It's Christy here.
Welcome to another episode of From the Vault, where we rummage through the Squiz Kids archives, brush past the cobwebs and dust off a classic shortcut episode.
This week, to celebrate World Turtle Day, we're diving beneath the waves to revisit one of Australia's greatest national treasures, the Great Barrier Reef, because if you're going to celebrate sea turtles, you really should visit one of their favorite hangouts.
And in this episode, Amanda and Bryce explore why the reef is one of the seven natural wonders of the world, what coral actually is because surprise, it's not a rock or a plant and how this colorful underwater world is facing some pretty big challenges.
So grab your snorkel, pull on your flippers and get ready to drift through one of the most beautiful, bustling and biodiverse places on our planet.
This is a Squiz Kids podcast.
Your fresh take on what's happening in the world around you.
It's one of the seven natural wonders of the world, the only living thing visible from space, and experts are worried it's in danger.
This is your Squiz Kids shortcut to the Great Barrier Reef the podcast where we dive into the who what when where, why and how of the big news stories.
I'm Amanda Bauer.
And I'm Bryce Corbett.
Bryce.
Every year, two million people visit the Great Barrier Reef to experience all that the massive Marine National Park has to offer.
But lately on Squiz Kids we've heard that experts from the United Nations came to Australia to study the health of the reef and were recommending that it be officially listed as in danger.
Yeah, that's exactly right.
Today we'll take you through why the Great Barrier Reef is so famous, what exactly is a coral reef and how one of Australia's top tourist attractions is in trouble.
Listen carefully, there's a squiz at the end.
Why?
Bryce.
The Great Barrier Reef is the world's largest coral reef and the National Marine Park is bigger than the states of Victoria and Tasmania together.
Wow.
It takes up...
2344000 square kilometres and extends from the northern tip of Queensland all the way down to just north of Bundaberg.
So that's 2,300 kilometres long.
If you wanted to drive that far...
And if you were able to speed along at 100 kilometers an hour without stopping for petrol, a sleep or even a wee, it would take you 23 hours.
Whoa.
So one reason the Great Barrier Reef is famous is that it's just so big.
Of course, that's right there in the name, isn't it?
Great.
But that's not all.
This massive reef system contains not just 600 plus types of soft and hard corals.
There are also 1,625 different types of fish.
3,000 varieties of mollusks, which is a fancy word for shells.
500 species of worms.
133 varieties of sharks and rays.
More than 100 types of jellyfish.
And more than 30 species of whales and dolphins.
Humpback whales come to the Great Barrier Reef all the way from chilly Antarctica.
When they arrive in the warmer waters off the Queensland coast in May, they date, they mate and they have their babies before heading back in September.
Now Amanda, I've heard of lots of humans having their honeymoon in Queensland, but I guess it's also a place that attracts other species too.
Remember how we talked in our Squeeze the World trip to Costa Rica about biodiversity?
Yeah.
It's the number of different plants and animals in a space.
And the Great Barrier Reef is precious because of the extraordinary diversity of marine life.
It is really beautiful underwater.
There's incredibly colourful coral.
It's teeming with fish and shells.
And my personal favourite creature name, nudibranchs...
I'll put some video links into your episode notes so that you can get a sense of what those 2 million tourists who travel there each year are able to see and why they love it so much.
Of course, those tourists also create about 65,000 jobs for people.
There are tour boat operators, restaurant and hotel staff.
And then, of course, there are all the jobs created for scientists who study the reef.
Now Amanda, you said that the Great Barrier Reef was the only living thing visible from space, which made me realise that I might need some more information on what exactly is a coral reef.
What?
Squiz Kids, did you think coral was a mineral like a rock?
Because you've touched a piece and it was super hard and scratchy.
Or maybe you thought it was a plant, because they sure do look like trees and shrubs growing on the ocean floor.
Well, actually corals are alive, so they're not rocks, and they don't make their own food like plants do, which means they're animals.
Each single coral animal is only about a centimetre and a half big.
The size sort of depends on the species.
And that animal is called a polyp.
Those branches or blocks of coral that we see are really colonies of hundreds or even thousands of polyps, all living next to each other.
The polyps secrete, which is a word that means produce, an outer skeleton of limestone.
And that's what feels hard to the touch.
Those skeletons attach onto rocks, as well as the skeletons of dead polyps, to form those incredible coral colonies.
Now Amanda, I remember learning in primary school science that living things move.
But if coral is attached onto rocks, it doesn't move, does it?
Well, actually, those polyps do move.
They have these tentacles that they stretch out to sting and capture tiny plankton.
That's their food.
And they can also pull those tentacles back into the hard shell of the coral if they're threatened.
Now, I also remember that all living things reproduce.
So how do mummy and daddy corals make babies?
I am so glad you asked Bryce, because this is one of the coolest things about the Great Barrier Reef.
Most coral species don't have a mummy and a daddy, because one coral polyp can produce both sperm and eggs.
And every year and only once a year.
Coral colonies have what's called a mass spawning event.
So the polyps release tiny egg and sperm bundles into the water all at the same time to increase the likelihood that fertilisation will happen.
If they're all there at once, then it's more likely that it will happen.
Now, this mass spawning looks like a huge snowstorm in the water.
It only happens at night, it only happens after a full moon and it only happens after the water has warmed up to a temperature that stimulates the coral to get going.
Oh yeah, I remember talking about this on Squiz Kids today.
The spawning lasts up to a week because different species of coral release their eggs and sperm on different days to prevent hybrids from being produced.
Yeah, that's right.
And it happens at different times on the reef, depending on the depth of the water, which of course influences the temperature and other factors.
Once an egg is fertilized, it develops into coral lava, which I would love to call a baby, but the proper scientific word is a planula.
The planula floats around in the water for a few days before it settles on the ocean floor, starts to grow and a new colony develops.
Wow, what an amazing system.
How then are these amazing coral reefs in trouble?
Well, Bryce, over the past few years, there have been some coral bleaching events on the reef.
If you bleach your hair or your clothes, they turn white, right?
And that's what's happened to the coral.
It's lost those incredible colours and sort of become a dull, lifeless white.
And the main reason that happens is when water temperatures get too warm.
And that's something that's happening with climate change.
Yeah, that's right.
And the United Nations sent a team of ecosystem experts from lots of different countries to Australia to look at the reef and find out how much damage has been done by climate change, as well as other factors like runoff, which is when water becomes polluted by human activity in towns on the coast, and things like the use of pesticides and fertilizers on farms that runs off into the water that has the coral in it.
Now, meanwhile, there are lots of things that visitors can do to help protect the reef.
If you're snorkelling or diving, you make sure you don't touch the coral, and be especially careful if you're wearing flippers, because kicking the coral can do some serious damage.
And, of course, don't feed the fish because that can make them sick, and don't throw food scraps overboard if you're on a boat.
You should check that your sunscreen is reef safe or even better, just wear a rashie.
There are lots of other ways to be a responsible reef visitor.
I'll pop a link in your episode notes because every little thing counts.
Time for the quiz.
This is the part of the podcast where you get to test how well you've been listening.
Question number one.
What's the name given to one living piece of coral?
That's right.
It's a polyp.
Question number two.
Which animals come to date, mate and have babies at the Great Barrier Reef?
That's right.
It's honeymooning humpback whales.
My favourite kind of humpback whale.
Question number three.
What happens on the Great Barrier Reef once a year at night after a full moon?
That's right, it's a mass coral spawning event, which is a fancy way of saying coral reproducing.
That's all we have time for today.
Thanks for joining us as we explored the who what how where, when and why of the Great Barrier Reef.
Now get out there and have a most excellent day.
Over and out.
