Short Wave - Sea Camp: Did Life Start In Hydrothermal Vents?

Episode Date: August 11, 2025

How did life start on Earth? The answer is a big scientific mystery scientists are actively investigating. After talking with many scientists, host Regina G. Barber found that an abundance of water on Earth is most likely key, in some way, to the origin of life — specifically, in either deep sea hydrothermal vents or in tide pools. It's for this reason some scientists are also exploring the potential for life in so-called "water worlds" elsewhere in the solar system, like some of the moons of Jupiter and Saturn. This episode, Regina digs into two water-related hypotheses for the origin on life on Earth — and what that might mean for possible alien life.Have another scientific mystery you want us to cover on a future episode? Email us at [e-mail] to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwavers. Emily Kwong here with my favorite astrophysicist, Regina G. Barber. Thank you, M. I'm glad I'm your favorite. Am I the only astrophysist? You're the only astrophysicist I know, so as long as I don't mean another one. We are back with our next installment of Sea Camp, our summer series that dives deeper each week into the wonders and mysteries of the ocean. Yes, so many mysteries. It's been such an incredible series, honestly. You last week and producer Hannah Chin were hanging out in the midnight zone with deep sea giants.

Where are we going today? So today we're exploring this really cool phenomenon that happens in both the midnight zone. That's the one we just visited. And the zone below it, the abysopalgic. This is what we would call the abyss. Very interesting, very eerie. I'm ready to go to the abyss. And this sounds like our sea camp tour guide, Noel Bolin, yes, a marine biologist from the

National Oceanic and Atmospheric Administration. Yeah, she says the abyssal zone is interesting because, as we learned in the last episode, the average depth of the ocean floor is 4,000 meters, and that's where this zone starts, which means... It's only in certain places of the ocean around the world that you get into the abyssalologic. Hmm. Those lucky places are 4,000 to 6,000 meters underwater, and they're the home to today's topic. I'm so excited.

Hydro thermal vents. Oh, these are these underwater, minors. volcano-looking things that spew hot water and all these extremophiles, all these critters that are adopted to live there will live on them. Yes, exactly. They were first discovered in the 70s, when scientists dragged a probe across the ocean floor, and they detected these huge temperature differences, and they were really surprised. Since then, we've learned a lot about them. Some of them are really hot, over 700 degrees Fahrenheit, and they come in all sorts of sizes. Some are really small. Some are huge, like up to 180 feet.

That's 18 stories tall. Wait, there's vents as tall as buildings? Yes, yeah. They're these underwater chimneys, basically. Except instead of smoke, they're spewing minerals, gases, and hot water. Sometimes those minerals contain iron, copper, and zinc. And they're spewing, like, black stuff. So, like, scientists call them black smokers.

There are white smokers, too, that have, like, different elements. Wow. Okay. Yeah, and Emily, that warmth and mineral richness, that makes them really good spots for some. ocean animals to thrive. The giant tubeworm, I think, is one of the weirdest-looking animals. It can grow to be over six feet tall, but it is a worm. And it has like a kind of hard shell that it lives in, which is the same material that fingernails are made out of. And they are everywhere.

That's Heather Fullerton, a microbiologist at the College of Charleston, and she studies hydrothermal fence. She said that there are fish and crabs, muscles, there are. are loads of shrimp, so much life. In fact, some scientists think that life in its earliest forms could have started there. Really? Yeah. When Earth was first forming or had just first formed, the atmosphere we had was not protected from UV radiation.

And it has been studied that some of the kind of small building blocks of life can be formed at vents. My stomach just did a flip-flop. Okay, this is why I'm reporting on it. Cool. So when she's talking about like building blocks, she means like nucleotides, amino acids. Yeah. Heather says that DNA and RNA, for example, are extremely vulnerable to like UV light.

So maybe they first form deep in the ocean where they'd be protected from those rays. That's amazing. Wow. Okay. Yeah, so M, it turns out that hydrothermal vents, they could exist on other moons and planets too. What? Including my favorite, one of Jupiter's moons, like covered in water and ice Europa. As if you couldn't love Europa more. Now you have even more reasons to love it.

I mean, this is why. So if the building blocks of life on Earth started at Earth's vents, and there could be vents on other worlds like Europa, could there be life all the way out there? That's what I'm trying to find out with my reporting. I see why we're here today. So today on the show, Gina dives into a big question. How did life really begin on Earth?

And could the answer lead us to life in alien oceans elsewhere in our solar system? You're listening to Shortwave, the science podcast, from NPR. All right, Gina, I know you have been cooking on this question for a long time, even though it seems really simple at face value, how life started on Earth. What did you find? Yeah, it's actually something I've been like thinking about since I was like 16. And after talking to many scientists, I'm pleased to give you a very simple answer. There is no consensus.

Oh, great. That's Mike Long, friend of the show and an astrobiologist. One of the greatest outstanding mysteries of science is how does life begin? We really don't know yet, but that hasn't stopped us from theorizing. Mike Wong has turned my mood around. Okay. What are the theories? Well, there's multiple competing ideas on how and where life began.

Like two of the big ones have to do with water. All of life's origins, every single group of animals you can think of, every single group of even plants. It all comes from the oceans ultimately. That's Karma Nonglu, a paleontologist and a postdoctoral fellow at Harvard University, and he studies ocean fossils so old they're from before there was life on land. Yeah, I mean, it is true. Even before dinosaurs walked on land, we had animals in the sea. It's an incredible thing.

If you think about the ocean, it's very much a nurturing environment in many ways. You know, the burden of gravity is taken off you in many ways, so many animals become very large in the ocean as a result. Like whale sharks, which can be up to like 12 meters or 40 feet. Or giant manta. Yeah, so big. Those are over 15 feet wide or about like 4.5 meters for like metric levers out there. Oh, there's also things like temperature stability because of, you know, obviously water's thermal properties. Then you consider land and being in the open air. It's way harsher by comparison.

But vents are harsh. Yeah. They're hot. And there's obviously no sunlight down there. Yes, these are great points. M. And it turns out that heat is actually one of the reasons some life thrives down there. Like, it's where they get their energy. Yeah. Karma says life around these hydrothermal vents is unique because, like, a lot of food chains on earth get their energy from sunlight. But these animals and bacteria are so far down in the deep, dark ocean, that their food chain is built on something else. They have to kind of, like, base the food web on something that's not based on photosynthesis. And so many of these animals undergo a process called chemosynthesis, which is basically building up energy and building up usable, you might colloquially say, food stores, by synthesizing,

chemicals rather than requiring light energy. Yeah, so in this scenario, it's possible early life didn't need much, if any, sunlight. Okay, so that's the first idea for how life could have begun in the oceans. What's the other

idea? So the second leading hypothesis deals with shallow water, specifically like tide pools. And researchers who are in this second hypothesis of origins of life camp, they basically think oceans are too wet all the time for life to have emerged there. I mean, wetness is a signature trade of oceans. Yeah, but that's potentially

like a problem. Some scientists think for complex molecules to build up, you need these like wetting and drying cycles to bond molecules together. Oh, wetting, drying cycles. Yeah. So because the material in tide pools is only submerged in water some of the time. Yeah. That's why they're a good alternate candidate for life on Earth. Yeah. So like the tide pools you were just talking about that you've encountered, those were like on a beach. These tide pools could also exist like in the middle of oceans. Like think of like a volcanic mount, like the tippy top of a volcano that like shot up. I'm going to bring back Mike Wong to explain this like tide pool theory a little more. He says that this bit of volcano maybe pops out of the water. It's probably sloped. So when it rains,

a pool will fill up. And if no rain comes for quite some time, then it'll dry up. And this is important because in order to link up the pieces of RNA, that chemistry has to go through what's called a dehydration reaction, which means it has to get rid of a water. It has to spit out a water molecule in order to make that link. Yeah, and Mike is talking about RNA because scientists generally think it's one of those like fundamental molecules that early life could have been based around. So between these two scenarios, the all ocean all the time scenario and the tide pools everywhere scenario, which is it? Yeah, so here's the thing. more I talked to all of these different scientists, the more I realized I had to like rethink my questions. Like across these two ideas, we've been talking about location a lot. Yeah. And maybe we

shouldn't. Wait, what do you mean? Well, I talked to Lori Barge, another astrobiologist and geochemist, this time at NASA's Jet Propulsion Lab. And she added this layer of nuance to my search. So I think that the right question is less, which environment did life originate in and more what conditions were required for the origin of life. Like, it's more about the process. Yeah. So environment matters, but different conditions can exist in the same environment. And so I think the discoveries that we need are to know what reactions were necessary for

the origin of life. And then what environments had those conditions. And there might be more than one answer is the thing. Because early Earth was a very big place. And was there only one origin of life? I don't know if there was. Her lab focuses on chemistry, really like testing to see if they can be. figure out how primordial matter and chemical reactions might have been affected by things like

other minerals or ions in seawater or by molecules in the atmosphere. This makes sense. Like, how can we know where to look for something if we don't know what we're looking for? If we haven't defined that. Exactly. Right. And some of those conditions scientists are looking for could be around some hydrothermal vents. So Lori and other researchers are taking samples from the Earth's oceans and trying to simulate in their lab,

what they think some vents in early earth would be like. So in our experiments, we make little chimneys, and we put organics in them sometimes. So she's making her own little hydrothermal vent in your lab? Yeah, yeah. Her and her team make these small hydrothermal vents. You know, remember those black and white smokers from the beginning of the story. Yeah.

And we're trying to look at, first of all, where do the organics go? And then we also look at the energy that the chimneys can generate. So if you put, let's say, electrical leads in the tuesday. chimney and in the ocean, you can measure the potential, the electrical potential they generate. So in that sense, it's kind of like a battery. So you have all these different properties. So you can, depending on the experiment, it's designed for different reasons. So what have they found? What, like, what conditions lead to life on Earth and maybe on other planets? Right. So they are still working on that. But the fact that there could be the right

conditions in some vents brings us back to these icy moons in our solar system, like Enceladus and Europa. They are wet all the time. No tide pools, no drying in wedding cycles. So do you think there could be vents on Enceladus in Europa? Is that where you're going with us based on what she's saying? Yeah, maybe, like a big maybe. But Mike and I admit, me too, are part of this optimistic scientist club inspired and enthralled by this idea that ingredients of life could exist elsewhere in our universe, like in these vents. These hydrothermal systems are just infused with all of this rich chemical and thermal energy that could have helped spark metabolic systems into existence. And because we think that there are similar hydrothermal systems at the bottom of these oceans of the icy ocean worlds, Europa and Enceladus, maybe you would get another origin of life.

But obviously, Europa and Enceladus, they're not the same as Earth. No. You'd have to take an organic reaction that we think we understand on Earth and say, what if? What if the ocean was alkaline like Enceladus or what if minerals were present like on Europa? And would it be different? And if so, how? If life could happen there, it might look a little different than life here on Earth. But what's cool about Enceladus in particular is we've actually gotten a glimpse of what it's like already. Like NASA's already gotten direct data of its like ocean through a geyser shooting water into space. I love that Enceladus just spews water.

space. It does. And it doesn't seem like at the end of the day there is a lot of resolution, though there is a lot of interesting science. Yeah. And so we end this episode the way we end so many of these episodes. To answer the big questions, we need more data. More research, like needs to be done. That seems to be a theme on Shorewave. Yeah. But like, I don't know. It's kind of like beautiful and like humbling that there's still so many big questions out there. We don't know exactly yet how life emerged on Earth. And so there's, is this question of could it have emerged more than once and only one survived to be the tree of life that we know? Could it happen multiple ways and it just didn't happen on earth? We don't really

know. And so when we go out to look for life elsewhere, we have to consider, first of all, could an earth-like origin of life have happened, but also could other things have happened that may not have happened on the earth? We really don't know. So there you go, Emily, after all this reporting, no answer, but I've learned more. And I still have hope that these like little chimneys may be on the bottom of Europa's ocean. I hope that for you too. And that there's a hydrothermic alien Santa Claus that'll come out of them.

Oh my God. Maybe. I just want a little shrimp. I just want you a little Europa shrimp. Gina, thank you for bringing us this story that you are clearly very passionate about. I am. Thank you. This episode was produced by Hannah Chin.

It was edited by a showrunner Rebecca Ramirez and Tyler Jones Check the Facts. The audio engineer was Robert Rodriguez. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. Special thanks to Max Barnhart for his biology expertise. Thanks, Max. I'm Emily Kwong. I'm Regina Barber. And thanks to you, Shortwavers, for listening to Shortwave from NPR.