In short
A field-to-lab look at “mesophotic” twilight reefs (about 30–150m) in Palau and other Pacific sites, and how scientists use ARMS (Autonomous Reef Monitoring Structures) to study deep coral ecosystems that are hard to dive and observe.
Guest backgrounds
Luis Rocha, a zoologist at the California Academy of Sciences; Susanna Baer, postdoc at Cal Academy and a diver; plus Smithsonian and university researchers processing ARMS (Johanna and Lynn Bonomo/Cal Academy; Chris Meyer/Smithsonian; Sarah Tweed/Smithsonian; Tito Lutufo/University of São Paulo; Emily Rutkowski/University of Hawai‘i; Terry Gosler/Cal Academy; others including Daniel Eisenhower/University of Guam).
Key claims
Deep reefs are understudied because technical diving is risky and time-limited; ARMS standardizes sampling and preserves organism associations for later DNA and morphology work.
Notable examples
3,000 specimens from one project; ~3% identified to species; discovery of likely new nudibranchs; “pom-pom crab” holding anemones; sea-snail/coral mimicry; ARMS plates disassembled into photo mosaics, tissue sampling, and DNA “milking” workflows.
Written by AI. May contain mistakes. Listen to the episode to check what was said.
Chapters
Tap a time to open that second in VOExploring the Twilight Reefs
0:11 to 0:27
Understand the mysterious mesophotic coral ecosystems and their significance.
“Fetch is the most complete pet insurance for dogs and cats, according to consumeradvocate.org.”
Exploring the Twilight Reefs
1:33 to 3:06
Understand the mysterious mesophotic coral ecosystems and their significance.
“I was watching several people preparing to scuba dive.”
Diving Deeper into Coral Reefs
3:06 to 5:42
Learn about the challenges and life forms found at varying depths of coral reefs.
“And today on the show, how do you solve a puzzle like the deep reefs?”
The Unknown Depths and Biodiversity
5:42 to 7:44
Explore the unknown aspects of deep reefs and their biodiversity.
“the temperature will start to drop and the sunlight will start to fade.”
Challenges of Deep Diving Research
7:44 to 10:40
Discover the limitations of deep diving and the quick tasks divers must perform.
“But even at that level, those ecosystems are unknown.”
Innovative Research with ARMS
10:40 to 14:00
Learn how Autonomous Reef Monitoring Structures provide insights into reef biodiversity.
“Usually, because it's so limited and we have so much gear, each diver has one task.”
Luis's Journey to Deep Reefs
14:00 to 14:58
Discover Luis's frustrations and his quest to explore deep reefs.
“So Luis, this seemed like a solution to some of his frustrations, a way to really get a long look at these deep reefs instead of the reef glimpses he was getting from diving.”
Retrieving the Arms
14:58 to 16:05
Join the divers as they prepare to retrieve research equipment from the ocean.
“when Luis and his fellow divers had just jumped into the water to retrieve some arms.”
Retrieving the Arms
16:09 to 17:16
Join the divers as they prepare to retrieve research equipment from the ocean.
“It's the only business software you'll ever need.”
The Retrieval Process
17:29 to 19:15
Witness the intricate process of retrieving arms from deep reefs.
“Just crossed over into the twilight zone.”
Show all 19 chapters
Documenting the Findings
19:15 to 20:20
Learn how researchers document their findings upon returning to the lab.
“which is an institution devoted to coral research that was letting these scientists use their facilities for this work.”
The Lab Work Begins
20:20 to 24:30
Follow the team as they analyze and process the collected specimens.
“So picture like a little gray square canvas, but covered in splotches and streaks and swirls of red and orange and yellow and green.”
Identifying Marine Life
24:30 to 27:22
Explore the collaborative effort to identify various marine organisms.
“When I first got to the lab, every time someone started to ask what something was, I kind of expected them to say, I've never seen this before.”
Discoveries of New Species
27:22 to 28:00
Hear about the potential discovery of new species during the research.
“might be able to pin down exactly what these things are.”
Discovery of New Sea Slug Species
28:00 to 29:56
Learn about the process of identifying potentially new sea slug species and the excitement it brings to researchers.
“they actually found several species that he thought were new.”
Research Collaboration and Excitement
29:56 to 32:16
Explore the collaborative atmosphere among researchers as they share their findings and excitement about marine life.
“It's just, you know, another day's work.”
The Puzzle of Marine Ecosystems
32:16 to 33:54
Understand the analogy of puzzle pieces in marine research and the importance of connections between species.
“And while she did this, I was talking to her about my puzzle piece idea.”
Contributions of Various Researchers
33:54 to 36:19
Learn about the team of researchers involved in the project and their individual contributions to marine science.
“So I was talking to him about the idea that debriefs are a really hard puzzle, and I asked him why he would even want to work on a puzzle that was so hard and had so many gaps.”
The Ongoing Nature of Research
36:19 to 38:10
Discover the ongoing nature of marine research and the collective effort needed to explore complex ecosystems.
“They'll work out what's new and what's not new, but also how things connect.”
Transcript
Automatic transcript. May contain errors.0:00Daniel Eisenhauer:Are you a pet owner? Every six seconds, a pet owner in the U.S. gets hit with a vet bill over$1 ,000. Always an unwelcome surprise. That's where Fetch comes in. Fetch is the most complete pet insurance for dogs and cats, according to consumeradvocate.org. You get paid back up to 90 % of vet bills at any vet in the U.S. and Canada, with claims paid back in as little as two days. Go to FetchPet.com slash save right now for your free quote. That's FetchPet.com slash save.
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1:32Luiz Rocha:On a bright, beautiful day last May, I was standing on a boat floating in the waters of the Republic of Palau. I was watching several people preparing to scuba dive. Beneath our boat, there was a gorgeous coral reef ecosystem, a turquoise world that was teeming with life. But these divers were planning to go beyond those shallow reefs, go deeper.
2:03Yara Tibirica:Recreational scuba divers are often going 18 meters down, max, maybe 30 or 40 if they have extra certification.
2:10Luiz Rocha:But two of these divers were planning to go down to 45 meters, and the other two were going to go even further, about 100 meters into the deep.
2:20Lynn Bonomo:Are all divers mentally and physically prepared to dive? Absolutely. And they were doing all this, preparing to descend so far, because they wanted to retrieve some scientific structures they'd left down there,
2:33Luiz Rocha:down in a mysterious, understudied world known as the mesophotic coral ecosystems. which is a mouthful, so I will call them debriefs for short. But they're a world that one of the divers, a zoologist named Luis Rocha, has a lot of questions about. And the hope is that these structures will help him and others get some answers, help them put together some of the pieces of a very puzzling ecosystem that they fundamentally do not understand.
3:06Chris Meyer:But the games begin. So this is Unexplainable.
3:09Yara Tibirica:I'm Brad Pinkerton. And today on the show, how do you solve a puzzle like the deep reefs?
3:32Yara Tibirica:Luis Rocha started exploring the ocean early.
3:35Chrissy Piotrowski:So I grew up in a small town in coastal Brazil. So, oh, it was small when I was growing up, not so small now, but always going to the beach every weekend. And I always had this interest and attraction to the ocean. So I always wanted to go deep. I always wanted to go to a place where people don't go to very often or never been to before. I wanted to see things that nobody has seen before. So I started with tide pools and then snorkeling and then scuba diving and then scuba diving a little deeper and then deeper and deeper and pushing the limit of depth. and always very excited about discovering new things.
4:11Luiz Rocha:So it makes sense that Luis, as part of his work for the California Academy of Sciences, explores these mysterious deep reefs. But what is a deep reef exactly?
4:25Yara Tibirica:The term can be used to describe ecosystems that go way down into like the ocean's abyss. So places with no sunlight at all, sometimes thousands of meters down, But for the purposes of this story, we're going to use deep reef to refer to a world that's a little closer to home. So a few tens of meters from the surface down to about 150 meters.
4:47Luiz Rocha:And to understand that world a little better, let's pretend we're Luis for a minute and do some of our own exploring. First, we will go somewhere with deep reefs.
4:57Yara Tibirica:Let's say Palau for now. And then we'll dive. For the first 10, 20, 30 meters of our descent, we'll be in bright, clear waters, and we'll see the kinds of coral reef you might be more familiar with. These are complex ecosystems full of crackling crustaceans and stinging anemones and darting, flashing, munching fish. And at their heart, they have hard corals. So these little animals that secrete the calcium carbonate structures that make up the reef itself. But these corals partner up with photosynthesizing algae that need sunlight to thrive. And as we go deeper, down to 40 meters, 50, 70, 100, the temperature will start to drop and the sunlight will start to fade.
5:46Yara Tibirica:It actually fades so much that people sometimes use the term twilight reef to describe this ecosystem. And that dimming light means that there is less and less opportunity for photosynthesis at these depths. But it does not mean that there is no life down here. Instead, we're descending into a world of animals that can survive with less light. Sponges and sea squirts, mollusks and crustaceans, bryozoans, even corals that have adaptations that let them make the most of low light.
6:22Chrissy Piotrowski:And the deeper portion of reefs is really, really the unknown portion. So almost everything we know about coral reef biology, about coral reef ecology, about coral reef evolution comes from science done in the top 30 meters of reef. Anything between 30 meters and 150 meters is really, really unknown because it requires a different kind of diving. It requires technical diving. It requires much bigger time commitment from the scientists. And it's riskier. Even from the human perspective, it's risky for the divers.
6:56Luiz Rocha:People have used remote-operated vehicles and submersibles to explore the deep reefs, but those can be expensive. And if you drop a camera down there, it might not be able to capture the really small species or the hidden ones. And so deep reefs are just trickier to study than their shallow neighbors are. And there's lots left to learn.
7:18Chrissy Piotrowski:Whenever we go somewhere, the first thing we find is new species. I'm talking about fish here, which is one of the most charismatic organisms you can find in a reef. But if we started looking at sponges and gorgonians and crustaceans and mollusks, I mean, there's so many new species. It's like the most basic thing in science you can do is describe a species. And it's the first step that kind of starts the chain to do everything else. But even at that level, those ecosystems are unknown.
7:51Luiz Rocha:If you imagine the project to understand shallow coral reefs, so the coral reefs that we know more about, like a whole bunch of people all collaborating to try and solve a 10 million piece puzzle. That puzzle, obviously, still has a lot of gaps.
8:07Yara Tibirica:We have lots of questions about coral reefs. But humans have been collecting pieces of that puzzle and snapping them together for a very long time now.
8:17Chrissy Piotrowski:We probably have like 8 to 9 million pieces. And of those, I'd say 5 million are assembled.
8:24Luiz Rocha:So if you squint at the shallow coral reef puzzle, you can at least get a pretty good picture of what's there, right? Who's eating whom and how species interact and what gaps you might want to focus on next. If you try to compare that to the deep reef puzzle, though, Luis told me the puzzle itself might actually be a bit smaller, just because less light can mean less diversity.
8:48Yara Tibirica:But he can only guess at how many pieces this puzzle has right now. And we've pulled up fewer of those pieces to look at.
8:56Chrissy Piotrowski:So it's a lot less information to go with. So there's so many big questions that need to be answered.
9:02Yara Tibirica:Luis wonders about things like, what's the main energy source for everything down there in this dimmer light, right? What does the food chain look like?
9:11Luiz Rocha:Or how do things evolve to live down at these depths? And then how similar are they to the shallow ecosystems?
9:18Yara Tibirica:Or how different? How are they affected by climate change? These are some of the big, basic questions you might ask. But also...
9:29Chrissy Piotrowski:In some ways, we don't even know what questions to ask. When we go to ecology and evolution, we could ask the same questions as we do for the shallow reefs, but that's kind of not the same. We really only know what questions to ask after we have a baseline understanding of what the ecosystem is. And for deep reefs, we don't know that yet.
9:50Luiz Rocha:So for years now, Luis has been gathering bits of basic information on these reefs, been diving down, exploring at these depths, collecting fish, which are a specialty. But the problem with diving is that even with specialized equipment, it has limits. As you go down, gas gets pushed into your tissues. kind of slowly turning you into the human equivalent of a carbonated soda. And the deeper you go, the more pressure there is. So the faster you get carbonated, or nitrogenated, really. So if you want to descend to 100 meters to explore the deep reefs, you get gassy very fast.
10:31Chrissy Piotrowski:We have a very, very short time. And by short time, I mean five minutes, six, seven minutes.
10:36Yara Tibirica:What can you do in five minutes?
10:40Chrissy Piotrowski:Usually, because it's so limited and we have so much gear, each diver has one task. So if my task is taking pictures, I come down with my camera and I take as many pictures as I can. If my task is doing transects, I do two transects and we start moving up. If my task is collecting fish, I collect two or three fish and we start moving up.
11:01Yara Tibirica:And that moving up can then take hours, because he has to let the gas in his tissues out sort of bit by bit, kind of like you'd slowly turn the cap on a shaken up soda bottle to keep everything from exploding out too fast. Sometimes he's able to do more science on the way up, but other times he has had to try and entertain himself with like an iPad in underwater housing.
11:25Chrissy Piotrowski:I tried playing Angry Birds in it. It was very, very, it made me very angry because I could never get, the touchscreen is not very precise. I could never get the ball to go the right way. But it was a good, it was a good pastime.
11:43Yara Tibirica:It is obviously not super efficient to try and explore something in five-minute bursts. And about a decade ago, Luis started to explore another option, too.
11:53Chrissy Piotrowski:There was a method of sampling a lot of biodiversity on the reef that was pioneered in the early 2000s. And it's called Autonomous Reef Monitoring Structures.
12:06Luiz Rocha:ARMS, or ARMS for short.
12:08Chrissy Piotrowski:It's PVC structures consisting of PVC plates that are stacked together. And the plates have a standard size. They're stacked together the same way. So you can build each structure, each one of these structures is identical to the other.
12:23Yara Tibirica:Arms were developed, basically, to study underwater ecosystems in a standardized way. So if you pick up an encrusted rock from a reef, it'll be different from other encrusted rocks on other reefs. It'll be unique. Arms are built to be not unique. Very similar and very comparable. So you take what looks like a little nine-floor hotel the size of a toaster oven, these sort of stacks of gray PVC plates. And you bring however many of them you want, three, 13, 34, whatever, down to various spots that you want to study or compare. Then you secure them in place and you leave them for a while.
Read the full transcript
13:06Chrissy Piotrowski:As soon as you drop any kind of clean structure on a reef, it starts getting colonized by larvae of everything around it. Sponges, gorgonians, corals. And then because there's a lot of hiding spots between the plates, so between the floors of the hotel, they start getting colonized by shrimp, by mollusks, by ascidians, by anything you can imagine in the ocean. And it becomes this stable, diverse, like mini reef, if you will, packed with a lot of biodiversity that would be very hard to collect all at once in any given reef.
13:46Luiz Rocha:Years later, you come back, you scoop the arms up, and then you can study this mini reef that you've made. You can see and touch and smell things, sample them, photograph them, send everything in for DNA analysis, whatever you want. So Luis, this seemed like a solution to some of his frustrations, a way to really get a long look at these deep reefs instead of the reef glimpses he was getting from diving. And so between 2016 and 2018, he went out to four different locations, Palau, Guam, the Marshall Islands, and French Polynesia. And in each place, he, along with a group of other researchers, dove down to put a bunch of arms at 10, 50, and 100 meters.
14:34And then they waited.
14:37Luiz Rocha:They actually waited a little longer than Luis would have liked, because he needed funding, and COVID messed up some plans. So almost a decade passed. But eventually, at long last, some private funders agreed to underwrite the retrieval of the arms that he'd left.
14:57Luiz Rocha:Which takes us right back to where we started. when Luis and his fellow divers had just jumped into the water to retrieve some arms. What they found after the break.
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16:46Daniel Eisenhauer:Support for the show comes from Google Gemini. You know that moment when curiosity strikes? You're exploring a new city with the family and a sculpture catches your daughter's eye. What is that? Who made it? With Gemini, you can snap a picture and get a fully interactive breakdown of its history, architecture, and even hidden secrets. Gemini is built for moments like that. Whether you're learning something new, solving a problem, or looking for your next favorite thing, Google Gemini is here to help. Download Gemini, Google's AI app, or visit gemini.google.com to learn more.
17:29Johanna Loacker:Just crossed over into the twilight zone.
17:40Emily Rutkowski:I think one of them is coming.
17:43Yara Tibirica:Over the course of several days, I watched a whole team of people pull arms out of the deep reefs of Palau. So a boat full of divers, including Luis, would go down into the deep and actually get the arms. But then because the deep divers had to stay at depth a long time and decompress, they would pass the arms up, kind of relay style, to shallower divers, who then brought them up to a second boat full of scientists from lots of different institutions.
18:11Emily Rutkowski:They're a boat length away.
18:14Yara Tibirica:The shallower divers would emerge, and they would pass a small, clear tub to the people waiting on the boat.
18:20Chris Meyer:You got it? Yes. All right.
18:23Yara Tibirica:And inside that tub was an arms, sort of cube-like stack crusted over with red and orange light. Looks like a goodie. Some arms were a little sparser. Others were almost fuzzy with organisms.
18:37Tito Monteiro da Cruz Lotufo:Lots of sponges on this one. Emily!
18:39Yara Tibirica:But each one was quickly transferred from the small tub into a big black storage bin full of seawater.
18:49Yara Tibirica:And then once all the arms were ready to go, usually around two of them each day, we'd take off back to the lab. Because they wanted to start documenting everything while it was as fresh as possible.
19:03Luiz Rocha:We would motor back through aquamarine waters, past little islands covered in green forests. And eventually we would pull into the Palau International Coral Reef Center, or PICRC, which is an institution devoted to coral research that was letting these scientists use their facilities for this work. And you might imagine that the main focus here would be new species, right? Unknown things. Instead, I watched the researchers racing to just document everything they found, new or old, in as much detail as possible. It's like a well-oiled, cheese-it-fueled, sort of beautiful disassembly line.
19:45Emily Rutkowski:Do you have another size wrench?
19:47Yara Tibirica:Step one was just breaking down the arms. Two researchers from Cal Academy named Johanna and Lynn were often helping with this part. And they would pull on bright red elbow-length rubber gloves. They kind of look like the gloves they use for insemination of cows. And then they would open up a bin and use a wrench to pull the stacks of nine gray arms plates apart.
20:11Emily Rutkowski:Which one? This one? Okay. Let me, I'm on.
20:14Yara Tibirica:Sort of one thick square plate at a time.
20:17Emily Rutkowski:I think I got it. Hold on. Okay.
20:19Yara Tibirica:Each plate, as they lifted it out, was almost like a modernist painting. So picture like a little gray square canvas, but covered in splotches and streaks and swirls of red and orange and yellow and green. And they would place each of these works of art into a little wire rack in a new tub of seawater. And then when all nine plates were in, they would pick the tub up.
20:43Tito Monteiro da Cruz Lotufo:Two, three, lift.
20:47Yara Tibirica:And haul it over to a cool, air-conditioned lab nearby, before then returning to the bin that they had disassembled the arms in.
20:56Emily Rutkowski:And now, back to the sounds of sloshing work.
20:59Yara Tibirica:They would sieve through the water in the bin, and then they would hunt through those sieve sediments for anything moving. Lynn told me it was kind of like a game of I Spy. So imagine that, but with sea slugs and worms and lots of crustaceans.
21:14Emily Rutkowski:Crab, some shrimp, shrimp, shrimp, shrimp, shrimp, tumble shrimp. And then meanwhile, some of the other members of the team had set up stations
21:25Yara Tibirica:to process what they called the furniture of the plate. So everything that was not moving that these various creatures had been crawling around on. And they began with the big picture, literally.
21:37Johanna Loacker:So we are going to start late photographing.
21:40Yara Tibirica:Chris, a Smithsonian curator who directs the Global Arms Program, was the guy in charge of this big picture photography.
21:47Johanna Loacker:Oh, you know what? This is kind of an important part. This piece here needs to be plugged into the computer. Don't forget to do that. Not much happens.
21:55Yara Tibirica:Once he had things properly set up, he would take a series of high-resolution pictures of each plate, and then those were all stitched together into sort of one beautiful, complete image. So this is the photo mosaic fun part.
22:11Johanna Loacker:It's kind of like nature's art.
22:13Yara Tibirica:When Chris was done photographing both the front and the back of the plate, it would move on to a trio of samplers who were sort of the next step in the arms disassembly line.
22:24Tito Monteiro da Cruz Lotufo:So what we're doing is we're looking for every unique thing, which we call a morpho species, and we're trying to get some representative tissue samples from all of these things so that we can sequence the DNA and match the DNA to the organism.
22:42Yara Tibirica:Sarah is also from the Smithsonian, and she was in charge of grabbing and photographing samples of soft corals and other kind of encrusting creatures on each plate.
22:51Tito Monteiro da Cruz Lotufo:You know, this red one here is distinct from this one. These may be the same species.
23:00Yara Tibirica:This one, let's see. Next to her was Tito from the University of Sao Paulo. And he was doing basically the same thing Sarah was doing, but for these animals called tunicates. So things like sea squirts, which, he told me, are actually our closest invertebrate relatives.
23:18Chris Meyer:They just decided to take a different route on evolution and become simpler rather than complex. So they can solve all their problems very, very easily.
23:30Yara Tibirica:Across the table from both of them, Emily from the University of Hawaii was sampling sponges.
23:35Emily Rutkowski:Guys, this sponge is so cool.
23:37Yara Tibirica:Kind of poking and prodding them, cutting them up.
23:40Emily Rutkowski:Sometimes when you cut them, they'll have like, there's this one that has like a strong garlic smell when you cut it. so you got to make sure to smell them as well. Yes. You got to ask them what they do on the weekends.
23:52Yara Tibirica:You know, it matters.
23:55Emily Rutkowski:It matters.
23:57Yara Tibirica:Emily also spent a lot of time just showing me sponges. So she showed me a sponge that sparkled with little silver filaments and then this thin flat sponge that felt dry underwater. A little sponge like a sandcastle. All part of her campaign to convince people that sponges are cooler than we give them credit for.
24:16Emily Rutkowski:You know, I do, I convert one person and then they convert one person. It's like a triangle, you know. A pyramid scheme.
24:24Yara Tibirica:Mostly, though, all three of these researchers were just in an ongoing conversation with each other as they tried to identify the obscure, colorful lumps on these plates.
24:34Chris Meyer:You have to see the other side. Well, you already did, right?
24:36Tito Monteiro da Cruz Lotufo:Yeah, it's on the edge.
24:38Chris Meyer:It's a sponge.
24:41Tito Monteiro da Cruz Lotufo:No.
24:43Luiz Rocha:When I first got to the lab, every time someone started to ask what something was, I kind of expected them to say, I've never seen this before. It's a new species. But before these researchers could even begin to wonder about something like that, they had to answer much more fundamental questions. It's firm.
25:03Emily Rutkowski:Yeah, it's not a sponge.
25:04Luiz Rocha:Like if something was a sponge or a tunicate or what?
25:08Chris Meyer:It may be a tunicate, but it's really small. I couldn't see the siphons. So that's why I wouldn't call 20-day-20.
25:21Yara Tibirica:And while all this was happening, the people playing I Spy would be trying to identify the animals they were finding. They would carry creatures and cups over to a researcher sitting in the corner by a microscope. Earlier on, this was Yara, later Daniel, both from the University of Guam.
25:40Chris Meyer:So the family is Pagurupsudidae, which literally means fake hermit crab.
25:44Yara Tibirica:And then people would also bring creatures out to another room, where these two zoologists from Cal Academy, Chrissy and Terry, were sitting next to a whole bank of microscopes ready to identify things. Oh, it looks like it's another one of these Scalibragmatidae, the maggot worm. Really, though, everyone in the lab was contributing to this sort of overall project of trying to figure out what was what.
26:09Tito Monteiro da Cruz Lotufo:Is that a marginal one?
26:10Yara Tibirica:It was this constant course.
26:12Tito Monteiro da Cruz Lotufo:Wow, he's cool. What is that? Like, who builds that?
26:15Johanna Loacker:Oh, that's an ostracod. I think it's an amphipod.
26:18Tito Monteiro da Cruz Lotufo:Could you write down 1570 is caprellidae?
26:22Johanna Loacker:Oh, it's not a binsofacial. It's not a decapod. I think it's a polynoid.
26:26Yara Tibirica:I think this is the hard tech.
26:28Johanna Loacker:This one's labraliniata.
26:31Yara Tibirica:Sometimes they could identify things with specificity. Oscarella. Oscarella, for sure. Other times they were documenting things. they were maybe less familiar with. So at the end of this particular project, they had close to 3 ,000 specimens. And they're still processing the data, so the estimates are changing. But at last check-in, around 3 % had species name tags. A little less than 20 % were a step up from that. So they had a genus, but not a species. And then many, many others were more broadly identified by family or subfamily or at higher taxonomic levels.
27:10Tito Monteiro da Cruz Lotufo:Take a look.
27:11Yara Tibirica:And that's why they were trying to grab samples of everything and document those samples so well, so that down the line, people with more time and more access to genetic tools might be able to pin down exactly what these things are.
27:26Johanna Loacker:Did you guys get this brachiopod? Look in this green sponge up here. See the brach right in the middle?
27:31Tito Monteiro da Cruz Lotufo:No, I don't have that at all.
27:33Johanna Loacker:Can you grab it? Okay, let me get a tweezer. Grabbed some tweezers. I haven't seen that one.
27:38Yara Tibirica:There was one guy. This guy named Terry. He's a nudibranch expert, so he studies a type of sea slug. And he really could look at certain sea slugs and basically make the on-the-spot call about whether he thought they were at least likely to be new species to science, pending genetic confirmation. And on the first day that I was following the team, they actually found several species that he thought were new.
28:04Emily Rutkowski:It's your lucky day.
28:06Johanna Loacker:What have you got?
28:07Emily Rutkowski:A third nudibranch. Johanna found it.
28:11Johanna Loacker:How exciting.
28:12Yara Tibirica:At one point, Johanna found a little sea slug.
28:15Luiz Rocha:It looked sort of like a small yellowish oval with little horns and a branching, veiny pattern.
28:24Yara Tibirica:Lynn carried that slug over to Terry, and he was pretty quickly able to guess what family it was in. Look at it.
28:30Johanna Loacker:Look at it. I think it's a discadoran of some sort.
28:34Yara Tibirica:Okay. But he waited a bit for the slug's gills to open up, and then he pulled out this document on his computer. It's a book he's been revising that's full of pictures of Mudebranks. He basically just started scrolling through, like, an incredible number of multicolored slugs. This very loud machine started running in the background as Terry was scrolling, but eventually he landed on one slug in particular.
29:02Johanna Loacker:Okay, so it's similar to that, and it has that sort of network-like pattern, but it's distinct. So my conclusion is that until we have some genetic evidence that it's a third new species, most likely.
29:26Yara Tibirica:Terry told me he felt fantastic about this, and he seemed quite pleased. But he wasn't like, everyone stop what you're doing, you know, come see the new species. And earlier that same day, when I was talking to him about a different sea slug that he also believed to be a new species,
29:46Luiz Rocha:I even said to him, you seem very blasé about a new species.
29:53Johanna Loacker:I'm not blasé. I'm excited. It's just, you know, another day's work. But I still...
30:05Emily Rutkowski:So do you want this here? What? This is for you, here.
30:10Johanna Loacker:What is that?
30:11Emily Rutkowski:A limpet, I believe, that Chris just sent over. Do you want it here?
30:16Yara Tibirica:To be fair, these arms took a long time to unpack, and work often stretched late into the night. So nobody really had too much time to dwell on anything. But also, over the days, it kind of struck me that many people on the team were definitely excited about the idea of seeing something new. But they seemed just as excited about relationships between species, whether or not they were new.
30:42Johanna Loacker:Oh, Tito, is this our Medusa guy?
30:46Yara Tibirica:Chris and Tito, for example, were interested in a tunicate they found that was full of snake-like worms. And then when I walked into the lab one day, several people told me to go look at something known as a pom-pom crab. He's so cute. Which turned out to be a tiny yellow crab holding purple anemones in its claws.
31:06Chris Meyer:Red to the face of his cell.
31:09Yara Tibirica:Sarah, meanwhile, seemed especially excited about creatures that mimic other creatures. So one night at 1.12 a.m., she showed me what she called the frosting on the cake of the day.
31:20Tito Monteiro da Cruz Lotufo:So these are ovulets.
31:22Luiz Rocha:These were bright red sea snails. But Sarah was so jazzed about them because she also had the bright red octocorals that they lived on and sort of looked a lot like.
31:31Tito Monteiro da Cruz Lotufo:And the mimicry is so precise that that isn't a polyp on a coral. It's a papillae on the snail. This is a polyp on a coral. if that's the coral.
31:44Luiz Rocha:In another conversation with Sarah, she said something that's kind of the key to all of this for me. So the researchers had just gone through some final steps in processing the arms. They had scraped the plates clean with a paint scraper, ground everything up in a blender before pouring it into a very fine mesh bag. And Sarah was in the process of doing something
32:07Yara Tibirica:that some people called milking the turd, which was removing the water so that the remaining material could be sampled and sent off to be analyzed for DNA.
32:19Luiz Rocha:And while she did this, I was talking to her about my puzzle piece idea. So this idea that, you know, we have very few pieces from the deep reefs and this was a project to bring up more. And she said to me...
32:31Tito Monteiro da Cruz Lotufo:Oh yeah, so to be fair, you know, we have had, we have collections in museums, for instance, from exploring expeditions. and people would dredge and pull up weird, you know,
32:45Luiz Rocha:miso-to-deep things. They would grab individual puzzle pieces from the deep twilight reefs, but those pieces weren't really in context necessarily. The beauty of something like the ARMS project isn't just pulling up pieces. It's more like that thing where you open a puzzle box and some of the pieces are still stuck together. So if you lift them out gently, you get not just a few pieces, but how they connect.
33:14Tito Monteiro da Cruz Lotufo:Something really powerful is taking note of associations, like who likes to live with who? What likes to live on what? What gets along? What doesn't seem to get along? I think that's particularly exciting to document because it's not always easy to keep organisms together where they live when you're collecting them. And I think that ARMS allows you to do that in a really nice way. Which is why you were so excited at 2 a.m. Which is why I was so excited at 2 a.m.
33:44Luiz Rocha:That idea about individual puzzle pieces versus the connections between them feels connected to a conversation I had with Luis. So I was talking to him about the idea that debriefs are a really hard puzzle, and I asked him why he would even want to work on a puzzle that was so hard and had so many gaps.
34:08Chrissy Piotrowski:It's the reward at the end of it. If it's a hard puzzle, at the end of it, the reward is always bigger.
34:16Luiz Rocha:But you're not... Like, in our lifetimes, will we assemble the deep-read puzzle?
34:22Chrissy Piotrowski:No, no, we will not assemble the puzzle, no. But we will generate some good pieces for the next generation to assemble.
34:31Lynn Bonomo:So you might not even get the reward of the really hard puzzle.
34:35Chrissy Piotrowski:No, no.
34:38Yara Tibirica:At the time, it felt like a little bit of a contradiction in his thinking, honestly. But listening back to my conversation with Sarah and with other researchers, I realized I was thinking about Luis a little like an individual puzzle piece and not as a piece connected to other pieces. My name is Johanna Loeker.
34:59Luiz Rocha:Obviously, I am aware that science is a process that involves a large number of people all working together.
35:06Yara Tibirica:I'm Lynn Bonomo. But there's still this impulse to focus on one individual and their contributions to a project.
35:12Luiz Rocha:I'm Emily Rutkowski. So I expected for this story to focus mostly on Louise, maybe one other researcher in the lab. I'm Sarah Tweed. But when I arrived, I quickly realized that if I focused on any one person, I'd kind of lose the plot of how the arms were brought up and disassembled. I'm Chrissy Piotrowski.
35:32Johanna Loacker:My name is Terry Gosler. My name is Matt Schmidt.
35:35Luiz Rocha:I'm Lauren Scheinberg. And the project of processing these arms won't end with this group.
35:40Chrissy Piotrowski:So my name is Luis Rocha.
35:42Luiz Rocha:From here in Palau, some of the samples collected will go back to the California Academy of Sciences. Others will go to the Smithsonian.
35:49Johanna Loacker:It's Chris Meyer.
35:50Luiz Rocha:The University of Sao Paulo and elsewhere.
35:53Chris Meyer:Full name is Tito Monteiro da Cruz Lutufo. Short version Tito Lutufo.
35:59Luiz Rocha:Last year, they brought up the arms that they'd left in Guam.
36:02Chris Meyer:I'm Daniel Eisenhower.
36:03Luiz Rocha:And the University of Guam kept many of those samples in their collections. And these samples will be available for people to study. So other scientists will pick through the organisms that the team have collected here. They'll identify things more precisely. They'll work out what's new and what's not new, but also how things connect.
36:23Chris Meyer:So I'm Susanna Baer. I'm a postdoctoral fellow with the California Academy of Sciences.
36:28Luiz Rocha:Susanna, also known as Susie, was one of the divers, and she works with Luis. She's already analyzed some of the Guam samples to understand how much the species change as you go deeper. The Palau samples will let her sort of check that work and see if her findings hold up here too. And there is plenty more work to be done on that question and on all the other big questions that people have. So, sure, yes, Luis is not going to solve the very hard puzzle of these deep twilight reefs all alone. And it almost certainly will not be solved in our lifetimes. But to me at least, there is something kind of rewarding and exciting about the idea.
37:15Luiz Rocha:That there's so much work left to be done. And that it will take so many people working together to do it.
37:22Tito Monteiro da Cruz Lotufo:What's this bunch?
37:23Chris Meyer:Oh, this is correct to me.
37:25Tito Monteiro da Cruz Lotufo:Yeah, start. I'm gonna play the nudibranch songs. The nudibranch songs?
37:31Emily Rutkowski:What's a nudibranch song?
37:35Lynn Bonomo:Sorry, Yara has pulled up a video that's called Psychedelic Sea Slug Dance on YouTube.
37:42Chris Meyer:Wait until you listen to the tune of this.
37:45Lynn Bonomo:You don't need to see.
37:47Tito Monteiro da Cruz Lotufo:You can't just listen.
37:49Chris Meyer:The nudie branch started way long ago In the ocean deep below It was the latest crazy town It was the greatest dance around The nudie branch branch The psychedelic seas of dance dance Do the nudie nudie nudie branch It's the latest It's the greatest Come on baby Do the nudie branch dance
38:13Yara Tibirica:This episode was produced by me, Bird Pinkerton It was edited by the wonderful Lissa Soap and by Jorge Just. Thanks, Jorge and Lissa, for everything. Joanna Solitaroff and Meredith Hodnot both also weighed in on aspects of this episode.
38:29Luiz Rocha:Meredith runs the show, and Joanna is executive director. Christian Ayala did the mixing and the sound design. Melissa Hirsch checked the facts. Noam Hasenfeld does our music. and the nudibranch song you're hearing is the psychedelic sea slug dance by Will Thompson.
38:50Luiz Rocha:Miles Uwell, Chris Shurtleff, and Davon Howard helped me with gear. Valerie Schenkman, Alex Coles, Kareem Correa, and Sally Helm are the fact that some corals can fluoresce. Thanks always to Brian Resnick for co-creating the show with me and Noam. Thank you to Megan Ely at Cal Academy for all the work that she put into coordinating my visit. Thank you to Clara Diaz for taking the time to help me understand the mesophotic. And thanks to Shannon Bennett for her time as well. And big thanks to every single one of the people who were working on this Palau project who walked me through what they were up to.
39:27Luiz Rocha:But an especially big thanks to Johanna Loeker for taking so much time, both before my trip and during my trip, to explain things to me. If you, our listeners, have thoughts about deep reefs or about the mesophotic or your own stories about exploring the ocean, please reach out. We are at unexplainable at vox.com. We'd also love to hear your ideas for show topics. If you'd like to support the show and the journalism that Vox does, we would love it if you would become a member. It's very easy to do. Just go to vox.com slash members and you'll get access to all of Vox's journalism, but also know that you are supporting all of Vox's journalism.
40:08Luiz Rocha:For those of you who have emailed us to let us know that you signed up because of Unexplainable, thank you. And thanks also to those of you who have left us a nice review on your podcast platform of choice or just told someone in your life about the show. You are the best. Unexplainable is part of the Vox Media Podcast Network, and we will be back very soon with another episode about everything that we do not know.
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From the publisher
Down beneath the waves, where the light starts to fade, there's an ecosystem scientists don't fully understand. About a decade ago, some researchers left structures in this mysterious world and let them grow encrusted with life. Now they're pulling them back up again and unwrapping them like scientific presents.Guests: Luiz Rocha, ichthyology curator at the California Academy of Sciences, along with Johanna Loacker, Lynn Bonomo, Chris Meyer, Sarah Tweedt, Tito Monteiro da Cruz Lotufo, Emily Rutkowski, Yara Tibirica, Daniel Eisenhauer, Terry Gosliner, and Chrissy PiotrowskiFor show transcripts, go to vox.com/unxtranscripts For more, go to vox.com/unexplainable And please email us! unexplainable@vox.com
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