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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. I cannot permit this opportunity to pass by without describing to you, in the best way I am able, a most extraordinary phenomenon.
There's a miles-long swath of glimmering, milky water. 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. 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. And a lot of them... We're ridden off as just, you know, drunk sailors at the bar trying to impress each other with more, you know, better tall tales than someone else had.
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. I think in the 1900s, we started receiving... more reports from sources such as navies, commerce vessels. These are trustworthy accounts. These aren't pirates and sailors of yore.
talking their, you know, spinning their tall tales like Justin was just mentioning. One group definitely not spinning a tall tale, the lone research vessel that accidentally wandered into a milky sea and took the only scientific sample in 1985. 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.
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. Really? Come on, let's go. Hear that? That's the sound of my customers leaving. When your broadband doesn't work, neither does your business. Will Sky Business keep me up and running?
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We do long-form interviews with people behind the best in film, books, TV, music, and journalism. Here our guests open up about their process and their lives in ways you've never heard before. Listen to the Fresh Air podcast from NPR and WHYY. 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 a Milky Sea database has been made. Many have been made over the last couple centuries, right? 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.
At sea? 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. 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? 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 complained the account that it just tastes like normal seawater 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. Right. A form of bacteria that will glow upon reaching a critical... 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 pretty nasty things that can happen inside of our bodies. So the idea of drinking the water may not always be the best advice thing to do. So, like, this bacteria, Vibrio harvei, right? And like you said, like, we think it causes these other things. It's been pretty well studied. Stephen, can you tell me more about this bacteria and why we think it's—
the cause of the Milky Seas? Sure. So there are a number of different strains of luminous bacteria in nature, free living in the water. But at one point in there... 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 auto-inducer 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. Oh, interesting.
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. Justin, what's so special about this bacteria? 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? 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 bioluminescence you see out in the ocean... It's 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 that's on the shore. And it glows as it's 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 think is behind it, it's glowing actually not to scare away predators, but to attract predators intentionally. So Justin, like scientists at this point... We're like, we know it's this like luminous bacteria. And you mentioned that there's a story from like the 1700s of Captain Newland. And he said he thought it had to do with some like microscopic organism.
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? Yeah, I have a couple of 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. Captain Newland, 20 years later, sort of in that same, I guess, scientific discourse comes to 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 a little depressing and shows just kind of how hard it is.
to actually study this. Is that the whole point of this database, Stephen? So that we... can finally know a little bit more. Can you tell me why this database is so needed? 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 C's happened and other parameters that we measure all the time. the nuances of sea surface temperature changes, and which directions the winds are blowing, and the circulations that happen seasonally and subseasonally.
And the plan is to pair the database with other tools, like satellite images, right, to get a real-time look at things. Yeah, 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 resources 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. 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 yeah i guess something that has kind of it's come up in our research on milky seas there's others like
rare forms of bioluminescence 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... driving into more of those. Wow. What about you, Stephen? We think of Milky Seas as perhaps being this culmination of this communication that's going across these different regimes of our Earth system.
leading to this really remarkable kind of seventh natural wonder of the world type display, which visually is really cool to see. 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. Stephen, Justin, thank you so much. You're welcome. Thank you for having us. Yeah, thank you for having us on. 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.
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 Martin 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 Shortwave from NPR.
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