you just want to go see it all, you can totally do that, you know? Wait, how? Oh, there's commercial operations. Like how deep do they go? Uh, 2000 feet. If these are going to cost me like my, like, $50,000? They might be right. Yeah, something like that. Okay. Okay, well, I'll work on that public radio team up. Good luck. If you are interested in more deep-sea stuff, Radio Lab has got the content for you. I would say go check out OctoMOM, which is about an octopus and her brood of eggs. It also happens to feature a diving buddy of Edies. And then we also produce something called the Darkest Dark, which is about darkness. And it features a former mentee-now colleague of Edie. Because apparently nothing happens in the deep-sea that Edie Wooder doesn't know about. I don't actually know if that's true. But for now, I will just say, thank you so much for listening. This is Radio Lab. I'm Molly Webster. Goodbye. Hi, I'm Bhaaseth Kari and I'm from Somerset, New Jersey. And here are the staff credits. Radio Lab is hosted by Lulu Miller and Lethif Nasir. So, Runeer is our executive editor. Sarah Sandbag is our executive director. And our managing editor is Pat Walters. Dylan Keith is our director of sound design. Our staff includes Simon Adler, Jeremy Bloom, W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhun Nia Sanbandam, Matt Kielty, Mona Madgavkar, Annie McEwan, Alex Niesin, Sara Kari, Anisa Vita, Arian Wack, Molly Webster, and Jessica Young. With help from Rebecca Rand. Our fact checkers are Diane Kelly, Emily Krieger, Anna Pujol-Mazzini, and Natalie Middleton. Hi, I'm Maddie and I'm from Frederick, Maryland. Leadership Support for Radio Lab Science Programming is provided by the Simmons Foundation and the John Templeton Foundation. Foundational Support for Radio Lab was provided by the Alfred P. Sloan Foundation. Thank you.