SYSK Selects: How Coral Reefs Work

Welcome to Stuff you Should Know from House Stuff Works dot com. Hey, and welcome to the podcast. I'm Josh Clark with me as always as Charles W. Chuck Bryant, and that makes this stuff you shouldn't know. So I just noticed your cold is cleared up. Yeah a little bit. I still have the the an interior lining and very thick all right. The other than that, Yeah, you sound fine, that's all. You know what it was tons of emergency used to wash down tons of vitamin B stress, which

is like tons of just different vitamin b's. I eat solar ray um and Scotch right single malt Scott just my secret ingredient um and lots of licene, A couple of licenes every time, like thousands and thousands of percentages of daily value. Like just it just makes the FDA cringe that I take as much. That's what I do. I just load up on like everything, like triple it. Yep, there you go, take that body, So I'm fine. Good now you has it? Oh does she the same exact thing?

And she doesn't like when I tell her to take vitamins? Yeah, but that you know, you live together, you drink after one another. Just suck face, just like I'll leave like emergency here. They're like laying around. Oh did I leave that? Oops? That's already dissolved the water even and it's going down your gullet, um chuck. Yes, did you know that I am a certified scuba diver? I sure did. Oh yeah you did not thought for sure. You're gonna be like, no,

I didn't know. We've talked about this. Yeah, we've even scuba dive together, haven't. That's right. That was the first time I heard about it. I'm not the sharpest tack in the package, um, but I say that to tell you that I was certified at a place called Isla Mueris off the coast of Cosumel, which just so happens to also be the home of the second largest barrier reef known to man. What's it called to humans? I

don't know. It is not called anything, because there's the great barrier reef and then there's all the other all the other ones, but this is the second largest, which is pretty big. Because there's a lot of barrier reefs. There's a lot of coral reefs in the world. But after reading this article, I found that there is a lot about coral reefs that I didn't know. Unfortunately, we had Jennifer Horton, who I'm sure you'll remember worked at the site for a while. Yeah, she's a great writer.

He's a great writer. We had. We had her to explain it to us and like, I get coral reefs now. In fact, Jennifer has written many of the animal related podcasts that we've done, um Bison. I think maybe she wrote a lot of the animal stuff, animal migration, lots of good ones. To miss you, Jennifer, I hope you're well if you listen. I wonder who were they? Right? Remember those guys? I hated those two all right? Coral reefs.

This was all new to me. The rainforest of the sea of the Equatorial Seas home to about of all the species. Yeah, that's crazy. In fact, right, Um, the Great Barrier Reef has more more kinds of coral um on like one just single little outcropping of it, then you'll find in the entire tropical area of the Atlantic Ocean. Wow. Yeah, that's amazing. I don't know why I just said that. There. The Aussies are gonna they're gonna be so stoked with

this podcast. Probably anytime they can like claim to something like that, they're just like, yeah, yeah, drank exactly. They're gonna go poor beer on the Great Barrier Reef. Um. It's the coral reefs are very beneficial to humans in a number of ways. Economically, sure, because there's a lot of sea life and thus people fishing for shrimp and lobster and things like that. Right, in all sorts of weird ways which we'll get too later. Um. They also

protect the beach from erosion. They act as natural buffers from huge waves wave action, that's right. Yeah, Well, let's talk about that. Because you think of when you think of coral, you think of huge you know Great Barrier Reef. It's enormous. It's like, um, I think there's eighteen thousand miles total of coral face face that is on the Great Barrier Reef. Actually, an individual coral called a polyp um, is about three millimeters long. Yeah, that's small, super tiny

for those of you in America. Uh, they are, Well, science got it wrong early on. We should go ahead and say that they um at one point fairly uh understandably thought that it might be plant life because it sort of looks like it. Yeah, like you know, like the coral fan. Yeah, that's a bunch of those little three millimeter corals building up into a fan. It looks like it looks like a plant. Yeah. So they got it wrong, and they're actually not only are they real

living little sea creatures, but they're carnivores. Yeah, which is you know, you would never think about that. No, but they're in the phylum Sindaria Nideria. Why would they put the sea there? It's silent, man, You know, I appreciate a silent letter. I'm smarter than my pronunciations would suggest. I started looking this up because I feel like an idiot. So they're in the phial of nydaria, which means um that they have stinging cells, barbed stinging cells um called

ne maticist that's right. So um they use this to capture their prey, but the prey kind of has to come to them because they're also sessile, which means they're fixed to a certain spot. Yeah seriously, Yeah, uh so it is understandable also that they got it wrong because coral has a unique property. It is almost half plant because there's this algae in the cells. I want to pronounce it, Okay, go ahead. It's called zus anthely, you're right, very nice. Starts with a Z and there's an X

in there somewhere. And then so what happens with there's a very mutually beneficial relationship between the algae and the polyp. They do a little exchange the polyp itself, well supply, I'm sorry. The algae will undertake photosynthesis, yes, as algae tends to do. As algae will do, and it will say, hey, mr polyp, why don't you take all this stuff that i've I've made within your cell walls and and convert

it to proteins and fats. It poops out like amino acids and cards for the polyp, and in return, why don't you give me a nice shelter, And you can also produce some carbon and nitrates and pop fates that I need to produce the photosynthesis to give you the proteins and fats that you need. So it's what you might call a symbiotic relationship. Exactly, one's helping the other.

And um, you can make the case that the coral is getting the better end of the deal because coral gets about the energy produced through photosynthesis by the zoos anthely, right yeah, um, but that also makes the coral more dependent on the zoos anthely. And the zoos anthely it's a algae of very little needs. It's not needy, it's not grabby. It's not gonna call you up every Friday night wondering what you're doing, Why you aren't here? Are you talking about me? No? No, Jerry like that one.

So um. The the symbiotic relationship between the zuox anthely and the coral polyps also produce coral reefs. Um. The polyps use some of that energy, some of that amino acid, to create something called calcium carbonate, and that's the hard stuff. Right, that's limestone, my friend. Yeah. They produce limestone out of their butt hawks to create a cup, a little shelter for the polyp to stay in. And since the algae

stays in the polyp, it creates a shelter for both, right. Yeah, and this limestone secretion can keep building and building and building because again, coral stays in the same place there cecile. That's right, and um as as long as they're still secreting lime stone, the limestone structure they build will just keep getting bigger and bigger. Eventually love it. That's just one three millimeter long, coral. Yes, what you want to

do is get thousands together strengthened numbers. Yeah, then you have a coral fan yeah, or a colony, and then those colonies will eventually meet up with other colonies uh and say, hey, you guys interested in forming a wreef because we're pretty indestructible, although that's not quite true. We're more indestructible if we all hook up my brothers, like you said, strengthened numbers, and when they hook up, their limestone secretions can start to join together forming a reef.

But they're also um connected by a thin piece of tissue. You got this one called a seen a sark. That's what I was gonna go for. I was just tired of humiliating myself for this episode. I would have called it a kna sark, So I was a way off. I'm really glad to look that Celia canth it's a scene of sark um. And that's how the the coral themselves are through limestone secretions and through this tissue called the sin of sark. They're connected, right, but how would

they grow? Well, there's two ways. Many they can reproduce. Yeah, a couple of ways, so right, sexually or a sexually? I know which one I choose. A sexual, Yeah, because you're cloning. That's pretty remarkable. Anyone can just get together and you know mate. Sexually, it's like here's some sperm in another one's like here's some eggs, and then they get together and then it's just it's no, there's not

much to it all, right. A Sexually, though, they actually do divide and produce identical clones of themselves, and that's one way they can grow. And the other way is just to keep pooping out limestone and that will connect with each other. And it just forms a big old yummy wreath. M Um. This is not a fast process though.

Like if there's a couple of coral that are a few inches away, say three inches away, and they're like, I would like to hook my sine a sark up to your sine a sark and let's poop some limestone I was together and get this reef going. That's beautiful. It's gonna take them about a year to get together. Can you imagine how frustrating that is to be three inches away and be like, I'd really like to consummate this. I'll see you next June. I'm not convinced that coral

can experience frustration. You don't think so, I don't. I think that's all they experience frustration. Either that or they're like really really patient, but that three inches of growth a year um has to take place. They're very specific conditions. Remember we said that coral reefs are in equatorial waters. Um, not the coral themselves, but the zoos anthely are actually very fickle and picky little organisms and they like specific conditions and as long as the conditions are right for them,

then the coral can grow. Because remember the coral are dependent on the zaxananthely to produce the calcium carbonate. That's right, Um, so what are the conditions chuckers Well, you said equatorial, specifically thirty degrees north or south. If you have ever dived in the Bahamas and said, no, that's thirty two degrees north and they have plenty there. It's because the warm Gulf waters spitting out towards the Bahamas, which is one reason the Bahamas is such a popular spot. I

would imagine, Yes, I've never been there. You no, my folks drove my car back from the Bahamas. Thoughts you had a car in the Bahamas, you're supposed to say, you're kidding, You're kidding, I must be The Bahamas are islands. It's a it's a dead milkman song. It's pitching camaro Oh that's from Bittnick Camara. Yeah, it's the beginning. Jeez, I'm a dummy. That's alright, Chuck. I'm not hip. I'm

not hipp either, Chuck. Sunlight is another thing that they need because, and it makes sense if you're gonna undertake photosynthesis, you need sun. So if the water is rich in nutrients, believe it or not. That's not great for them because if you've ever looked through if you've ever been under water and seen like a lot of plankton everywhere it filters the sunlight, it's dappled, that's right. And also, as we learned later, UM, the more nutrients there are, the

more it will attract uh competition for those nutrients. And that's not good for me either. No, they don't like competitions. Basically, they're just little prima donnas. Example, they are the water, since you're near the equator, should be between seventy three

point four and eighty four point two degrees fahrenheit. And I ultimately, if you put all these facts there together ample like clear water and between seventy three and eighty two or twenty three celsius and twenty nine celsius um, you can get up to about ten centimeters or three point nine inches of growth in a year, twice as much on sunny days. Yes, but they're still not going to exceed that three point nine inches most likely because

it's might be all the time. But what's cool then is if you think, well that's crazy, you know there's some coral that Um, I've seen coral reefs, and they're big. And if it takes three point it takes a year to grow about three point nine inches, say horizontally or vertically, maybe even die diagonally. If it was like a crazy year for them. Um, it must take thousands of years for coral reef to build up. You would be right, my friend, Which is why scientists very affectionately consider coral

reefs the old growth forests of the sea. UM. Because when you're looking at coral reef, you're looking at something thousands, if not tens of thousands of years old. Which is my question is how long does the coral live? So one thing I didn't get out of this this article. Did you, oh, how each individual coral, each polypic boll? I don't know. And are they are there their cups, the protective cups that they secrete? Um? Are they inhabited

by like successive generations, their clones maybe my guests? And I'm guessing here is that there are so many, hundreds of thousands and millions of these packs so tightly together that if one of the little guys dies, it ain't no big thing, because he's surrounded by his living brothers and sisters. But I don't know how long each one lives. At this good question, someone will know. Coral sand. If you look at the reef and you think, hey, coral

is obviously the skeleton here of this great reef. Uh, it's not just the coral. Coral sand, from what I understand, is little remnants, tiny pieces of coral that are either eaten and pooped out or just chip away because of erosion and waves crashing and bad weather and stuff like that. Right right, yeah, and um, but the cool thing is that it doesn't necessarily go anywhere. It can fill in gaps or holes, and then, as luck would have it, there is a type of algae called coral line algae

that goes and covers it up. And the structure of the algae acts is like an adhesive that glues the coral sand. So basically it's like this self sustaining repair process that's always going on. Waves of road the coral into coral sand. Certain types of fish choose the coral into coral sand. The sand goes in just drifts into

like little pockets where it gets caught in. The algae lays over it bam strong coral well and coral sand is mind which is one of the threats to reefs because they use it for bricks and cement and road fill. So if you're mining the coral sand, there's not gonna be that natural spackle to fill in the holes, and thus the reef is jeopardized, which is just one of many ways that research in jeopardy. Apparently one estimate is that um of the world's reefs could be gone in

the next few decades. That's scary, very sad. I hope you're scared. I'm scared. Um. This is where I got a little confused, was well, let's talk about the kinds of reefs, because I'm not confused about that. There are basically three categories, depending where they form the fringing reef. It's most common it's directly from the shore and they form a border projecting out to the sea. Yeah. It's kind of like, Um, if you go to like Marble

Head in Ohio, there's a lighthouse. Um, I think it's limestone. It's like it just comes right off the land, right. I don't understand how that would be because it's in Lake Erie, which is not fresh water, but who knows. It's very similar to that. It's like just a rocky projection jutting out from the land. But it's a coral reef, right, or if it were a coral reef, that's a fringing reef. Interesting reef attached to land. Very reef, very similar to the fringing reef, but it has a gap of water

between the land and in the reef. Correct. And then my favorite, of course, the atoll. It's a nice one, which is when at one point there was an island or volcano and it sunk, but you still have the circular wreath reef with I guess like a lagoon or something. Yeah, the reefs keeps building, but the mountain is now submerged. Pretty cool. Yeah, so you got your three types fringing barrier and at all, Right, the zones is where I get a little confused. So all of these reefs um

are kind of broken down into zones. Like remember the bio speleology. How could I forget? Okay, So you've got like the different zones of the This is very similar to that. You've got the back of the reef, and the back is the side closest too short. I think that's what confused me. And then really it is a little confusing but it's from the it's from the viewpoint

of the sea. Um. So you've got just imagine like a line and then a bump and then another line, and that's our reef right um on the shore side of the bump, that's the back of the reef. And this is actually where the most life is. Yeah. Um. Sometimes it's left high and dry by low tide, but most times it's just this little shallow area that's got tons of sunlight. So there's tons of plankton, which means there's tons of fish. There's a feeding frenzy, there's diurnal

temperature changes. It's just very pretty. It's what most people think of when they think about diving on a coral reef. Right. Then that bump, that's the ridge or the crest. Okay Um, that part the the crest is always exposed at low tide, and it may be exposed even at high tide sometimes depending on how big. But it's the tallest point. It also um serves as the wave break for that function of um reefs that protect the lane. This is what the waves smack into, so it's gonna be more easily

eroded and probably have more of that natural spackle. Right yes, that was it coralline algae. Probably that was called cora line, yeah, oka or coraline whichever, however you want to say it, Chuck, I'm not gonna stress you out, all right, um. And then there's the four reef that's the the ocean side,

the seaside, right um. And in that part of the four we find the other side of the crest, the seaside of the crest, there's the buttress zone, which is awesome if you ask me, And that's where you're gonna find if you're shark hunting, that's where you're gonna find like sharks and barracuda and interesting things like that, right, But does it buttress? Is that why they call it

the buttress zone? So the buttress consider a buttress is just like a jutting projection of coral limestone, right, just jutting out, and then in between these projections are little

channels holes that can go all the way through. I'm not quite sure what the physics are of it, but basically, once a wave goes through this coral reef and hits shore and then gets drawn back out to see these channels, um funnel these spent waves back out to sea, and by funneling them it gives them a more energy, so then they crash into oncoming waves, which reduces the oncoming waves velocity. So all this is is in an attempt naturally to combat the erosion of pounding waves. Yes, awesome,

Yeah it's pretty cool. Um, that's also a really excellent um shelter for a little fish ease and things like that. They want to go into the channel. So, josh, we've talked about the Great Barrier reef uh here and there, but we should give it its proper do as the largest living structure on the planet scene from outer space. Everyone loves to throw that back around. Yeah, can see it from outer space. And then made me look something up, chuck, Um,

that's it's the largest living structure. Okay, So if if coral reef is an organism, do you know what the second largest living organism is? Um, it's a fungus in Oregon named amarially Ois stay years old. Takes up four square miles or ten square kilometers, single organism. Where is it Oregon, Oregon? Yeah, it's a It's at our friend Van Nostrian's house. So it's a big mushroom. Yeah. Interesting,

didn't that gross. That is gross. So uh, the Great Barrier reef, we're talking four dwy nine miles or clicks and um, it is not a single reef. It's about three thousand I got so. I'm not sure if that number had declined since this was written or not. But um, Jennifer points out, and like you pointed out earlier, the the full edge of the reef is about UM eighteen and a half thousand miles. So she says, if anyone's ever told you they've died the entire Great Berry Reef,

their dirty liars. Yes, she said, they're lying because there's no way you couldn't do it in a lifetime. She said, I wonder if somebody told her that, and she like inserted it in the article. I don't know. It's definitely an accusation, it is. It's a weird tien. It's one of the seven natural wonders of the world. More than four coral species, two thousand fish species, four thousand mollusks,

and six of the seven sea turtle species. Ease, all right there for the for the googling, nice and the um, like you said, the Australians are gonna be proud of this and they should be back. In nineteen seventy five, apparently it was in some jeopardy and the Australians moved to protect it as a National Marine Park UM and that basically ensured its survival. It's still you know, kind of in rough shape here there is, as I understand.

But um, six years after that, so let's see, that's one it became a World Heritage Site UM and one percent of the eighteen and a half thousand square miles or eighteen and a half thousand linear miles UM are open to the public except for that one percent to just one percent is dedicated to research only just research, just pretty cool, not very much because all they need

bona fide scientists to dive that part. The rest of it, Jennifer points out, is divided into National park zones, which is where you can go, recreate and learn some things. And then the rest of it is general use, which means commercial fishing, which I guess there's no better time to get into the threats than right now. Yes, um, there are some coral reefs in trouble um the Great

Barrier Reef. Like I said, it's pretty well protected. But say, if you look at some of the reefs in the Philippines have been destroyed and five percent, just five percent are in good condition these days, um ten percent of the world's reefs are now beyond recovery, not just because of human causes, because of the natural causes as well. Because everything exists on a life cycle here on Earth, we humans just tend to accelerate it. Ument may die

in the next ten to twenty years. So what are Some of the natural threats are obviously harsh weather like hurricanes, um el Nino a weird weather pattern. It's going to increase temperatures, mess with the salinity, a lot more rainfall. So an El Nino season could can do some serious damage. Bleaching coral bleaching. When they experience as little as like one degree rise in temperature, the algae will be ejected basically from the coral. The algae takes off. Oh it leaves. Yeah,

it's like see you in hell, coral. There's a fine line between ejection and and self leaving. It's the chicken and egg thing, maybe you think so. The algae gets the heck out of dodge, turns the coral white, and if you google pictures you can see a lovely coral with like white patches here and there. That's the parts

where it's bleached out. And if if this keeps up long enough, the coral dies because again coral has a symbiotic relationship where it's dependent on this zu is Anthony's algae and if the us Anthony's leaves, then the coral dies very sad um. And like you said, it was just a as much as a one degree temperature increase, right, that's not much. There's also predators, like there's things that eat um the coral, the polyps themselves, crabs, worms, snails, barnacles,

parrot fish. Those are really pretty I can't do anything about that, pal that's nature at work. But there are things we can do, such as not using dynamite when we fish on coral reefs. It's it's a pretty good start. There's forty countries in the world. Over forty countries in the world that allow blast fishing, people using explosives that they drop onto the reef to stun the fish so they can just swoop them up with the net and um basically go fall like a slack jawed yokel wearing

nothing but overalls. While they just bring their nets in. They just threw dynamite in the water to stunt fish. Well, the dynamite also has a deletrious impact on the reef structure as well. You're gonna go to the grave with that one, aren't you. I saw on Facebook you you put the apostrophe in y'all after the again, mix it up. You know what's weird is the iPhone corrects it incorrectly. Oh really, yeah, Well they don't know, y'all. They're from California.

I've always done why apostrophe a l L? That's correct, you all y'all. Now see someone pointed out to me on email that it was, in fact, why a apostrophe LLL? No, it's you all, so I've been doing it right the whole time. No, you're doing it why a apostrophe LLL? Because someone told me to change it. You can't just listen to any know who. Email fans have a delterious effect on me, deletrious. Do you want to look it

up right now? Let's talk about blast fishing again. Our cyanide fishing, which is the ugly step sister of blast fishing, which is dumping cyanide onto reefs to kill fish. Again, you have to wear nothing but overalls, no shoot, nothing, no service over fishing period has got a negative effect obviously. Yeah, because you're basically affecting the food chain. You're like, oh, we like these guys because they're tasty and I'm sure they won't be missed. Whenever you take any key species

out of a an ecosystem, you're in trouble. No good. Um, there's also a runoff. It's a big one because, um, remember they like clear light, the algae do, and uh or clear water and when they're when the water is not clear, they shrivel up because they need sunlight for photosynthesis. Yeah.

The pollutants went also. Um, I thought it was gonna be pollutants because just pollutants are bad, which they are, but really the reason is pollutants and sewage actually in increase the nutrients, so that attracts harmful algae and uh competition and that's no good. Right, And then we already talked about the mining. So what can we do, chuck, Um, we we've got a few things we can do. You can adopt a reef, you can tons of organizations will

let you do that. In fact, if you want to go to adopt dot nature dot org, slash coral reef. You can adopt a reef in the Bahamas, Dominican Republic uh poo and Popua New Guinea. Nice, just like that. Yeah, you can funnel money to an organization that will take care of that reef exactly. Um, and that's just one. I think you can do it through all kinds of places. Didn't you say that you can get your congress person

to lobby for stricter oversight of phishing methods. Um, you can boycott products from countries that allow blast fishing or cyanide fishing. Really put the squeeze on the common then in the other country, make him go to his You cannot chip off bits of the coral when you scooba dive because it's just so pretty that you want to take it home. Yeah, that's a big one. Give it

to your daughter. Yeah, not good. There's a lot of stuff you can do that you probably should do if you want to save the coral reefs, that's right, and nothing else. Why would you save them? Do you say, if you don't care about snorkeling or anything like that, Well, my friend, if you care about the economy, you will want to save corals because they are valuable the the total value of the asset, that is, the reefs, the

reef systems in Florida. In Florida alone, just Florida eight point five billion dollars when you take into account not just tourism, which is a big part of it, but also the estimated hundred and seventies seven thousand jobs that all the industries surrounding it UH create. That's just Florida worldwide, just from tourism and recreation, just tourism recreation that reefs bring in nine point six billion dollars annually. So if

you like money, then you should support coral reefs. Twelve of Bolivia's g d P is created by reefs, isn't it crazy? Yeah? So, um, if you don't have a heart about money, makes you liy, then that's you get you going on saving coral reefs as well. That's right. So if you want to learn more about core reefs, including um seeing a diagram of where the four and the back of the reef is, you can type in coral reefs in the search bar how stuff works dot com.

It'll bring up this great article by Jennifer Horton. Um. And since I said Jennifer Horton. It's time now for listener mail. All right, listener mail, Okay, alright, I'm gonna call this good cause from a good person. UM. Hello, s Y s K Team. I wanted to take a minute and thank you for helping me in a really

big way. I've been working alone as a volunteer in Malawi, South of Tanzania Malawi Malawi UH since September of two thousand nine, and I happily passed the time listening to your show during my super long, super awesome minibus rides. I am building a library and a small village, and a big part of my library is an audio video collection that I've been putting together for the past few years.

Many of the people in the village are illiterate, so a library full of books just wouldn't do them any good. So I started to think of ways I could include everyone in a learning activity. My answer was UH to incorporate documentaries and podcasts on a variety of subjects. So basically, we will choose a topic for the week and use the podcasts as a way of getting people interested, then direct them to read articles and books on the topic

or watch documentaries, and have some group discussions. Pretty cool. Um. I really believe in the beauty of being inquisitive and interested in life in videos and podcasts really help immerse people in new subjects. Uh. This first library of its kind in the country. Wow. And I'm really hopeful that it helps to open the world up to people who

are so often cut off fingers crossed. And that is from Diane Bowls, the founder of the Future found And if you want to check out Diane's awesome work she's doing, you can go to the Future found dot org. Excellent, Chuck, very cool. It's Diane, Diane in Malawi. Yeah, building building, the only library of its kind and it's so cool. Um, thank you very much Diane for doing that. Um. What do you want to hear? If you want to hear of other people making a difference in the world, we

always love that. Yeah, you're a sap for that kind of thing, or some good harrowing scuba diving stories one or the other. Okay, So um, that's a great one, Chuck, either doing good in the world or not doing needed whatsoever. Um. That could be directed to Chuck and I via Twitter at s y SK podcast. That's our Twitter handle on Facebook dot com. If you go to stuff, you should know his page. That's that um and you can also email us directly. We both get emails sent to the address.

Stuff podcast at how stuff works dot com. For more on this and thousands of other topics, is it how stuff works dot com. To learn more about the podcast, click on the podcast icon in the upper right corner of our homepage. The how stuff Works iPhone app has arrived. Download it today on iTunes.