Are Brine Pools deadly to Humans and Sea Creatures?

Summary

Podcast Summary: Who Smarted?

Episode: Are Brine Pools Deadly to Humans and Sea Creatures?
Original Air Date: October 29, 2025
Podcast by: Atomic Entertainment / Starglow Media
Summary prepared by: [Your Name or Podcast Summarizer]

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Episode Theme & Purpose

In this episode, the hosts dive deep—literally—into the bizarre and mysterious world of brine pools: underwater lakes so salty and dense they form at the bottom of the ocean. With trademark humor, banter, and an interactive trivia style, the episode explores what brine pools are, how they’re formed, why they’re so deadly for most sea life (and humans!), and what rare creatures manage to survive near them. The goal is to turn what sounds spooky (and a little gross) into a fascinating science lesson for kids, families, and classrooms.

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Key Discussion Points & Insights

What Are Brine Pools?

• Description and Location: Brine pools are dense, salty “underwater lakes” on the ocean floor, visually distinct from the rest of the seawater due to their density.
  • Quote:

    "Brine pools are sometimes called underwater lakes or seafloor lakes because they are a distinct body of water with way more salt in them than the rest of the ocean. And because they have more salt, they're much more dense."
    — Boogaloo the Shrimp, 04:48

• They often have actual shorelines, just like lakes on land.

How Are Brine Pools Formed?

There are three main ways brine pools can form (05:34):

1. Freezing (Brine Rejection): When ocean water freezes in polar regions, salt separates and sinks, forming a dense brine layer at the sea floor.
   • Quote:

     "When ocean water freezes, the salt separates from the frozen water and gets pushed further and further down, creating a salty, dense brine that moves below the sea ice to the sea floor."
     — Boogaloo, 05:38

2. Geothermal Heating: Where tectonic plates shift and magma is exposed, seawater mixes with minerals and gets superheated, forming brine pools as it cools.
   • (06:54)
3. Salt Tectonics: Ancient seas (like the Jurassic-era Gulf of Mexico) dried, leaving thick salt layers which, when resubmerged and under pressure, dissolve and gather in deep pools.
   • Notable Fact:

     "The deepest brine pool in the world is the Orca Basin in the Gulf of Mexico." (07:43)

Why Are Brine Pools So Deadly?

• Insanely Salty & Anoxic: Brine pools lack oxygen (anoxic) and have way more salt than regular seawater, making them lethally inhospitable to most marine life.

  • Quote:

    "Because of this salinity and lack of oxygen, most sea creatures that accidentally swim into a brine pool die pretty much instantly from the shore shock." — Boogaloo, 09:06

• Pickling Effect: Creatures that die in brine pools are “pickled” by the salt, staying preserved for decades!

  • Quote:

    "They get pickled. No, not tickled. Pickled. Even though they die, all that thick, salty water keeps them perfectly preserved." — Boogaloo, 09:42

Who (or What) Survives Brine Pools?

• At The Edges: The “shorelines” are the only places with enough nutrients to support life. Here, brave creatures including:
  • Shrimp (like Boogaloo!)
  • Mussels
  • Tube worms
  • Bacteria
• Inside The Pool: The only animal that can actually survive in the pool itself is the Gulf hagfish.
  • Quote:

    "The Gulf hagfish is one of the only creatures that can actually swim into the brine pool and survive." — Trusty, 11:22

  • The hagfish feeds on other pickled creatures.

How Do Some Creatures Survive?

• Chemosynthesis vs. Photosynthesis:
  • No sunlight at these depths, so creatures use chemicals (like methane, hydrogen sulfide) for energy.
  • Quote:

    "Chemosynthesis happens in places where there is no sunlight, like in a brine pool." — Boogaloo, 14:06
    "Chemicals like methane and hydrogen sulfide are released through the underwater hydrothermal vents in the brine pool. Then bacteria turns these chemicals into organic molecules. Our sea creatures can feed on those bacteria, grow and reproduce, and then get eaten by shrimp like me, the mussels and worms." — Boogaloo, 14:18

What Happens If Humans Enter a Brine Pool?

• Humans would not survive. The same “pickling” (preservation by salt) would likely occur.
  • Quote:

    "I'm sorry to say, but you would probably get pickled, too, Trusty." — Boogaloo, 15:06

Brine Pool Fun Facts

• Size Variation: Brine pools can be as small as three feet across or as large as twelve miles.
  • Quote:

    "In the Gulf of Mexico, where there's quite a few brine pools, they can be anywhere from just 3ft or 0.91 meters across to 12 miles or 19.3 kilometers long." — Boogaloo, 16:07

• Gulf Hagfish: Listeners are encouraged to look up what a Gulf hagfish looks like (spoiler: it’s super creepy!).

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Notable Quotes & Memorable Moments

• On the spooky basement analogy:

  "Is it in the basement?" — Boogaloo, 00:21
  "No, it's not the basement. Oh, no. I'm talking about something far more sinister and scary. I'm talking about brine pools." — Trusty, 00:37

• Humorous Reluctance:

  "I'd much rather be a trusty narrator than a pickled narrator." — Trusty, 15:11

• On animal feast:

  "Our friend the hagfish just comes along and eats them right up. Nom, nom, nom, nom, nom." — Boogaloo, 12:15

• Listener Engagement:
  Throughout, listeners are quizzed and encouraged to shout out their answers, keeping the episode interactive.

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Timestamps for Important Segments

• 00:49 – Introduction to brine pools (what and where)
• 05:34 – The three ways brine pools are formed
• 06:19 – Explanation of “anoxic” and its impact on sea life
• 09:30 – Why most marine life dies instantly in brine pools
• 10:44 – The rare creatures that survive at the brine pool’s edge
• 11:22 – The Gulf hagfish, the only animal in the pool itself
• 13:26 – How chemosynthesis sustains brine pool life
• 15:06 – Why humans wouldn’t survive a brine pool
• 16:07 – Brine pools: measuring their surprising size differences

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Conclusion

This episode expertly turns a strange, scary-sounding underwater phenomenon into a captivating science story full of fun facts, biology, chemistry, and silly banter. Kids (and grownups) learn that even the weirdest, most inhospitable places on Earth are full of science—and a little humor goes a long way in exploring them.

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For More:
Google “Gulf hagfish” for a look at these bizarre brine pool survivors, or listen to other Who Smarted? episodes on ocean and animal biology!

Transcript

[A]

And now it's time for who's Smarted?

[B]

Psst.

[A]

Hey, smarty pants. On today's episode of who's Smarted? I'm taking you to explore a deep, dark, mysterious place. A strange and secluded world filled with weird creatures of all shapes and sizes. A place so bizarre, you'll wonder how it could even exist.

[B]

Is it in the basement?

[A]

Uh, no, I'm not talking about the basement.

[B]

You sure? Because your basement is pretty deep, dark and mysterious. And I'm pretty sure I saw some pretty weird creatures of various shapes and sizes.

[A]

No, it's not the basement. Oh, no. I'm talking about something far more sinister and scary. I'm talking about brine pools.

[B]

Oh, brine pools. They're not so scary.

[A]

They're not? It seems like they are, aren't they? Deep, thick, murky underwater lakes. Lakes at the bottom of the ocean, in fact. It doesn't get more strange and secluded than that.

[B]

Sure, that's exactly what and where they are. But the more you know about them, the less scary and more fascinating they'll become.

[A]

Drats. I was really getting into that ominous music. Oh, well, I suppose you would know. You do appear to be a crustacean of some kind.

[B]

How dare you.

[A]

Uh, what did I say? I'm sorry. I just.

[B]

Ha, ha. Just messing with you, pal. I am a crustacean.

[A]

Oh.

[B]

A shrimp, to be exact. The name's Bougal. Boogaloo the Shrimp. Nice to meet you.

[A]

Hi. Boogaloo the shrimp. I'm Trusty the narrator. Welcome to who's Smarted, where we make learning funny. Except when we're talking about brine pools. That's when we make learning mildly scary.

[B]

Oh, wow. You just can't help yourself, now, can you?

[A]

Where's the lie? Brine pools are the furthest, murkiest, saltiest depths of the sea. Am I right?

[B]

Well, I guess if you put it that way. They do sound kind of. Of spooky.

[A]

Plus, I've heard brine pools can be kind of dangerous.

[B]

They can be, but so can getting a haircut. No, but, hey, brine pools also support life for a select group of sea creatures. So not all bad.

[A]

Well, like I said, we're here to explore and learn all about them. For instance, how are brine pools formed? How do the creatures living inside of them survive? And what would happen to a human if they found themselves inside a brine pool?

[B]

Good questions, trusty. Fortunately, I've got answers. Great.

[A]

Then it's time for a nice big whiff of science, history and ominous music.

[C]

On who smarted. Who's smarted? Who's smart? Is it you? Is it me? Is it science or history? Listen up, everyone. We make smarting lots of fun. But who's smart? And.

[A]

Hey there, smarty pants. Want even more WhoSmarted and less ads. Introducing WhoSmarted plus more WhoSmarted.

[B]

Yay.

[A]

That's right. With WhoSmarted plus, you unlock an extra new episode every week. Zero ads plus our special segment, SmartYQs, where we tackle your curious questions, like, why is the sky blue? Exactly. And guess what? There are even more surprise bonuses from me, your trusty narrator. Wow. Wow. How much? Less than $4 a month with an annual subscription. And hey, try it out with an adult's permission. With a one week free trial from Apple Podcasts or from WhoSmarted.com I'm in. Let's get smarter. WhoSmarted plus more to learn, more to love. Subscribe now.

[B]

Wow.

[A]

Boogaloo. Being under the sea is pretty co. And would be a lot less scary if they'd stopped playing that scary music. Sting.

[B]

Sorry, how's this?

[A]

Uh, no. How about no music for a minute?

[B]

Suit yourself.

[A]

Anyway, right now I'm in a deep sea submersible headed down, down, down to learn how brine pools are formed. But before we learn about that, let's first talk a bit more. What do you say? Oogaloo the shrimp?

[B]

Well, as you mentioned earlier, brine pools are sometimes called underwater lakes or seafloor lakes because they are a distinct body of water with way more salt in them than the rest of the ocean. And because they have more salt, they're much more dense. And it's that density that creates a visible separation from the rest of the ocean. Did you know sometimes brine pools even have their own shorelines?

[A]

I did not know that. Did you, smartypants? Anyway, we'll get back to that a little later. First, I'm super curious how brine pools come to be in the first place. What do you think, smarty pants? Do you think they're formed by freezing, by heat, or by shifting tectonic plates? The answer is all three.

[B]

Whoa.

[A]

Really? Like all three at the same time?

[B]

Good question, but no. There are three distinct ways brine pools are formed. Number one, by freezing. This is what's known as brine rejection in polar regions. When ocean water freezes, the salt separates from the frozen water and gets pushed further and further down, creating a salty, dense brine that moves below the sea ice to the sea floor.

[A]

And this forms a brine pool.

[B]

You got it. Trusty. In a matter of weeks, the brine, which is already too salty for most sea life, also becomes anoxic.

[A]

Ooh, nice work, smarty pants. Do you know what anoxic means? Is it A, water that glows, B, water that lacks oxygen, or C, water that's very bitter? If you guessed B, you're right. And as you may have learned in our ocean episode, much of the ocean's sea life depends on the oxygen it extracts from the seawater to survive.

[B]

Correct.

[A]

See, that is kinda spooky. Cue the ominous music. What about the other two ways brine pools are formed?

[B]

Well, besides brine rejection, there's also geothermal heating that happens in areas where tectonic plates move, exposing new magma, which creates a new seafloor. Seawater flows into newly created fractures and mixes with other minerals. The resulting brine is then superheated, thanks to that magma I mentioned. Then it rises and cools, eventually setting inside of holes like brine pools.

[A]

Oh, boy. We've got brine pools created by freezing and brine pools created by cooking. But then there's also a third way.

[B]

Yep, this one is called salt tectonics, and it's responsible for the deepest brine pool in the world.

[A]

Ooh. Any guesses where that is, smarties? Let me give you a hint. It's in a big body of water in North America, right between two countries. If you said the Great Lakes, that's a great guess. But nope, it's actually in the Gulf of Mexico, and it's called the Orca Basin.

[B]

During the Jurassic period, which was over 100 million years ago, the Gulf of Mexico was just a shallow sea that dried out, but then a thick layer of salt and minerals were formed. And I'm talking thick, black, like, five miles thick.

[A]

Five miles? That's like 10 times the height of the world's tallest building. That's so salty.

[B]

You bet. And when that area eventually refilled with water, the salt deposits were pushed further down, eventually creating, you guessed it, brine pools.

[A]

Who knew brine pools could be formed in so many different ways? Not me. So what actually happens inside of brine pools? Inside those deep, dark, murky, salty depths where no man, woman, or smarty pants dares to go?

[B]

You are so committed to the spooky vibe, aren't you?

[A]

Well, we already paid for the music.

[B]

So to be honest, there isn't that much going on inside of a brine pool. It's mostly dark and dense and super salty. And because of this salinity and lack of oxygen, most sea Creatures that accidentally swim into a brine pool die pretty much instantly from the shore shock.

[A]

Wait, what?

[B]

I'm afraid so. They just can't handle the lack of oxygen and high levels of salt. But as a result of those conditions, something really cool happens to them.

[A]

What's that?

[B]

They get pickled. No, not tickled. Pickled.

[A]

Pickled.

[B]

Pickled. Even though they die, all that thick, salty water keeps them perfectly preserved.

[A]

Well, I guess it is called brine for a reason. Before refrigeration, people would brine or salt pack their food to keep it fresher for longer.

[B]

And get this, pickled sea creatures can stay perfectly preserved for decades.

[A]

Wow. Although personally, I don't think I'd eat a 20 year old cod.

[B]

Even though the insides of brine pools are pretty bleak. It's the edges of brine pools, the shorelines if you will, where the action happens. Lights, camera, action. You see, brine pools are just full of minerals. And when those minerals seep out of the brine, they form crusts along the edge of the brine pool. Those edges are where there's most nutrients, so that's where it's easiest to sustain life.

[A]

And what kind of life are we talking about specifically?

[B]

Well, not much. Very few things can survive on the border between the ocean and a salty pool of death. But I can.

[A]

Whoa, you go on with your bad self. Boogaloo, the shrimp.

[B]

Aw, thanks trusty. Yep, pretty much the only creatures that can survive down here are shrimp, mussels, tube worms and bacteria. Ew. Oh, and one really creepy long eel like fish called the Gulf hagfish.

[A]

Smarty pants. True or false? The Gulf hagfish is one of the only creatures that can actually swim into the brine pool and survive. The answer is true.

[B]

Unbelievably, the lack of oxygen and intense saltiness doesn't affect the hagfish like it does so many other creatures. And you want to hear something really creepy?

[A]

Oh, I do. And so do the smarty pants. And we will, right after this quick break and a word from our sponsors. Now back to who smarted. Okay, Boogaloo the shrimp. You were just about to tell us something really spooky. Or was it creepy about this strange looking Gulf hagfish, one of the only creatures that can survive inside a brine pool?

[B]

Well, remember how I mentioned that all the other poor creatures that don't survive the brine pools wind up getting pickled? Yeah. Well, our friend the hagfish just comes along and eats them right up. Nom, nom, nom, nom, nom wow.

[A]

But hey, what do you expect? The ocean is a dog eat dog. I mean, fish eat fish world. But hang on. If it's so hard for most creatures to survive in and around brine pools, how is it that shrimp and mussels and tube worms can do it? What makes you so special?

[B]

Well, why don't you steer the submersible a little further down to get us right to the edge of the brine pool?

[A]

Okay. It takes a steady hand. There. Right at the edge of the pool of death.

[B]

Oh, hey, I can see my cousin. Hey, Pinky.

[A]

All right, so how is it that you and a select few creatures can survive down here and not much else can? Smartypants, do you have any ideas? Go ahead and shout them out. Yeah, I have no idea myself.

[B]

Oh, trusty. It's all thanks to a little something called chemosynthesis. Ever heard of it?

[A]

Um, no.

[B]

But I bet you have heard of photosynthesis.

[A]

Yeah, I have. Hey, smarty pants, do you know what photosynthesis is? We actually covered it on a who Smarted episode on plants. Go ahead, call it out if you know it.

[B]

Uh huh. Uh huh huh.

[A]

I hear a lot of smarty pants know what it is. And in case you're not sure or don't know, photosynthesis is a process where light, like from the sun, is converted into energy and used by organisms like plants. So what's chemosynthesis?

[B]

Chemosynthesis happens in places where there is no sunlight, like in a brine pool.

[A]

So instead of energy coming from light, the energy comes from chemicals?

[B]

Exactly. Chemicals like methane and hydrogen sulfide are released through the underwater hydrothermal vents in the brine pool. Then bacteria turns these chemicals into organic molecules. Our sea creatures can feed on those bacteria, grow and reproduce, and then get eaten by shrimp like me, the mussels and worms.

[A]

Is that why I can see big mussel beds around the edge of the brine pool?

[B]

No doubt. The border of a brine pool is like a watering hole for mussels full of lots of organic matter for them to eat.

[A]

Ask this, but have humans ever been inside a brine pool? What would happen if I tried to take a closer look?

[B]

I'm sorry to say, but you would probably get pickled. Too trusty.

[A]

Yikes. I'd much rather be a trusty narrator than a pickled narrator.

[B]

In any case, you or any human definitely wouldn't survive. But thanks to our submersible, we can maneuver a little bit closer. Wanna go it?

[A]

Sure, why not? It's safe, right?

[B]

Oops. Sorry, that was an accident. It's safe as long as you stay in the sub.

[A]

Wow, it sure is dense and murky down here. Ah, I just saw a Gulf hagfish swim by.

[B]

Oh, hey, that's Hagar. Hi, Hagar.

[A]

I'm telling you, smarty pants, you gotta see what these fish look like. After the show, have an adult help you Google search Gulf hagfish. As for the brine pool itself, I gotta say, it doesn't seem very big. Are they all this small?

[B]

Brine pools vary in size, like by a lot. For example, in the Gulf of Mexico, where there's quite a few brine pools, they can be anywhere from just 3ft or 0.91 meters across to 12 miles or 19.3 kilometers long. Whoa.

[A]

That's almost the entire length of Manhattan in New York.

[B]

Oh yeah.

[A]

Speaking of New York, I think it's time I head back up to the surface.

[B]

Yeah, I should get back to my brine pool. Cousin Pinky is having a bacteria barbecue.

[A]

Sounds great. Have fun. Boogaloo the shrimp. Alright, smarty pants, let's get out of here. This place gives me the creeps.

[B]

Whoops, wrong song.

[A]

A big shout out to my smarty friends Sophie and Jax in Bloomfield, New York. We're so glad you love smarting along with Whosmarted on the way to and from homeschool classes and that you especially love episodes about animals. Well, you're in luck, because nobody loves animals more than we do here at who Smarted. So listen out for lots more episodes featuring animal friends. This episode, Rhine Pools, was written by Phil Jeremy and voiced by Taya Garland, Adam Tex Davis and Jerry Colbert. Technical direction and sound design by Josh Hahn. Our associate producer is Max Kamasky. The theme song is by Brian Suarez with lyrics written and performed by Adam Tex Davis. Who Smarted was created and produced by Adam Tex Davis and Jerry Colbert. This has been an Atomic Entertainment production too.

[C]

Smart and.