Solving A Centuries Old Maritime Mystery

Summary

Solving a Centuries-Old Maritime Mystery

Short Wave
Episode: Solving A Centuries Old Maritime Mystery
Host: Regina Barber
Release Date: June 2, 2025

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Introduction to the Milky Seas Phenomenon

The episode opens with Regina Barber setting the scene in 1849, describing a serene night at sea disrupted by an inexplicable glow emanating from the ocean's surface. This luminescent phenomenon, known as "milky seas," has baffled sailors and scientists alike for over four centuries.

Regina Barber [00:16]: "You're on a ship coasting through the middle of the ocean at night... a glow not from another ship or the night sky, but from the surface of the sea."

Historical Accounts and Early Skepticism

Justin Hudson, an atmospheric science researcher at Colorado State University, delves into the historical documentation of milky seas. He highlights how early accounts, often dismissed as tall tales by intoxicated sailors, gradually gained credibility over time.

Justin Hudson [01:28]: "A lot of them were written off as just, you know, drunk sailors at the bar trying to impress each other with more... better tall tales."

Regina notes that it wasn't until approximately a century ago that these reports began to be taken seriously, thanks in part to more reliable sources like naval and commercial vessels.

Stephen Miller [02:00]: "These are trustworthy accounts. These aren't... pirates and sailors of yore talking... spinning their tall tales."

The Scientific Pursuit: Building the Milky Seas Database

Justin Hudson's PhD research involved compiling a comprehensive database of milky sea sightings and satellite images, aiming to unravel this enduring mystery. Highlighting the scarcity of scientific samples, Regina mentions the lone research vessel that successfully collected a sample in 1985.

Regina Barber [02:30]: "One group definitely not spinning... took the only scientific sample in 1985."

Stephen Miller explains the logistical challenges in studying milky seas, primarily due to their remote locations in the vast oceans.

Stephen Miller [02:40]: "Milky seas tend to be very remote and... very few people out in any one given spot."

Unraveling the Mystery: The Role of Vibrio harveyi

A significant portion of the episode is dedicated to understanding the biological underpinnings of milky seas. The leading hypothesis centers around a specific bacterium, Vibrio harveyi, known for its bioluminescent properties.

Stephen Miller [07:25]: "Certain bacteria will colonize... their population will increase... they'll start to glow."

These bacteria emit chemicals called autoinducers, which trigger them to glow once they reach a critical concentration. This bioluminescence is theorized to attract predators, facilitating the bacteria's return to the gut of marine creatures.

Stephen Miller [07:25]: "They emit... a chemical... which they can also detect as being unique... triggers these bacterial colonies to begin glowing... to attract a higher order predator like a fish."

Comparing Bioluminescent Mechanisms

Regina poses a critical question about how Vibrio harveyi differs from other bioluminescent organisms like fireflies and dinoflagellates.

Regina Barber [09:06]: "What does this bacteria do? How does it glow? And how is that different from the bioluminescence we have seen in fireflies or other marine bioluminescence?"

Justin Hudson clarifies that unlike dinoflagellates, which use bioluminescence as a defense mechanism, Vibrio harveyi uses it as an attractant for predators. This distinction underscores the unique ecological role of the bacteria in creating milky seas.

Justin Hudson [09:21]: "...with this Vibrio harveyi... it's glowing and actually not to scare away predators, but to attract predators intentionally."

Historical Insights and Modern Challenges

Justin reflects on historical perspectives, noting that figures like Benjamin Franklin and Captain Newland had already hypothesized the involvement of microscopic organisms in the 18th century. Despite their early insights, significant progress in understanding milky seas has been slow.

Justin Hudson [10:13]: "It's a little depressing and shows just kind of how hard it is to actually study this."

The Importance of the Database and Future Research

Stephen Miller emphasizes the necessity of the database in correlating milky sea occurrences with environmental parameters like sea surface temperature and wind patterns. The goal is to leverage real-time satellite imagery to predict and study these rare events more effectively.

Stephen Miller [11:31]: "We're looking for relationships between when Milky Seas happened and other parameters that we measure all the time... sea surface temperature changes... wind directions."

The researchers aim to deploy resources swiftly upon detecting potential milky seas, acknowledging the transient nature of these phenomena.

Stephen Miller [12:12]: "Milky sea may not last more than a few days."

Broader Implications and Future Directions

As the episode draws to a close, both Justin and Stephen discuss other unexplored bioluminescent phenomena in the ocean. Justin expresses interest in rare forms of bioluminescence that remain undocumented, while Stephen highlights the broader scientific intrigue of milky seas as a reflection of complex Earth system interactions.

Stephen Miller [13:13]: "Milky Seas... a really remarkable kind of natural wonder... scientifically it's very, very cool and intriguing as well."

Conclusion

Regina Barber wraps up the episode by thanking her guests and summarizing the significance of their research in demystifying a centuries-old maritime mystery. The collaboration between historical accounts, modern databases, and scientific inquiry exemplifies the ongoing quest to understand the ocean's enigmatic phenomena.

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Notable Quotes:

• Regina Barber [00:16]: "You're on a ship coasting through the middle of the ocean at night... a glow not from another ship or the night sky, but from the surface of the sea."

• Justin Hudson [07:25]: "Certain bacteria will colonize... their population will increase... they'll start to glow."

• Stephen Miller [09:06]: "You know, this is a hypothesis. We don't know for sure that this is what's happening, but it's the leading hypothesis."

• Stephen Miller [13:13]: "Milky Seas... a really remarkable kind of natural wonder... scientifically it's very, very cool and intriguing as well."

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This episode was produced by Rachel Carlson, edited by Rebecca Ramirez, and fact-checked by Tyler Jones. Audio engineering was handled by Jimmy Keeley, with special thanks to Mark Patience for the sailor voiceover.

Transcript

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[Regina Barber]

You'Re listening to Shortwave from NPR. It's 1849. You're on a ship coasting through the middle of the ocean at night. It's calm glassy waters and a clear sky full of stars. Then you see off the side of the boat a glow not from another ship or the night sky, but from the surface of the sea. It's coming from the water.

[Justin Hudson]

I cannot permit this opportunity to pass by without describing to you in the best way I am able. A most extraordinary phenomenon.

[Regina Barber]

There's a miles long swath of glimmering milky water.

[Justin Hudson]

The vessel shortly after entered a vast body of water of the most dazzling brightness and of highly phosphorescent nature. In fact, it looked as if we were sailing over a boundless plain of snow or a sea of quicksilver.

[Regina Barber]

This is just one of many written accounts of milky seas that goes back 400 years, according to Justin Hudson, an atmospheric science researcher at Colorado State University. He compiled a database of recent satellite images and all the reports of milky seas he could find from over the years as part of his PhD thesis.

[Justin Hudson]

And a lot of them were written off as just, you know, drunks, drunk sailors at the bar trying to impress each other with more, you know, better tall tales than someone else had.

[Regina Barber]

Justin's research advisor, Stephen Miller, says it wasn't until about 100 years ago that tales of glowing seas began to be taken more seriously.

[Stephen Miller]

I think in the 1900s we started receiving more reports from sources such as navies, commerce vessels. These are trustworthy accounts. These aren't, you know, pirates and sailors of yore talking. They're, you know, spinning their tall tales like Justin was just mentioning.

[Regina Barber]

One group definitely not spinning a tall the lone research vessel that accidentally wandered into a milky sea and took the only scientific sample in 1985.

[Stephen Miller]

And the reason for the lack of sampling is simply because milky seas tend to be very remote and about 70% of the world is covered in ocean and there's just very few people out in any one given spot.

[Regina Barber]

So today on the show, Maritime Lore deconstructed how a database of sailor stories and satellite images could help scientists better understand an enduring mystery of the sea. I'm Regina Barber. You're listening to Shortwave, the science podcast from npr.

[Justin Hudson]

Foreign.

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[Regina Barber]

Justin A lot of the stories like the one we heard at the top of the episode here are from this database that you compiled as part of your PhD. But this is not the first time MLKC database has been made. Many have been made over the last couple centuries. Right.

[Justin Hudson]

So about every 40 years someone seems to learn about Milky Seas, gets fascinated by the idea, and then builds the best database they could of all the sightings they were able to gather on Milky Seas. And what has happened to all of those previous databases is that they've all been lost in some way.

[Stephen Miller]

Wow.

[Regina Barber]

At sea.

[Justin Hudson]

Not at sea, I hope. The last person to make a database before us his name was Dr. Peter Herring, and as far as he knows, his database, if it still exists, is just in some unknown archive room in the UK Navy storage somewhere.

[Regina Barber]

We say that there's the first scientific sample in 1985, but people did take samples in these historic references. So somebody might have drank it.

[Justin Hudson]

Yeah, there are a few accounts in the database where the best scientific tool someone had to study this was just taking a swig of this strange glowing water out of the ocean and seeing what they could figure out from there. And there's this one account from the early 1800s where the ship surgeon had heard about this before from sailors in the Middle east and they had claimed that the water tasted fresh. And so when he encountered one, he immediately took up a bucket and tasted it himself. And he actually complains the account that it just tastes like normal seawater.

[Stephen Miller]

Yeah, I think that just adding to this a little bit of irony is that the leading idea for what causes milky seas is bacteria, a form of bacteria that will glow upon reaching a critical population. But anyway, the vibrio bacteria that are thought to be causing milky seas are also of the sort that would cause things like cholera and other, you know, pretty nasty things that can happen inside of our bodies. So to the idea of drinking the water may not always be the best advice thing to do.

[Regina Barber]

So, like this bacteria. Vibro harvei. Right. And it's. And like you said, like, we think it causes these other things. It's been pretty well studied. Steven, can you tell me more about this bacteria and why we think it's the cause of the milky seas?

[Stephen Miller]

Sure. So there are a number of different strains of luminous bacteria in nature, free living in the water. But at one point in their history, they got pooped out from some creature like a fish. And they like to live in the guts of creatures in some happily ever after scenario for them. But when they're free living in the water, they're also serving the function of breaking down organic material. That's one of the things bacteria do. And when certain bacteria will colonize, say, a speck of organic material like a piece of algae, their population will increase. And at the same time, they are emitting into the water around them a chemical which they can also detect as being unique. It's kind of like a key into a lock. This chemical is known as an autoinducer and will actually trigger these bacterial colonies to begin glowing at populations of about 100,000 per cubic centimeter of water. If they get to that critical population, they'll start to glow. And why would they do that? Well, it gets back to the idea that coming from whence you came. So they make that piece of food glow like a lure in the water, such that it would attract a higher order predator like a fish to come and consume that particle. And guess what? Now they're eaten. But they're exactly where they want to be, back into a gut of a creature.

[Regina Barber]

Oh, interesting.

[Stephen Miller]

You know, this is a hypothesis. I want to clarify that. We don't know for sure that this is what's happening, but it's the leading hypothesis.

[Regina Barber]

Justin, what's so special about this, this bacteria? Like, what does this bacteria, how does it glow? And how is that different from the bioluminescence? We, like, have seen in, like, fireflies or other marine bioluminescence.

[Justin Hudson]

Yeah. So the main way it differs is kind of what Steve touched on, is that it's the. The function behind why they're bioluminescing. So a firefly, its bioluminescence is sort of like communication of other fireflies. And the more typical bilingual essence you see out in the ocean is caused by this organism called a dinoflagellate. And it glows in response to some kind of shock. Something nudges it, or it gets inside a crashing wave. It's on the shore and it glows, as is called a burglar alarm response, as sort of a way to tell whatever is trying to eat it that, like, you've been spotted so you're in danger and you should get away from me. Whereas with this vibrio, Harvey, that we behind it, it's glowing and actually not to scare away predators, but to attract predators intentionally.

[Regina Barber]

So, Justin, like scientists at this point, we're like, we know it's this luminous bacteria. And you mentioned there's a story from, like, the 1700s of Captain Nuland, and he said he. He thought it had to do with some, like, microscopic organism. Like, how does that make you feel? Like we're only just, like, a little bit further than what he thought. Right. Like, how much further are we?

[Justin Hudson]

Yeah, I have a couple different emotions about that, actually. Ben Franklin actually has a letter he wrote to a friend of his in the 1750s where he was complaining how he had carried all these experiments to prove that it was actually electricity and lightning in the ocean causing bioluminescence. But actually, he has come to the conclusion that's just some unknown living being we can't see. You know, Captain Newland, 20 years later, sort of in that same, I guess, scientific discourse, comes the same conclusion about milky seas. And I'm just kind of impressed that they were able to sort of really narrow it down that well back then. And then the fact that we still haven't been able to come that much further since then is kind of. It's a little depressing and shows just kind of how hard it is to actually study this.

[Regina Barber]

Is that the whole point of this database, Stephen, so that we can finally know a little bit more. Can you tell me, like, why this database is so needed?

[Stephen Miller]

We need to find a way to position ourselves, to sample very thoroughly, spatially and temporally what a milky sea is made out of and how it's different from the surrounding waters. So what we're doing is forming a Database then looking for relationships between when Milky Seas happened and other parameters that we measure all the time, like the nuances of sea surface temperature changes and which directions the winds are blowing and the circulations that happen seasonally and subseasonally.

[Regina Barber]

And the plan is to pair the database with like other tools, like satellite images. Right. To get a real time look at things.

[Stephen Miller]

Yeah, that's, that's the goal. We're watching our satellite imagery to see if something forms. And in the in between part, we've maybe deployed some res to that area where we're thinking one might form. Finally, the satellite hopefully sees something and we're able to strike at it. Realizing that a milky sea may not last more than a few days.

[Regina Barber]

Yeah, this is both of your attempt to kind of help with one myth and one mystery. Helping with that. Are there any other things that are in the ocean that like you're interested in learning more about?

[Justin Hudson]

Yeah, I guess something that has kind of. It's come up in our research on milky seeds. There's others, like rare forms of bilingual essence that happen out in the middle of the ocean that are both equally as not understood and as well as just there really isn't any documentation on them. And trying to understand. Diving into more of those.

[Regina Barber]

Wow. What about you, Stephen?

[Stephen Miller]

We think of Milky Seas as perhaps being this culmination of this communication that's going across these different regimes of our Earth system and leading to this really remarkable kind of seventh natural wonder of the world type display, which visually is really cool to see, but scientifically it's very, very cool and intriguing as well because we A, don't understand exactly what conspires to form these things. B, we didn't think it was possible for this many bacteria to blow up overnight in any one place. So just realizing the connection between the various parts of the Earth system, it's just really intriguing and just shows us that there's a lot more to learn about our own planet.

[Regina Barber]

Steven, Justin, thank you so much.

[Stephen Miller]

You're welcome. Thank you for having us.

[Justin Hudson]

Yeah, thank you for having us on.

[Regina Barber]

Thank you so much for listening. Make sure you never miss a new episode by following us on whatever podcasting platform you're listening to to. This episode was produced by Rachel Carlson, it was edited by Rebecca Ramirez and fact checked by Tyler Jones. Jimmy Keeley was the audio engineer. Special thanks to Mark Patience for the amazing sailor voiceover in the top. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to short wave from NPR.

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