All language subtitles for Serie.BBC.Great Barrier Reef S01E03 Reef and Beyond.en

The Great Barrier Reef is huge.

It stretches for over 2,000km along
Australia's north-east coast.

It's so vast,
it's clearly visible from space.

And it's not simply
a collection of coral gardens,

but a network of very
different habitats.

It means there's a complexity
of life here

on a scale found almost nowhere else
in the world,

and it doesn't exist in isolation.

Violent storms are unwelcome
visitors.

And ocean voyagers arrive
here from many parts of the globe.

The Great Barrier Reef is such
a rich system that

animals are drawn in from the vast
empty spaces of the open ocean,

from the tiniest plankton
to ocean giants.

It means that the Great Barrier
Reef's an international hub,

home to some of the greatest
wildlife spectacles on Earth.

This green turtle's
a summer visitor.

She's travelled hundreds
of kilometres across the ocean

and she's heading to the very beach
where she was born.

The turtle's come to lay her eggs

and she's not alone.

Out here, on the edge of the reef,

she's joined by thousands more
female turtles.

They're all driven by the
same instinct,

to return home to nest.

It's the largest breeding population
of green sea turtles in the world.

After her long journey,

she takes a few days to rest and
recover.

Butterfly fish provide a cleaning
service,

clearing away dead skin and the
parasites acquired

from many months at sea.

It's always exciting to see

a large animal in the sea

and of course the turtle is a very
iconic species in the marine world

and I'm surrounded by them on this
dive,

hundreds and hundreds of turtles in
the water column above me,

passing over the reef crest and out
in the blue water.

The turtles all converge
on small islands

made of coral rock and sand, known
as coral cays,

but not all are suitable
for nesting,

some are sandbanks exposed
only at low water,

and many others have beaches
that are swamped at high tide.

Islands with deep sand

and a covering of vegetation are
more stable

and one island in particular
seems just right.

In the far north of the
Great Barrier Reef is Raine Island.

It's so wild and so special,

that few people are permitted
to land.

It's one of the most protected
islands on Earth.

This speck in the ocean is
barely a kilometre long,

yet it attracts thousands of turtles
and enormous flocks of seabirds.

The birds have flown in from
New Guinea and Japan to the north,

Fiji to the east

and even from the Asian mainland
thousands of kilometres away.

In summer, Raine Island's the most
crowded destination on

the Great Barrier Reef.

It may look chaotic,
but there's some order here.

Brown boobies are everywhere

but other species prefer
specific nesting sites.

Red-footed boobies hang out
on branches,

a scarce commodity on
the outer reef.

Caspian terns from Japan
nest on the sand.

Frigate birds find
low-growing shrubs

and red-tail tropic birds hide
amongst the limestone rocks.

The birds, like the turtles,
are here to breed.

But the turtles, unlike the birds,

are about to face the greatest
challenge

of their visit to Raine Island.

By late afternoon,

they move towards the prime-nesting
beach that surrounds

the entire island.

All around me it's like the troops
are massing,

the landing force is preparing
itself and I can see

heads popping up, the dark shapes
moving in the shallows

and then a glistening back will
appear.

This is the moment of transition

when they leave
the weightlessness of the sea.

The bulk of her heavy body

presses down on all her
vital organs.

She's beautifully adapted
to a life at sea

but ill-equipped to move
about on land.

Her progress is slow

and probably painful.

It's quite common for 5,000 turtles

to emerge in one summer evening

but tonight is anything but
ordinary.

26,000 turtles are coming at the
island from all sides.

A world record.

It's going to be a long night.

These green turtles are only one
of the many visitors to the reef.

Another ocean voyager is
heard before it's seen.

WHALE CALLS

It's a dwarf minke whale,

one of the smallest of the great
whales.

The turtles have swum from as far
away

as islands in the South Pacific,

but the whales have travelled
considerably further,

all the way from the Antarctic.

They come to the Ribbon Reefs,

south of Raine Island,

to calve in the warm,
tropical waters

or to mate.

Whale watching's become a local
tourist attraction

but some whales turn the tables,

they go people watching.

These are adolescent whales,

and they're extremely inquisitive.

The moment of the first encounter is
extraordinarily intense because

you see the animal materialise
beneath you.

The first thing you see is the white
stripe on the pectoral fin

and then the water seems to
solidify.

This is a big animal,
five or six tonnes,

and then you gradually
see it turn

and the eye focuses on you
and you focus on the eye.

The animals are plainly studying you

and gradually getting closer and
closer.

You're an object of curiosity
to this whale

and it is a remarkable sensation.

By hanging onto the rope,
my position is predictable,

so the whales are quite unafraid.

The mechanical
twang of their call

is so powerful you feel it
rather than hear it.

Being on nodding terms with a minke
whale is a whole new experience.

And to be here not on ours

but on their terms is quite amazing,

to be in the audience
of the ultimate underwater ballet.

More musical sounds announce the
arrival of even bigger whales.

Humpbacks.

They're one of ten species of whale
that visits the reef each year.

They were once hunted, almost to
extinction,

but numbers here have bounced back
to 15,000,

about half the
pre-whaling population.

Like minkes, humpbacks come up from
the Antarctic to mate and to calve.

This mother gave birth a couple
of weeks ago,

and already her calf weighs over
two tonnes

and is more than six metres long.

For the turtle mother,

the final and what may turn out to
be the most arduous part

of her journey, has only just begun.

With thousands of turtles
arriving at the same time,

their trails criss-cross the sand
like tank tracks on a battlefield.

There are just too many
turtles for the space available.

She spends much of the night

heaving her bulk back and forth
across the sand,

searching for a
vacant nest site.

Such is their enthusiasm
for digging,

neighbours are in real
danger of being buried alive.

Some even dig up eggs that have
already been laid.

After several hours searching,

the female finds a suitable place,

where the sand is still moist.

Her flippers may be
a liability for moving on land,

but now they come into their own.

Using her front flippers,

she first digs a protective
hollow for herself.

Then, with her back flippers,

she delicately scoops out a
deep pit.

Each one of her
clutch of 100 eggs is

the size of a ping-pong ball.

A soft shell prevents them from
breaking as they drop into the hole.

When she's finished, she'll cover
the nest

and over the coming weeks her eggs
will incubate in the warm sand.

This is a deeply private
moment for this turtle

and I do feel I'm rather intruding.

You can see she is flicking
sand to fill the hole

and very successfully flicking
it straight in my face as well.

But this is a huge physiological
effort for this animal

you will see the turtle... Oh!
Good one, right in my eye.

That was right on the button.

I think I'm going to take
the subtle hint

that I should leave her alone to
get on with it.

By morning, she joins the mass
evacuation of the island.

Most of the exhausted turtles head
back to the sea at the same time,

so there's an even bigger
pile-up at the water's edge

than when they arrived.

But quite a few
stragglers are left behind.

It's been an absolutely
exhausting night

for any of the turtles
that you can see behind me.

In fact, you can make out this old
girl here is absolutely shattered.

She's completely spent and she is
desperately trying

to get back into the sea
before the heat of the sun kicks in.

For the last to leave,
it's a race against time.

In a couple of hours the temperature
on the sand will soar.

And, on one part of the island,
there's a major obstacle that

wasn't there when they arrived.

Rocks exposed at low tide

make the return to water anything
but easy.

Being reptiles,

sea turtles have little control
over their body temperature.

There's no shade anywhere,

so those left on the beach risk
being cooked alive.

For the unlucky few

this is the last journey
they'll ever make.

Every turtle that leaves the
sanctuary of the ocean

is taking a gamble.

And it's a knife edge
whether they will live or die

and obviously for this turtle that
gamble didn't pay off.

There's a number of factors that
can kill them,

it can be exhaustion, it could be
overheating

or it could be being buried, which
may have happened in this case,

by other turtles laying their eggs.

If turtles trapped by the rock wall
can make it to a pool,

they might survive.

The seawater cools their bodies.

All they have to do is
wait for the incoming tide

and whatever that will bring.

Raine Island is part of the outer
barrier reef,

so it's right next to
the open ocean.

Here the mottled hues of the shallow
reef meet the dark blue of deep sea.

The reef wall plunges
down vertically

to the ocean floor
1,000 metres below.

It's here that reef life and
creatures of the deep coexist.

For migration to the reef is not
only from across the ocean,

it's also up from the depths.

As a diver I can explore the first
100 metres or so.

It's a very contrasting face

to the gloriously kaleidoscopic
world of the upper reef

and the dark, cold,
echoing world of deeper water.

So, to see what's living down there,

we need a remotely operated
vehicle, an ROV.

It enters an alien world,

pitch black,
with crushing water pressures.

And extremely cold.

At four degrees,
it's the same temperature

as the sea in the Antarctic.

The ROV reaches a depth of
800 metres,

not quite at the bottom,
but not far off.

A pile of coral sand at the base
of the reef wall

slopes gently into the abyss,

and here we find
signs of real deep-sea creatures.

Some, like this sea anemone,
are familiar.

Others are less well known,
like this chambered nautilus.

It's an ancient relative of octopus
and squid,

a living fossil, the last survivor
of a group of animals

that dominated the world's oceans
500,000,000 years ago.

It moves around by jet propulsion,

squirting water backwards, in order
to go forwards.

At night,
it's the nautilus's turn to migrate.

It swims up towards the surface

to feed on shrimps beside the
reef wall,

returning back down during the day.

This is a baby nautilus,

the first time
one's been filmed in the wild.

It's no bigger
than a two-pound coin,

yet it makes the same daily
up and down journey

as its plate-sized parents.

But that pales into insignificance
when compared

to the daily vertical migration

of these microscopic animals
called zooplankton.

At sunset,

all of these tiny creatures
swim upwards,

and, under cover of darkness,

they graze on floating algae close
to the surface.

Many of them are fish larvae.

In fact, almost every fish species
on the Great Barrier Reef

starts life in the plankton.

There are billions upon
billions of them

making the roundtrip, the greatest
daily migration on Earth.

They all travel an extraordinary
distance,

size for size, it would be like me
running a marathon twice a day.

That's if they're not caught
on the way up.

On the reef wall,
at about 150 metres deep,

are huge sea fans.

They look like plants, but they're
colonies of animals,

whose branching arms capture
the rising plankton.

Hidden amongst the branches is
a pygmy seahorse.

It's a tiny fish that also
feeds on plankton.

At little more than a centimetre
long, fully grown,

it's one of the world's
smallest fish.

Contrast that with this monster,

a tiger shark.

Like the tiniest marine life,

it too rises up
from the ocean's depths,

but, unlike the plankton,
it's planning to stay a while.

Tiger sharks travel over 800km
to reach Raine Island,

and each year they
show up at exactly the same time,

the time when turtles are nesting.

Turtles trapped in rock pools begin
to refloat on the incoming tide.

For some, it's a second chance.

Now all this female must do is cross
the lagoon to reach the reef edge

and the safety of the open ocean.

But swimming in with the incoming
tide is her number-one predator.

It's crossed the reef
and is heading towards the beach.

A tiger shark could
dismember this turtle

and can even saw through her shell.

She's on high alert.

She turns and tilts rapidly,

presenting her widest profile.

It's too much of a mouthful
for the shark,

but the tiger shark doesn't
give chase.

It can't be bothered.

There's a much easier way
to get a meal.

It's been waiting
for fresh turtle carcasses

to float out on the rising tide.

To predict such an event is
an amazing thing for a shark to do.

This is no mindless killer,
this shark is smart.

It pitches up at the peak
of the turtle nesting season

and simply waits for the tide
to deliver its food.

Ah, look at that.

So distinctive,

right under the boat.

Tigers have been found with all
matter of interesting things

in their stomachs and,
as an opportunistic predator,

she's come in and had a look at
the boat a little look at me.

Just a nudge of the boat.
She's using the nose,

all those senses packed into
the nose, to try and figure out

what we are and what I am. And now
she's heading back to the carcass.

I hope.

Watch this bite.

Good grief! What she is doing now is
sawing using the weight of her body.

These are huge, bulky animals

and you get a lot of torsion
with that weight.

And with that torsion she'll clamp
the jaws on to the flipper or head

and just rip from side to side
and the mechanical action

and the cutting action of the teeth
will tear lumps of flesh off.

Vibrations from the commotion
and the odour of mashed turtle flesh

are carried on the currents,
attracting more sharks to the feast.

But, this is no feeding frenzy.

Sharks of this size could do
each other real damage,

so instead they take it in turns,

with smaller sharks
deferring to the larger ones.

Tiger sharks are generally solitary,

so this gathering of 16
is extremely unusual.

This is the largest number
of tiger sharks seen in one place

at any one time.

When you hunt the dead,
there's no need to hurry.

It means the living
can slip away, for now.

She'll not go far,
for she'll be back again,

up to eight times during a single
breeding season

to deposit up to 100 eggs
on each visit.

Only then can she head back
to her feeding grounds,

where who knows what will
happen to her.

Away from the Great Barrier Reef,
sea turtles are caught to eat.

And sharks aren't immune either.

These tiger sharks bear the scars
of hooks from long-line fishing.

It's not surprising then

that the older sharks
are conspicuous by their absence.

While at Raine Island, the sharks
and turtles are in a sanctuary,

but even sanctuaries
can come under threat.

Although not necessarily from us.

Brief thunderstorms are a welcome
break from the heat and humidity,

but they can also
build into the mother of all storms.

The summer heats up the ocean,

creating tropical storms that
spiral in from the Coral Sea.

In America, storms of this
intensity are known as hurricanes,

and in Japan they're called
typhoons.

But here they're known as cyclones.

A cyclone can be over 500km across,

with winds swirling around the eye
at 300km per hour.

It's the most destructive force
the Great Barrier Reef must face.

And in February 2011,

this part of the reef was hammered

by the biggest storm
in living memory,

Cyclone Yazi.

'This is a special broadcast of
9 News with Peter Overton.

'Live in the cyclone...'

'Good evening and welcome to
a special edition of 9 News,

'live from Airlie Beach.

'The Cyclone Yazi bears down
on North Queensland.

'These are the latest satellite
images of the biggest cyclone

'Australia has experienced
in more than 100 years.

'Estimated to have the same intensity
as Hurricane Katrina,

'it's a category 5, you can't get
anything more powerful.'

Daybreak exposed the ferocity
of Cyclone Yazi.

'We are expecting to wake up
tomorrow morning

'to scenes of devastation and
heartbreak, that's unprecedented,

'not only in Queensland,
but Australia's history.'

Island resorts were destroyed.

And a massive storm surge
smashed into marinas,

demolishing everything it touched.

In the direct path of the cyclone,

waves pulverised the reef

and huge swells seriously
damaged corals 500km

from the eye of the storm.

Cyclones form when humidity
and air temperature build,

but that's not the only time high
temperatures directly affect

the Great Barrier Reef.

In summer,
the air temperature can soar.

Close to the ground, heat reflected
by the sand compounds the problem.

On Raine Island, the turtle eggs
are incubating safely below ground

but for the seabird chicks, the cay
becomes a searing furnace.

Birds must find shelter wherever
they can.

Bizarrely, one option is to shade
your head with your own rear end.

But with global warming,

temperatures are increasingly higher
than the norm,

and then an unusually high water
temperature

can be just as
destructive as a storm.

An ominous white glow along the edge
of the reef

indicates it's under stress.

The corals have lost their colour.

This bleaching occurs

because corals can only
live in a narrow temperature range.

Healthy corals get their colour
from microscopic algae

living in their tissues.

These manufacture food for the
corals by photosynthesis

but when the temperature rises

just two degrees above the normal
summer maximum,

the algal cells are expelled

because they no longer
benefit the coral.

The bleaching effect is the white
chalky skeleton

showing through the coral's
transparent tissues.

But they're not dead. Not yet.

They can survive in this bleached
state for several weeks.

If the temperature drops,

the corals acquire new
algae from plankton floating by.

But, if the warm water persists,
the coral dies.

Coral bleaching hadn't been seen
on the Great Barrier Reef

before the 1980s.

Due to global warming,
bleaching's now more common

and cyclones are likely to be
more frequent too.

And there's something even
more insidious.

Temperatures are rising because
more and more carbon dioxide

from human activity enters
the atmosphere.

This dissolves in seawater turning
it weakly acidic,

which can stop coral growth.

If they can't build their chalky
skeletons,

reefs will start to crumble.

With such threats, it's a wonder
the reef has any future at all

but it does have a chance,

for the reef has a neat way
to help itself recover

and it's evident for just one
week in late spring.

A few days after a full moon,

each hard coral species,
along the entire reef,

spawns at the same time,
on the same night.

Eggs and sperm unite to form
free-swimming larvae.

Smaller than a pinhead, a coral
larva is a like a space capsule.

It floats away on the current
and seeks a new place to grow.

Some larvae travel no more
than a few metres

others drift thousands
of kilometres across the ocean,

depending on where
the current takes them.

Attracted to settle by the sounds
made by reef life,

like fish, shrimps or even sea
urchins,

the larvae searches
for a spot to call home.

It transforms into a coral polyp,

like a miniature sea anemone
anchored to the seabed

and here it starts a brand
new colony of coral.

This constant process of re-seeding

may help ailing reefs to recover,

as long the damage is not
too severe or too frequent.

Sunrise on Raine Island marks
another mass movement of wildlife.

The first light of dawn
is just touching the horizon.

And there's an exodus taking
place from the island.

The seabirds behind me just massing
prior to leaving the island

and heading out
to the open sea to hunt.

Both parents normally take turns
to search for food,

but as the chicks grow
and become more demanding

they both go to sea,
leaving their offspring on its own.

Along with other predators,

the parents search far
offshore for dense shoals of fish.

Here, sharks, tuna, and seabirds
are competing for

a tight ball of fish that'll last
just a few minutes.

The birds rely on sharks and tuna

to drive the smaller fish closer
to the surface.

Their chicks' very survival
depends on their success.

A hungry young booby waits patiently
for its parents to return.

This time it's lucky.

They've flown in
with plenty of food.

By late summer,

Raine Island is the largest nursery
on the Great Barrier Reef,

with seabird chicks growing
on top of the sand

and turtle eggs developing
underneath.

But Raine is not the only island
with nesting seabirds,

on Heron Island, shearwater parents
return not at sunset,

but after dark.

It's a hangover from times

when these birds nested
on islands with predators.

Flying in and out at night was one
way to avoid them.

Parents find each other in the dark
by their raucous calls.

The pair reaffirms its bond
before the returning bird

enters the underground nest.

Although there's a little
housekeeping to be done first.

Both parents share nursery duties,

and they take turns to fly great
distances in search of food.

They may be at sea for several days.

They leave as they arrived,
in the dark.

Well before sunrise,

they line up in clearings
like aircraft taxiing for takeoff.

And then it's away out to sea.

Back on Raine Island,
the very last birds to nest

are rufous night herons.

They haven't travelled far,

just out from the mainland

and they surely have the most
unattractive chicks on the reef.

They've hatched late in the season
for a very good reason,

because their food is not out
at sea, but right on the doorstep.

In late afternoon, the parent birds
take their positions.

They scan the sand,
alert to any movements.

At sunset, the temperature change
triggers the start.

It's what the herons have been
waiting for.

The clutch of turtle eggs
has been incubating

under the sand for two months.

At the right moment, the hatchlings
all emerge together.

They must reach the water
in the shortest possible time.

Baby turtles are food
for baby herons,

so the heron parents have
timed the peak of their nesting

to coincide
with this mass emergence.

Even ripples in the sand

slow the hatchling's headlong rush
to the sea.

It could mean the difference
between life and death.

But the herons have had their fill.

They simply couldn't eat another
baby turtle.

It's been a narrow
escape for this one.

The first wave of hatchlings
has taken the brunt of the attacks,

but the sacrifice of a few
hundred ensures

the following thousands have a
better chance to get to the sea

but some babies go the wrong
way, just like their mothers.

The wall of rock's an even bigger
obstacle for the hatchling

than it was for the adult.

And there's something even more
sinister up ahead.

Rock crabs,

they like baby turtles too.

Their powerful pincers can tear
a hatchling limb from limb.

Another lucky escape
but there's still a way to go yet.

Come on, little fella!
Keep going, keep going!

It's a delicious little
package of protein.

It's made the difficult
and dangerous journey

from the dunes there
and it's still going and,

of course, this transition
into the marine environment

doesn't mean this hatchling is safe.

It faces a whole new set of hazards

as it tries to swim out,
over the reef top.

Everything out there is waiting
for these hatchlings.

He's nearly there,
that tiny, tiny, little turtle

and that's a huge expanse of ocean.

Exactly where this little hatchling
goes is a mystery.

But she'll be at sea and she'll
not return to Raine Island

before her 30th birthday,

when she'll come back to lay eggs
on the same beach

that she's leaving today.

That's if she survives in an
uncertain and often hostile world.

Raine Island has the biggest
concentration of wildlife

on the Barrier Reef, but
many of its animals are visitors

and at departure time they leave
behind the sanctuary

of one of the world's largest
marine parks.

The migrants cross
international borders

travelling to places
where animals are not protected.

It means their survival is linked
very much to events in other

parts of the world.

The Great Barrier Reef is still
an amazing place.

It's a magical, underwater world,
stunningly beautiful

and a never-ending source of wonder.

But how will it be
when our turtles return?

The reef has proved to be
resilient in the past,

surviving great natural changes.

But nothing like the pace
of man-made change today,

especially the pace
of climate change.

We've seen how the
Great Barrier Reef

is connected to
the rest of the world, in many ways.

It means we're all, no matter how
remote, involved in its future.

Now, only we can decide
what that future will be.

Whether it remains the glorious
marine spectacle of today,

one of the richest and most
diverse of all environments

and the largest biological structure
on the planet

or whether it become something
much poorer.

It's a future
that is entirely in our hands.

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