Deep Dive
Shownotes Transcript
This message comes from HomeTap. With a home equity investment from HomeTap, you get access to your home equity in cash without monthly payments. Use it to pay off debt, pad your emergency fund, and more. See if you pre-qualify today at HomeTap.com. You're listening to Shortwave from NPR. When it comes to the ocean, some species get more attention than others.
There's a lot of interest and excitement, including for me, of whales. Sharks and dolphins also tend to get a lot of love. But marine biologist Drew Harvell fell in love with a different group in the ocean. Really, it's the invertebrates that make the gears turn round in terms of function and how the ocean works. These unsung icons of the sea have no backbones. And there's a lot of them. There are over 34 phyla of marine invertebrates.
from sponges to corals to octopus to sea stars. And as such a big group, they're pretty versatile. Invertebrates live everywhere, from the bottom to the top, from shallow water to deep water,
from attached to the bottom and in the plankton. So they're everywhere in the ocean. Drew was so fascinated with spineless creatures that she wrote a whole book about these ancient critters and how their long evolutionary histories have led to some interesting biology. I think of them as kind of biological impossibilities, sort of like...
you know, Superman flying or having invulnerable skin, right? For an animal to photosynthesize, that's legitimately a superpower. And it's not the only one. Across these marine invertebrates, there's a whole bunch of superpowers. Everything from regeneration to super strength and even stealing other animals' abilities. Drew says understanding these animals' superpowers not only helps researchers understand the rules of life, the lessons scientists learn from them can transform our medicines. ♪
Every one of the ones that I talk about in my book also has an important application for humans. So today on the show, the strange world of the ocean's spineless creatures, what their ancient superpowers are, and how they continue to inspire human innovation today. I'm Regina Barber. You're listening to Shorewave, the science podcast from NPR.
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Okay, Drew, we're talking about the superpowers of marine invertebrates from your book, The Ocean's Menagerie. We're going to talk about a few starting with sponges, which I have trouble imagining. What should I imagine? They're amazingly beautiful. They come in all colors and sizes and shapes from vases to runners to huge barrel sponges. And they're brown and yellow and green and red and purple.
That's amazing. And so, I mean, I just get lost when I'm diving just watching them because they're so beautiful. And, you know, functionally, they seem to be very, very simple. But then when you look deeper, they have amazing functions. And sponges have been of great interest to natural products chemists.
Because it was found that the highest hit rate for anti-cancer drugs was from tropical sponges. Oh, wow. We thought the sponges themselves made the chemicals.
but we've learned that often it's the bacteria, particular species of bacteria that are housed within the sponge that actually do the chemical synthesis of these compounds. Can you give me an example? I love this one because a sponge that's bright green, it's in the inner tidal, everywhere, hyalocondria panacea, very common. It houses a strain of streptomyces bacteria,
that produces a chemical and that is now being used in clinical trials for a whole range of different cancers, melanoma, pancreatic cancer, and renal cancer. It's being used now? It's being used now. They don't actually pull it out of sponges now. They've actually learned how to create a synthetic derivative. I could go on and on. And I kind of do in the book, I talk about quarks
Quite a few examples of cancer drugs that have actually been discovered and produced from sponges. Let's talk about sea slugs next. Introduce us to these critters. Like, what should we know about sea slugs? Oh my God, sea slugs are just, they're the most enchanting of the invertebrates in many ways, just because they're a ridiculous circus of colors and shapes that
Black backgrounds with lime green stripes and polka dots or yellow or pink. They have these beautiful projections that look like flowers all over their backs. I mean, I think everybody who's seen a nudibranch falls in love with it just because they're so beautiful.
A nudibranch being like another name for sea slugs. Right. Yeah. And I've learned sea slugs are a relative of snails, but instead of having a shell, they have these like chemical defenses in which they can eat other animals and steal their powers. Can you tell me more about like one of those? We have a nudibranch that lives in the Pacific Northwest that eats sea anemones.
And when it eats a C. anemone, it uptakes the stinging cells that C. anemones use in their own defense. They select the immature stinging cells so they don't explode when they're eating them. They pass them all the way through their digestive system and into these little packages on their back. The stinging cell completes its development and is then used as a harpoon by the nudibranch.
And the diversity of this particular group of nudibranchs that does this is very high. They've been very successful, particularly in our shallow waters in temperate and tropical ecosystems. Wow.
So the beauty of the bright colors is a warning to fish and other predators that don't eat me. I'm dangerous. I've got explosives and I'll use them. It's almost as if I were to eat a venomous snake, then somehow I could have venom or something like that. So what lessons can humans learn from that? Yeah, I think the lessons we can learn from the ability of
nudibranchs to uptake these foreign organs from other groups is in transplantation surgery. It's very hard for us to transplant kidneys, for example, even among different humans, let alone what we try to do from pigs to humans. And the way we do that now is we try to suppress our immune systems. That's not what nudibranchs are doing. They're playing around with the recognition process.
And so it strikes me that there's a real opportunity there to really think a little bit outside the box about other ways to go in and optimize our transplantation surgery. All right. Last but not least, my favorite, maybe yours, are Seastars? You know, Gina, I think we share that. They are certainly one of my favorites because...
I mean, first, they're like Martians. They have multiple arms. They have thousands of tube feet for running around. They have eyes on each end of each one of their arms. Yeah, all their arms are heads. I remember doing a story about that. Right? Yes. Yeah. And so, you know, just as an animal, they're very, very strange. And yet the thing that just, as a marine ecologist, blows my mind is
is they are incredibly important ecologically. We think of sea stars as ecosystem engineers because of their power. They're predators, so they eat prey, and they eat a lot of their prey, whether it's mussels or clams or sea urchins.
Recently, we've been studying one that lives in deeper waters that used to eat all the urchins and control them, but it was decimated by a huge outbreak of disease. I kind of call it the COVID of sea stars because it affected... It's the wasting disease, right? It's the sea star wasting disease and it affected over 20 species in addition to...
to the sunflower star, which is the biggest and fastest in the world. I mean, this thing is three feet across. It's huge and it eats a lot of urchins. When you remove all those sunflower stars, the urchins explode and they've decimated our kelp meadows. And so along the entire West Coast from San Diego up to Washington, we've had declining
Kelp beds partly due to the removal of just this one species of sea star. Wow. And weirdly, for such a big, powerful critter...
it was the most susceptible to this disease. And so it's now on the endangered species list. And we've been working for a decade on a recovery program for it. I really like this. You're talking about how these sea stars, they're eating these urchins. They also eat a lot of clams. So how are sea stars doing this?
The trick, the superpower, is that it takes them a long time and they can hang on without spending much energy. And they hang on because they have hundreds of tube feet, which are like little suction cups.
that grip incredibly strong. And then the other part of the superpower is their smart skin. They can basically cross-link the microtubules in their skin to make it stiff and
under nervous control and then hold that without it costing them anything. And so that's how they win by hour after hour, just hanging on and pulling till the clam is opened. So what could humans do with this superpower of like neural control? Well, there's been a lot of interesting research trying to use the ideas in the smart skin of sea stars and sea cucumbers in
in tendon replacement therapies because of the ability to change under neural control.
So all of these organisms, and they tend to be invertebrates that have these so-called smart tissues, are a lot of interest in transplantation therapy. In the epilogue of your book, you write, the most precious resource on our planet is not oil or metal. It's the deep secrets that string our web of life together. What would you like to see in the future in how humans care for the ocean, like in honor of the statement?
You know, I think that the first step is to try to help people understand just the incredible wonder of these resources and their extreme value. And then from there to take the next step of protecting them.
These spineless invertebrates have been on our planet for over 600 million years. They're phenomenal adaptations to change, to a changing climate. There are secrets and mysteries that they have solved that are going to be of a lot of use to us. Thank you so much for talking with me today, Drew. I had a wonderful time. Thank you. This has been a really fun session, Regina. I loved it too.
Drew Harvell's book, The Ocean's Menagerie, is out now, where you can read about other invertebrates like jellyfish, octopi, giant clams, sea fans, and corals. And if you like nudibranchs, check out our past episode all about these fascinating creatures. We'll link it in our show notes. This episode was produced by Burley McCoy. It was edited by our showrunner, Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineer was Jimmy Keeley.
Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Shortwave from NPR.
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