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The Great Barrier Reef, Australia.
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A World Heritage Site.
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It's an underwater oasis.
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The largest coral reef on the planet.
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Big enough that it can be seen from space.
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And directing its complex rhythms, the moon.
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In the summer, a festival of life unfolds.
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Ocean life reproduces in concert
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with the movements of the moon.
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The gravitational pull of the
moon causes the spring tide,
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which helps sea turtles swim ashore to complete
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the circle of life.
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The night of the new moon,
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more than 20,000 turtles come ashore all at once.
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One by one, they crawl slowly onto beaches
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and lay egg after egg.
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The climax of this festival of life,
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a mass coral spawning.
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Suddenly, on this one night, they come to life
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and, in synchrony, release these magical particles,
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which float upwards, like upward
snow, towards the surface.
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A crew set out to capture
this grand spectacle,
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using the latest, super high-definition cameras.
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This coral spawning takes place just once a year.
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All along the Great Barrier Reef,
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hundreds of millions of coral release their eggs
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simultaneously, filling the ocean
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with what looks like stardust.
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A mystical place, guided by the moon.
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Witness how the diversity of life unfolds
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on the worlds largest coral reef.
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Coral reefs are often referred to
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as the rain forests of the sea.
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They exist in warm, clear, shallow waters,
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and those waters must be clean and tropical.
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The Great Barrier Reef is, by far,
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the largest coral reef on the planet.
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It's off the coast of northeastern Australia,
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covering a range of more than 2,000 kilometers,
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an area roughly the size of
Japan, Italy, or Germany.
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It's considered the world's
largest single structure
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made by living organisms.
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Coral reefs, like tropical rain forests,
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harbor the greatest diversity of life on Earth.
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The Great Barrier Reef is home to more than 1,500
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species of fish and some 3,000 species of mollusks.
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Even compared to other coral reefs,
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its biodiversity is astonishingly rich.
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It is literally teeming with life.
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Accompanying us is Russell Kelley,
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who has observed coral reef
life for more than 20 years.
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Kelley guides us to a special spot.
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An underwater garden,
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filled with corals of all shapes, sizes and colors.
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From small fish to big, they all feel at home here.
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The reef is made up of stony corals.
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Some have thin branches stretching out.
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Others form rows of thick pillars.
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Some are flat, like tables.
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Others look like giant brains.
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There are 400 coral species
on the Great Barrier Reef,
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1/3 of the world's total.
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Corals are actually animals,
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so small they can't be seen by the naked eye.
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Corals are simple animals,
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like jellyfish and anemones.
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What we are looking at is a coral colony.
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This skeleton is actually made
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by many individual coral animals,
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which live in these tiny holes.
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Take this table coral, for example,
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at first glance, it looks like hard stone,
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but it was formed by the
accumulation of tens of thousands
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of corals.
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The coral has fine tentacles.
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A single coral is only a few millimeters in size.
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Corals construct a calcium carbonate skeleton
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around themselves, and this builds up over time
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to form large coral reefs.
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At night, the corals expose their tentacles
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and wave them about.
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This is how they capture their main source of food,
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plankton.
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Another source comes courtesy
of these brown particles,
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zooxanthellae.
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They're a type of algae that live in corals
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and share a symbiotic relationship.
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And they help to sustain the
coral by photosynthesizing
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sunlight into nutrition.
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The coral, meanwhile, cleans
itself by expelling mucous,
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to remove dirt.
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This allows lots of light
to reach the zooxanthellae.
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The coral mucous is, in turn,
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eaten by crabs, shrimp, and plankton.
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Countless tiny corals become connected into reefs
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and, as a result, they support many forms of life.
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Some creatures profit more from coral than others.
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The bumphead parrotfish measures more
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than one meter in length.
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They have tough-looking faces
and big, strong teeth,
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which they use to eat coral.
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They gnaw the hard calcium carbonate skeleton.
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They feed on the algae around
it and the corals within.
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They grind the undigested
skeleton into a powdery substance
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and scatter it with their waste.
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And so, in essence, bumphead
parrotfish transform coral
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into sand.
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Each fish can produce five tons a year.
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The sand collects, forming a white powdery base.
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This creates an environment
that nurtures other life.
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The creatures sheltered and fed by the coral,
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work to forge new connections
within this vibrant ecosystem.
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Coral is the key to the creation
of a rich undersea world.
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So, what is the role played by the moon?
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Although it is 380,000 kilometers away from Earth,
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the moon's gravitational pull is still very strong.
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It creates the tidal force, which controls the seas
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and oceans.
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This force is at the height of its power
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when the sun and the moon are aligned,
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when the gravitational pull of the moon and sun
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are combined.
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This is the reason for the spring tide.
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Spring tides occur twice a month,
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at full moon and new moon.
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During this time, the difference
between high and low tide
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is at its greatest.
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More than 10 meters in some places.
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The moon's movements pull the Earth's oceans
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this way and that.
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It's happened for billions of years
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and it's a process that is incredibly significant
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for ocean life.
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The day of the spring tide arrives.
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As the tide reaches its highest point,
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swarms of fish appear from nowhere.
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These surgeonfish ride the tide.
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Moving up and down in what appears to be
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a choreographed dance.
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For a second, it looks like
they've rehearsed this before.
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Suddenly, they begin to spawn.
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The females ascend rapidly and the males follow.
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They spawn near the water's surface.
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Everywhere you look, you see darting fish
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and clouds of sperm and eggs.
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It's as if clouds are forming in the ocean.
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Then, another fish dives into the fray.
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It eats the eggs.
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Then schools of smaller fish join in.
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The eggs become an irresistible feast.
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The spawning began as the
tide moved from low to high,
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when the current is at its strongest.
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The surgeonfish lay their eggs
on the strong spring tide
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to make them as hard to eat as possible.
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For these sea creatures, the changes in the tide,
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caused by the moon, are crucial.
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The moon's spell also helps world travelers.
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This is a green sea turtle.
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In early summer, it comes to the Great Barrier Reef
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to lay its eggs.
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Green sea turtles live in
tropical waters and eat seaweed.
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They reach adulthood after about 20 years
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and return to where they were born to lay eggs.
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As many as 100,000 turtles are believed to flock
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to the Great Barrier Reef each summer.
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They travel thousands of kilometers from islands
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in the South Pacific, from as far away as Indonesia
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and Vanuatu.
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Many of them head to one place in particular.
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It's one of the largest green
sea turtle spawning areas
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in the world.
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Raine Island.
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The sandy island is some two
kilometers in circumference,
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and the Australian government has put it under
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strict protection.
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The team received special permission to land here
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with some researchers.
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Their arrival coincided with the
middle of the mating season
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for Raine's island birds.
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This is one of a few sanctuaries left for animals
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coming and going across the oceans.
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Green sea turtles are big compared to other
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salt water turtles.
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They weigh more than 100 kilograms.
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That makes climbing onto land to lay eggs
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extremely hard work.
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They choose their arrival carefully.
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And that means they often spend a lot of time
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bobbing up and down in the waves as they wait...
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And wait, and wait, near the island,
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for the right moment to land.
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Today is a new moon and, therefore, a spring tide.
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As the sun goes down, the tide suddenly rises.
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The sea turtles all begin to move.
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Just before sunset,
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they start to ride the rising tide onto land.
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As it gets higher and higher,
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they are able to beach their bodies
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and haul themselves inland, inch by inch.
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It's a slow, methodical,
determined race to procreate.
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By nightfall, the beach is crowded.
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And the turtles are busy using their flippers
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to dig into the sand.
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Eventually, they form a hole big enough
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to accommodate their bodies.
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Any latecomers are hard-pressed to find a spot.
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The fight for space can be arduous and bitter.
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Those who have found room,
prepare to lay their eggs.
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The turtles skillfully maneuver their hind flippers
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as they carefully dig their holes.
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Then, finally, it's time.
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Each turtle lays more than 100 eggs,
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which are immediately warmed
by the heat of the sand.
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Then they gently cover them up.
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Offspring they will never meet.
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The sea turtles work all night to lay their eggs,
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which will hatch in about two months.
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In the past, over-hunting led to a drastic fall
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in sea turtle numbers.
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They have been protected for about 50 years
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and the population has bounced back slowly.
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During filming, in 2013, their
numbers hit a record high.
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As you can see, there's a lot of disturbance.
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So, some turtles, when they start laying,
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other turtles will bump into them and scare them
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and so they won't lay a complete clutch.
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The count that we did last night,
we counted 23,152 turtles.
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So, it's a very, very high year (mumbles).
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Thanks to research and protection efforts,
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the turtles of Raine Island are making a comeback.
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It's dawn.
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For the turtles, the ordeal begins.
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On this tropical island, when the sun rises,
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the temperature on the beach
approaches 50 degrees Celsius.
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Sea turtles can't regulate their body temperature,
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so this can be fatal.
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There's another serious problem.
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The tide is out.
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This rocky expanse was underwater at high tide.
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The turtles struggle forward,
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weighed down by shells that are
like heavy suits of armor.
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The slightest ridge or hollow in the rocks
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becomes a serious obstacle.
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One misstep can take them off
course and leave them stuck.
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Getting out is no easy matter.
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This one has been struggling for two hours.
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She's been losing energy minute by minute.
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And, all the while, the tropical sun beats down.
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Many sea turtles die because of dehydration.
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Finally, the long-awaited moment arrives.
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The sun is high in the sky.
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The moon begins to cast its spell again...
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and the tide comes pouring in.
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For animals that traverse sea and shore,
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the changing of the tide can mean the difference
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between life and death.
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The waves come rushing toward the turtle
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that was trapped in a gap.
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She feels the approaching tide...
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and she starts to move, as if reborn.
261
00:30:37,390 --> 00:30:40,862
She musters up the last of her strength...
262
00:30:52,106 --> 00:30:55,663
and, finally, she is free.
263
00:31:02,334 --> 00:31:04,341
With their path no longer blocked,
264
00:31:04,342 --> 00:31:08,923
the sea turtles return to the
ocean one after another.
265
00:31:13,759 --> 00:31:16,440
These ones remain close to Raine Island,
266
00:31:16,441 --> 00:31:19,883
returning several more times to lay eggs.
267
00:31:26,251 --> 00:31:28,026
Their bodies prepare the next batch
268
00:31:28,027 --> 00:31:31,876
as they wait for their landing two weeks later.
269
00:31:42,366 --> 00:31:46,935
In the sea, danger awaits the exhausted turtles.
270
00:31:58,097 --> 00:31:59,532
Sharks.
271
00:31:59,533 --> 00:32:04,068
The tiger shark is one variety
that preys on sea turtles.
272
00:32:05,083 --> 00:32:07,021
At more than three meters in length,
273
00:32:07,022 --> 00:32:10,546
they're considered the king of the coral reef.
274
00:32:11,620 --> 00:32:14,127
Tiger sharks can even crush the turtles' shells
275
00:32:14,128 --> 00:32:16,804
with their powerful jaws.
276
00:32:18,853 --> 00:32:21,162
This one has been lying in wait, near the island,
277
00:32:21,163 --> 00:32:24,571
while the turtles laid their eggs.
278
00:32:27,061 --> 00:32:31,386
It approaches what could be its next prey.
279
00:32:44,273 --> 00:32:48,676
But, all of a sudden, the tiger shark turns.
280
00:32:55,055 --> 00:32:59,009
It heads for the floating
body of a dead sea turtle.
281
00:33:10,055 --> 00:33:13,827
It seems it's decided to take
the path of least resistance,
282
00:33:13,828 --> 00:33:16,714
and feed on easy prey.
283
00:33:35,246 --> 00:33:38,732
It's a lucky escape for the other sea turtles.
284
00:33:44,406 --> 00:33:48,151
Scenes like this are repeated everywhere.
285
00:33:55,031 --> 00:33:57,858
The coral reefs of Raine Island are the setting
286
00:33:57,859 --> 00:34:01,414
for a fierce life or death drama.
287
00:34:16,397 --> 00:34:18,300
Within the Great Barrier Reef,
288
00:34:18,301 --> 00:34:21,342
there are about 3,000 individual coral reefs
289
00:34:21,343 --> 00:34:24,009
and around 1,000 islands.
290
00:34:24,010 --> 00:34:27,326
Nothing on this scale exists elsewhere.
291
00:34:27,327 --> 00:34:30,317
So, how did it come to be?
292
00:34:32,250 --> 00:34:34,095
The key to unlocking this secret
293
00:34:34,096 --> 00:34:37,515
is the topography of the ocean floor.
294
00:34:42,153 --> 00:34:45,055
During the ice age, 15,000 years ago,
295
00:34:45,056 --> 00:34:47,806
sea levels were more than 100 meters lower
296
00:34:47,807 --> 00:34:49,939
than they are today.
297
00:34:49,940 --> 00:34:53,176
The area that is now the seabed
at the Great Barrier Reef,
298
00:34:53,177 --> 00:34:55,478
used to be land.
299
00:34:59,846 --> 00:35:04,251
After the ice age ended, sea levels gradually rose.
300
00:35:04,252 --> 00:35:06,953
This created shallow, warm seas.
301
00:35:06,954 --> 00:35:09,652
Perfect for coral to grow.
302
00:35:14,008 --> 00:35:17,015
If the conditions are right, coral reefs can grow
303
00:35:17,016 --> 00:35:19,846
20 centimeters in one year.
304
00:35:19,847 --> 00:35:23,096
As sea levels rose, the ones
in the Great Barrier Reef
305
00:35:23,097 --> 00:35:27,153
grew to more than 100 meters tall.
306
00:35:30,156 --> 00:35:34,555
And so, these microorganisms
created a 2,000-kilometer-long
307
00:35:34,556 --> 00:35:36,861
wall of coral.
308
00:35:43,728 --> 00:35:48,297
Strong waves crash ceaselessly from the open sea.
309
00:35:52,969 --> 00:35:57,969
The coral acts as a breakwater,
cancelling out the waves.
310
00:36:03,846 --> 00:36:07,515
The Great Barrier Reef, just as its name implies,
311
00:36:07,516 --> 00:36:12,376
is a giant barrier protecting
a paradise of wildlife.
312
00:36:23,279 --> 00:36:27,721
Outside the barrier, lies a different world.
313
00:36:29,572 --> 00:36:32,996
Beyond the coral reef, on the
edge of the continental shelf,
314
00:36:32,997 --> 00:36:35,257
is a huge precipice.
315
00:36:35,258 --> 00:36:39,177
It plummets to a depth of 2,000 meters.
316
00:36:48,712 --> 00:36:51,265
Below, the deep ocean opens up
317
00:36:51,266 --> 00:36:54,514
as if ready to swallow anything.
318
00:37:07,220 --> 00:37:11,511
At night, small visitors
venture up from the depths.
319
00:37:11,512 --> 00:37:15,412
Shrimp, fry, and tiny plankton
swim closer to the surface
320
00:37:15,413 --> 00:37:17,826
in search of food.
321
00:37:20,246 --> 00:37:22,752
They use the cloak of darkness to avoid becoming
322
00:37:22,753 --> 00:37:25,430
the prey of bigger fish.
323
00:37:36,128 --> 00:37:37,927
Lurking deeper down,
324
00:37:37,928 --> 00:37:41,126
is a creature from ancient times.
325
00:37:44,940 --> 00:37:47,934
It's a living fossil that
has barely changed its form
326
00:37:47,935 --> 00:37:53,526
from 500 million years
ago, the nautilus.
327
00:37:56,109 --> 00:37:58,938
Living 400 meters below sea level,
328
00:37:58,939 --> 00:38:01,446
it feeds on the remains of shrimp and fish
329
00:38:01,447 --> 00:38:04,901
that have sunk from shallower waters.
330
00:38:16,122 --> 00:38:19,453
The proximity of the coral
reefs to the ocean depths
331
00:38:19,454 --> 00:38:22,686
has provided advantages that continue to nurture
332
00:38:22,687 --> 00:38:25,851
this primeval creature.
333
00:38:36,410 --> 00:38:39,544
November, the day of the full moon has come
334
00:38:39,545 --> 00:38:42,016
to the Great Barrier Reef.
335
00:38:52,020 --> 00:38:56,530
On the boat, the team holds an urgent meeting.
336
00:38:56,531 --> 00:39:01,531
So, the idea is that it's miles out of...
337
00:39:01,740 --> 00:39:03,320
According to Russell Kelley,
338
00:39:03,321 --> 00:39:05,819
the mass spawning is about to begin.
339
00:39:05,820 --> 00:39:07,787
I can get you in the right area.
340
00:39:07,788 --> 00:39:10,658
On the full moon afternoon, the
giant clams will be spawning
341
00:39:10,659 --> 00:39:14,915
in the mid-afternoon, from 3:00 to 4:00 PM.
342
00:39:14,916 --> 00:39:19,775
Then, sea cucumbers will
spawn in the early evening.
343
00:39:20,895 --> 00:39:23,070
The timing of spawning varies according
344
00:39:23,071 --> 00:39:25,988
to an animals reproductive strategy.
345
00:39:28,989 --> 00:39:31,772
Everything depends on the moon though.
346
00:39:31,773 --> 00:39:34,929
Its force constantly tugs at the oceans,
347
00:39:34,930 --> 00:39:38,464
but that changes according to its position.
348
00:39:40,965 --> 00:39:42,987
It is strongest during spring tide
349
00:39:42,988 --> 00:39:45,042
at full moon and new moon.
350
00:39:45,043 --> 00:39:46,981
It is weakest at half moon,
351
00:39:46,982 --> 00:39:50,374
when the so-called neap tide occurs.
352
00:39:54,240 --> 00:39:57,881
This diagram shows how the moon affects the ocean.
353
00:39:57,882 --> 00:39:59,483
On the Great Barrier Reef,
354
00:39:59,484 --> 00:40:02,560
the difference between high
and low tide is two meters
355
00:40:02,561 --> 00:40:04,487
during spring tide.
356
00:40:04,488 --> 00:40:09,150
During neap tide, it's one
meter, so half as high.
357
00:40:12,266 --> 00:40:15,853
According to Kelley, the giant
clam and the sea cucumber
358
00:40:15,854 --> 00:40:19,495
time their spawning for the full moon spring tide.
359
00:40:19,496 --> 00:40:22,947
The corals spawn at neap tide.
360
00:40:26,271 --> 00:40:28,618
This, we hope, is going to be the big night
361
00:40:28,619 --> 00:40:31,741
that we'd like to film and
it is the biggest spectacle
362
00:40:31,742 --> 00:40:35,960
that is world-famous from the Great Barrier Reef.
363
00:40:39,692 --> 00:40:43,545
John, which side do they want?
364
00:40:43,546 --> 00:40:45,557
This one here?
365
00:40:48,338 --> 00:40:50,716
Even on the same full moon day,
366
00:40:50,717 --> 00:40:54,184
different animals spawn at different times.
367
00:41:02,943 --> 00:41:06,200
It looks like Kelley has found something.
368
00:41:10,722 --> 00:41:14,607
It's a giant clam, the world's biggest clam.
369
00:41:14,608 --> 00:41:17,609
It will be the first to spawn.
370
00:41:21,214 --> 00:41:23,964
It's more than one meter wide
371
00:41:23,965 --> 00:41:26,844
and it opens its shell to bask in the sunlight,
372
00:41:26,845 --> 00:41:30,385
because it hosts algae and
lives symbiotically with them,
373
00:41:30,386 --> 00:41:33,016
just as corals do.
374
00:41:35,471 --> 00:41:37,780
The giant clam roots to the ocean floor
375
00:41:37,781 --> 00:41:40,492
and never moves again.
376
00:41:43,250 --> 00:41:47,447
This hole is an opening to
release water for breathing.
377
00:41:53,123 --> 00:41:56,126
A change is about to take place.
378
00:42:01,936 --> 00:42:05,489
The clam's entire body tightens,
379
00:42:06,887 --> 00:42:07,871
and then...
380
00:42:19,221 --> 00:42:21,518
What looks like white smoke is actually
381
00:42:21,519 --> 00:42:23,704
the giant clam's spawn.
382
00:42:35,154 --> 00:42:37,578
On this day of the spring tide,
383
00:42:37,579 --> 00:42:41,857
it started spawning when the tide was fully out.
384
00:42:44,407 --> 00:42:48,257
The water level is two meters
lower than at high tide.
385
00:42:48,258 --> 00:42:50,305
The clam releases eggs and sperm
386
00:42:50,306 --> 00:42:53,089
when there is the least amount
of water, it's believed,
387
00:42:53,090 --> 00:42:56,913
to increase the chances of fertilization.
388
00:43:13,277 --> 00:43:17,974
As the sun sinks in the sky, the tide rises.
389
00:43:20,928 --> 00:43:24,963
Under the water, something strange is happening.
390
00:43:29,949 --> 00:43:33,524
The sea cucumber usually hides beneath the coral
391
00:43:33,525 --> 00:43:37,026
but, for some reason, it has climbed up.
392
00:43:40,108 --> 00:43:43,028
Then, it raises its head.
393
00:43:46,365 --> 00:43:50,319
The male sea cucumber is spreading its sperm.
394
00:43:56,418 --> 00:44:00,331
When it's high tide, the range
of the tide is two meters.
395
00:44:00,332 --> 00:44:04,523
That makes the current stronger
closer to the surface.
396
00:44:11,329 --> 00:44:14,697
So, by climbing as high as it can, the sea cucumber
397
00:44:14,698 --> 00:44:18,808
increases the chances that
his sperm and, hence, genes
398
00:44:18,809 --> 00:44:22,391
will be spread as far as possible.
399
00:44:27,250 --> 00:44:29,779
It is yet another example of how sea creatures
400
00:44:29,780 --> 00:44:32,322
have adapted to the changing of the tide
401
00:44:32,323 --> 00:44:35,499
in order to breed effectively.
402
00:44:56,083 --> 00:44:58,726
After the full moon, preparations begin
403
00:44:58,727 --> 00:45:01,827
to film the mass coral spawning.
404
00:45:03,565 --> 00:45:05,538
This large-scale, underwater lighting
405
00:45:05,539 --> 00:45:08,052
is used in shooting movies.
406
00:45:13,317 --> 00:45:14,918
It has been specially brought in
407
00:45:14,919 --> 00:45:18,571
to capture the right moment, in all its glory.
408
00:45:24,498 --> 00:45:27,155
The location and direction are calculated
409
00:45:27,156 --> 00:45:28,966
and everything is carefully set up
410
00:45:28,967 --> 00:45:31,888
over the course of several days.
411
00:45:35,341 --> 00:45:39,659
At last, preparations are complete.
412
00:45:39,660 --> 00:45:42,441
Now, the team waits for the spawning.
413
00:45:44,362 --> 00:45:47,967
But the most difficult part still lies ahead.
414
00:45:50,062 --> 00:45:54,468
As fast as the coral spawning starts, it ends.
415
00:45:56,273 --> 00:45:59,720
The coral must be observed
with a non-invasive red light
416
00:45:59,721 --> 00:46:02,061
to watch for signs.
417
00:46:05,178 --> 00:46:08,184
Although the spawning happens around the neap tide,
418
00:46:08,185 --> 00:46:10,110
it can be affected by sea temperature
419
00:46:10,111 --> 00:46:12,613
and weather conditions.
420
00:46:15,627 --> 00:46:19,339
This makes accurate predictions next to impossible.
421
00:46:19,340 --> 00:46:22,967
All the team can do is keep watching.
422
00:46:26,560 --> 00:46:30,015
Four days have passed since the full moon.
423
00:46:38,623 --> 00:46:41,996
The calmer neap tide is approaching.
424
00:46:46,598 --> 00:46:50,831
Kelley says, "The signs are not
yet there for the spawning."
425
00:46:52,439 --> 00:46:55,501
While they wait, they calibrate the equipment.
426
00:47:02,261 --> 00:47:05,394
They'll shoot with the latest
in high definition cameras,
427
00:47:05,395 --> 00:47:07,089
which can record rich colors,
428
00:47:07,090 --> 00:47:10,505
even in the dark, nighttime waters.
429
00:47:16,710 --> 00:47:18,749
Cameras and lighting.
430
00:47:18,750 --> 00:47:23,236
All team members work together
to finalize the preparations.
431
00:47:29,433 --> 00:47:33,483
Today, something seems different in the ocean.
432
00:47:34,801 --> 00:47:38,623
It's quiet, as if the currents have stopped.
433
00:47:47,593 --> 00:47:50,853
Kelley has been checking the coral.
434
00:47:50,854 --> 00:47:55,202
After 9:00 PM, he notices a sudden shift.
435
00:48:00,006 --> 00:48:01,943
Something is floating up from the tips
436
00:48:01,944 --> 00:48:03,926
of the coral branches.
437
00:48:07,992 --> 00:48:10,797
All the lights are turned on.
438
00:48:13,542 --> 00:48:18,073
At last, the long-awaited spawning has begun.
439
00:48:26,562 --> 00:48:29,483
Particles of less then one millimeter in diameter
440
00:48:29,484 --> 00:48:33,066
are floating up from corals everywhere.
441
00:48:35,646 --> 00:48:38,594
The other varieties of coral follow suit
442
00:48:38,595 --> 00:48:41,899
and they all begin to spawn.
443
00:48:59,675 --> 00:49:02,797
The number of coral species spawning simultaneously
444
00:49:02,798 --> 00:49:06,497
has been known to reach as high as 100.
445
00:49:08,151 --> 00:49:10,820
But why do different species coordinate the timing
446
00:49:10,821 --> 00:49:13,091
of their spawning?
447
00:49:17,401 --> 00:49:19,793
The particles they release are capsules
448
00:49:19,794 --> 00:49:22,809
containing eggs and sperm.
449
00:49:23,952 --> 00:49:26,551
They float up to the surface and open,
450
00:49:26,552 --> 00:49:29,995
allowing the sperm to fertilize the eggs.
451
00:49:34,598 --> 00:49:37,395
If more coral spawn at the same time,
452
00:49:37,396 --> 00:49:40,356
their genes can mix, increasing the likelihood
453
00:49:40,357 --> 00:49:43,068
of hybrid species.
454
00:49:45,558 --> 00:49:48,653
Experts believe this leads to greater diversity
455
00:49:48,654 --> 00:49:52,480
and, as a result, stronger coral.
456
00:49:58,392 --> 00:50:01,607
The grandest spectacle of the Great Barrier Reef,
457
00:50:01,608 --> 00:50:03,973
mass coral spawning.
458
00:50:03,974 --> 00:50:07,142
It is also the secret behind the coral's evolution
459
00:50:07,143 --> 00:50:10,481
and survival to this day.
460
00:50:25,928 --> 00:50:27,819
The fish nibble away,
461
00:50:27,820 --> 00:50:31,481
but, with this much spawn, it makes no difference.
462
00:50:36,487 --> 00:50:38,541
The most important thing for the coral
463
00:50:38,542 --> 00:50:40,549
is successful fertilization,
464
00:50:40,550 --> 00:50:44,131
once the sperm and eggs reach the surface.
465
00:50:55,539 --> 00:50:58,742
During the neap tide, the ebb and flow of the waves
466
00:50:58,743 --> 00:51:02,315
is at its smallest, and the surface is calm.
467
00:51:02,316 --> 00:51:05,052
This means there is a higher rate of fertilization
468
00:51:05,053 --> 00:51:07,064
for the eggs.
469
00:51:24,772 --> 00:51:29,609
The mass coral spawning lasts a mere 15 minutes.
470
00:51:29,610 --> 00:51:33,716
It disappears as if it were an illusion.
471
00:51:41,417 --> 00:51:44,992
A mysterious moment, when tiny lifeforms showed
472
00:51:44,993 --> 00:51:46,884
an amazing synchronization
473
00:51:46,885 --> 00:51:50,014
with the rhythm of the Universe.
474
00:51:59,412 --> 00:52:02,603
The next morning, a long stream floats off
475
00:52:02,604 --> 00:52:05,478
with the ocean's currents.
476
00:52:07,586 --> 00:52:12,282
The fertilized eggs head out
on a journey to new lands.
477
00:52:21,150 --> 00:52:24,509
When the newborn coral reaches the ocean floor,
478
00:52:24,510 --> 00:52:29,102
it will build a foundation and
gradually grow from there.
479
00:52:34,349 --> 00:52:37,558
The corals here have taken
tens of thousands of years
480
00:52:37,559 --> 00:52:40,601
to build the Great Barrier Reef,
481
00:52:44,261 --> 00:52:47,789
and they will continue to maintain its diversity
482
00:52:47,790 --> 00:52:50,877
and nurture different populations of wildlife
483
00:52:50,878 --> 00:52:53,601
through mass spawning.
484
00:53:03,789 --> 00:53:06,880
Raine Island, where the green sea turtles gathered
485
00:53:06,881 --> 00:53:08,967
to lay their eggs.
486
00:53:11,387 --> 00:53:14,923
Here too, new life is born.
487
00:53:27,580 --> 00:53:29,681
The hatchlings come to the surface
488
00:53:29,682 --> 00:53:32,602
and head straight for the ocean.
489
00:53:37,847 --> 00:53:40,035
Some need a little more time than others
490
00:53:40,036 --> 00:53:42,550
to orient themselves.
491
00:53:47,131 --> 00:53:50,065
But they are all guided by
the reflection of the moon
492
00:53:50,066 --> 00:53:52,664
on the ocean's surface.
493
00:54:19,912 --> 00:54:21,998
The moon watches over the hatchlings
494
00:54:21,999 --> 00:54:24,181
as they set out on their voyage,
495
00:54:24,182 --> 00:54:27,996
as it has done since time immemorial.
496
00:54:40,714 --> 00:54:45,666
The world's largest coral
reef, the Great Barrier Reef.
497
00:54:45,667 --> 00:54:49,703
The story of life goes on here, beating in time
498
00:54:49,704 --> 00:54:52,731
to the rhythm of the moon.
39183
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