Unexplainable - A magical world at the ocean’s edge

Episode Date: July 2, 2025

In coastal California, researchers grapple with potentially losing a landscape they love. Guests: Rebecca Johnson, Director of the Center for Biodiversity and Community Science at the California Academy of Sciences; Peter Roopnarine, Curator of Invertebrate Zoology & Geology at the California Academy of Sciences For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠[e-mail]⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠ Help us plan for the future of Unexplainable by filling out a brief survey: ⁠⁠⁠⁠⁠⁠⁠voxmedia.com/survey⁠⁠⁠⁠⁠⁠⁠. Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hey, I'm Matt Bouchelle, comedian, writer, and floating head you may or may not have seen on your FYP. And I'm starting a brand new podcast. Wait, don't swipe away. It's called, That Sounds Like a Lot. You know that feeling when you check your phone, read a few headlines and think, That sounds like a lot. I can't do this. Well, I can, and I'm going to get into it every Friday.

You can watch on YouTube or listen wherever you get your podcast. I'm going to start by breaking down whatever insanity is happening in the world. And then I'll sit down with a comedian or actor or writer or, honestly, anyone who responds to my DMs. This is not the place to get the news, but it is a place to get the news. but it is a place to feel a little bit better about it. That sounds like a lot. Coming May 1st, part of the Vox Media Podcast Network. All right.

I am at the California Academy of Sciences. It is in the middle of a park. So I'm surrounded by trees that are, I guess, evergreens. I can't really see it because it is 5.04 a.m. Full moon. Not particularly overcast. We will see. Yes, she is a bumper sticker that says I break for wildflowers. Hi, good morning. It's so nice to see you in person. How are you? Thank you for driving me out. Sure. Thanks for getting out so early.

Okay, so I'll take you kind of to my favorite Rocky Intertidal Reef, which is called Pillar Point Reef, which is in San Mateo County, south of San Francisco about 45 minutes. This is the Pillard Point Marsh and you can see into the bay. And, yeah, I often them there at like five in the morning. Kind of beautiful, foggy light. Oh, well, wow, well. When you walk out to Pillard Point, you have to walk about a half mile, like a long, a dirt road. And you pass like a little hard, it's on a harbor.

Are those seagulls or pelicans? I think there were some, yeah. And so there are like mudflats. and other little parts that you have to keep on walking. And as you turn west, you just see this, like, oh, wow. Huge beach with this huge expanse of kind of flat. It looks like flat, rocky seaweed-covered area.

There's some big rocks off to the west. It's called Sail Rock. You can see that one looks like a sail a little bit. The white one. I see it. I see it. All right. Should we go in?

We'll go further. When you go tide pulling, and especially if you're going as the tide is dropping, like you want to go out as far as you can then and not get distracted by all the little stuff that you see as you're walking out. What? But I always tell people this, but I always break my own rule and I get distracted. Oh, and it's moving. It's amazing.

Oh, it's so cool. So this is this white. It looks like a little daddy long legs. Yeah, it's like the daddy long ones of sea stars. But it like, it has these tiny little white arms that are like

dancing and contorting. You head out onto the rocky reef and as you head out there, you know, it's covered with algae, like seaweed, all different species of seaweed. There are some that are big and fleshy and iridescent and there are some that are like little, I don't know, they look like little

scouring pads. And then at Pillar Point, especially in the spring and summer, there's this one species that's called C-Sac. And it looks like tiny little fingers of a glove, like puffed up, but they're green. Step on one. Sometimes you pop some of them, but it's okay. Like, you just keep walking. You know, as you're walking, you are walking on seaweed and animals. You used to be really careful. And as you just keep walking, it kind of gets more and more like deeper, pools, more habitat. Ooh, what is this? Oh, that's a slug.

It's just out of the water. It's so orange. And then my favorite place at Pillar Point is this place that we call the Nudabrank Pool. Oh, wait, there's two Nudabranks, I think. And you'll see little Nudabranks or sea slugs. Oh, wow. Kind of crawling along. It's the pink one.

Is it really? Yes. So pink. And if you're like still and careful, you might see Third one. Four different species, five different species, just like in that one spot. Fourth one. Wait, fifth one? Oh, my God.

They're just everywhere. It's just like, oh my God. These colors, right? They're like pink sponges and tunicates and amphipods. There's a thing called an octocoral that's bright pink. I feel like I'm seeing all these celebrities. So it's just like this. Like mosaic of colors and worms and other things, and it's all right there.

Ooh. So for me, it's just like this place that you can just stand there, and you can see so many different things without even really looking that hard. Well, thank you, Pillar Point. Appreciate it. Okay. Be very careful not to step on anything. The first time I ever went tidepooling.

I was maybe 10 or 11 at a summer camp. We woke up at 4 a.m., crawled out of our sleeping bags, pulled on like two pairs of jeans, so one over the other, and these thick wool socks, before hiking out to a little rocky cove. And when we got there, the tide was way out and still receding, actually. And in its wake, it had exposed this whole world of rocky, pools, which is what a tide pool is, right? A little pool of water full of creatures that are normally hidden away beneath the waves. And as we scrabbled out over these slippery rocks to explore and look and touch, I remember being cold and wet and completely enchanted. It was like

realizing that magic was real. Rebecca Johnson gets it. It's magical in so many different different ways because if, okay, I'm standing at this neuterang pool at like six in the morning now on some like foggy Thursday, you know, another day 12 hours or six hours later, I would be underwater. Like I wouldn't be able to see any of that. So you also have to go at the right time. If you go a different time, it's still a beautiful beach and there's sandy, you know, but you don't see any of that. It's completely hidden to you. So it's like you get this little peak, this little like window. And that's one of the things I love the most. most about it. Rebecca is the only person I've ever met, who's arguably more gone for tide pools

than I am. She's the director of the Center for Biodiversity and Community Science at the California Academy of Sciences. And she's been studying tide pools for decades. The spot that she took me to, Pillar Point, she has been visiting it for around 30 years. I mean, it's one of the places in the world that you can like at a low tide, walk out onto a rocky reef. and see, like, hundreds of species of invertebrates all really, really concentrated. But the reason I'm here talking to Rebecca and exploring tide pools with her is that this enchanted place is at risk. Like so many ecosystems around the world, it is being hit by a lot of different changes all at once.

I wanted to understand what those changes meant, right? And how researchers like Rebecca figure out what the future of an ecosystem might. it look like. But I also wanted to understand how they deal with the possibility that that future might be grim. These tide pools are part of the reason I am a science reporter. They were part of my realization that science fact is as amazing as any science fiction. And so this is unexplainable.

I'm Bird Pinkerton. And today on the show, I talk to someone who loves these tide pools as much as I do, to try and understand how to process a rapidly changing world. Oh my gosh. Okay. So, what is the story? For Rebecca, the story really started about a decade ago, around the time when a wave of marine heat spread up the California coast and then just kind of stuck around for a while.

You know, we have programs that we have been running for years then that brought people to the tide pools to make and share observations of all the different things they saw. And they started seeing some changes. They started seeing a lot more of one particular animal, this sea slug called the Hopkins Rose Nudabrank.

It looks like a little, I don't even know, like a little kush ball, you know, those little kush balls, but bright pink. These pink sea slugs aren't usually all that common at these tide pools that Rebecca studies. But when the warm water came, it became like the most common thing. They used like hundreds and hundreds and hundreds on the reef.

And that wasn't the only weird thing that was happening. Even before the heat wave really hit, other disturbing reports had started coming in from up and down the coast. People that were diving in Washington State and further north and some places in California started reporting this weird thing that they were seeing in starfish. They were seeing white lesions on starfishes. And they were seeing,

not only these white lesions, but they were seeing the starfish kind of like disintegrate in front of them. Like they would see it one day with these lesions. They'd come back the next day and it was like almost dissolved and then almost gone. So people started to see this and started reported and document it. And a lot of it was documented by amateur divers. And then it was reported by scientists who went out to try to verify this. And very quickly, it was pretty apparent that this sickness, whatever it was in, lots and lots of species along a huge stretch of coast. Wasting isn't unheard of in sea stars. It does happen. But it doesn't usually happen to so many different species in such a huge geographical area all at the same time. The exact cause was hard

to pin down. There were a lot of theories. And one researcher told me that they actually only recently figured out the infectious agent that was probably involved. But scientists also drew a connection to the warm water, saying the stress of the heat could have made things worse. Ultimately, though, huge numbers of sea stars wasted away. Some places lost over 90% of their stars. And the spot that Rebecca has been visiting for decades, Pillar Point, that was hit hard, too. At one point, she decided to drive out for a visit. My colleague Allison Young and I, we were like, okay, like, this is a pretty good low tide. like, let's just go see what we can see.

And we went out to pillar point, and there were no starfish. Who was just like the most bizarre feeling. I was still at this place that was like spectacularly beautiful, covered with algae, covered with seaweed, all these other invertebrates are there. But like, there's just something kind of off about it. It's like going to a familiar place and something. and something being wrong. You know, it's like going into your room

if somebody had like moved your stuff like all slightly. Right? And you're like, what's wrong with this room, right? So it has that, it had that, has that like disconcerting, like unsettling feeling. And for us, I mean, at that moment when we saw all these stars that had disappeared, like we didn't know what was going to happen.

And they like play this huge role in maintaining these ecosystems. And so to have them just gone, It was this moment of like really deep uncertainty. It's all about you. And when you fly with Virgin Atlantic in their upper class cabin, they take the VIP treatment to the next level. With a private wing to check in and your own security channel at London Heathrow,

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I'm Maria Sharpova and I'm hosting a new podcast called Pretty Tough. Every week, I'm sitting down with trailblazing women at the top of their game to discuss ambition, work ethic, and the ups and downs that come on the path to achieving greatness. We'll dive into their stories and get valuable insights. from top executives, actors, entrepreneurs, and other individuals who have inspired me so much in my own journey. Follow Pretty Tough wherever you get your podcasts. I'm a Sted Hearnden, and this is America, actually. We're all talking to each other to see what did we do wrong? What did we not see?

I'm in Washington, D.C. this week to interview Ruben Gallego. He's a Democratic senator from Arizona, and he's been thinking openly about running for higher office. But he's recently run into some hot water because of his connection, to Congressman Eric Swalwell. I have to learn from this, and I will learn from this. But, you know, for me, it's not a 2028 question. It's about what it means to be a better first boss in my office and also a better senator to my constituents.

This week on America, actually, we asked Gallego about predatory behavior in Washington, his plans for immigration reform and more. It's very, um, thylassic. Phyllassic oceanics. When Rebecca looked out at her familiar tide pools and saw that the sea stars were mostly missing, she was worried because she thought a big change like this might throw that tide pool ecosystem she loved out of balance. And that was, it turns out, a pretty reasonable concern, because it is exactly what happened

to another ecosystem, one that is not very far away distance-wise from some California tide pools, but can seem like kind of a different planet almost. To get there, you have to move a little ways beyond the rocky intertidal into water that's maybe 50 to 100 feet deep. And that's where you can find the California kelp forests. Imagine, if you would, golden brown kelp. It can be massive, sometimes 100 feet tall. And these are called kelp forests for a reason. ideally there's sort of lots of kelp growing together, like trees almost, with sunlight kind of filtering through them in green and gold. Also like a forest, these places are full of a huge diversity of animals. So in this case, everything from sea lions to octopus to abalone.

Now, on land in a forest, right, you have gracers, herbivores like deer, and you have predators like wolves that eat those deer. So a herd of hungry deer can decimate trees and undergrowth by eating everything, but some wolves can keep them in check, right, and keep the ecosystem healthy and balanced. The same is true for the California kelp forests. They have grazers, animals like the purple sea urchin, which is a, a spiky purple pin cushion that eats a lot of kelp. And then they have a very important wolf that keeps the pin cushions in check, which is the species of sea star known as the sunflower sea star. Sunflower stars are amazing.

I mean, they're gigantic. Imagine, it's like as big as like a car hub cap, maybe. The ones I saw as a kid were so big you had to hold them with two hands. They have tons of arms, like 20, in the 20s, 22, 24. Some people think that they can like count them and there's consistency, but I'm actually not sure. They're really beautifully colored. Like they have a lot of variation, but they're generally like purply with some pinks, sometimes a little more orange, and they are voracious predators.

They eat tons of stuff, and they're pretty indiscriminate. Like they eat lots of different things. Including grazers like urchins. But because they're sea stars, they also fell victim to that sea star wasting sickness that I told you about. In fact, they were one of the hardest hit species. This lack of the sunflower star in the kelp forest, especially in the kelp forest, especially in Northern California, along with the warming waters, because remember we have warming waters, right,

led to the increase of urchins. And the urchins then ate all the kelp. And the warming water didn't help kelp because kelp don't really want warmer water. So in many places you have these urchin barrens where it's like mostly urchins, we lost a lot of kelp forests along the northern California coast. The transformation from dense, diverse kelp forest to urchins, Barrens is just one example of what can happen when things get out of balance in an ecosystem. So again, it makes sense that Rebecca was worried when she noticed that the stars were missing

from her tide pools all those years ago. She didn't know exactly what could happen, but she was afraid that such a big change could have real consequences for the tide pools. Ultimately, though, while some species like the Sunflower Sea stars have not bounced back in California, other species like bat stars and leather stars and ochre stars, they have made a comeback. And the tide pools have not met the same fate as so many of the California kelp forests, right? They have not been turned into some equivalent of urchin barons. What worries Rebecca is that as more things change, something else might disrupt the tide pool's balance. She's worried, for example, about the hungry, hungry grazers that have been a very,

have gobbled up the kelp forest. They still need something to eat. And she says that she's been seeing more of them coming into the tide pools. They've come into the inner tidal. And they're eating their like, you know, not first choice food, but they're eating the kelp, the inner tidal kelps. That could affect the ecosystems there. And meanwhile, temperatures are still warming over time. So tide pool ecosystems are still changing, which is having its own effects. things are shifting their ranges. Like, ranges are moving north. We don't actually know what happens when they move north.

We don't know exactly what those changes will lead to for neuterbranks, for CNMEs, for sponges, for other encrusting things. Like, we just don't know all the, like, downstream effects of that. Part of Rebecca's job is predicting what comes next for these ecosystems. But that's hard, right? It's hard because it's hard to nail down cause and effect in the ocean. It's hard to tease out exactly what the effects of the marine heat wave were, or what the effects of ocean acidification are,

or sea star wasting, or changes in predators, or any number of different factors that can potentially shake up an ecosystem. But also, it's hard to make sense of how big a deal any given change might be, right? these ecosystems have bounced back from some pretty big blows in the past. Like, fur traders wiped out stellar sea cows, which is a species that help shape the kelp forests. And then sea otters, an important predator, they were also hunted close to extinction. Things like sea star wasting and heat waves have also happened before. So sometimes stuff big or small just changes, you know.

And how do you know what changes? might be okay, ultimately. That's a good question, and I've spent a lot of my career studying exactly that. And literally what I study is the question of why do ecosystems persist as long as they do. I met up with Peter Ritneryne in his office full of bookshelves and fossilized shells. He is a paleontologist at the Cal Academy of Sciences who studies how ancient ecosystems. were affected by things like dramatic climate change. And he's trying to figure out how that might relate to ecosystems today.

If you look in the fossil record, one of the things that's really remarkable is that ecosystems can last a very long time, millions of years. Species will come and go in those ecosystems, but what makes ecosystems, so the types of species, what they do, who they do it to, and so on, that doesn't change. That can last for millions of years. It's kind of like a baseball team. The team's always going to need pitchers and shortstops and outfielders, but a specific pitcher can retire. The seater is leaving Northern California because it's been hunted almost to extinction. The team might hire another pitcher or just have one of their other star pitchers step up.

The sunflower sea star will be taken over more of the pitching. Look out for its famous five-armed curveball. But Peter's research also looks at the moments when ecosystem teams, fall apart. They do eventually come to an end. And that's the ball game. They tend to come to an end during major events in Earth's Earth dynamic. So things like volcanism, you know, the size of Siberia, an asteroid hitting the planet,

you know, really extreme, extreme changes. Too many changes, and you just can't play baseball anymore. So Peter can't know exactly what the future holds for California's tide pools or its kelp forests or any marine ecosystem. But he is worried. You know, the thing that many of us lose sleepover is that, yes, these things that we love, we treasure, we could be staring down the barrel of changes that we're not really imagining yet. And as you pointed out, I mean, the world is different. My world, I grew up, I'm from the Caribbean, and I grew up there loving the ocean. I still remember my first time on a reef.

I was really little, and it blew my mind, and I think it changed me forever. So I share that experience with you. But my parents, you know, my mom was from Jamaica, my dad was from Trinidad. They described things that I never saw. And so that's interesting. That's always been a little bit disturbing, but there's still beauty out there. And now these days I just wonder, well, you know, we can still find beauty in a kelp forest that has too many urchins and no sea cows. We still find them beautiful.

We get that sense from them. How long is that going to persist? I think that's a question that everybody should be asking themselves very seriously because I've only very recently come to the answer that, yes, I do think we're looking at potential end point for some of these systems. And yet, he keeps doing his research, hoping that it will be helpful. And so does Rebecca. I wouldn't be out here if I didn't have hope that, like what we're doing can make a difference. There are lots of people who are still trying to do something.

There is a collaborative, large-scale program to try and rear sunflower sea stars in captivity and potentially reintroduce them to the ecosystem and restore a baseball star. The California state government has partnered with nonprofits and commercial fishermen to try and clear urchins and restore kelp. There are researchers studying the genomes of sea stars that did recover from sea star wasting to see what could be learned about what made them resilient. And Rebecca has projects with a community science app called I Naturalist. I don't know if you know about I naturalist.

It basically lets people ID plants and animals, so anyone who goes to the tide pools can upload all the life forms they see. And those photos with locations and timestamps, they can help Rebecca and her team figure out how populations are changing or model the future of this ecosystem and even potentially serve as a warning system if there are big die-offs again so scientists can try and intervene earlier. As one researcher told me,

no one person can protect marine ecosystems alone. But she at least takes heart in all the different people contributing to the effort. And Rebecca, for her part, wants to get as many people excited about the tide pools as she can. You're like, okay, well, here I am.

How can I enjoy this place, teach other people about this place? Bring people to this place so they love it, and they can bear witness to that change. She brought me to her favorite place, Filler Point, to show me the new-to-rank pool and the brittle stars and a clam that squirted a massive stream of water right at me. Just treasure after treasure. It's not a rock, but look. Wait, it's a sponge.

It's a sponge. It's a sponge. You're feeling. It looks like a rock. I wish people. And when we spotted other tide pools, Rebels. Rebecca brought over some neuterbranks to show them too. I couldn't resist picking them up to show me.

They're amazing. So this is them out of water. They're sea slugs. That's fabulous. That's gorgeous. Walking around with Rebecca, I felt the way I felt as a kid. I'm just happy to be alive and outside. There's also a great blue her in hunting.

Do you see it? It looks like straight ahead. It made me realize that right now, there are still brightly colored sea slugs off the coast of California. But also we got some snails. There are still crabs and clams and urchins and sea stars. And we can still hold them in our hands.

Oh, like there's these tiny, tiny shells, like iridescent shells. And we've been just like walking across that. Yeah, we're just looking right over it. We can still explore the tide pools and share them with each other. In the midst of climate change and, like, a future that is going to be hotter and harder and harder and more difficult for people, like, you have to have joy. And you have to just still have this quest to understand how things work and how things are changing. And also being like, hey, what are the things we can do?

What are the things that we have control over? Like, I struggle with it. I feel like marine systems especially are, like, pretty complicated to think about restoring, to think about, like, what do you actually do out here? How do you protect things? But that's just, like, you can't stop doing that because then you've kind of lost everything. Okay, I promised my editor that I would sit and think about the tide pools for a few minutes. So I'm going to sit and...

I'm going to sit and think. Okay. It's closer to 8.30. The sun has come up completely, but like the weather is kind of gray. And I'm just sitting on like a rock that's sort of covered in iridescent algae.

It was literally its name, but also it is quite iridescent. So, okay, the camp I would go to every year, the camp that actually brought me out here, was kind of granola. Like, we would sing a lot of songs around the campfire, like old classics. And there's a song, but I feel like keeps coming to mind as I work on this story, which is a song about, like, loving cradads and, like, you go fishing for cradads and everyone loves crawdads. And then at the end of the song, it just makes a sudden shift where they're suddenly singing about, like, what are you going to do when the lake goes dry? And the song repeats. It goes, what are you going to do when the lake goes dry? What are you going to do when the lake goes dry? What are you going to do when the lake goes dry? What are you going to do when the crowd goes dry? What are you going to do when the crowd ads die? What are you going to do when the crowd ads die? What are you going to do when the crowd ads die? Sit on the bank. until I cry.

As a kid I was always like, what the heck are these verses? Like, this is such a fun song, and now it's so sad. Now I'm just really glad those verses are in there, because yeah, I don't know. This is such a fun song, but it's also a little sad.

Anyway, I found a hermit crab. Rebecca, look at this hermit crab. Like, look at this shell. Oh my gosh, this shell is amazing. What kind of shell is that? I think it's an epitonium that's called. It's all covered with farlene algae, so it would be like... Oh, that's why it's like...

What you're going to do when the lake go drive, baby. Lord, Lord... What you're going to do when the lake go dry? Oh, and bang what you call that a honey, bang, walk. If you'll tell my cross that three-for-d-d-dine, babe. No, no. Tell my cross that three-for-dine. I would tell more, but he ain't none of mine.

Honey, pay. No, no. What you're going to do when the lake go dry, babe? No, no. What's you going to do when you're going to drive? Honey. Honey. If you want to contribute to Rebecca's,

I Naturalist Project, please look up Snapshot Cal Coast. We will link to that in the description as well. Meanwhile, this episode was produced by me, Bird Pinkerton. It was edited by Jorge Just, with help from Meredith Hodnott, Matt Colette, and Paige Vega. Noam Hassanfeld made the music. Christian Ayala did the mixing and the sound design. Kim Slaughterback checked our facts. Julia Longoria is the fact that some frogs have little spade-like feet that help them burrow. And I am always, always, always, always, always grateful to Brian Resnick for co-creating the show. Thanks also to Drew Harvel, Ashley Kidd, Lauren Shebelhut, Kylie Love, Natlow, and Chloe Davis for taking the time to speak with me for this story. Thanks to Megan Ely for all her help in organizing things.

And thank you forever to the last. late, great Michael Rossman, and to Lee Temkin. You changed my life. The 1939 recording of the Crodad song that you heard was from the American Folklife Center. If you have an ecosystem that you love someplace in the world that makes you happy to be alive, please tell us about it. Tell us why you love it. Tell us if it's changing. Write in. Send us a recording of it if you can. We are at unexplainable at Vox.com. If you want to support the show and help us keep making it, please join our membership program that is at Vox.com slash members.

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and we're off next week for the holiday, but we'll be back in your feed on July 14th.