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I'm here, surrounded by one
of nature's greatest wonders.

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A living structure so enormous,
it can be seen from space.

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The Great Barrier Reef.

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Home to one of the most extraordinary
communities of animals on the planet.

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'I've been fascinated by it
for almost 60 years.'

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Here, unknown species
are still being found.

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And scientists are making
astonishing discoveries

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about the creatures
that we thought we knew.

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'In this series, our research vessel,
the Alucia,

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'will allow us to explore the reef
as never before.'

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Using the latest technology,
I'll visit its mysterious depths.

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Nobody has ever dived as deep as this
before on the Great Barrier Reef.

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I'll learn of its surprising origins.

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And discover how this
wonderfully diverse community

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has been created by some of the very
smallest creatures on the reef.

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But visited by some of the most
impressive animals on the planet.

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It's an ecosystem like no other.

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Vital to our oceans.

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And surprisingly, we are still
uncovering its many secrets.

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The Great Barrier Reef lies
on Australia's north-east coast.

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It's 1,400 miles long...

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..and at its widest,
150 miles across.

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It consists of almost 3,000
individual coral reefs...

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..and 900 islands.

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And for me, it's truly

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one of the most extraordinary places
on the planet.

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People say to me,

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"What was the most magical thing
you ever saw in your life?

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"What was the most magical moment
in your career as a naturalist?"

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And I always say,
the first time I put on a mask

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and went below the surface

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and moved in three dimensions
just with a flick of my fin

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and suddenly saw all these
amazingly multicoloured things

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living in communities right there.

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Just astounding things.

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Unforgettable beauty.

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I first came to the Barrier Reef
nearly 60 years ago.

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And I remember very clearly
how amazed I was

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to see such a complexity of life.

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But today, we have ways
of looking at the reef,

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technical ways,
which we never had before

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and give us a completely new vision
of this wonderful place,

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which is surely one of the greatest
treasures of the natural world.

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'Now I've returned.

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'And taking me on this journey
is the Alucia,

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'a 56-metre state-of-the-art
research and exploration vessel.

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'For this expedition, we've
been granted unprecedented access

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'to some of the most remote corners
of the Great Barrier Reef.'

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Onboard is a team of experts.

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And at our disposal,
all the latest technology.

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Our mission is to reveal
a hidden world

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and to complete a series of dives

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that have never before been attempted
on the Great Barrier Reef.

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But to do that, we have had to bring
in a very special piece of equipment.

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This is a Triton submarine.

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The very latest
in submersible technology.

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And the first of its kind
to be brought to these waters.

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The submersible's captain,
Buck Taylor, will lead the dive team.

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With 2,000 dives under his belt,
his expertise is unparalleled.

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While our film crew
rigs the submersible

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with no fewer than eight cameras,

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Buck gathers the rest of the team
together

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to brief us on the dives ahead.

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COMPUTER: "Welcome to the MV Alucia
submersible team..."

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'The submersible offers
spectacular filming opportunities,

66
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'but it's not without its dangers.'

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Coming from the rescue background,

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I've been in a submersible
up to my waist in water,

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I've had a fire in a submersible.

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COMPUTER: "No smoking,
smoking materials..."

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'As well as these hazards,
Buck is also obliged to raise

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'one of the more intimate limitations
of submersible life.'

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We do have facilities
of a toilet onboard.

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Obviously, because it's quite
confined, it's not very discrete,

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so we do have some towels out
that we can hold up around you.

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It's quite interesting trying to
explain about going to the toilet

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in a three-man submersible
in a sort of sphere

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that's less than two metres
diameter. It's quite intimate.

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He was six foot three...
LAUGHTER

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We've got cameras
pointing from every direction.

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Good. Thank you.

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Thanks very much.
I'm looking forward to it a lot.

83
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The Alucia's first mission

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is to take us to
the Barrier's stunning ribbon reefs

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in the north of its extensive range.

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It's an area of
outstanding natural beauty

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and the perfect place
to begin our explorations.

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The story of the Great Barrier Reef

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starts with its most important
inhabitant, the coral itself.

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Hidden inside
these branching structures

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are the thousands of tiny creatures
that build these reefs.

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And they have an enormous
claim to fame.

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Together, they've built the largest
living structure on earth.

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But these fascinating coral creatures
are only active at night.

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So to capture their behaviour,

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we'll need to do something
I've never done before.

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Tonight, a team of specialist
divers, scientists

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and programme-makers, like myself,

99
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have gathered together to have
a closer look and a longer look

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at the reef at night
than perhaps has ever been possible.

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When I came here 60 years ago,

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the idea of a night dive
was almost inconceivable.

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It seemed to me, a beginner,
to be far too dangerous.

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But now, technology
is going to help me.

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'Once I'm in, it's over to Buck
and the support team,

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'who remain onboard the Alucia,

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'to make sure
everything goes smoothly.'

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INDISTINCT RADIO

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'They've spent months
preparing for this moment.'

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SIREN WAILS

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'Our submersible, known to the crew
as the Nadir,

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'has, of course, made dives like this
all over the world.

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'She's descended to the deepest part
of the oceans,

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'but she's never visited
the Barrier Reef.

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'It's a first for all of us.

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'But before we can go anywhere,
we'll need to position the Nadir

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'at a safe distance from the Alucia.

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'It's a substantial operation,

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'but finally, we're ready
to get underway.'

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S.O. Nadir, just approaching
the buoy. Am I clear to vent?

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RADIO: "Roger, Nadir. You are
clear to vent, clear to vent.

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"Have a good dive, guys."

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'Sinking beneath the waves
is a very surreal experience.

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'Your first instinct
is to hold your breath.

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'At night,
the reef is a ghostly world.

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'Tiny shrimp-like creatures
dance in the lights.'

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Look at that! Wow!

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'With little light,
there is a lot less colour,

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'but this is still
a very magical place.'

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Ah! There's something! My first fish!

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'Our submersible will eventually
take us to depths of 300 metres.

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'Now, we're only 30 metres down,

133
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'but that's exciting enough
for a start.'

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In these dark waters,
Buck needs to be careful

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as we move around the front
of the reef.

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Coral reefs are sometimes described
as marine cities.

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And the comparison
is indeed a good one.

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We're here to take a closer look
at the reef's architecture.

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Its coral buildings.

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There are more than 450
different species of hard coral.

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The plant-like structures we can see
are actually made of limestone.

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And living inside are thousands
of highly industrious little animals

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called coral polyps.

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At night, the water around the reef

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becomes filled with clouds of
tiny microorganisms

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called the zooplankton.

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And that's what the corals eat.

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The coral polyps themselves
emerge from their stony skeleton

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and start groping in the water
with their tentacles.

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To see just what they're doing,
we need specialised cameras.

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The coral polyps never leave
the safety of their limestone homes,

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even at night.

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If something edible
comes within reach,

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the polyps fire the microscopic
harpoons that line their tentacles.

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The prey is stunned or killed and
then pulled into the polyp's mouth.

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When you can't leave your home,
it pays to be accurate.

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The coral's stinging armoury
isn't used only for collecting food.

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They also use it to fight.

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Because, as has been discovered
only comparatively recently,

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corals, like many animals
that live on land,

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are extremely territorial.

162
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But in order to see the battles,

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you have to speed up time.

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The polyps of each colony
collaborate to defend their patch.

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As in any big city,
space is precious.

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If a rival grows too close,
there will be trouble.

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These fights can last for hours.

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The competition is fierce

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as the coral colonies
jostle with one another

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for the best feeding sites.

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When they're not locked in battle,
the corals have work to do.

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'They must extract calcium carbonate
from the surrounding seawater

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'and with it, build their homes.'

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Each coral species has its own
particular way of building.

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And together, they eventually create
the huge reefs

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that provide homes for all kinds
of other, much larger creatures.

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At night, the reef seems like
an extraterrestrial world.

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But down here, we are the aliens.

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And here comes a turtle!

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Attracted by our lights.

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Come on!

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Coming straight to us.

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Isn't that great!

184
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'Coming face-to-face
with a green turtle

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'in this setting is a rare privilege,

186
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'but its presence here, along with
all the other reef residents,

187
00:16:01,320 --> 00:16:05,240
'is only made possible
thanks to the great coral builders.'

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00:16:05,240 --> 00:16:07,800
He doesn't look very upset, does he?

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00:16:11,280 --> 00:16:13,280
It happens all the time on this reef.

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00:16:23,680 --> 00:16:26,880
It's the perfect end
to my first dive.

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00:16:30,760 --> 00:16:35,000
The time has come for us to make
our way back up to the Alucia.

192
00:16:45,560 --> 00:16:47,120
Welcome back, gentlemen.

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00:16:52,520 --> 00:16:56,280
Diving on a reef at night
is a thrilling experience.

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00:16:59,440 --> 00:17:03,280
What I want to see next is how
exactly these tiny coral creatures

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00:17:03,280 --> 00:17:06,080
have created such a vast
and extensive habitat.

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00:17:10,280 --> 00:17:12,480
To answer that, we'll need to
look at the reef

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00:17:12,480 --> 00:17:14,360
from another angle entirely.

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00:17:51,400 --> 00:17:53,640
At this height,
you can begin to appreciate

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00:17:53,640 --> 00:17:56,720
the immense size of the Barrier Reef.

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00:17:56,720 --> 00:18:01,600
It's 2,300 kilometres long,
1,400 miles.

201
00:18:01,600 --> 00:18:05,000
It's the largest living structure
on the planet.

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00:18:09,000 --> 00:18:12,240
Reefs much like these develop
in the shallow tropical waters

203
00:18:12,240 --> 00:18:15,240
that surround many an island
and continental coast.

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00:18:18,000 --> 00:18:20,240
But few can match the Great Barrier

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00:18:20,240 --> 00:18:22,280
in either size or complexity.

206
00:18:24,960 --> 00:18:28,680
So, what is so special about
the north-eastern coast of Australia?

207
00:18:31,240 --> 00:18:35,200
A clue to the answer
lies in the shape of the sea floor.

208
00:18:37,480 --> 00:18:39,360
If we strip away the ocean,

209
00:18:39,360 --> 00:18:43,200
we can reveal the reason why such
extraordinary growth is possible.

210
00:18:45,240 --> 00:18:49,120
The reef has grown on
a very shallow continental shelf.

211
00:18:49,120 --> 00:18:53,320
Beyond which, there is a sudden
and very steep 2,000-metre drop-off.

212
00:18:56,320 --> 00:19:01,080
It stands in waters with
an average depth of just 35 metres.

213
00:19:01,080 --> 00:19:05,520
That's just about as far as sunlight
can penetrate with any strength.

214
00:19:08,600 --> 00:19:12,440
Light is crucially important
to reef-building corals

215
00:19:12,440 --> 00:19:15,120
because they have developed
a special partnership

216
00:19:15,120 --> 00:19:17,960
with microscopic algae -

217
00:19:17,960 --> 00:19:20,960
plants that actually grow
within tissues.

218
00:19:24,800 --> 00:19:27,040
The algae get a safe home

219
00:19:27,040 --> 00:19:30,120
and, like all plants,
when they photosynthesise,

220
00:19:30,120 --> 00:19:31,600
they produce energy.

221
00:19:35,880 --> 00:19:40,480
The coral polyps use this energy
to construct their limestone home.

222
00:19:46,000 --> 00:19:48,600
Together, they've built
an underwater city

223
00:19:48,600 --> 00:19:52,040
on a scale that is almost impossible
to comprehend.

224
00:19:56,120 --> 00:19:59,720
But amazingly, just 10,000 years ago,

225
00:19:59,720 --> 00:20:02,200
there was no coral here at all.

226
00:20:06,720 --> 00:20:11,120
The Great Barrier Reef as we know it
today simply didn't exist.

227
00:20:15,440 --> 00:20:18,280
How and when these coral communities
began

228
00:20:18,280 --> 00:20:22,120
is something scientists have only
recently started to investigate.

229
00:20:24,360 --> 00:20:26,680
Marine geologist, Dr Robin Beaman,

230
00:20:26,680 --> 00:20:31,200
has been leading an ambitious project
to scan the entire reef.

231
00:20:31,200 --> 00:20:34,920
And his data has allowed us
to map the sea floor.

232
00:20:36,760 --> 00:20:40,240
David, this is a three-dimensional
model of the Great Barrier Reef.

233
00:20:40,240 --> 00:20:42,920
In deeper waters,
we tend to use sonar,

234
00:20:42,920 --> 00:20:46,480
in shallow waters, we tend
to use underwater laser beams

235
00:20:46,480 --> 00:20:48,120
to image the sea floor.

236
00:20:51,680 --> 00:20:55,440
'By combining computer modelling
and radiocarbon dating,

237
00:20:55,440 --> 00:20:57,320
'his team have been able
to reconstruct

238
00:20:57,320 --> 00:21:00,920
'the key stages in the development
of the Great Barrier.

239
00:21:02,160 --> 00:21:04,800
'Their research has helped identify
an event

240
00:21:04,800 --> 00:21:07,440
'between 10,000 and 20,000 years ago

241
00:21:07,440 --> 00:21:10,880
'which may explain how
the Great Barrier Reef was formed.

242
00:21:14,520 --> 00:21:19,000
'But surprisingly, scientists are not
the only ones to tell this story.'

243
00:21:20,760 --> 00:21:24,080
Australia's Aboriginal peoples
arrived on this continent

244
00:21:24,080 --> 00:21:26,480
around 50,000 years ago.

245
00:21:30,920 --> 00:21:34,040
They have been telling the story
of how the reef was formed

246
00:21:34,040 --> 00:21:37,040
long before the world's scientists
even knew it existed.

247
00:21:39,120 --> 00:21:43,200
To hear that story, the Alucia
is taking us to Northern Queensland

248
00:21:43,200 --> 00:21:46,200
to meet a community
with a very special connection

249
00:21:46,200 --> 00:21:48,120
to this underwater world.

250
00:21:58,000 --> 00:22:01,400
They are the Gimuy Walubara
Yidinji people.

251
00:22:01,400 --> 00:22:04,880
And they live just outside
the city of Cairns.

252
00:22:11,720 --> 00:22:15,640
This community has dwelt alongside
the reef for thousands of years.

253
00:22:17,640 --> 00:22:19,320
THEY SPEAK YIDINY

254
00:22:21,280 --> 00:22:25,800
And many of their traditions
hark back to those ancient times.

255
00:22:25,800 --> 00:22:28,160
THEY SING IN YIDINY

256
00:22:30,320 --> 00:22:34,520
And one of them tells
how the reef came into existence.

257
00:22:34,520 --> 00:22:38,640
It's a legend that has been passed
down from generation to generation

258
00:22:38,640 --> 00:22:40,560
in the form of a dance.

259
00:22:44,120 --> 00:22:47,600
Tell me the story
that's connected to this dance, sir.

260
00:22:47,600 --> 00:22:52,760
It's part of our law story that's
told to me by my dad, my father,

261
00:22:52,760 --> 00:22:56,280
and was told to him by his father
and his grandfather, as well.

262
00:22:59,040 --> 00:23:01,200
The part of the dance
that really interests me

263
00:23:01,200 --> 00:23:04,400
is the story of Gunyah
and the sacred fish.

264
00:23:07,280 --> 00:23:10,480
The story starts with Gunyah
going out to sea.

265
00:23:10,480 --> 00:23:14,520
And he saw a glitter in the water,
which he thought was a fish.

266
00:23:14,520 --> 00:23:17,760
And when he speared it,

267
00:23:17,760 --> 00:23:22,920
he actually speared our sacred fish,
the stingray.

268
00:23:22,920 --> 00:23:25,840
So the fish got angry
and it started to rise up.

269
00:23:25,840 --> 00:23:30,440
And with its wings,
it made the sea rough

270
00:23:30,440 --> 00:23:32,680
and it caused the sea to rise.

271
00:23:34,920 --> 00:23:39,200
Take us back to the time when
the first human beings arrived here.

272
00:23:39,200 --> 00:23:41,000
What was it like then?

273
00:23:41,000 --> 00:23:43,040
The coastline would have been
very different.

274
00:23:43,040 --> 00:23:45,400
So the coastline would have
been right out here,

275
00:23:45,400 --> 00:23:47,240
on the edge of
the Great Barrier Reef.

276
00:23:47,240 --> 00:23:49,320
The sea level was much lower

277
00:23:49,320 --> 00:23:52,160
and they would have fished
and hunted the coastline.

278
00:23:52,160 --> 00:23:53,680
These were limestone hills

279
00:23:53,680 --> 00:23:55,840
that would have been eucalypts,
marshlands.

280
00:23:55,840 --> 00:23:58,120
There would have been
mangrove swamps.

281
00:24:01,880 --> 00:24:04,880
But roughly 14,000 years ago,

282
00:24:04,880 --> 00:24:08,600
the climate started to
dramatically change.

283
00:24:08,600 --> 00:24:10,440
It was the end of the Ice Age.

284
00:24:10,440 --> 00:24:13,920
And all that water started to
inundate the continental shelf

285
00:24:13,920 --> 00:24:18,000
and start to flood this vast,
flat landscape.

286
00:24:18,000 --> 00:24:20,600
And in one man's lifetime?
Absolutely.

287
00:24:20,600 --> 00:24:24,880
So, people living here
are going to have to retreat?

288
00:24:24,880 --> 00:24:27,400
Absolutely. It would
have been a dramatic time for them.

289
00:24:27,400 --> 00:24:29,440
They would have been
following the coastline

290
00:24:29,440 --> 00:24:31,520
as it prograded
further and further back

291
00:24:31,520 --> 00:24:33,440
as the water was flooding the shelf.

292
00:24:33,440 --> 00:24:37,680
The rate of change was so great
that in these very flat areas here,

293
00:24:37,680 --> 00:24:41,520
the coastline would have moved back
by hundreds of metres every year.

294
00:24:41,520 --> 00:24:43,120
Every year? Every year.

295
00:24:44,760 --> 00:24:47,600
Gosh! That's formidable.

296
00:25:02,280 --> 00:25:05,840
So our story is about
the sea rising.

297
00:25:05,840 --> 00:25:09,040
And there used to be a cliff
further out.

298
00:25:09,040 --> 00:25:11,960
And past the cliff
is where the ocean used to be.

299
00:25:11,960 --> 00:25:13,840
Now, that's really remarkable.

300
00:25:13,840 --> 00:25:18,440
Because Western science is just
beginning to make discoveries

301
00:25:18,440 --> 00:25:21,360
that seem to suggest that the sea,

302
00:25:21,360 --> 00:25:25,600
10,000, 20,000 years ago,
was way, way out there,

303
00:25:25,600 --> 00:25:27,600
which is exactly
what your story says.

304
00:25:27,600 --> 00:25:29,680
Extraordinary. Yes.

305
00:25:29,680 --> 00:25:33,320
A folk memory of an event
that happened all that time ago.

306
00:25:33,320 --> 00:25:37,200
Yeah. And the only way
we can keep it alive

307
00:25:37,200 --> 00:25:40,360
is through our song and our dance.
Yes.

308
00:25:40,360 --> 00:25:43,440
Just to keep that going
through our culture.

309
00:25:44,680 --> 00:25:46,280
So the tradition lives.

310
00:25:46,280 --> 00:25:48,120
Yes. It's wonderful.

311
00:25:52,640 --> 00:25:56,480
'It is truly astounding to think
that this story has survived

312
00:25:56,480 --> 00:25:59,520
'for so many years
and across so many generations.

313
00:26:03,400 --> 00:26:07,200
'And that it coincides with
what scientists are now discovering

314
00:26:07,200 --> 00:26:09,560
'about the age of the Great Barrier.'

315
00:26:13,280 --> 00:26:16,800
The polyps that built the reef
arrived as spawn,

316
00:26:16,800 --> 00:26:18,920
swept here by the ocean currents.

317
00:26:21,120 --> 00:26:23,720
Corals are not new to the planet.

318
00:26:23,720 --> 00:26:26,920
They've been around for at least
500 million years.

319
00:26:34,880 --> 00:26:38,840
The new reefs provided homes
for thousands of animals,

320
00:26:38,840 --> 00:26:42,760
and very quickly, a whole new
community began to establish itself.

321
00:26:46,240 --> 00:26:48,080
Today, the Great Barrier Reef

322
00:26:48,080 --> 00:26:51,720
has one of the most diverse
communities of animals on the planet.

323
00:26:56,200 --> 00:27:00,000
And it's the story of
these remarkable reef residents

324
00:27:00,000 --> 00:27:02,280
that I want to investigate next.

325
00:27:04,720 --> 00:27:09,360
To do that, the Alucia is taking me
north to a very special place.

326
00:27:11,200 --> 00:27:13,440
Lizard Island.

327
00:27:21,080 --> 00:27:23,440
It's one of the 600
continental islands

328
00:27:23,440 --> 00:27:25,640
scattered across
the Great Barrier Reef.

329
00:27:30,360 --> 00:27:34,960
And its shallow lagoon is known for
its exceptional biodiversity.

330
00:27:39,480 --> 00:27:42,160
'With the Alucia
anchored in deeper water,

331
00:27:42,160 --> 00:27:45,960
'a more modest mode of transport
will be needed to reach the shore.

332
00:27:49,640 --> 00:27:52,440
'I first visited Lizard Island
in 1957.

333
00:27:54,480 --> 00:27:57,080
'Then, it was completely uninhabited.

334
00:28:00,320 --> 00:28:03,880
'Little did I know how important
this remote outpost would become

335
00:28:03,880 --> 00:28:06,640
'in helping us to understand
the coral reefs.

336
00:28:09,960 --> 00:28:12,560
'But today, that's exactly
what this remarkable place

337
00:28:12,560 --> 00:28:14,560
'is world-renowned for.'

338
00:28:18,600 --> 00:28:21,760
Here, for the past few decades,
there has been a research station

339
00:28:21,760 --> 00:28:26,400
where scientists can study
continuously and in detail

340
00:28:26,400 --> 00:28:30,800
the full complexity of the community
of animals that makes up the reef.

341
00:28:34,920 --> 00:28:39,560
Every year, Lizard Island hosts
100 different research projects.

342
00:28:42,120 --> 00:28:44,400
Here, scientists are shedding
new light

343
00:28:44,400 --> 00:28:46,480
on the lives of the reefs' residents

344
00:28:46,480 --> 00:28:49,480
and the way in which
this complex community works.

345
00:28:52,720 --> 00:28:57,480
Thanks to their research, we now know
that coral reefs rival rainforests

346
00:28:57,480 --> 00:29:00,160
in the vast numbers of species
they support.

347
00:29:03,640 --> 00:29:06,800
The first question is, where does
all that diversity come from?

348
00:29:11,680 --> 00:29:14,120
Lizard Island reefs
owe their richness

349
00:29:14,120 --> 00:29:17,240
to the special plants that,
in places, fringe the shores.

350
00:29:19,680 --> 00:29:21,760
They link land and sea

351
00:29:21,760 --> 00:29:24,440
and they're vital
to the coral reef community.

352
00:29:25,720 --> 00:29:27,280
They're mangroves.

353
00:29:29,880 --> 00:29:32,760
Taking shelter amongst the roots

354
00:29:32,760 --> 00:29:37,080
are thousands of juvenile fish
of all shapes and sizes.

355
00:29:37,080 --> 00:29:40,760
Many of these little fish
look harmless enough,

356
00:29:40,760 --> 00:29:43,400
but when they grow up,
they will become

357
00:29:43,400 --> 00:29:46,760
some of the most ferocious predators
on the reef.

358
00:29:46,760 --> 00:29:49,600
Indeed, the existence
of these mangrove nurseries

359
00:29:49,600 --> 00:29:53,160
is one of the reasons why
the fish populations of the reef

360
00:29:53,160 --> 00:29:56,640
are among the most varied and richest
in the world.

361
00:30:00,840 --> 00:30:04,480
The mangroves are not only nurseries,
they're playgrounds.

362
00:30:07,680 --> 00:30:11,800
The aim of the game here is to
survive the most vulnerable stage

363
00:30:11,800 --> 00:30:14,840
of any animal's life,
being a juvenile.

364
00:30:19,320 --> 00:30:21,120
Baby turtles...

365
00:30:22,760 --> 00:30:25,400
..rays and even sharks
take refuge here.

366
00:30:30,200 --> 00:30:34,360
These juvenile blacktips
are just a few weeks old.

367
00:30:34,360 --> 00:30:36,600
And only one sixth of the size
they will be

368
00:30:36,600 --> 00:30:40,120
when they make it out on to the reef
as adults.

369
00:30:42,040 --> 00:30:43,720
For the first year of their lives,

370
00:30:43,720 --> 00:30:46,920
the mangroves play a vital role
in keeping them safe.

371
00:30:49,320 --> 00:30:53,040
As infants, they're vulnerable
to predation from larger sharks.

372
00:30:55,600 --> 00:30:59,560
But the tangle of mangrove roots
keeps the big predators out

373
00:30:59,560 --> 00:31:02,160
and stops them making meals
of the youngsters.

374
00:31:07,320 --> 00:31:08,720
When the young are ready,

375
00:31:08,720 --> 00:31:11,640
they will eventually leave this
sheltered world behind

376
00:31:11,640 --> 00:31:15,080
and make their way to the reef
beyond the mangrove roots.

377
00:31:21,880 --> 00:31:24,760
The next challenge will be to find
their place

378
00:31:24,760 --> 00:31:27,240
in one of the most crowded ecosystems
on the planet.

379
00:31:35,520 --> 00:31:38,960
Getting on the property ladder here
is no easy feat.

380
00:31:41,720 --> 00:31:45,240
Which is why one of the reefs'
most celebrated characters

381
00:31:45,240 --> 00:31:47,880
has developed
a very special relationship.

382
00:31:51,760 --> 00:31:55,400
Clownfish deal with the problem
of overcrowding

383
00:31:55,400 --> 00:31:59,840
by sharing space with another
creature, gigantic anemones.

384
00:32:05,360 --> 00:32:08,600
They've formed a relationship
in which both parties benefit.

385
00:32:11,480 --> 00:32:15,320
Anemones have tentacles
that are packed with stinging cells.

386
00:32:15,320 --> 00:32:19,520
Most fish touching one
get a very nasty sting,

387
00:32:19,520 --> 00:32:21,920
but not the clownfish,

388
00:32:21,920 --> 00:32:25,840
thanks to the protective layer
of mucus that covers its body.

389
00:32:29,080 --> 00:32:31,880
The clownfish keeps the anemone
in good health

390
00:32:31,880 --> 00:32:33,840
by removing unwanted parasites.

391
00:32:35,240 --> 00:32:39,080
And in return,
the anemone offers security.

392
00:32:39,080 --> 00:32:42,560
Its stinging cells ward off
the sort of creatures

393
00:32:42,560 --> 00:32:44,840
which would otherwise threaten
the clownfish.

394
00:32:49,640 --> 00:32:54,680
When the time comes for a pair to
breed, that protection will be vital.

395
00:32:59,280 --> 00:33:02,640
A female may lay up to 1,000 eggs

396
00:33:02,640 --> 00:33:05,040
on the rock beneath her anemone home.

397
00:33:09,320 --> 00:33:11,200
As she delicately attaches them,

398
00:33:11,200 --> 00:33:15,760
the male follows closely behind,
fertilising the eggs as he goes.

399
00:33:20,120 --> 00:33:23,560
A week will pass
before the young are ready to emerge.

400
00:33:27,600 --> 00:33:30,080
Hatching only happens at night,

401
00:33:30,080 --> 00:33:33,000
so to record it, we have to use
infrared cameras

402
00:33:33,000 --> 00:33:35,920
in a specialised filming environment.

403
00:33:38,120 --> 00:33:42,000
This is the very first time
that this behaviour has been filmed.

404
00:33:44,720 --> 00:33:47,320
With gentle encouragement
from their father,

405
00:33:47,320 --> 00:33:49,560
the young are helped on their way.

406
00:33:58,000 --> 00:34:01,520
Once the little larvae are set free,
they're on their own.

407
00:34:03,200 --> 00:34:05,720
They'll spend the first few weeks
of their life

408
00:34:05,720 --> 00:34:07,600
developing in the open ocean.

409
00:34:10,680 --> 00:34:12,320
But how will the young clownfish

410
00:34:12,320 --> 00:34:14,840
find their way back to
the coral reefs

411
00:34:14,840 --> 00:34:17,480
after drifting many miles out to sea?

412
00:34:25,040 --> 00:34:28,600
To understand that, we will have
to tune into a sense

413
00:34:28,600 --> 00:34:32,400
we don't normally associate with
this colourful underwater world.

414
00:34:35,360 --> 00:34:36,880
Sound.

415
00:34:42,400 --> 00:34:46,480
Coral reefs are surprisingly
noisy places.

416
00:34:46,480 --> 00:34:50,280
Fish and invertebrates
produce a whole range of clicks

417
00:34:50,280 --> 00:34:52,840
and grunts and snaps.

418
00:34:52,840 --> 00:34:57,400
The healthier the reef, the more
varied and numerous its inhabitants

419
00:34:57,400 --> 00:34:59,720
and the louder this chorus is.

420
00:35:02,320 --> 00:35:05,240
We now know that fish,
just like birds,

421
00:35:05,240 --> 00:35:08,560
vocalise most at dawn and dusk.

422
00:35:11,240 --> 00:35:14,680
Damselfish call to defend
their territory.

423
00:35:14,680 --> 00:35:17,280
GRUNTING

424
00:35:18,800 --> 00:35:21,520
Seahorses click to attract a mate.

425
00:35:21,520 --> 00:35:24,000
CLICKING

426
00:35:26,680 --> 00:35:29,320
Others create a very different
soundscape

427
00:35:29,320 --> 00:35:31,720
simply by carrying out
their daily duties.

428
00:35:31,720 --> 00:35:33,720
SQUAWKING

429
00:35:36,840 --> 00:35:39,800
Parrotfish crunching
through the hard coral

430
00:35:39,800 --> 00:35:41,880
are a constant on the reef.

431
00:35:44,520 --> 00:35:47,200
Fish perceive sound
in two different ways.

432
00:35:47,200 --> 00:35:50,240
Many have internal ears,
but underwater,

433
00:35:50,240 --> 00:35:53,040
they can also feel sound
as a vibration.

434
00:35:56,720 --> 00:36:02,240
The noise is a key indication
that the community is in good shape.

435
00:36:02,240 --> 00:36:04,920
In fact, the louder the noise
on a reef,

436
00:36:04,920 --> 00:36:07,880
the more inviting it is to newcomers.

437
00:36:07,880 --> 00:36:11,000
Newcomers like the young clownfish.

438
00:36:16,480 --> 00:36:19,080
This little male
is no bigger than a button,

439
00:36:19,080 --> 00:36:23,080
but the time has come for him
to find his place in the big city.

440
00:36:29,880 --> 00:36:33,880
At this stage, his swimming abilities
leave something to be desired.

441
00:36:39,400 --> 00:36:43,000
But his hearing is so sensitive,
he can tell over hundreds of metres

442
00:36:43,000 --> 00:36:44,440
if a reef is suitable.

443
00:36:47,440 --> 00:36:49,320
His journey can last days.

444
00:36:51,000 --> 00:36:54,280
The final approach is usually made
at night to avoid predators.

445
00:36:56,400 --> 00:37:00,080
How fish hear and respond to sound
of a healthy coral reef

446
00:37:00,080 --> 00:37:03,160
is a major area of study
here on Lizard Island.

447
00:37:03,160 --> 00:37:07,200
And the scientists have a simple way
of collecting these fish for study.

448
00:37:08,560 --> 00:37:11,280
A light trap, like this one
at Lizard Island,

449
00:37:11,280 --> 00:37:15,680
is one way of assessing
the way that the reef is working.

450
00:37:18,000 --> 00:37:22,400
Like moths to a flame, the young
are attracted by the light.

451
00:37:24,200 --> 00:37:26,960
'By sampling the newest members
of the community,

452
00:37:26,960 --> 00:37:29,680
'scientists can figure out
how far these juvenile fish

453
00:37:29,680 --> 00:37:32,360
'are willing to travel
for a good home.'

454
00:37:36,880 --> 00:37:40,720
In the case of the clownfish,
juveniles have been known to travel

455
00:37:40,720 --> 00:37:43,960
250 miles before they find a reef.

456
00:37:51,120 --> 00:37:55,120
Fortunately, for the majority,
it's usually a much shorter journey.

457
00:37:59,920 --> 00:38:02,160
While they rarely return to
the particular anemone

458
00:38:02,160 --> 00:38:04,040
beside which they hatched,

459
00:38:04,040 --> 00:38:07,520
60% find a new home on the same reef.

460
00:38:13,840 --> 00:38:17,400
For the clownfish and the anemone,
cooperation is the key

461
00:38:17,400 --> 00:38:20,840
to success in this extremely
crowded environment.

462
00:38:27,640 --> 00:38:31,080
Other residents, however, take a very
different approach.

463
00:38:33,720 --> 00:38:38,040
Rather than share their home, they
fiercely defend their territories.

464
00:38:41,840 --> 00:38:43,880
This is a mantis shrimp.

465
00:38:46,840 --> 00:38:49,760
Spotting the competition is
half the battle.

466
00:38:51,840 --> 00:38:54,280
There are many different
species of mantis shrimp

467
00:38:54,280 --> 00:38:56,840
but they all have one
thing in common,

468
00:38:56,840 --> 00:38:58,720
superb vision.

469
00:38:58,720 --> 00:39:03,000
The 400 million-year-old visual
system of the mantis shrimp

470
00:39:03,000 --> 00:39:07,840
is the most complex in the entire
animal kingdom.

471
00:39:07,840 --> 00:39:12,360
Its eyes are mounted on two stalks,
giving it independent vision,

472
00:39:12,360 --> 00:39:15,360
but whereas our eyes produce
binocular vision,

473
00:39:15,360 --> 00:39:19,000
each one of theirs produces three
different images.

474
00:39:20,240 --> 00:39:25,160
Not only that, whereas we have three
photoreceptors in our eyes,

475
00:39:25,160 --> 00:39:30,160
the mantis shrimp has up to 16,
giving it access to

476
00:39:30,160 --> 00:39:34,800
parts of the spectrum that we can't
even see, let alone imagine.

477
00:39:37,920 --> 00:39:42,160
And they can use their amazing
vision to devastating effect.

478
00:39:47,080 --> 00:39:50,440
While some are armed with spears,
others carry clubs.

479
00:39:57,000 --> 00:39:59,600
Many are champion boxers.

480
00:39:59,600 --> 00:40:01,120
They can deliver a punch

481
00:40:01,120 --> 00:40:04,520
that accelerates faster than
a .22 calibre bullet.

482
00:40:10,240 --> 00:40:12,880
These powerful blows are used to
stun their prey

483
00:40:12,880 --> 00:40:14,480
and defend their burrows.

484
00:40:19,680 --> 00:40:24,000
Mantis shrimps are one of the more
house-proud residents on the reef.

485
00:40:25,800 --> 00:40:27,880
In fact, they're compulsive cleaners.

486
00:40:35,840 --> 00:40:38,440
They keep their burrows
meticulously neat.

487
00:40:41,520 --> 00:40:44,240
With all that effort, it's hardly
surprising that they're

488
00:40:44,240 --> 00:40:45,560
fiercely territorial.

489
00:40:48,400 --> 00:40:50,800
In fact, mantis shrimps have
earned themselves

490
00:40:50,800 --> 00:40:53,320
a reputation for being
somewhat ill-tempered.

491
00:40:55,040 --> 00:40:58,360
But scientists have discovered that
there's another side

492
00:40:58,360 --> 00:40:59,760
to these macho males.

493
00:41:01,440 --> 00:41:05,040
This young hopeful is trying to
catch the eye of a potential mate.

494
00:41:06,400 --> 00:41:09,200
He starts by showing
off his paddle-like antennae.

495
00:41:13,440 --> 00:41:16,240
His technique may not be very
impressive to us

496
00:41:16,240 --> 00:41:19,640
but he is, in fact, sending
the female secret signals.

497
00:41:22,840 --> 00:41:26,000
And that is possible
because mantis shrimps can see

498
00:41:26,000 --> 00:41:29,320
and reflect a kind of light that
absolutely no other

499
00:41:29,320 --> 00:41:31,840
creature in the world that we know
of can see...

500
00:41:33,480 --> 00:41:34,480
..including us.

501
00:41:36,960 --> 00:41:41,200
The male's display is a private
invitation for this female to dance.

502
00:41:49,920 --> 00:41:51,840
So far, so good.

503
00:41:51,840 --> 00:41:54,000
She makes her way to the
dance floor.

504
00:42:01,960 --> 00:42:05,200
If the male can impress the female
with his performance,

505
00:42:05,200 --> 00:42:07,600
she will choose him
to father her offspring.

506
00:42:17,680 --> 00:42:20,400
It seems that this male has all
the right moves.

507
00:42:25,360 --> 00:42:28,440
The final phase of courtship,
however, usually takes place

508
00:42:28,440 --> 00:42:32,080
out of sight, within their burrows.

509
00:42:38,400 --> 00:42:41,680
The mantis shrimp is arguably
one of the reefs most colourful

510
00:42:41,680 --> 00:42:44,560
characters and typifies the key
to survival here.

511
00:42:49,080 --> 00:42:54,760
Each resident species has had to
carve out its own particular niche

512
00:42:54,760 --> 00:42:58,480
and that is what has created this
extraordinary diversity.

513
00:43:00,480 --> 00:43:05,360
Here, life can evolve 50% faster
than in other marine environments.

514
00:43:07,960 --> 00:43:11,240
The tiny creatures that have built
this remarkable ecosystem

515
00:43:11,240 --> 00:43:16,880
have created a habitat so complex
that it supports all kinds of life.

516
00:43:21,200 --> 00:43:24,040
But none of the reef's
residents would be here

517
00:43:24,040 --> 00:43:26,440
without one truly
extraordinary event.

518
00:43:28,240 --> 00:43:30,320
It occurs just once a year

519
00:43:30,320 --> 00:43:33,320
and is one of the greatest of all
natural spectacles.

520
00:43:37,280 --> 00:43:41,360
It wasn't until the 1980s that
scientists discovered it,

521
00:43:41,360 --> 00:43:43,080
here on the Great Barrier.

522
00:43:45,520 --> 00:43:47,000
On a few nights of the year

523
00:43:47,000 --> 00:43:48,840
when the conditions are just right,

524
00:43:48,840 --> 00:43:51,040
all along the length of the reef,

525
00:43:51,040 --> 00:43:55,080
corals of many different species
suddenly erupt.

526
00:43:55,080 --> 00:43:58,160
It's the great spawning event

527
00:43:58,160 --> 00:44:00,760
and it's one of the wonders of the
natural world.

528
00:44:02,800 --> 00:44:04,440
It's the one time in the year

529
00:44:04,440 --> 00:44:07,880
when the corals themselves don't
just grow by branching,

530
00:44:07,880 --> 00:44:13,200
but reproduce sexually, and it's
vital for the survival of the reef.

531
00:44:13,200 --> 00:44:15,440
In recent years, we've learned
a great deal

532
00:44:15,440 --> 00:44:19,040
about the many factors that
influenced the moment of spawning.

533
00:44:22,320 --> 00:44:25,560
But even though we know it occurs
within days of the full moon in

534
00:44:25,560 --> 00:44:29,720
October or November, the trigger that
starts it all is still a mystery.

535
00:44:34,920 --> 00:44:38,200
The light of the moon is, perhaps,
the most influential,

536
00:44:38,200 --> 00:44:40,000
but there are many other factors,

537
00:44:40,000 --> 00:44:45,000
including the temperature of the
water and the state of the tides.

538
00:44:45,000 --> 00:44:47,280
And as the moment approaches,

539
00:44:47,280 --> 00:44:49,680
all along the length of the reef,

540
00:44:49,680 --> 00:44:51,720
there's a mounting sense of
excitement.

541
00:44:55,880 --> 00:44:58,880
Fish and other predators gather.

542
00:44:58,880 --> 00:45:01,400
This will be an opportunity for
a feast.

543
00:45:09,800 --> 00:45:11,320
The timing has to be exact.

544
00:45:13,080 --> 00:45:16,960
Each species of coral has its own
particular triggers,

545
00:45:16,960 --> 00:45:20,760
but they must synchronise their
behaviour to ensure their success.

546
00:45:22,640 --> 00:45:25,200
Just half an hour before the big
event,

547
00:45:25,200 --> 00:45:27,800
there is the first
sign of the spawning to come.

548
00:45:31,560 --> 00:45:35,000
Small bundles of sperm
and eggs bulge from the polyps.

549
00:45:41,320 --> 00:45:44,240
When the moment is right,
there is a mass release.

550
00:46:12,000 --> 00:46:15,840
For hundreds of miles all
along the coast, the corals erupt.

551
00:46:39,000 --> 00:46:43,040
Only with daybreak can you see
the true scale of the event.

552
00:46:48,080 --> 00:46:52,600
Great ribbons of coral spawn drift
over the surface of the sea.

553
00:47:00,200 --> 00:47:02,240
After the coral has spawned,

554
00:47:02,240 --> 00:47:05,800
the billions of developing larvae are
swept far and wide

555
00:47:05,800 --> 00:47:07,480
by the tides and the currents.

556
00:47:08,880 --> 00:47:13,360
The vast majority will be
eaten by fish and other creatures,

557
00:47:13,360 --> 00:47:17,640
but the few survivors must then find
a place to settle,

558
00:47:17,640 --> 00:47:21,440
either on a newly-vacated site on an
existing reef

559
00:47:21,440 --> 00:47:23,480
or perhaps to found a new one.

560
00:47:31,440 --> 00:47:33,760
The newest coral recruits
will continue

561
00:47:33,760 --> 00:47:36,880
the work their ancestors began
almost 10,000 years ago.

562
00:47:48,680 --> 00:47:53,320
They are the essential organisms
on which the whole reef depends.

563
00:48:00,000 --> 00:48:02,520
The Great Barrier is what it is

564
00:48:02,520 --> 00:48:05,360
because the tiny coral polyps
never stop building.

565
00:48:08,240 --> 00:48:12,800
And what they have created is one
of the wonders of the natural world.

566
00:48:21,680 --> 00:48:24,720
Next time, we'll cross
the Great Barrier Reef

567
00:48:24,720 --> 00:48:26,760
to meet its extraordinary visitors.

568
00:48:34,520 --> 00:48:35,920
I will meet turtles

569
00:48:35,920 --> 00:48:39,120
that may have travelled
thousands of miles to get here

570
00:48:39,120 --> 00:48:40,720
and the remarkable people

571
00:48:40,720 --> 00:48:43,000
who are trying to save them from
disaster.

572
00:48:49,000 --> 00:48:53,080
I will come face-to-face with
the great predators of the reef.

573
00:48:53,080 --> 00:48:55,280
Wow. There's a huge shark.

574
00:48:55,280 --> 00:48:57,320
They are so beautiful in the water.

575
00:49:02,040 --> 00:49:05,880
And we'll meet a whale that seeks
out human contact,

576
00:49:05,880 --> 00:49:08,680
a behaviour that happens nowhere else
on Earth.

577
00:49:10,440 --> 00:49:12,600
Some come from the open ocean,

578
00:49:12,600 --> 00:49:15,880
others from the land immediately
inshore

579
00:49:15,880 --> 00:49:18,880
and still others from the sky,

580
00:49:18,880 --> 00:49:22,760
to complicate still further
the intricate community

581
00:49:22,760 --> 00:49:25,920
that is known as
the Great Barrier Reef.

582
00:49:45,000 --> 00:49:46,120
For this series,

583
00:49:46,120 --> 00:49:50,080
the production team set themselves an
ambitious challenge.

584
00:49:50,080 --> 00:49:54,000
They wanted me to experience the
Great Barrier Reef as never before.

585
00:49:58,320 --> 00:50:01,920
To achieve that, we teamed up with
a very special research vessel...

586
00:50:04,160 --> 00:50:06,240
..the Alucia.

587
00:50:06,240 --> 00:50:08,360
There aren't many boats like this in
the world and

588
00:50:08,360 --> 00:50:10,800
it's a kind of magic carpet for us.

589
00:50:10,800 --> 00:50:13,400
It allows us to float around the
reef

590
00:50:13,400 --> 00:50:15,720
and for David to tell different
parts of the story.

591
00:50:18,120 --> 00:50:21,120
On board, all the latest technology,

592
00:50:21,120 --> 00:50:23,480
helicopters, a laboratory

593
00:50:23,480 --> 00:50:25,280
and advanced mapping systems.

594
00:50:30,360 --> 00:50:32,080
At the helm of Alucia,

595
00:50:32,080 --> 00:50:33,400
Captain Frank Alika.

596
00:50:35,040 --> 00:50:37,720
The task of getting the ship
into position

597
00:50:37,720 --> 00:50:41,120
for the first big submarine launch
rests on his shoulders.

598
00:50:43,160 --> 00:50:45,680
Some parts are charted less
well than others,

599
00:50:45,680 --> 00:50:48,080
but this particular bit, there's
quite a lot of bombies

600
00:50:48,080 --> 00:50:50,520
and things out there that are likely
to jump up and bite you

601
00:50:50,520 --> 00:50:53,160
on the bottom, and that's
really not what you want.

602
00:50:56,480 --> 00:50:59,120
Fortunately, he's a lot more
hands on

603
00:50:59,120 --> 00:51:01,840
than the skipper was on my first
visit in 1957.

604
00:51:06,600 --> 00:51:08,000
But it was very primitive.

605
00:51:08,000 --> 00:51:10,600
The camera was wound up by clockwork

606
00:51:10,600 --> 00:51:13,280
and it was just me and the chap with
a 16mm camera

607
00:51:13,280 --> 00:51:14,480
and I did the recording.

608
00:51:16,080 --> 00:51:19,920
It may have been a modest shoot but
it was, in its way, ground-breaking.

609
00:51:22,160 --> 00:51:24,200
We worked on locations on the reef

610
00:51:24,200 --> 00:51:26,360
where film crews had never
been before.

611
00:51:29,200 --> 00:51:33,520
60 years later, I'm told we are
poised to make history once again.

612
00:51:36,600 --> 00:51:38,520
This time, to reach new areas of
reef,

613
00:51:38,520 --> 00:51:42,920
I'll have to rely on the Triton
submersible.

614
00:51:42,920 --> 00:51:46,920
And she's very flexible in terms
of how shallow we can come, as well.

615
00:51:46,920 --> 00:51:48,800
She'll work in 1,000 metres happily,

616
00:51:48,800 --> 00:51:51,440
but we can also work in the
splash zone,

617
00:51:51,440 --> 00:51:54,600
so her actual trim system is very
good.

618
00:51:54,600 --> 00:51:57,320
Amazing visibility, as you'll see
when you get in.

619
00:51:57,320 --> 00:51:58,920
Yes, she's a little bit flash.

620
00:52:02,720 --> 00:52:05,680
With just a few short
hours before the first big dive,

621
00:52:05,680 --> 00:52:08,480
the excitement and pressure is
building on deck.

622
00:52:12,160 --> 00:52:14,640
This will be the last
opportunity for the crew

623
00:52:14,640 --> 00:52:16,400
to check the camera gear

624
00:52:16,400 --> 00:52:18,640
and make sure everything is perfectly
in place.

625
00:52:21,080 --> 00:52:22,760
It's been a busy morning already.

626
00:52:22,760 --> 00:52:24,760
We've had soundmen, cameramen

627
00:52:24,760 --> 00:52:26,960
trying to fit all their gear into
the sub.

628
00:52:26,960 --> 00:52:29,400
We're sort of running out of space
for bodies.

629
00:52:31,840 --> 00:52:34,840
There are lots of worries when you
put your 88-year-old presenter

630
00:52:34,840 --> 00:52:36,120
in something like this.

631
00:52:36,120 --> 00:52:39,280
I mean, it's got a very small
area at the top to get into.

632
00:52:39,280 --> 00:52:41,240
There are all sorts of things that
can go wrong.

633
00:52:41,240 --> 00:52:42,560
We're always very cautious.

634
00:52:46,080 --> 00:52:47,880
And even the most limber of sub
operators

635
00:52:47,880 --> 00:52:49,480
will struggle getting in the sub.

636
00:52:49,480 --> 00:52:51,440
David's incredibly active and fit,

637
00:52:51,440 --> 00:52:53,360
but he's 88 and so we were
slightly worried

638
00:52:53,360 --> 00:52:55,400
about how he might get into the sub.

639
00:52:57,520 --> 00:52:59,840
Yeah, that's it, that's the one.

640
00:52:59,840 --> 00:53:01,640
OK, so we're just going to...

641
00:53:01,640 --> 00:53:04,680
See that landing, he'll guide you
right in.

642
00:53:04,680 --> 00:53:07,080
And then you can put your foot
there, David.

643
00:53:07,080 --> 00:53:09,280
Keep coming. Nearly there.
That's it. OK.

644
00:53:11,040 --> 00:53:12,840
You can rest against me if you want.

645
00:53:12,840 --> 00:53:14,400
Nearly sat on the pilot!

646
00:53:14,400 --> 00:53:17,720
That's all right, I'm used to it.
That's what he's there for.

647
00:53:19,000 --> 00:53:21,400
David, as usual, defied
all our thoughts

648
00:53:21,400 --> 00:53:23,640
and just went straight in without
any trouble

649
00:53:23,640 --> 00:53:25,640
as though he was a 25-year-old.

650
00:53:25,640 --> 00:53:28,680
Rest it on your lap. Is that OK?
Yep.

651
00:53:33,680 --> 00:53:37,840
So, that's hatch secure and we are
ready.

652
00:53:40,120 --> 00:53:42,720
The sub weighs almost eight tonnes

653
00:53:42,720 --> 00:53:45,520
and getting it into the water is
a major operation.

654
00:53:48,440 --> 00:53:51,040
There's something quite
extraordinary about the Triton

655
00:53:51,040 --> 00:53:52,880
being launched, standing here
on deck.

656
00:53:52,880 --> 00:53:56,280
Suddenly, the whole back deck area
of the ship comes alive.

657
00:53:56,280 --> 00:53:57,960
You've got people running around.

658
00:53:57,960 --> 00:54:00,800
Everything's incredibly detailed and
carefully planned,

659
00:54:00,800 --> 00:54:03,440
but you're sort of caught in a
whirlwind as ropes fly

660
00:54:03,440 --> 00:54:05,720
and the submarine starts to move
forwards.

661
00:54:05,720 --> 00:54:07,720
You know, this is a very
exciting moment.

662
00:54:07,720 --> 00:54:11,360
You know, this is a big day, even
in the world of David Attenborough.

663
00:54:17,640 --> 00:54:19,640
As we disappear beneath the waves,

664
00:54:19,640 --> 00:54:21,360
out on a support vessel,

665
00:54:21,360 --> 00:54:24,960
underwater cameraman Steve Hudson
prepares to film the sub

666
00:54:24,960 --> 00:54:26,360
as it explores the reef.

667
00:54:29,840 --> 00:54:32,320
So, Nick and I are going to
jump in the water,

668
00:54:32,320 --> 00:54:35,320
descend to a maximum depth of about
30 metres

669
00:54:35,320 --> 00:54:37,560
and shoot exterior shots of the
submarine

670
00:54:37,560 --> 00:54:39,160
as it cruises over the reef.

671
00:54:41,120 --> 00:54:42,880
It can be pretty tiring.

672
00:54:42,880 --> 00:54:45,360
You have to swim in front of it,
swim behind it,

673
00:54:45,360 --> 00:54:47,000
swim beneath it, swim above it,

674
00:54:47,000 --> 00:54:48,920
trying to get a multiple of shots.

675
00:54:51,160 --> 00:54:54,840
But today, because of the strong
currents, visibility is poor.

676
00:54:59,320 --> 00:55:03,880
At first, Steve struggles to locate
the sub through the cloudy water.

677
00:55:21,040 --> 00:55:23,040
Finally, he makes visual contact.

678
00:55:30,000 --> 00:55:32,840
Before we descend deeper and beyond
his reach,

679
00:55:32,840 --> 00:55:35,440
Steve must get his exterior shots of
the sub.

680
00:55:37,680 --> 00:55:39,240
Lead cameraman Paul Williams

681
00:55:39,240 --> 00:55:41,760
captures the action from inside
the vessel.

682
00:55:43,520 --> 00:55:45,040
To get the best footage,

683
00:55:45,040 --> 00:55:47,640
the divers need to coordinate with
the sub team.

684
00:55:49,480 --> 00:55:52,440
It's a task easier said than done.

685
00:55:52,440 --> 00:55:53,920
We're literally in a bubble.

686
00:55:53,920 --> 00:55:56,400
We can't talk to the divers outside.

687
00:55:56,400 --> 00:55:58,400
We had this rather crude
hand signal.

688
00:55:58,400 --> 00:55:59,840
You know, it's like,

689
00:55:59,840 --> 00:56:02,520
"Get out of shot," or, you know,

690
00:56:02,520 --> 00:56:04,280
"Well, just move over that way
a bit."

691
00:56:20,760 --> 00:56:22,840
Can you see his hand signals, yeah?

692
00:56:34,520 --> 00:56:36,360
He's saying, "Thank you."

693
00:56:36,360 --> 00:56:37,840
Thank you and...

694
00:56:37,840 --> 00:56:39,960
We're just going to do the
descent now.

695
00:56:48,160 --> 00:56:49,800
'As the vessel dives deeper,

696
00:56:49,800 --> 00:56:53,120
'we're treated to some spectacular
sights...

697
00:56:53,120 --> 00:56:54,160
Oh, how beautiful.

698
00:56:56,520 --> 00:56:59,120
'..which show why the reef is
one of the most dazzling

699
00:56:59,120 --> 00:57:00,760
'habitats on the planet.'

700
00:57:06,880 --> 00:57:08,720
Oh, look at this lot.

701
00:57:08,720 --> 00:57:11,160
It's jolly nice that someone of my
age

702
00:57:11,160 --> 00:57:13,720
can be taken down in fantastic
comfort.

703
00:57:13,720 --> 00:57:15,440
Grey reef shark there.

704
00:57:15,440 --> 00:57:18,640
No problem about breathing.
No problem about talking.

705
00:57:18,640 --> 00:57:21,720
No problem about your movements.

706
00:57:21,720 --> 00:57:22,640
There's another.

707
00:57:24,840 --> 00:57:26,200
You're just sitting there

708
00:57:26,200 --> 00:57:29,800
and looking at one of the most
extraordinary places on Earth.

709
00:57:29,800 --> 00:57:31,320
A privilege given to very few.