Stuff You Should Know - Sand Dunes: They Are What You Think They Are

Episode Date: July 18, 2019

Sand dunes are exactly what you think they are. But still pretty interesting. Learn all about them right now! Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

On the podcast, Hey Dude, the 90s called, David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're gonna use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s.

We lived it, and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Lance Bass, host of the new iHeart podcast, Frosted Tips with Lance Bass. Do you ever think to yourself, what advice would Lance Bass

and my favorite boy bands give me in this situation? If you do, you've come to the right place because I'm here to help. And a different hot, sexy teen crush boy bander each week to guide you through life. Tell everybody, ya everybody, about my new podcast and make sure to listen so we'll never, ever have to say. Bye, bye, bye.

Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts, or wherever you listen to podcasts. Attention, Chicago and Toronto. We're coming to see you guys soon. So we better hurry up and buy your tickets because they're going fast. Yeah, man, Chicago at the Harris Theater, July 24th.

We've actually sold a lot of tickets now. Yeah, you guys listen, thank you. Thanks for stepping up in Toronto at the Danforth Music Hall the next night, July 25th. It may be sold out by now. Yeah, well, there's only one way to find out. Go on to sysklive.com and you'll find links to the ticket sites and all the show info you need,

and we will see you soon. Welcome to Stuff You Should Know, a production of iHeart radios, How Stuff Works. Hey, and welcome to the podcast. I'm Josh Clark, and there's Charles W. Chuck Bryant, and there's Jerry over there, and this is Earth Science Time, baby. I love this stuff.

Yeah, this one was a little, well, it's about to say dry. I just caught myself at the last second. Thank you. It was a little dry though. It was, but I mean, we're talking sand dudes. There's just so much you can do with some things, you know what I mean?

Yeah, but it's also one of those that's kind of neat in that when next time I go to the beach or the desert, I will, I'm armed with a little more knowledge, which is always nice. You gonna go do some sand boarding? I don't think so, although I did look at some videos. Sounds pretty awesome to me. It looks like a great way

for a 48 year old to break his knee. Did you, oh man, breaking your knee, can you imagine? No. Did you listen to the sound of dune singing? Yeah, and I've heard that sound. Like in person? Uh-huh. What kind of life have you lived?

I mean, a life where I've been around some sand dunes. Wow, that's neat. I think I heard the dune singing on a TV commercial shoot out in the desert, that's where I heard it. Wow. What were they singing, do you remember? They were singing, Fresh Friends. No, no, no.

These were not European dunes. So you've been around dunes that were not beach dunes because my only experience has been just beach dunes. Standard, stay off the dunes, beach dunes. Yeah, these are desert dunes. That's pretty neat. Yeah, it looked like, in fact, I believe they had even done some Star Wars reshoots in this area of California.

Wow. It wasn't Tunisia, but it stood in for Tunisia. So I was told. Just like those hills stood in for Korea in MASH. That's right, but this is a Michael Bay Chevy commercial. Okay. And I got to stand around and watch him scream at everybody. That's neat, man.

What a good guy. Like I said, I've only been around dunes on the beach. Coastal dunes. Right, coastal dunes. But I was talking to Yumi, and I guess these would constitute coastal dunes, but she said she taught in Japan, you know, years and years ago in a prefecture called Tatori,

which is the least populated prefecture in Japan. And they actually had some amazingly beautiful dunes, which look like desert dunes, but it's coastal. So I guess they're coastal dunes, but they don't look like coastal dunes. They look like desert dunes. That ain't South Carolina. No, it's definitely not.

And I was like dunes in Japan that doesn't make any sense, but I saw them with my own eyes. And unless she Photoshopped these pictures, they were real, which would have really been something because they weren't even her pictures. They were posted on the internet. Yeah, that'd be a weird thing to do. I suppose she could have Photoshopped the pictures,

started a website with an unrelated name, uploaded them, and then made it look like she was searching just Google images, which she was just to fool me. And then she's like, I got you on a dune fake, burn. Classic dune fake. Dune fake. But she also, by the way, when she taught in Japan, she taught with our buddy, Raimi,

who we're gonna see in Toronto soon. That's great. Which by the way, if you haven't gotten your tickets to Chicago, it's probably too late for Toronto by the time this comes out. How about this? If you're listening to this and you haven't bought your ticket for Portland, Maine,

shame on you. Okay, so sand dunes. I love this article, by the way, by Debbie Ronca. Yeah, my old pal. Yep. And she basically says, a sand dune needs three things to form. You need loose sand,

because that's the kind that can blow around. You need wind to blow a sand dune around. And then you need an obstacle, which can be anything. It can be a bed of pebbles, it can be a big rock, it can be a tree, but something for the sand to hit and say, I can't go any further. And then as more and more sand hits that obstacle,

the sand dune starts to build, and then the sand dune itself becomes the obstacle. It's one of the most zen processes around on Earth. It really, really is. It's a true layering effect that if you see sped up with a time-lapse camera, it's pretty remarkable. Well, that actually reveals maybe the fact

of the podcast to me. Let's hear it. Sand dunes move. Oh, I thought you were gonna say time-lapse photography is possible. Right, but if you watch the sand dune over a long enough exposure, you would see it moving forward.

And here's the thing, it doesn't just move in that like, the sand gets blown around and the sand dune takes all these different shapes. It keeps its shape and just moves forward depending on the type of dune and the type of what's called wind regime in the area. That's right.

So I just think it is amazing. They're clearly alive and can feel pain. So you really shouldn't walk on the sand dune. And the shape is so dictated by the fact that maybe the wind always blows in one direction where you are. Maybe it blows in two directions only. Maybe it blows from many directions.

And that's all gonna dictate this malleable, living. Breathing. Breathing, feeling, emotional beast. Right. That will kill you if you don't treat it right. It has, it's killed a couple of people, at least. So let's talk about how wind can move sand around. It's generally a few different ways.

There's saltation, which is mostly like 95% of sand grains move like this. And that's just, the wind is just bouncing them along. Yeah, I thought these percentages were pretty specific. 95%, 4%, 1% like who came up with those percentages? God. Okay. All right, well then they probably are accurate.

There's creep. Yes, creep I'd never witnessed or heard of before, have you? I don't think so. That's the 4% of sand moves this way. And this is when grains are colliding with other grains, like maybe gravel or something causing them to move. It's like sand croquet. Yeah, not salmon croquettes.

No. That's different. Those aren't the best croquettes, if you ask me. Frankly, I'm just gonna come out and say it. The only way to eat salmon is raw. I'm sorry. Oh, I love a grilled salmon with that crispy skin. I like grilled fish.

It's just when salmon is cooked, it undergoes a taste conversion that I'm not a fan of. I prefer raw. No, I love raw salmon for sure, but I love that crispy skin so much. Hey, I'm not yucking your young man. If you like cooked salmon, have at it. And I do like fish skin, just crispy fish skin, I'm with you.

But I'm more like a cooked trout fish skin kind of guy. Yeah, when I was a kid, a very big 70s meal in my household was the canned salmon croquettes. Oh yeah, I've had this. Yeah. It's just the bones, you know? I don't like there to be bones in my food. I'm with you.

I'll eat something off the bone. I just don't wanna be expected to actually eat the bone. I guess, I don't know. Yeah, they'll keep on at a good butcher. Or a good fishery. Okay, but aren't there still like really, really tiny little bones? It depends on the salmon.

Okay. But sure, I'm with you. I don't like bones either. So obviously we're talking about sand dunes still. Yeah, but the suspension is the third way. We gotta finish that up. Right, right. That's where the wind blows very strongly,

so strongly and from enough different directions at once that it actually lifts the sand into the air. And this is what a dust storm is, or a sand storm, or any number of, basically if there's sand blowing around in the air, this is the suspension movement of sand. Yeah, that's up though in the air. Like when you go to the beach, sometimes you'll see sand in the right conditions

blowing along the ground a couple inches off the ground. That's not the same thing. Man, no, that's saltation. That hurts. That's really painful. Yeah, I guess it can hurt, can it? Oh, it can. It'll sting you.

It'll sting me. Yeah, hurts. So we've kind of already described like how a sand dune forms. Sort of. Sort of, but there's a lot of different kinds of sand dunes. We're gonna get into it, don't worry. But there's a general way that a sand dune forms

where the sand blows along, hits something that stops its forward momentum, and then it starts to pile up. And when this piling up happens, a sand dune typically undergoes a fairly predictable evolution, I guess. Whereas more and more sand builds up, the sand dune gets bigger and bigger,

and the sand just kind of smacks into the back of the sand dune. And the lighter sand will just continue up and over the sand dune. And then once it makes it down the other side, which is called the slip face, which is the side that's protected from the wind. The sand dune just kind of gets bigger and bigger.

But eventually enough sand will pile up on the backside, that it forms a crest where it basically piles up and forms a peak or a crest or something like that. And then this crest can get so big and so pronounced that it will actually crumble under its own weight. Yeah, I mean, it's just, it's like raw physics before your very eyes. These layers, those light sands blowing over

and its layer after layer building up, then that crest gets super tall. Like you could mess around with it if you had a big bucket of dry sand with your own hand. You sort of see this effect as you drop sand. Eventually when it does collapse, it's gonna avalanche down the slip face. And there is an angle, it's called the angle of repose,

where it's sort of, where that beautiful, what's the word I'm looking for? Not symbiosis, but when something's pushing against something, the other thing's pushing right back and it all agrees that just to stop there in the middle. I don't remember what it's called, but I know what you're talking about. It is beautiful for sure.

That's basically it. It's about 30 to 40, 34 degrees in general. And that's when it just reaches that perfect angle of steepness that it's all just stable and solid. Right, so now you have a dune. It's no longer being born, it's now living and it's still can keep growing, but it's gonna keep growing along these lines

where if enough gets built up, it's gonna fall down into the angle of repose. More likely the sand will just continue going over the edge and then being built up on the backside too. It's a rump will grow basically. Yeah, and I feel like winds are really strong. It's probably gonna be taller. If the winds are really gentle,

it's probably gonna be more spread out in the direction of the wind, the angle of the wind. And like we mentioned earlier, whether or not it's uni-directional, bi-directional, or multi-directional, that's all gonna play a part into what kind of dune you're gonna get. So let's take a break and then we'll come back and talk about the different kinds of dunes, okay?

All right. What's up? On the podcast, HeyDude, the 90s called David Lasher and Christine Taylor. Stars of the cult classic show, HeyDude, bring you back to the days of slip dresses and choker necklaces. We're gonna use HeyDude as our jumping off point,

but we are going to unpack and dive back into the decade of the 90s. We lived it and now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and non-stop references to the best decade ever. Do you remember going to Blockbuster?

Do you remember Nintendo 64? Do you remember getting Frosted Tips? Was that a cereal? No, it was hair. Do you remember AOL Instant Messenger and the dial-up sound like poltergeist? So leave a code on your best friend's beeper because you'll wanna be there

when the nostalgia starts flowing. Each episode will rival the feeling of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to HeyDude, the 90s, called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts.

Hey, I'm Lance Bass, host of the new iHeart podcast, Frosted Tips with Lance Bass. The hardest thing can be knowing who to turn to when questions arise or times get tough, or you're at the end of the road. Ah, okay, I see what you're doing. Do you ever think to yourself,

hey, what advice would Lance Bass and my favorite boy bands give me in this situation? If you do, you've come to the right place because I'm here to help. This, I promise you. Oh, God. Seriously, I swear. And you won't have to send an SOS

because I'll be there for you. Oh, man. And so, my husband, Michael. Um, hey, that's me. Yep, we know that, Michael. And a different hot, sexy, teen crush boy bander each week to guide you through life, step by step. Oh, not another one.

Kids, relationships, life in general can get messy. You may be thinking, this is the story of my life. Just stop now. If so, tell everybody, yeah, everybody about my new podcast and make sure to listen so we'll never, ever have to say bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple Podcasts,

or wherever you listen to podcasts. Oh, step you should know. Chuck, have you ever read the book, Dune? Nope. I haven't either, have you ever seen the movie? Nope. Me either. Oh, that's interesting.

You know, they're making it again. That's great. That Dennis Villanue guy, so. Oh, he's good, man. He's pretty good, yeah. Yeah, he's amazing. He did the arrival, right? I think so, yeah.

Or just arrival. The arrival is like an old Charlie Sheen movie, I think. Yeah, I think it's just arrival. Okay, yeah. So neither one of us has seen or read Dune. We're gonna get some email about this, I think. Yeah, and I'm not knocking David Lynch either, of course. I wanna throw that in there.

No, or Frank Herbert. How are you? I'm just kidding, I don't know anything. So like you were saying, dunes are the result of the winds that are prevalent in the area. And the most common dune on earth, and a little known fact,

well, maybe not little known, but interesting fact, the most common dunes on Mars are what are called crescentic or crescent shaped dunes. And these are far and away the most common, which means that more often than not, in any given area, the wind is going to be blowing in the same direction basically all the time.

Yeah, and this got a little confusing for me, because the more I researched the types of dunes, like I saw one place that said there are five main types of sand dunes, barken, transverse, blowout, linear, and composite. Who said that? A website that seemed very educational and reliable. Weird.

But I believe there are just different words for some of these, and some of these are subtypes of the main five. Right, right. Because I believe a crescentic is a barken dune. Yes. If I'm not mistaken. You're not.

Horseshoe shaped? Front curve facing the wind? I guess so, yeah, that's the big thing, is where is the curve pointing? Is the big differentiator for crescentic? Yeah, like I looked these up online, all these pictures, and like when I saw the crescentic, these look like sort of those big,

beautiful dunes from Star Wars or Lawrence of Arabia. Yeah, it's what most people think of when they think of a dune. Like a desert dune. Right, exactly, thank you. So crescentic is, if you imagine it as like a U shape or a V shape, the underside or the bottom of the U or the point, the outside point of the V

is going to be pointing in the direction opposite the wind. So it's pointing up wind. So the wind is blowing and hitting that outside point of the V or the bottom of the U, which doesn't really make sense to me. The parabolic, which we'll talk about later, makes more sense. But anyway.

Is the parabolic the same as a blowout? Because a blowout dune is the opposite of a barcan. Yes. In that the curve, the horseshoe curve, faces away from the wind. Yes. Okay. It's gonna take five minutes to undo the confusion we just created.

Well, and there are some, who studies this? What kind of? Geologists, I believe, desert ecologists. Yeah, I'm sure they are having a ball with this one. Just pour up a drink, everybody. Yeah, I'll 17 of them. Buckle up. So crescent shaped ones, again, say they're U shape

or V shape, and the bottom of the U or the point of the V is pointing facing the wind. So it's pointing up wind. The wind blows it, the sand that it's blowing onto the backside, onto the rump of this dune, blows up, it falls down, avalanches under the slip face which is the inside of the U or the V, and is not as protected from the wind.

And what's amazing about this is because the crescent shaped dune is the result of a wind regime where the wind is blowing in one direction basically all the time. These are the dunes that can actually move, and they can move pretty fast. Well, they're one of two kinds, but they can move pretty fast across the desert

so much so that sometimes these dunes when there's many of them will catch up to one another and they'll do some pretty amazing things when they catch up to one another. Yeah, and so much so that they can threaten villages and people have to try and stop these dunes. Yes, some people have been known to pour motor oil on dunes to keep them from moving because it wetens the sand

without it drying out. It's not a good one. You could plant vegetation, although if you're in the desert, that's not a great thing because your plants are just gonna die. More often than not, if you just put up fencing, that becomes an obstacle for the dune

and the dune will stop in its tracks and it will just keep building up on the backside. Eventually it might be big enough to overcome the dune, but it will certainly slow it down for a good many years for sure. Yeah. But the thing about that crescent shaped one, when a small one catches up to a bigger one,

a lot of things can happen. One thing is that it can appear as if the small one passes straight through the big one. Amazing. It is amazing. And then another thing that can happen is two dunes. I don't remember if they're the same size or different size when they come together

so that the arms or the wings or the horns of that crescent shape, right? Not the main part, but the points that come out. Those are called the horns. I've actually seen arms too. There's all sorts of different names. It's a giant mess. Nobody can agree on anything with dune ecology.

But when a different dune catches up and merges with it, it can actually go from two dunes to three, which is called breeding. And the two, so there's the one dune that remains. And then the other one basically splits into two dunes that come out the arms or the points of the original dune. So when you had two, now there's three, which is pretty astounding if you ask me

because we're talking sand dunes here and they're breeding new dunes. Amazing. I think it's pretty amazing too. So among the five types, there's also one listed as a transverse dune. I didn't understand them at all. Well, I think these are the ones

that they're long lines of rigid dunes and they're perpendicular to the wind. They have really steep slip faces at the back sides. And they're kind of wavy. So there's a lot of sand and not a lot of plants. And I think the dunes that you see behind the beach are a lot of times are transverse dunes. Okay.

If I'm not mistaken. My understanding was that parabolic were the most coastal dunes, maybe not. The most coastal. And I think there are different kinds of dunes even along the coast, right? Yeah, yeah, for sure. Again, it just depends on what the wind is like in an area

and because wind regime is gonna be different for every kind of area, there's different kinds of dunes. And what we're talking about are the standard simple kinds of dunes. Dunes can, like we were just saying, can merge with one another. Winds can change.

And different types of dunes will start to form. You've got compound and complex dunes too, which can be two different kinds of dunes merged together. So there's a lot of weird things that can happen with dunes. They're very rarely just a simple, straight up, straightforward kind of dune. Yeah, there are linear dunes.

These are mostly parallel to the wind and these form these long, straight ridges. And they think, geologists think that they are caused by wind that blows in one, they are definitely bi-directional as far as the wind goes. But they think they're caused when wind blows from one direction in one part of the year

and then another direction in another part of the year. Right, so they're like long lines, basically. Yeah, but it's interesting that, you know, the winds will shift over, you know, like the course of a year. So it's not like every day they're shifting. No, but it's enough and they're powerful enough that they're blowing any kind of rump or base of these.

And it's just a big, long line of sand, sometimes very sharp, depending on, you know, just how sharp the bi-directionality of the wind is. Yeah. Star ones, this is one of my favorites. Yeah, these are pretty cool. So if you have- It's what you would think.

Yeah. It's like a sand dune that looks a bit like a star. They have a pyramidal mound that goes up in the middle and then at least three arms with slip faces, you know, the avalanche face, radiating out from that middle. And these are the result of a bunch of different wind directions throughout a year building up.

So rather than moving along the face of the earth, these things just kind of build up in space. And they're actually some of the tallest ones. I think there's some that are like 500 meters or 1500 feet tall in deserts in China, which is pretty, pretty amazing. I mean, that's tall, especially if you're a sand border. Yeah, I mean, you can simulate all this stuff.

Like you can make your hand the wind. If you're at the beach and you're playing with sand. I mean, you just think about, if you're pushing the sand in one direction only, it's gonna look a certain way. If you push then in another direction, that's gonna look a certain way. And then in the case of a star,

if you're using your hand pushing sand in in all of these different directions, it's gonna grow upward and it's not gonna grow laterally. Right, right. We should have probably said at the outset that it helps a lot if you go look up images of the different types of dunes we're talking about. Yeah, please.

Like it helped me. And look up dune porn. Yeah, I'm sure it's out there. Okay, now there's parabolic or parabolic. I think parabolic. I say, you say parabolic? I say parabolic. Okay.

So these are basically the opposite of crescent shaped where this time the inside of the U or the inside point of the V is what the wind is blowing into. And then the outside of the U or the outside of the V is what's facing in the direction that the wind is going, but it's downwind, right? It's what you would think of.

Like if you're just thinking about moving sand with wind via physics, this one makes the most sense. But the thing about parabolic that really distinguishes it from crescent is that usually they're made of sand that has some sort of water attached to it or vegetation so that the arms are anchored. So the arms stay in the same place.

They just get longer and longer as the bulk of the dune, the middle part keeps moving further and further away. Yeah. Which is pretty cool. Especially if you imagine this stuff on like a time lapse or happening really quickly. Yeah. I mean, it can be little trees, shrubs, grasses,

what we'll talk more about what can grow in dunes. But these things very much serve as the anchor on those arms. And these are not gonna be very tall. Obviously, if you think about like the way they're gonna form the fact that those arms are anchored down, they're not gonna be super tall. And then where that vegetation is gonna stop, it's gonna slow the advance of that sand accumulation.

Right. They used to think it was strictly just the vegetation that anchors the arms, but they apparently have discovered recently that, no, it's actually more waterlogged sand like in the arms than we previously thought. And it's probably the water. It acts as motor oil.

That's right. And then on this original list of five main types, the composite dunes were the last one listed. And this is just sort of a combination of two or more types of other dunes. These are really big, they're very tall. They form these big hilly forms called draws, D-R-A-A-S. Okay.

And they're mostly transverse and linear dunes. And they can be like taller than 400 meters. They're gigantic. Wow, that's really cool. What makes them so big? I think just the combination of the dunes. Wow, just running together? I think so.

That's pretty neat. There's another one I wanna give a shout out to, Chuck, is lithified dunes or slick rock. Oh, sure. Like the kind that you see in a painted desert or whatever. That's actually like a hardened sand dune that over time, water has moved through. And as it moved through,

it basically fossilized the sand dune because it deposited minerals of different types. And these minerals can create like layers or strata that have different colors. But it's actually originally it was a sand dune. Gorgeous. I've been to Utah quite a few times. Yep.

And we should talk about the sub-aquias too. Okay. Because those are pretty great, they're underwater dunes. And if you've, like you see these a lot in natural channels like rivers and stuff. Yeah. But they can also form in a canal that man has built, which is pretty interesting.

They move downstream, always. And they tend to be of the same height and the same wavelength, the same frequency. Like they're equally spaced apart. And I didn't realize this, but it makes total sense. The presence of dunes on the bottom of like a channel or a river or something, it increases the river's likelihood of flooding

because it decreases flow. It increases resistance, decreases flow. And so the water actually piles up and overflows because it's running into sand dunes at the bottom. Amazing. It is amazing. I don't know if we've gotten this across yet or not everybody, but sand dunes are a little more amazing

than you might've thought. Certainly more amazing than say jackhammers. You wanna take another break? Yeah, let's do it. We're going to take a break everybody in case you didn't hear, and we'll be right back with Coastal Dunes. ["Costal Dunes"]

On the podcast, Hey Dude, the 90s called David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're gonna use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s.

We lived it, and now we're calling on all of our friends to come back and relive it. It's a podcast packed with interviews, co-stars, friends, and non-stop references to the best decade ever. Do you remember going to Blockbuster? Do you remember Nintendo 64? Do you remember getting Frosted Tips?

Was that a cereal? No, it was hair. Do you remember AOL Instant Messenger and the dial-up sound like poltergeist? So leave a code on your best friend's beeper, because you'll want to be there when the nostalgia starts flowing. Each episode will rival the feeling

of taking out the cartridge from your Game Boy, blowing on it and popping it back in as we take you back to the 90s. Listen to Hey Dude, the 90s called on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, I'm Lance Bass, host of the new iHeart podcast, Frosted Tips with Lance Bass.

The hardest thing can be knowing who to turn to when questions arise or times get tough, or you're at the end of the road. Ah, okay, I see what you're doing. Do you ever think to yourself, what advice would Lance Bass and my favorite boy bands give me in this situation? If you do, you've come to the right place,

because I'm here to help. This, I promise you. Oh, God. Seriously, I swear. And you won't have to send an SOS, because I'll be there for you. Oh, man. And so, my husband, Michael.

Um, hey, that's me. Yep, we know that, Michael. And a different hot, sexy teen crush boy bander each week to guide you through life, step by step. Oh, not another one. Kids, relationships, life in general can get messy. You may be thinking, this is the story of my life. Just stop now.

If so, tell everybody, ya everybody, about my new podcast, and make sure to listen, so we'll never, ever have to say bye, bye, bye. Listen to Frosted Tips with Lance Bass on the iHeart radio app, Apple podcast, or wherever you listen to podcasts. Okay, so the dunes that I am probably, most people have seen more than any,

or coastal dunes, the dunes at the beach. The dunes that have a sign says, stay off the dunes. There's probably some plants growing on them. And... Dunes are protected. They are protected, and they're protective too. That's right. But really, I realized this

as I was researching this, Chuck. They really protect human interests. They don't really do, you know, there's not a whole lot that they're doing besides replenishing the sand that makes up the shore ecosystem after a storm. They're basically like a reserve sand pile, so that when a storm happens, the sea goes,

give me some of that. And it takes the sand out and replenishes it, and then starts this process over again. Because that's where the sand dune originally comes from, is waves bring sand ashore, and the sand starts to blow inward inland, and runs into something in the way. And like I said at the outset,

it could be a bed of pebbles, it could be shells, it could be some vegetation that's already growing there, and it starts to build up. And that's where coastal sand dunes begin. Yeah, it's really cool they have, first of all, an embryo dune is a real term, which is really kind of funny. And kind of like, I imagine it's like sticky and yokey.

Gross. But how these things, like how vegetation comes to to work with dunes, and they kind of scratch each other's backs in this case, is rotting seaweed will come in from a storm, let's say, because a sand dune in itself originally doesn't have like a ton of nutrients to allow stuff to grow. Yeah, it's just minerals basically,

like quartz and ground up calcium carbonate, and not much else. Yeah, so you would be surprised if anything grew there. But what'll happen is the tide will bring in plant life and like rotting seaweed, and at it, they dump their nutrients there, and that allows what they call a pioneer species to colonize, because all of a sudden

there's some nutrients there, and this can be mainly grasses, like all different kinds of sea grasses. Yeah. And these plants, you know, these are sea grasses, so they can grow well in really harsh conditions, like super salty areas, they're getting beat by wind, and they really typically have these big, deep, long roots,

they're gonna go all the way down to the water table, and that's where they're gonna get their drink, and they're gonna just bind that sand together, and it's, like I said, they kind of work together to make the sand makes the plant stronger, the plants make the sand stronger, or the dune rather. Yeah, yeah, and once those pioneer species of grasses are established,

they start to change the actual composition of the dune, and they make it more inviting. Yeah, to other kinds of species that aren't quite as pioneering, but are still pretty hardy compared to say, like your rose bush or something. They, there's, you know, woody perennials, like beach elder, there's heaths and heathers.

In the UK, they grow on coastal dunes, and all that these do is create an even stronger, more nutrient-rich type soil as these things live and grow, and fix nitrogen, and turn more seaweed into even more nutrients, and they also allow it to retain water, although I think basically two species, any plant that can grow on a sand dune

is basically developed techniques to resist losing water. Like they have small crinkly leaves that don't evaporate water nearly as easily. So the name of the game is to get as many nutrients out of an unfriendly soil as possible, and keep as much of the water as you can get from the water table.

Yeah, which is why they protect dunes. I mean, when you go to the beach, you're gonna see signs that say, stay off the dunes, and you don't wanna, you know, cause the fear is that humans will go in there, which is exactly what would happen, and trample on these grasses, and then that little relationship is busted apart

when those grasses die off, or even worse, or pulled up maybe, because you wanna take some home or something, and then the sand dune is compromised. Look what I got from the beach. So even without human intervention, these coastal dunes can turn into parabolic dunes. If something happens, like a storm surge happens,

and carves out like a significant portion of the sand in front of the dune, because now there's nothing holding that dune in place, and it's exposed to the wind even further, and so the dune itself will start to move forward, but the arms will stay in place, and the coastal dune has just turned into a parabolic dune too.

And it's moving inland, which if you have a house built there, that's a problem for you, but one thing that I didn't realize, but I totally, now I've seen it all over the place, but I never put two and two together. If you've ever noticed an established beach will almost always have like a conifer pine tree forest,

and apparently that's like the end result like of the progression or evolution of a dune ecosystem, is a pine forest is gonna grow because they're adapted to grow in this soil that's been prepared over time, that started out as a single piece of dead seaweed and ended up into a whole pine forest. I mean, for sure there are a lot of pine trees

in the Florida Panhandle. Yeah, but you never think about it, but that's like a dune ecosystem, but that's part of the dune. That's like the, I think the climax ecosystem is what they call it. Yeah, and I don't know if you've ever been to a beach not so long after a hurricane has hit,

but it's just devastating to look at. I mean, you always obviously think of people in homes that are destroyed and stuff like that, but if you look at the actual beach itself, it's pretty brutal. Like it can take decades for that beach itself to recover and for those dunes to recover. Like I was in South Carolina a couple of years ago,

not too long after one of the hurricanes. And it was like you're used to seeing these big broad beaches with these big flowy dunes. And this was like a cliff. It was just sand that eventually went up. The waterline met just a hard like, jeez it, man. Some places like 10 and 12 feet, like a sand cliff. And it just looks completely unnatural,

like not like the beaches that you're used to seeing. And selfishly as a beachgoer, some parts were just completely impassable. Like you couldn't even get to the beach unless you like rappel down the wall or something. And you certainly couldn't get back up. From what I could tell though, that's just part of this natural process

of like removing and then slowly replenishing. And like I was saying earlier, the dunes protect human habitation. Like you want a dune if you live on a coastal beach area. It's like a big stack of sandbags. It is and like you build your house right behind it and it provides this buffer from storm surges and stuff like that.

But when it's taken away, if it takes decades to rebuild, you may want to move elsewhere. And apparently after Hurricane Sandy, there's parts of New Jersey still that they're saying like, I don't know if this is habitable anymore. Maybe it will be in like 50 years after the dunes come back, but this is not like, we can't live here anymore.

It's because the dunes have been removed. And people in New Jersey said, have you ever been to Newark? Yeah. Actually Newark's come a long way. Has it? Oh, sure. Okay.

But when I first started going there in the early to mid 90s, it was a different story. Okay. I love Newark, it's great. Do you really? Sure. Okay. I love all of New Jersey.

That's my second home. All right, there you go. Speaking of second homes, we should talk about what little critters make their home, their first home in the dunes. Do you like that? Yeah, I did. That was pretty nice.

That was a classic SK segue. So, I mean, kind of like we were talking about before, like a big pile of sand is not an intuitive place for plants to live or animals to live. But because of all the nutrient dumps that the ocean brings in, it can... It's like Raymond Burr.

It can end up being a really thriving ecosystem. There can be little flower, dune flowers. There can be little rats and mice, certainly snakes and lizards if you're in the desert. But obviously these are only gonna be things like, you can't completely discount like nature. These all have to be very, very drought tolerant plants. Oh yeah, for sure.

But they're adapted to grow on these dunes. And when you add a plant and a lizard and an insect and a bird or something like that, you got yourself a nice little ecosystem going. And there are definitely dune ecosystems that have developed over time. Beetles, crickets. Yeah, I was looking up.

I was like, are dung beetles a dune bug? Apparently my friend, dung beetles are an anywhere beetle. They're on every continent in just about every ecosystem except for Antarctica. Oh, really? Yeah, we're gonna have to do at least the short stuff on the dung beetle, because it's a poop beetle. It gathers poop and I think that's pretty neat.

Yeah, I remember watching those guys roll those little poop balls around in the, what was it, the planet earth videos? Yeah, for sure. Pretty great. Or maybe it was microcosmos, I can't remember. It was, I mean, they're pretty frequent TV guests. They did a lot of movies.

Remember when they were on the Mandrel Sister show? Yeah. Oh man, that was so pretty. The house down Mandrel Sister, wow. Did you watch that? No, I grew up in Ohio. We didn't have that. Oh, it was nationwide.

Are you kidding me? No, I'm sure I'm kidding. This is when like people in New York City watched He-Haw. Right, yeah, I know. Everybody was on CBs and acted like they were truckers wore trucker shirts. Crazy. Yeah, it was a cool little period in the 70s, you know?

Yeah, it was a little weird. Trucker culture took over. Yep. What else is gonna hurt dunes? Deforestation, sounds weird to use that word about sand dunes. But yeah, I mean, there's those conifer forests. Yeah, you can deforest a conifer forest just like any other forest you jerk.

Not you, I'm saying the person who cuts down the conifer forest. That's right, yeah. What else, you got anything else? No, we talked about the singing sand dunes, which if you haven't heard, go listen, it's pretty neat. And it's really just sand, dry sand falling over itself in an avalanche.

And again, proof positive that sand dunes are alive and can feel pain. That's right. That's it for sand dunes. I think the last thing we have to say is stay off the dunes. If it says stay off the dunes, just don't go on them. Especially with your dune buggy. Yeah, that was another 70s little fad too, dune buggies.

Yeah, they also have beaches still where you can drive your car, I'm not a big fan of that. No, because even if it's not eroding the beach, it's smog on the beach, come on. It's just ugly, you don't want to go to the beach and see someone's stupid car. Nope, I can barely stand seeing people's bare feet. Agreed.

Well, since we said that, it's time, of course, friends, for Listener Mail. Chuck got me out of a parking ticket. Nice. Hi guys, my name is Camber. I'm a grad student at Indiana University, Go Hoosiers. Yeah. But I work in Indianapolis, I'm a fairly new listener

about six months, but I have to drive a lot for school and work and family. So I spend a lot of time listening to you guys. And I need to let Chuck know that he saved me hundreds of dollars. With Geico. So rewinding back to Friday night, I was driving to Louisville, Kentucky,

about a two hour drive and might have been going 70 in a 55. I get pulled over and I think this is it. I'm going to have to take out extra loans, get another job. My entrance is going to go up. And then I remember what Chuck said about getting out of his speeding tickets and just surrendering myself to the law. So I thought, why not give it a try?

And it worked. Not only did I not have to pay for a parking or for a speeding ticket, but you saved my insurance from spiking. I'll always remember this in future situations. But of course, I'm going to work on my lead foot first. Thanks so much for the advice and thank you for the podcast, guys. Listen, almost every day, don't know what my morning

commute would be without it. That is from Camber Soulburger. Nice. First of all, Camber, great name. Camber Soulburger, even greater name. That's one of the great names. And then, yeah, Chuck, getting you out of a ticket, that's just an all around fantastic listener mail, Charles.

Greed. Well, if you want to get in touch with us, like Camber Limburger, Camembert Limburger did, you can go on to stuffyoushouldknow.com and check out our social links. Or if you want to write us an email, you can fill it out, smack it on the bottom, and send it off to stuffpodcast at iHeartRadio.com.

Stuff you should know is a production of iHeartRadio's How Stuff Works. For more podcasts from iHeartRadio, visit the iHeartRadio app. Apple podcasts are wherever you listen to your favorite shows. On the podcast, HeyDude, the 90s, called David Lasher and Christine Taylor, stars of the cult classic show, Hey Dude, bring you back to the days of slip dresses and choker necklaces.

We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it. Listen to iHeartRadio's How Stuff Works. And if you want to get in touch with us, you can go to iHeartRadio's How Stuff Works. Come back and relive it. Listen to Hey Dude, the 90s,

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