12/25/2020

These Worms Are Superheroes Of The Sea

17:09 minutes

If winter has felt gray and colorless for you lately, cheer up and join us for a special, festive edition of the Charismatic Creature Corner. This month, we’re looking not at one creature, but a whole class of them: Meet the polychaetes, also known as bristle worms. (“Polychaete” translates to “many bristles.”)

Yes, they may seem short on charm—they’re worms, after all. Many, like the bloodworm, the bobbit worm, and the bearded fireworm, pack either razor-sharp jaws, or a painful venom. 

But they’re also both gorgeous and mighty. Polychaetes come in iridescent colors, with feathery fronds or intricate patterns. Just in time for the holidays, consider the cone-shaped branches of the Christmas Tree worm, which makes its home on coral reefs. Others, like tube worms, produce energy for whole ecosystems from chemicals in the deep ocean’s hydrothermal vents or even the bones of dead whales. Still others, like alciopids, have remarkably human-like eyes. Gossamer worms can shoot yellow bioluminescence out of their arm-like bristles. And thousands more species provide lessons in marine evolution and invertebrate biology for the eager explorer. 

This week’s Charismatic Creature Correspondent, producer Christie Taylor, asks Ira to consider polychaetes—all 10,000 known species—for entry to the Charismatic Creature Corner Hall of Fame. Helping make the case is Karen Osborn, curator of marine invertebrates for the Smithsonian National Museum of Natural History, and a seasoned ocean explorer and discoverer of new species.

a rainbow colored spindly worm
The bobbit worm, via Wikimedia Commons
various red and white tube-like worms jutting out from sea rocks
A hydrothermal vent worm. Credit: NOAA
a neon blue worm with long thing anntenas and dozens of thin tiny arms, each glowing at the tips
A gossamer worm (tomopteris). Credit: Karen Osborn

Further Reading

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Segment Guests

Karen Osborn

Karen Osborn is curator of Marine Invertebrates at the Smithsonian National Museum of Natural History in Washington, D.C..

Segment Transcript

IRA FLATOW: I’m Ira Flatow, and this is Science Friday. It’s time for another Charismatic Creature Corner. Joining me is this week’s Charismatic Creature Correspondent, Producer Christie Taylor hey there Christie

CHRISTIE TAYLOR: Hey, Ira.

IRA FLATOW: All right. I know this is your first time on the Charismatic Creature beat. But remind our listeners of the concept, if you will.

CHRISTIE TAYLOR: Yeah, what we do here is pretty simple. I bring you a creature. I bring in a scientist for backup. And we, together, try to convince you that this particular creature is worthy of entering the hallowed Charismatic Creature hall of fame, which means it gets to sit at the same imaginary charismatic table as some of the more popular creatures out there, like your red pandas, your sugar gliders, your blue whales, et cetera.

IRA FLATOW: All right. I got you. Go ahead.

CHRISTIE TAYLOR: Yeah, and as you probably remember, we like to challenge ourselves here at Sci Fri. We have tried to convince you of the charisma of everything from slime molds to vampire bats.

IRA FLATOW: And somehow, I have been sweet talked into liking both of those creatures. OK. So what is today’s offering?

CHRISTIE TAYLOR: Well Ira, I want you to think of it as a belated Hanukkah present. Or perhaps it’s a Christmas present that I am giving myself. But either way, we’re going to debate marine polychaetes, which are also known as bristle worms. What does that evoke for you?

IRA FLATOW: Well, I got to tell you that as a saltwater aquarist, I know what they are. And I have seen people keeping them in tanks. They’re like crawly things, sort of covered in bristles I have the feeling that you may have to do some real fast talking to convince me of their charisma.

CHRISTIE TAYLOR: All right. That’s fair. I will say, after looking at dozens and dozens of photos of these things, I think they’re enthralling. And to convince you of their charisma, I am calling in a scientist for backup, Dr. Karen Osborn, a Marine Scientist at the Smithsonian’s National Museum of Natural History. Welcome to Science Friday, Karen.

KAREN OSBORN: Thanks for having me.

CHRISTIE TAYLOR: Before I start to make my case about cuteness, I do have to get the bad stuff up front. We have to acknowledge that we have some really noxious stuff going on. I mean, some of the polychaetes that we’re talking about are bloodworms, fireworms, bobbit worms. Tell us about that, Karen.

KAREN OSBORN: Yeah, so there are some pretty nasty characters out there in the polychaete group. The bloodworms have four big hook like jaws, and their entire mouth everts. And as the mouth everts, those jaws come out and latch on to something. A lot of the polychaetes, or the bristle worms, are predators, right? They need some way to catch their prey. And that often equates to big jaws.

The bobbit worm is a really cool worm that lives in coral reefs. And it has these huge jaws that are about twice as wide as its body. And it sits there and has them spread open like a bear trap or something. And if a fish or something goes by, they snap close and catch it.

CHRISTIE TAYLOR: Wow.

KAREN OSBORN: So there’s some pretty tough characters out there.

IRA FLATOW: OK, One minute– time out. For those of us who may not ever have heard of these creatures, can you just tell us more about what makes a polychaete a polychaete? Did they have other names?

KAREN OSBORN: Polychaetes are a group of marine worms. They’re segmented worms. They’re related to earthworms and leeches. But the marine worms are called polychaetes or bristle worms. And the reason they’re called that is because they have many bristles all the way down the side of their body. If you rub your fingers down the side of an earthworm, you’ll feel that they have some little, really stubby little bristles, just a few of them on the side of their body.

But marine worms, many of them, have lots and lots of these bristles. And oftentimes, they’re really long. And you can see them. They’re even really beautiful, the way they reflect the light. But their name, polychaete, it means many bristles. Now you’ve learned a new term.

IRA FLATOW: Thank you. I feel much better about that.

CHRISTIE TAYLOR: And Karen, I know that there are many, many, many, many different kinds of polychaetes. So I feel like our best strategy for winning Ira over is to go through a few examples of species that are especially charismatic. And there’s one I actually know, Ira, that you already like, which is deep sea tubeworms.

IRA FLATOW: Tubeworms! Whoa, now you got my attention. I love tubeworms. One point for you guys, now.

KAREN OSBORN: Well, these are some of the largest and most charismatic worms in the polychaete group. And the tubeworms that we find at hydrothermal vents can be as big around as your forearm. They have these big, red, velvety looking plumes that stick out of a tube. And they have millions of bacteria that live inside their body and help them make energy from the chemicals that are seeping up out of the ocean or bubbling up through the hydrothermal vents.

But there’s a bunch of different kinds of tubeworms in the polychaete group. And they are fantastic. And they live in these really extreme habitats. And they’re really important parts of their communities. Because all the other animals that live around these hydrothermal vents hide in between their tubes, or live on the side of their tubes, or try to eat the worms. So they’re really cornerstone members of those communities, and really important.

IRA FLATOW: You know, you really know how to get to my soft spot. Because you hit it when you said that they had a giant microbiome living inside of them.

KAREN OSBORN: Absolutely. They are the kings of that. So almost their entire body is made up of these chemosynthetic bacteria. They provide the sulfur they pull out of the water, and they also provide the oxygen that they pull out of the water. And all those bacteria in their special organ that fills most of their bodies make energy for them, not to mention that they’re really beautiful, with those big red plumes, and the way they come in and out of their tubes.

IRA FLATOW: On the other hand, though, don’t some of them still kind of– I know this term isn’t very scientific. Do they just gross you out?

KAREN OSBORN: Of course! Of course! They’re worms, after all, right?

IRA FLATOW: Absolutely.

KAREN OSBORN: I mean, I spend most of my time trying to convince people like you that polychaete worms are absolutely beautiful, amazing creatures. And if you take a close look at them, they come in all the colors. That come in all different sizes. The way that they move, then you kind of start to see the beauty in them. And that’s really easy to do with some of the worms. Some of the worms are just absolutely gorgeous.

One of my favorite ones are the gossamer worms, or [INAUDIBLE]. Think of like a palm frond or fern frond that’s completely transparent, a little bit shimmery blue, maybe, and just weaves its way through the water, and does it in an incredibly graceful way. And as a bonus, they can also shoot yellow bioluminescent light out the tips of their arms.

IRA FLATOW: Wait, wait, wait a minute. Say that again?

KAREN OSBORN: They can shoot yellow bioluminescent light out the tips of their arms, that they use to swim.

IRA FLATOW: Wow. Wow.

KAREN OSBORN: That’s one of those features you’d like to have yourself, right?

IRA FLATOW: Yes. I also note, there’s also a Christmas tree worm, right? Seasonal now.

KAREN OSBORN: Exactly. Christmas tree worms are one of the most beautiful worms, actually, one of the ones that hooked me when I was just a college student, and I was diving on a reef, and looking at these beautiful little multicolored Christmas tree shapes that would stick out of the coral. And if you waved your hand over the top of them, they would instantly disappear, and then they come back out again in a few minutes.

Those are sabellid polychaete worms. Absolutely beautiful little animals. Also, tubeworms, right? They have a tube that goes down into the coral, that they retreat into when they feel like they’re in danger. They’re also really cool, because they have eyes on the tips of each of those branches that you see. Can you imagine your Christmas tree with eyes on the tips of all the branches?

CHRISTIE TAYLOR: That’s the only way I want to decorate my Christmas tree now.

IRA FLATOW: OK, so you’re sort of describing great superheroes. They have all this wonderful stuff going for them, especially the light shooting. But what other special abilities do they have? Can they really be super?

KAREN OSBORN: I mean, other than capturing prey in amazing ways– oftentimes prey bigger and stronger than themselves, there’s some scale worms that live symbiotically on things like sea stars or corals. And they live on the animal, and they run around and clean it. They tend to be like a chameleon and match whatever animal is that they’re living on. There’s alciopids, which are another one of the worms like the gossamer worms, that lives up in the water column– not at the surface, not at the deep sea floor, but all that water in between.

But one of the groups of worms that lives there is alciopids. And they– this is another eye story. Their bodies can be up to a meter long, so like three or four feet long, but only about as big around as a pencil. But on the front end of that pencil, they have eyes that are as big as the eraser on a pencil.

IRA FLATOW: Oh.

CHRISTIE TAYLOR: Wow.

KAREN OSBORN: And they’re actually lensed eyes. They can see about as well as we can, which is just not really what you want to think about when you think about a worm, right?

IRA FLATOW: I’m thinking, yeah.

CHRISTIE TAYLOR: So Karen, I feel like you’re undermining your case now, suddenly.

KAREN OSBORN: I mean, as a person who works on how vision has evolved, it’s really, really interesting to look at all the different ways that all these different types of polychaetes have figured out how to survive in their habitat, and to get the things that they need, and to keep themselves safe, right? And so just the thought of thanking of them looking at you as a little bit weird. But if you actually look at the animals themselves, they’re so beautiful. And those big eyes, with their crystaline lenses at the end, are just really nice.

IRA FLATOW: I think I’ll leave you two together to gaze at each other.

CHRISTIE TAYLOR: I’m still a little creeped out by a worm that can look at me as well as I can look at it. But going back to how they’re adapted for so many habitats, isn’t it true that we can find polychaetes basically anywhere in the ocean, including ice floes?

KAREN OSBORN: Yes, anywhere in the ocean, we find polychaetes, all the way down to the deepest places that we’ve sampled. We find them in the ice in Antarctica. We find them in methane ice as well, which is pretty awful stuff to live in. Pretty much every habitat, even up in freshwater, we find polychaete worms.

CHRISTIE TAYLOR: Well, and here’s what I find really fascinating. There’s this kind called zombie worms– which Halloween wasn’t too long ago. And they literally help us recycle dead whales. Tell us about that.

KAREN OSBORN: They do. The zombie worms are fantastic. So, and I was actually involved in the discovery of them, which was really fun and exciting at the time. And they brought me this worm. And they, we don’t really know what this is. And I’ve looked at it. And it looked like a worm on top.

But on the bottom half, it had this lumpy body that had roots growing out of it, in different directions. And I was like well, it looks like a worm on top. But I don’t know what’s going on on the bottom there. What they are is– they’re polychaete worms. They make gelatinous tubes. And basically, there are as larvae floating around out in the ocean. And if there is a whale that dies and sinks to the bottom, and one of these larvae hits that whale, it turns into a female. And it settles on the bone, and it starts to grow roots down into that bone.

And again, they have a really super cool, helpful microbiome that helps them digest the bone and turn the sulfur in those bones into energy. And so they have that big, globular part of the body and all the roots, is the organ that all bacteria are in. And they just grow continuously through the bone and digest it. And the worm has a pretty red plume that sticks up into the water and gets oxygen for those bacteria and for itself. And–

IRA FLATOW: It’s called a zombie worm? Did you name it?

KAREN OSBORN: I did not. I did not name that one.

IRA FLATOW: OK, OK, OK. We’ve definitely got some neat traits here. But can polychaetes get beyond the gee whiz factor? There certainly is the gee whiz factor. And what I mean by that is, can we learn anything from them?

KAREN OSBORN: Oh, absolutely. So the zombie worms are a nice example of something that we didn’t understand how these things happened before the zombie worms were discovered, right? So in the past, there’s been lots of whales. What happens to their carcasses when they hit the ground? Pretty quickly, scavengers come in, right? And they get all the flash, and all the blubber, and all of that off. But then the bones could potentially just sit there.

But what happens is, the zombie worms, they grow through the bones, and they digest them slowly. And as they make them more brittle and more hole-y, other animals can come in and break pieces off, and then can access the nutrients there. There’s an entire succession that happens on a whale as it breaks down in the ocean over a couple of years and provides this really huge source of nutrients for things that live in the deep ocean.

And so as we’ve been learning more things about worms and other animals out there in the ocean, we better understand how carbon flows in the ocean, and how important the diversity of animals is that are out there. We also can learn lots of cool things, like how they move. So one project that I’m working on is looking at, actually, gossamer worms. And they swim really fast. And they’re really maneuverable.

But what we know about how animals that have long bodies with lots of segments, what we know about how they swim, the gossamer worms should not be very fast. They shouldn’t be maneuverable, and they shouldn’t be able to swim for long periods of time. But we watch these things with the submersibles and the RRVs. And we see them outrun us and outmaneuver us.

And that’s really embarrassing, right? When you’ve got like a $2 million machine, and this little worm just outran you, and you can’t catch it? It makes you wonder how they do it. And so we’ve started collecting them and videoing them with high speed cameras, and looking at the mechanics of how they actually move, and how they’re able to be so maneuverable and move themselves through the water. And there’s lots of really interesting things that we can then use for things like building a robot to, say swim up one of your veins, to look at something that’s obstructing there.

Once you pick those animals up, and you bring them back into the lab, and you look at them under the microscope, and you see what fantastic structures they have to solve their challenges in life, it’s really cool. Like the bristles on bristle worms, they come in– I don’t know– thousands of different shapes. There’s 10,000 different types of polychaetes that have been described so far, and probably about that many that haven’t been described yet. And there’s at least– I don’t know– a guesstimate would be something like 500 to 1,000 different kinds of bristles on those different worms.

And they’re all to do different things. Some of them are to be able to crawl around in their tubes. Some of them and to be able to cut holes in their tubes, so they can make branches on them. Some of them, they’re to be able to catch things. Some of them, they’re to be able to dig into the type of mud that they’re crawling around on.

IRA FLATOW: Amazing, yeah.

KAREN OSBORN: So there are really all these cool mechanical things going on with these animals.

IRA FLATOW: I’m Ira Flatow, and this is “Science Friday.” If you’re just joining us, we’re debating marine bristle worms, or polychaetes, with Dr. Karen Osborn, and this week’s Charismatic Creature Correspondent, Producer Christie Taylor.

CHRISTIE TAYLOR: Karen, Ira, let me see if I can summarize the case for charisma with these polychaete. We have things like 10,000 species. They can shoot yellow bioluminescence. Some of them have human eyes. They have cool microbiomes. Ira, you love these. They also d things like help keep their friends clean. And they can live anywhere. They’re vital to marine ecologies. They live in the bones of whales. I mean, Karen, is there anything else we could possibly be missing from this list of amazing traits?

KAREN OSBORN: Well, I don’t know. How much time do you guys have?

IRA FLATOW: You’ve already convinced me. I have to just admit, going into this, knowing the bristle worms, I wasn’t too crazy about it. But Christie, you rattled off all those great things, especially the light shooting out from the arms, and the microbiome.

CHRISTIE TAYLOR: Everyone loves a laser show.

IRA FLATOW: Yeah, these are like the superheroes of the ocean, to me. They can do all these kinds of things. And the environment that they lived at– how far down in the ocean do they live, some of these?

KAREN OSBORN: As deep as we’ve ever gone. So down to the bottom of the Marianas Trench, we can find them.

IRA FLATOW: These are the superheroes, I think, of the ocean. So OK, you’ve done it again. You have turned around. They must be included. Maybe a special spot in the hall of fame here.

KAREN OSBORN: Oh.

CHRISTIE TAYLOR: Wow, OK. So Karen, does it bring you joy?

KAREN OSBORN: It does beg me joy. I mean, it’s a little bit of a cheat, right? Because there’s 10,000 species. So there’s a lot of room there to describe a lot of cool different things. And we could keep talking about them for a long time. But yeah, there are some really–

IRA FLATOW: OK. Name all 10,000. Go ahead. I’ve got time.

KAREN OSBORN: Can I just make up a bunch of weird sounding words?

[LAUGHTER]

CHRISTIE TAYLOR: All right, well Thank you so much, Karen. Dr. Karen Osborn is curator of marine invertebrates at the Smithsonian’s National Museum of Natural History in Washington, DC and a polychaete champion. Thank you so much for joining us, Karen.

KAREN OSBORN: Absolutely. It was really fun.

IRA FLATOW: And Karen, let me add to that. Thank you so much for helping me see the charisma of polychaetes. And thank you, Christie. Christie Taylor, a Science Friday Producer and this week’s Charismatic Creature correspondent.

CHRISTIE TAYLOR: Thank you, Ira.

IRA FLATOW: If you’d like to see some of these polychaetes we’ve been talking about, by the way, you can go to our website, ScienceFriday.com/worms, just in case you need a bit more proof that they are truly beautiful.

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About Christie Taylor

Christie Taylor is a producer for Science Friday. Her day involves diligent research, too many phone calls for an introvert, and asking scientists if they have any audio of that narwhal heartbeat.

About Ira Flatow

Ira Flatow is the host and executive producer of Science FridayHis green thumb has revived many an office plant at death’s door.

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