Science Friday - Wild Horses, Hidden Structures Behind Structures, Florida Flamingos. Feb 23, 2018, Part 1

Episode Date: February 23, 2018

The gentle curve of a beam. The particular shape of a clay brick. The sharp angles of a series of trusses. You might view these elements of buildings, bridges, and structures as part of the aesthetic and artistic design, or maybe you have overlooked them completely. But for London-based structural engineer Roma Agrawal, these visual charms play an important role not only in the beauty of a building, but in the physics that keep a structure from tumbling down. Agrawal reveals the hidden engineering and physics in the buildings and bridges around you. Until recently, scientists believed the only horses in the world left untouched by humans were the Przewalski subspecies, in central Asia. But now, researchers discover there are no more wild horses left anywhere on Earth. Do Florida's flamingos really belong there? New research argues that the colorful birds are a species native to Florida, and should be protected. Plus, the reason why you don't see 'goosefoot' on your Thanksgiving dinner table, and other stories in science.  Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Iroflato. When we think of Native American agriculture, we think of corn. You know, the stuff Europeans couldn't get enough of once they got here. But before that crop became popular, indigenous people were farming things like erect knotweed, goose foot, little barley. So what happened to these domesticated plants? And why don't they have a place on our Thanksgiving tables? Here to tell us about these lost crops as well as other short subjects inside. Science is Annali Newitz, Tech Culture Editor at Aris Technica.

Annali, welcome back to Science Friday. Hey, thanks for having me back. Oh, you're welcome. So what are these, what are they? Where do they go? Things we've never heard of like goosefoot, little barley. Give us the story on it. That's right.

So about 1,000 to 2,000 years ago, indigenous people in the Americas had a very different set of meals than they would have had much later and that we have today. And there's a archaeobotanist, which is somebody who studies ancient plants named Natalie Mueller at Cornell University who's been studying these lost crops. And she focuses specifically on erect knotweed, which if you're a gardener, you've probably heard of Asian knotweed, which is an invasive plant. This is not that.

This is a local indigenous plant. Loves to live near the water in the south and the Midwest. And it has these really hard fruits. that have starchy seeds inside that were quite delicious. And what's interesting is that these crops, which were so popular for so many centuries, really finally got pushed out over time. Once Mays arrived from Mexico, came up from the south, these crops became less popular. And then when Europeans arrived and started colonizing and killing off indigenous people,

but also, more importantly, moving them around, basically kicking them off the farms and kicking them out of areas where they had been farming these crops, the knowledge about these crops, the seeds for these crops just disappeared. And so the examples we have of these domestic plants all come from very ancient sources, like they've been found in ancient campfires and ancient campsites that belonged to indigenous people a thousand years ago. So they're still looking for these wherever they can find them? We're still looking for them. Natalie's work is great because she's done a terrific job showing the difference between the domesticated erect, not weed, and the modern wild version.

And you wouldn't be surprised to know that when farmers farmed these crops, they looked for ones with bigger seeds and bigger fruits. And so the domestic version has bigger fruits. And they also germinate more quickly, which means when you plant them, you're sure that they're going to bear fruit that year. And what's really fascinating about this work is that this is a very rare example of a plant that we can study that was wild and then domesticated and then went wild again. And so Natalie is working with geneticists at the Smithsonian trying to sequence the DNA of these ancient plants as well as the modern ones, which indeed the modern ones are endangered. So part of this is about trying to protect these contemporary wild plants as well. But they're trying to figure out, like, what happens when a plant or anything goes from being, you know, cultivated to being wild. Well, speaking of plants, it turns out that there are 100,000 million years older.

They're that old than we thought? It turns out land plants are older than we thought. A new paper that just came out shows through DNA analysis that plants on land evolved about 100 million years early. earlier than we thought. So they evolved about half a billion years ago right around the time that multicellular life was evolving in the ocean. And what's cool about this story is, well, first of all, it just shows us what Earth was like when our ancestors, the multicellular animals, were hanging around in the ocean. There were indeed things like mosses, very simple plants, like liverwort and such on land. But what's really cool is that these were plants with root

systems. And what root systems do is actually kind of destroy the environment because at that time, you know, oxygen, free oxygen was still a relatively new thing on Earth. And the process of putting down roots and kind of making the dirt, shake up the dirt, kind of make it into smaller pieces. So when it rains and when there's weathering from wind, that dirt runs off into the oceans much more quickly than it would if it hadn't been kind of messed up by these root systems. And so that means that this jump started a geochemical process that drew carbon down out of the environment.

That whole process of weathering pulls carbon down and allows more free oxygen to hang around, which was great for those multicellular animals in the oceans. They love that oxygen. It helped them develop. It gave them enough energy. So now we have a picture of how basically land plants helped us. our ancestors develop in the ocean. And so we have a much more complete view of how that time on Earth during the Cambrian explosion,

what that time was like, basically. So plants were our heroes, is what I'm trying to say. They're still my heroes. Moving on, this is something really weird. Researchers in Sweden found a group of 8,000-year-old heads on spikes. Sounds like a Game of Thrones plot here. What was going on there? This is a story that is great because it reminds you that first impressions are not always correct.

So this was a stone age site. It's in central Sweden and some construction workers were demolishing a bridge and found this ancient structure made of stone and wood in the middle of a lake. And on it, they found human remains, skulls, which still had spikes in them. So we know that they were mounted on spikes. And at first, you know, your first impression would be, well, this must have been some Game of Thrones stuff, you know. King Jeffrey at work doing something. Yeah. Cut off their head, stick it on a spike.

But actually, when they examined the skulls, it turned out that these were the skulls of people who had been injured, possibly in battle. They had like a lot of blunt force trauma on their heads, but they'd recovered from the injuries. So it seems as if these were people who were the survivors, possibly of battle, possibly of some other. kind of very dangerous activity. And this may have been more like a war memorial or a place to honor them because, you know, they hadn't been, they weren't killed from these injuries. And so it's a great, as I said, it's a great example of how when we look at something through modern eyes and we imagine what it might mean, we really have to look at the evidence

to see that there's actually multiple interpretations here. This might really have been, you know, a place where people gathered for social events and ritual events to celebrate their culture, not just to do mean things to their enemies and chop them up and put them on stakes. It's always good to present the evidence. Wait for to make your conclusions after you analyze the evidence. Thank you very much.

Exactly. Yeah, NLA, thank you. Annali Newitz, Tech Culture Editor at Ars Technica. And now it's time to play. Good thing, bad thing. Because every story has a flip side. Now, we've talked about the Wild Mustangs of the Western United States before,

that are technically not wild. They're a feral population of domesticated horses brought here by the Spanish almost 500 years ago. And until recently, scientists believe the only true wild horses, unimpacted by humans, were the Chivalski horses in Central Asia. But in a surprising study published this week, scientists report that what we thought we knew about horse ancestry, well, it was wrong. There are actually no more wild horses left anywhere on Earth. Boy, if you're a fan of horses, this is some really bad news, isn't it? But is there a silver lining? Well, here to tell us the good and the bad of this new finding.

It is Dr. Alan Otrum, Professor of Archaeological Science University of Exeter. He joins us by Skype. Welcome to Science Friday. Hello, hello. So you looked at the genome of the Shavalsky horse, and what did you find? Who are they actually descendants of? Well, the earliest unambiguous evidence for horse domestication comes from sites in Kazakhstan about 5,500 years ago.

And those had never been sequenced before, so we sequenced quite a large number of ancient genomes from Batai, expecting them to be rather like modern domestics, but actually found out that they are the direct ancestors of the Shavalsky horse. So they were under human management a long time in the past. So it's actually not unlike the story you were telling a little bit earlier about the plants that Native Americans were farming in the past. They were wild, became domestic, and then went wild again. And the same applies to the Shevalski. So the modern horses don't come from the battalion, is what you're saying, like we thought they did.

No, that's right. So, in fact, there must be, that's the other interesting feature of this, is that there must be some sort of second domestication event elsewhere. So why is it so important that we have some wild horses left to study now? What makes them different from the feral horses out there? Well, I guess it is nice to be able to study something that has been unimpacted by humans to see what their natural behavior would have been like. It will help us understand how they acted in the very deep past. But actually, there's nothing gone, nothing's actually gone extinct here in a way.

these Chavalsky horses are still alive. So it's not like suddenly we've made a whole species extinct. It's simply that they have been under human control at some point and now have gone back to being feral. So that's the good news here then. Yes, I mean, nothing's actually, before anybody gets really worried, an extinction has been caused by our paper this week.

It hasn't. These horses are still alive and well and still their behavior is probably about as close to wild as we're going to see because they've been feral for a very long time. So are these feral horses enough like the wild horses that we can still learn, study, learn from them? Well, I think we probably can still learn an awful lot from them, and it's certainly the closest we now have. I suppose we can't actually check that because there are no other true wild horses to examine.

But I would imagine that they're the best thing that we can possibly still study, and they're still incredibly important as a result of that. Do we know where the first modern horse comes from? Could it be? Yeah. Well, that is the next phase of work that we have to work on. We are doing, this is a continuing project, and we're working on other potential areas.

The north area of Kazakhstan that we've studied in the Batai culture, and is not the only candidate for early horse domestication. There have always been other candidates, including the area of Ukraine and Russia to the western. side of the Ural Mountains. And that is certainly an area we'll be looking at, but they can also look at eastern Anatolia and places like that. Sounds great.

We'll have you back on, Wynette. You learn more about it, Dr. Oacham. Thank you for taking time to be with us today. Okay, thank you. Dr. Alan Oacham, Professor of Archaeological Science at the University of Exeter. Coming up, our buildings get taller and taller, but how exactly are engineers making it happen? We're going to talk about the secrets of building immense structures.

Anything you ever wanted to know about building? Now is the time to get online and give us a call our number 844-8255. We're going to be talking with the Roma Agrawal Structural Engineer, author of Built, The Hidden Stories Behind Our Structures. Give us a call. Anything you'd like to know. We'll be right back after this break. This is Science Friday.

I'm Ira Flato. If you're a regular listener to this program, you may have heard me mention more than a few times how much I love talking and thinking about. Concrete. Yes, concrete, yeah. I know. Sement turning into concrete. You know. So when I read our next guest book with the opening line of a chapter reading, I've been known to stroke concrete, I knew I had found a kindred spirit. Roma Agrawal is a structural engineer who's helped design towering skyscrapers, including the shard. That's that 95-story tower in London. and in her new book, Built, the Hidden Stories Behind Our Structures, Roma shares the secrets behind how skyscrapers are built, why ancient Romans were the masters of concrete,

and one of my favorite stories, how John Robling may have designed the Brooklyn Bridge, but his daughter-in-law, Emily, with no formal education in engineering, was the driving force behind getting it built. Sort of a hidden figure, right? So if you've been wondering why buildings, bridges, sewer systems are built the way they are, or, you know, you look around you outside and say, hey, I see this building going up. What's this piece, too? What does that do?

Give us a call, 844-8255. You can also tweet us at SciFRI and 844 SciTalk is our phone number. Roma Agrawal joins me from London. Welcome to Science Friday. Thank you very much. You know, I'm so happy to talk with you because, you know, I'm a fellow geek about construction and structural engineering. And as I said, when I saw the way you described concrete, I knew we're going to bond immediately, so to speak. I'm so excited that I've found someone else that's as obsessed with concrete as I am.

Well, I'm glad because we can talk all day, but I will have to go in a lot of different directions. First, tell me what's, why is it such an amazing substance concrete? So what I really like about it is that it has so many different forms. It's quite an indeterminate material. So it starts off as being a rock. We then kind of break it down. We heat it up. We fire it.

We then turn it into a liquid. And then that liquid is poured into any shape that you could possibly want. And then it starts to solidify and you get different textures from it, different colors. And so I just love the fact that it can be anything you want it to be. And had it heard that it takes months and years to set and dry, it never really totally dries out? Is that true? Right. So concrete, interestingly, needs a lot of water, so it doesn't actually lose the water, but it reacts with the water. And that process, you know, most of it happens in the first 28 days of it being poured. But you're right, it actually takes months and years until concrete reaches its full, complete strength,

and that chemical reaction is completely finished. You know, and I still can't wrap my head around the fact that we can pour concrete and let it dry underwater, which you describe in your book. That just blows my mind about that. It's amazing, isn't it? So it was all about finding that special ash, which is what the Romans did. They found pot-salanic ash near their volcanoes, and they started mixing that into their concrete, and they found that, yeah, you know, it sets underwater because it basically doesn't need air for that reaction to happen in that.

particular mixture. Speaking of concrete, we're already getting a lot of questions from our audience. While we're on that subject, let me get a tweet from Christophero who says, why is it that the Coliseum still stands and yet our highways are falling apart every few years? That's a really interesting question. So I think what's really interesting about old structures is obviously they didn't have the kind of computing power that we have today. So when they built their structures, they put lots and lots and lots of material in there

to make sure it was safe. And then obviously we've been looking after our historic structures pretty well. So combined with the fact that there's lots of material and we look after stuff really well, a lot of these ancient structures have lasted. And I expect with highways and so on, they get so much wear from all these trucks and heavy vehicles driving over them that they just probably need a bit more love. But they wear a lot better than asphalt does, don't they? Yeah, I mean it depends.

And we know what the design life is for these various things. So, you know, we can't make our roads last forever. There's a finite life for them that makes sense financially and how long it takes to build them and so on. And so it is normal that they do need maintenance. So that's what it's about is going in and looking after things better. Now, one of the first projects as an engineer that you worked on was that 95-story tower in London, the shard, which it looks exactly like the name.

What were the challenges of making something that tall? So it was such a fun project to work on. I think I'll pick two challenges. One is the ground. So unlike Manhattan, where you've got this lovely strong rock that you can build your beautiful towers on, here in London we're on the banks of a river. So we've got this kind of wet, soft clay.

So building the foundations was challenge one. And what we do is we put these big, huge, concrete piles into the ground. They're like big giant concrete columns, to basically anchor it like the tree roots do for the tree, and then it keeps the tower stable. So I'd say ground is kind of big challenge number one, and the second one that I love talking about is the wind. So we think, oh, the wind is quite harmless.

You know, we like a nice little breeze, but they can play havoc with skyscrapers. So we need to make sure that the buildings are stable when wind hits it from all the different directions. That is a challenge. Our number 844-7-24-825-boy, how fast this phone line has filled in. Let's go to Jersey City or Jersey. Hi, Matt.

Welcome to Science Friday. Hey, guys. My father was a project manager at One World Trade, and he always spoke about how they needed to account for seismic activity from terrorist attacks. And my question is, as these buildings get taller, is that more difficult to account for? Is man-made disasters and things of that sort? Good question. Thanks for calling. No, thanks very much for that, Matt.

Yes, it is something that we do need to think about. So we do a lot of assessments to figure out which ones of our buildings we think are most vulnerable. We had an example in the UK, which in the 1960s actually had a catastrophic collapse because of a gas cylinder explosion. So it's not just about intentional explosions. It's also about, you know, accidental explosions that might happen. So it's definitely something that we need to think about. And there's various techniques that we can use to try and know. mitigate or minimize the amount of damage that happens. You know, I watch construction here all the time

in New York. It's around us every place. There's a giant building going up right next to Grand Central. I've watched from the day one. And I watch steel coming down the street. First thing I notice about the steel eye beams is that they're rusted, even before they go in. Is that on purpose? So because the steel beams are ultimately going to end up in our buildings, which are air-conditioned and temperature-controlled and humidity-controlled, so yes, they do get a little bit of rust on the very surface. But that rust actually, as long as there isn't more moisture and oxygen going to affect it, that actually protects the steel a little bit.

So it's fine for it to have a little bit of rust, and then it goes into our buildings, and then it doesn't rust anymore because of the temperature control. So it is quite normal. It is counterintuitive, but yes, our steel beams and columns may come to our building slightly rusted. Now, when you build a building 60, 70, 80, 100 stories tall, How do you keep it from just squashing the bottom members? I mean, it's so heavy.

How can it be held up? I mean, the rest of the building stay up like that. Yeah, it's incredible. And this, I mean, all of this comes down to getting the right materials. So we have a lot of experience now. We've got computing power. So we can do a lot of kind of mathematical analysis to understand how heavy the building itself is, but also all the stuff that's going inside the buildings like people,

like box in a library. or what else. And we basically crunch the numbers, and then we make sure that the base of the columns are the right material, and there's enough material there to resist those forces. Years ago, my father used to work on the World Trade Center

up in the 80s, and that floor's up there, and he used to talk about feeling the building sway just a little bit. You talk about that, that you will allow the building to sway so it doesn't break, but not enough to make people nauseous. That goes into

the calculation? It does. Isn't that incredible? So we have an idea for what humans can perceive. What is the acceleration of a building that would make us feel a little bit queasy? So when we do our analysis and we're looking at how much the building is moving

but more importantly how quickly the building is moving, we try and make sure that that movement is slower than you know we can really perceive or that makes us feel nauseous. Let's go to the phones. Let's go to Pete. In 9 where they're building one of my favorite bridges,

and I've been watching the Tappenzie Bridge going up. I mean, we'll talk about what it's mad of. Hi, welcome to Science Friday. Hi, that bridge is pretty amazing, isn't it? It is amazing, yeah. My question is specifically about concrete, and the steel reinforcing bars that I know short-term help to strengthen the concrete,

but I think long-term, the steel reinforcing inside the concrete helps to force it apart. Is that something your guests can speak to? Sure. Thanks for the question, Pete. So those steel bars actually do a lot of work and they're working hard for the entire life of the structure. So where things can start to go wrong,

where those steel bars might actually split the concrete is if they rust. So we've just been talking about rust. We don't want the steel bars inside concrete to rust. So that's about making sure that water and air can't reach that steel. So we need to embed it, embed it deep enough into the concrete so that it's properly protected, and then they're going to work the entire life

of that concrete structure. Number 844-8255. Let's talk about appreciation of a lot older structures. Someone called up and asked about the Coliseum, Romans were the masters of concrete, and you know some of the tricks they used to make buildings like the Pantheon, both beautiful and strong.

Tell us about some of those. Yeah, I mean, the Pantheon is probably my favorite structure in the entire world, and I've been lucky enough to visit Rome twice and see it. And, you know, again, it comes down to material, it comes down to concrete. But the Romans had, I think, this amazingly can-do attitude about construction as well. And, you know, they just built. They built big, they built complicated, they tried new materials.

They were really, really experimental. And I really, really admire that can-do attitude that they showed. We're talking, you know, you mentioned the Brooklyn Bridge, which I want to get to a little bit later, but it was one of the great span bridges, you know, a lot of different bridges like that. But now we see all the new bridges are what, they have a different kind of suspension.

They're very stiff-looking suspension instead of the beautiful arching there. What do you call them stayed suspension? Yeah, the suspension bridges. And why change the design? What is better or different about the new ones than the old ones? Why change it? So I think we still use a lot of the same design

techniques and materials, in fact. So the Brooklyn Bridge was in fact the first building in the world that used steel cables rather than iron, which was quite usual at the time. And I think what's probably changing our structures a little bit is the fact that we're getting longer and longer and longer. So you can use the kind of the older techniques for spans up to a certain point. But if you're really going to push the boundaries on longer bridges, then we need to start looking at slightly different designs for them. Before the break, I want to make sure we talk about Emily Robling and her role. I mean, most people don't know of her role, although as you show in the book, there's a little plaque on the Brooklyn Bridge.

Most people think that it was her father or her husband that was most crucial in getting this done, but it was Emily. It was, and she's such a heroine of mine. I love the fact that, you know, she was a woman in an era where people genuinely believed that women were intellectually inferior to men. she couldn't get a degree in engineering, but she was basically pushed into this situation through the tragic demise of her father-in-law and then the accident her husband faced on site. But she went in, and what I really particularly admire,

is that not only did she learn all the technical skills you need as an engineer, but Washington Roebling, her husband, said her biggest contribution to the build was her talent as a peacemaker, and that is such an important part of engineering structures. Our number 8447-825, five. Let's see if we can get another phone call or two before the break. Let's see if we can get that one. No, I can't get that one. Let me just get a tweet in. A lot of people, there's so many

of them. How efficient and long-lasting is mud mortar as a binding agent? It's a very old one, right? Yeah, so mud, we've used mud. We've used mortars that are made of gypsum, that are made of lime. And I even talk about in my book how the Chinese actually used sticky rice in their mixture for mortar. So it really depends on what the mix was. Some lime mortars that are used in the Tower of London, for example, are over 900 years old and they've lasted. There's mortar between the giant stones of the pyramids in Egypt, and those have done incredibly well. But there are, of course, other structures where the mortars would have worn away over time. So it really depends on the skill and the mix of the substance that the engineers put together at the time.

Are there secrets that we have lost over the years in construction that we could benefit from? I'm sure there are, but I think, again, we're talking a lot about concrete, but let's talk about it more. So concrete, we lost the art of making concrete, at least in the West, for about a thousand years after the Roman Empire collapsed. And I just, I wonder sometimes if, you know, we have these amazing Gothic cathedrals in Europe that are made from stone. And I sometimes wonder what our architecture and our engineering would have looked like if we actually had managed to preserve that knowledge of concrete instead. This is Science Friday from PRI Public Radio International. Talking with Roma Agrawal, author of Built the Hidden Stories Behind Our Structures. It's a wonderful book, Ms. Agrawal.

I mean, and you can read the passion that you have for your subject material in there. Did you always know you wanted to be a structural engineer? So, I mean, the simple answer to that is absolutely not. I always knew that I loved science. I was pretty good at physics and maths in particular. I also enjoyed design. So I studied design technology in the equivalent of high school in London. And I tried to then have a think about, well, how can I bring all of these

passions together. So I actually studied physics as an undergraduate degree, but then I thought about, well, how do I apply that physics to make real objects? And I found out that engineering was the answer. So I was about 20 or 21 years old when I decided I want to be an engineer, which is pretty late for a lot of people that have decided, you know, aged five that they want to be an engineer. Let me see if I can get a quick call from Stephen in the Bronx. Hi, Stephen. Hi, how's it going? Hi there, go ahead. So I study art history.

So my question is now that things like concrete and infrastructure and buildings have become so commercialized, has there been a loss of attention to like aesthetic qualities of infrastructure and buildings and stuff like that and more of a focus on their functional practical purposes? Yeah, good question. That's an absolutely brilliant question. So I think there's a balance between the two. So I think so where we need to build lots of good quality infrastructure, structure, lots of good quality housing, and we need to do that reasonably quickly. I think quality

and being able to build things efficiently are probably rightly the main driver. But we always still have those beautiful signature projects. So I'm thinking Olympic stadiums, I'm thinking the kind of beautiful big skyscrapers or the signature bridges. So I think it really depends on what the context of the structure is. But, I mean, you may not have visited the shard because it's quite far away from you guys, but we paid so much attention to every single bolt and weld at the top of the tower, which is where the viewing gallery is, because the visitors come in and you can see all the steel. It's all completely exposed. So, you know, there's the right time and place to pay full attention to the aesthetics and so on. Well, we'll have more talk with Romagrawal, author of Built, The Hidden

stories behind our structures after the break. More questions? Stay with us. We'll be right back. This is Science Friday. I'm Ira Flato. We've been talking about the stories behind the bridges and the towers and the other structures we might take for granted. My guest is Roma Agrawal, structural engineer, who's worked on one of the tallest buildings in the UK, and she's the author of a new book that tries to make engineering more visible to the rest of us. It's built. The book is built. The hidden stories behind our structures. And you can see some of the the structures we've been talking about and the engineering tricks involved on our website at Science Friday.com slash built. Romo, let's talk about climate changes. Is it forcing new

kinds of decisions when we design large structures? So climate change is such an interesting topic. It makes us more conscious about the sorts of materials that we're using. So the most used man-made material on our planet is once again concrete. And concrete does emit a lot of carbon. So we're thinking about how can we make concrete more eco-friendly. We are actually recycling a huge amount of the steel that we now use. So almost 95% of steel can be recycled and reused, which is fantastic. So that's one of the key drivers for us. When you think about buildings more broadly, then we're thinking about energy consumption because our buildings use a lot and lot of energy.

So we're also thinking about how can we insulate them better, what kind of cladding can we use, can we use more efficient air conditioning and so on. So there's lots of different angles that we need to look at from a building point of view, but then of course when you're thinking about cities and so on, then that's a whole other level of consideration. Let's go to the phones.

Let's go to San Francisco. Richard, welcome to Science Friday. Hi. Hi there. Go ahead. As you said, I live in San Francisco. We have a high-rise building in San Francisco. It's located downtown, and it's managed to settle. And I'm wondering if a guest would take if she was designing a building that was to be erected on conditions like we have in San Francisco, such as a lot of mud and fill from landfill that has taken.

place in the past. Good question. Ms. Ackrawal. Yes, thank you. So I was actually in San Francisco almost exactly a year ago now, and I really loved your city, so great to talk about it. So I think your ground sounds quite similar to London. So we need to use piles, which is what I mentioned earlier, so these giant concrete columns that we install inside the ground. And the piles are very interesting because they actually work in two ways. So one is with friction. So you get the surface friction between the concrete face and the mud that it's installed in. And also the actual very bottom, the base of the pile can just push directly into the ground as well. So between these two different kind of physical effects, they should be supporting our structures really well.

So the settlement shouldn't really happen, to be honest. But, you know, I talk about Mexico City in my book. And Mexico City was actually built to the center of Mexico City, as it is now, was built over a lake. And over there, they've had settlement of, about, you know, the equivalent of three stories in the last 150 years, which is absolutely fascinating. Yeah, you know, and it is fascinating. You talk about a lot of hydraulics issues there.

Getting back to the piles, and then here, you know, in major cities we watch pile drivers working all the time, sinking piles in, but I've always wondered in a town, in an island like Manhattan, where there's so much bedrock, and they're looking for bedrock. How do you put piles or steel or concrete into the bedrock? I mean, does it lie on top of it? Do you dig a hole in the bedrock?

Why is that so important? How does it actually happen? So from what I understand, you don't really need to go into the bedrock because the bedrock's really, really strong, and it's not going to let the buildings go anywhere. So all you really need to do is find at the top of the bedrock or a nice strong layer of the bedrock, and you need to put your concrete foundations

just onto there, and then after that, kind of nature does its thing. So it's actually a lot easier to build skyscrapers in Manhattan, say, than presumably in San Francisco or in London, in fact. You know, over the years you've seen, I've seen so many bridge structures, and you don't see riveters anymore. They don't show people putting rivets, a lot of bolts.

Why do they have so many bolts and rivets in a steel bridge? What is that? Yes, I mean, I love that. Yeah, it's beautiful to look at all. They're fantastic, aren't they? They kind of have this old world nostalgia, I guess, about them. So you're right, we don't really use that technique much anymore. So a lot of the structures which had the rivets at the time were made from iron.

And iron is a cousin of steel, but it's got slightly different properties. So it needs more connection. It needs a bit more strength than steel does. And that's part of the reason we've moved to steel because it's a better material to build with. But at the time, the rivets were a really effective way of joining different pieces. of iron together. So that change of the base material led to a change in the way we actually join the metal up together. All right. In the few minutes we have left, tell us your eye view of walking around the city and looking at stuff. What should we look at structurally

to be impressed and be amazed by how buildings are erected? Right. So this is one of my main aims for my book. And I say I want everyone to look at our world through the eyes of an engineer. So what I do when I go up to the viewing gallery in the shard, for example, everyone's taking photographs of the river and of St. Paul's Cathedral. I'm looking up at the steel and I'm looking at the bolts and the wells. And I'm thinking about, well, I can see how it was put together. So, you know, walking around Manhattan, for example, you look up at the towers. And I guess try and peel away the layers.

Think about the glass that's cladding the structure. How was that glass made? how is it flat enough that the reflections and the light actually traveling through the glass makes sure that it's quite clear and that it's flat? And what lies behind that? You know, what's actually supporting that glass? But then think about trying to use some kind of x-ray vision to look below your feet as well. So I talk a little bit about the sewers of London in my book

because they're absolutely fascinating structures. So you're walking around London or Paris and below. you are these absolutely stunning brick structures that carry all the waste of these incredibly large cities. So I feel like, you know, you should be looking for peculiar details, you should be looking for the materials, but you should also very much try and look beyond what you can actually see and try and delve deeper into our structures. Well, I agree with you. The beauty is in the details, and there are plenty of beautiful details in built the hidden stories behind our structures written so well by Roma Averroval out

now. Thank you for taking time to be with us today. And I hope you have another book in you there because it's so nicely written. I love to read more about it. Thank you. Thank you so much. I will definitely consider that. Thank you for taking time to be with us today.

When you think Florida, right, you probably think sun, maybe a little golf, certainly spring training, hint, hint, all right up there with other Florida. icons, the familiar Flamingo. But does the Flamingo really belong in the Sunshine State? Are Flamingos a native Florida species? It might seem like a trivial question, but it's one that has big implications for conservation and how the species is managed. Stephen Whitfield is a conservation biologist at Zoo Miami, and one of the authors of a paper published this week in the journal, The Condor Ornithological Applications, about the Flamingo in Florida. Welcome to the program. Thank you.

Thank you. So why is this a question at all? So Florida is an interesting place because we have a large number of introduced species and at the same time, a large number of species that are threatened with extinction. And for a long time, it's been unclear what actually is happening with flamingos. When you talk to ornithologists, and many of them tell you, oh, the flamingos that are seen around Florida are not native, their escape from captive populations, and other people will tell you, well, there used to be flamingos here in large numbers, but they were all hunted out. So when people were trying to make

recommendations with what to do with the flamingos, you basically have two different, really different management perspectives. Introduce species, you try to control to keep them from causing problems in the environment, whereas a threatened species, the ideal management is some kind of population recovery. So you have to decide whether it's an introduced species or one that you have to manage for a different reason. Exactly. And it was somewhat surprising that for such an iconic species, this information was not really clear. Wow. You mentioned in your paper described historical sightings of the flamingo.

It's sort of like the description of the buffalo roaming across the prairies. Yes. Early naturalists in the 1800s described large flocks of hundreds or thousands of flamingo. goes in the Florida Keys. Wow, and you also look through museum egg collections, is that correct? Yeah, this is kind of strange, but in the late 1800s, it was a somewhat popular hobby to collect eggs of wild birds. People would collect them, keep data on where they came from, and now a lot of those

specimens are in natural history museums. And so we were able to find four egg collections. of flamingo eggs from Florida, which seems to suggest that they weren't just birds passing by, but they actually were resident birds that nested within the state. Were the eggs that they might turn into an omelette also? Did people eat the birds? People definitely ate flamingos.

Virtually all of the accounts by early naturalists in the 1800s mentioned either people hunting the flamingos themselves were mentioned hunting pressure by locals in the area. So it was pretty clear that what drove the flamingos out of Florida was the hunting pressure by people. And they had such pretty feathers. I imagine the feathers were useful, too. Yeah, in the late 1800s, it became fashionable for women's hats

to have lots of feathers. And a industry of bird hunting in South Florida took off where people would come in and kill birds by the tens of thousands, to sell them for their feathers for fashionable hats. Wow. Wow. Do the flamingos migrate? I would imagine they stay in Florida.

It's a nice temperature there. So they're not typically migratory. You think of migratory birds as birds that go one place for the winter and back for the summer. Flamingos can clearly travel long distances looking for foraging areas, but in places where they nest, they tend to stay around in the area. So they don't have typical seasonal migratory patterns. So people in Florida birdwatch flamingos like they might birds watch other birds in the lakes and swamps? Yes, and this is actually really important for our study because in the absence of kind of robust monitoring data for flamingos, we were able to reconstruct the history of flamingos in Florida from around 1950 to the present by using data collected by bird watchers,

over that period. Wow. This is Science Friday from PRI, Public Radio International, talking about the history of flamingos in Florida with Steve Whitfield. You know, we all know about the iconic pink flamingos. Are all flamingos pink? Well, there's six species of flamingos around the world, and they're all pink or pinkish.

Their color is acquired by things. they eat. It's acquired by their diet. So they're actually, they hatch gray and turn pink over their life. And so what's the wild status in Florida now? Are people seeing, I know you're saying it's important that people keep track of them. Are we seeing a rejuvenation of the flamingos? Yeah. Over the past 50 years or so, we're seeing more and more flamingos appear in the state. And there's a couple ways you can interpret this. One that we think is unlikely is that there's a growing introduced population. The second, which seems more likely, is that flamingos, after they've been hunted out for more than 100 years, are now starting to slowly return by dispersing from

nearby populations in the Caribbean. Is that right? What parts of the Caribbean would they be coming from? So there's breeding colonies in the Bahamas, in Cuba, and in Mexico. And in the Yucatan of Mexico, there's been a banding program where they put leg bands on flamingos as their s-chicks. And in the past 10 years, there's been two individual birds that showed up in Florida with leg bands indicating that they came from Mexico. So this is pretty clear evidence that there are wild birds flying into the state, and we probably shouldn't treat them as a non-native species. You should not treat them as a non-native species.

Yeah, there's not a lot of evidence, actually, that flamingos are escaping from captive populations. There certainly appear to be too many individual birds and group sizes that are too large. The largest group of flamingos who've seen in Florida in the past, probably past 100 years, has been 150 individuals. And if someone had 150 flamingos and they all disappeared, you know, they would probably notice. So how far north do you find flamingos? So occasionally they'll get up into northern Florida, but most of almost all of the flamingo observations from within Florida are from the very southern part of the state. And you're using genetic testing or other studies that could help settle this question about the invasive or threatened species? Yeah, so we're trying to do a number of approaches to figure out where the flamingos are coming from.

One is by doing genetic testing of the flamingos here in Florida with flamingos from all around the Caribbean. We're also working on some techniques using stable isotope ecology, which can help distinguish wild versus captive birds, and satellite telemetry to try to see where the flamingos are coming from. There's such iconic birds about Florida. I imagine there must be a lot of interest in knowing more about them. There certainly is, but it's so far somewhat of a mystery. Well, thank you for helping us talk about that mystery, Stephen. All right.

Thank you. You're welcome, Stephen Whitfield Conservation Biologist at the Zoo Miami, at Zoo Miami in Miami, Florida. One last thing before we go, Science Friday is kicking off our first live taping of the year. Speaking of Miami, it's a different Miami. This is going to be at Miami University in Ohio. Mark the calendar April 21st at Miami University in Ohio. We're doing our first live taping.

Come out and watch Science Friday. We hope to see you there. And we have a whole bunch of other events. We're going all around the country and other events. And you can check out where we're going to be. There's more information at tickets at Science Friday.com slash events. So we want to see you as we travel around the country. Watch a live taping of Science Friday.

It's a lot of fun. People have a lot of fun in the audience. Charles Berkowitz is our director, senior producer, Christopher Entaliata. Our producers are Alexa Lim, Christy Taylor, Katie Heiler. We have technical and engineering help from Rich Kinn, Sarah Fishman, Jack Harowitz. And we are active all week on Facebook. And we see you there, Facebook, Twitter, Instagram, all the social media. And if you have a smart speaker, you can ask it to play Science Friday whenever you want.

So every day now is Science Friday. You can also email us SciFri at ScienceFriday.com. I'm Ira Flato in New York.