All language subtitles for Great Barrier Reef S01E02 Reef to Rainforest

The Great Barrier Reef is the
largest coral reef on our planet.

It's one of the seven recognised
wonders of the natural world.

The reef itself is the place
that most people explore

but there's much, much more.

The coral reef is actually a very
small part of this underwater world.

As little as seven per cent.

The remaining 93% of the marine park

encompasses a variety of habitats,
each one remarkable in its own way.

And beyond the marine park

there are even more environments
that are important to the reef.

Some close to shore.

Others inland.

Altogether there are more than a
hundred different types of habitat

in and around the Barrier Reef,

each with its own
distinctive plants and animals.

There are creatures that
you would expect to see on a reef,

and others that you would not.

All the places in which
these animals live

are linked to a vast
deep-water lagoon

which lies between the coast of
mainland Australia

and the outer reef.

These habitats interconnect,

and all are vital to the well being
of the Great Barrier Reef.

This is the little known story
of one of the most complex

and spectacular ecosystems on Earth.

The Great Barrier Reef is over
two thousand kilometres long,

which means the lagoon that
lies between the outer reef

and the Australian mainland
is vast.

An area one and a half times
the size of the British Isles.

Pick a spot anywhere in the lagoon
and you'll probably find sand,

as about two-thirds of the seafloor
here is a shifting underwater desert.

It looks barren,
but there is life here.

It's just that you don't
often see it.

Garden eels

and an unlikely alliance.

A fish and a shrimp
that share a burrow.

In a world where most food
is out of sight,

it takes a predator
with special talents to find it.

And this is that predator...

The ray.

The ray's special skill is to find
living things under the sand,

and the largest species
to do this here is the stingray.

It finds its prey by detecting
the minute electric fields

produced by muscles
when they contract,

including the heart muscles.

Something no animal
can ever switch off.

But they do have to swim directly
over a beating heart

to know that it's there.

By sucking and blowing,

this stingray excavates its target
deep under the soft sand.

Many rays feeding together produce
a series of furrows on the sea floor

and all that puffing and blowing
can attract unwelcome attention.

The hunter can just as easily
become the hunted.

This is a stingray's worse nightmare.

A great hammerhead shark.

It has electro-receptors too.

They're spread across the underside
of its very broad head,

which it sweeps back
and forth searching for prey.

The stingray has a formidable
weapon, a venomous barb.

But one hammerhead was found
with 96 barbs in its body,

and seemed none the worse.

The stingray's first line of defence
is to remain very still

in the hope that the shark
doesn't find it.

The commotion warns the other rays
to escape,

but it attracts other sharks,
like jackals at a kill.

Dramas like this are played out
every day on the floor of the lagoon,

but few people are there
to witness them.

It seems surprising that the lagoon
remains a relatively unexplored
environment.

But if you're a diver,
why would you explore the lagoon?

It's relatively hostile,

particularly when you compare it
to the crystal clear reefs

that are short boat ride away.

Yet there's plenty of life down here.

Prawns, squid and all manner
of fish species

are caught by local fishermen.

Diving here is not easy
but it's well worth the effort.

Dotted across this vast underwater
desert are ghostly oases

where amazing life forms
have taken hold.

It's a strange, almost alien world.

And if the place seems strange,

many of the creatures living here
are even stranger.

These oases are created
not by plants but by animals.

They're corals, but not
the normal reef building ones.

Unlike their hard coral cousins,
they don't have a chalky skeleton

and they thrive at depths
where the light is less intense,

capturing food from
the water currents

with eight feathery tentacles.

These soft coral gardens
are important

because baby fish hide amongst them.

Nearly half of all the adult fish
on the reef proper

grow up in nurseries on the lagoon.

They arrive as larvae,
swept in from the ocean by the tide.

Then, as the tiny fish grow,

they hop from one refuge to the next
across the floor of the lagoon

to reach their final destination
back on the Barrier Reef itself.

As long as they hide
amongst the corals and seaweed,

they're relatively safe.

The danger comes
when they break cover.

This baby Queensland grouper may
just be a few centimetres long now,

but one day he'll weigh half a tonne.

That's if he lives that long.
He can't stay hiding forever.

It's dangers like this
camouflaged stonefish

that force all life down here
to find somewhere to hide.

The floor of the lagoon
is relatively flat and featureless.

It's like the plains of the desert.

But every now and then you get
a little oasis of life.

And this sponge, here,
has been heavily colonised

by these feather stars and it
provides a vital bit of cover

for juvenile fish on their journey
both to the reef

and their journey to adulthood.

And that journey includes stopovers
at almost anything that sticks out
above the sand,

like this tube dwelling sea anemone.

A carpet anemone becomes
a welcoming roadhouse.

Even the spines of a sea urchin
will do the trick.

A surprising refuge is this
highly venomous Stoke's sea snake.

It's picked up some hitchhikers,
baby trevally,

and become a mobile nursery.

Wherever it goes, they go.

With hiding places at a premium,

fish will go to incredible lengths
to hide down here.

and none more so than this.

The pearl fish is vulnerable
out in the open,

so while it's not feeding
it must conceal itself.

But it has a peculiar taste
in hiding places.

This is a sea cucumber.

Its body is basically a tube.

It sucks in sand at one end,
extracts anything edible

and passes waste out of the other.

Just what the pearl fish
has been looking for.

But NOT the mouth end.

It's attracted to the odour
of the other end.

Sea cucumbers are repulsive
to most predators

so the pearl fish is safe inside.

It'll stay there until
it's time to feed again.

It doesn't harm its host,
but the bad news for sea cucumbers

is that pearl fish are happy to share
their temporary home with others.

It seems there's
plenty of room for all.

The Barrier Reef
we see today is comparatively young.

It began to form
during the last Ice Age

when sea levels were 120 metres
lower than they are today.

When the ice sheets began to melt,

the growth of corals kept pace
with the rising seas,

blocking off the waters
of the lagoon.

And during that one great event

another important habitat
was created.

Stretching away behind me
to the horizon

is the great expanse of the lagoon
and yet a mere 10,000 years ago,

that's a blink of an eye
in geological time,

the beach I'm standing on
would have been the slope of a hill

overlooking a plain
covered in Eucalyptus forest.

But the sea level rose,

the plain was inundated
and the hill became an island.

These "continental islands",
as they're known,

are essentially pieces of mainland
cut off by the rising water.

There are six hundred of them
scattered about the lagoon.

Any land animals cut off from the
mainland had to adapt or perish.

And on this island one species
has done so well,

it's positively flourished.

This is a yellow spotted
monitor lizard,

or goanna, if you're
from this neck of the woods.

And it's a very successful and
abundant animal on this island.

It made a real impression
on Captain Cook

when he came here in 1770.

To the degree that when he sat
down to think about a name for
the island,

not a terribly long process,
I don't think,

he thought, "It's an island
and it's covered in lizards."

"Got it! Lizard Island."

Which is rather clever, I think.

Do you see what he did there?

When hunting, the goanna
is alert to any movement.

If the grasshopper remains still,

it has a chance of escaping
the goanna's attention.

Balancing on its back legs and tail
like a tripod

is a trick few others lizards
can perform,

but it's effective to get to those
just out of reach places.

The goanna's sense of smell
is as important as its sight.

Its forked tongue helps it to detect
food from a distance.

By comparing the strength of a smell
reaching each of the two prongs

it can pinpoint where it comes from.

A rotting fish is irresistible.

They're usually solitary,

but here on Lizard Island
they'll tolerate others,

as long as there's plenty of food
to go round.

Small goannas give way
to larger ones.

Foraging a variety of foods
has helped the goannas

build a large population
on Lizard Island,

but there's another important factor
and that's how they react to me.

HE WHISTLES

There are people living
on the island

and the goannas
are not afraid of them.

In fact, quite the opposite.

He's followed the scent
of my barbeque

and over the last few years these
animals have adapted their behaviour

to get used to the presence of man

and use man as a potential
food source.

This ability to learn and change
as the environment around you changes

is a very neat evolutionary trick.

He's used to hunting invertebrates,
he's changed his behaviour

to home in on this appallingly cooked
barbequed sausage.

In the modern world where man has
encroached on virtually every habitat

it's a very good way
of ensuring your survival.

And adaptability has enabled a
reptile with a more chilling interest
in people to thrive in these waters.

It's the saltwater crocodile,
better known locally as the 'salty'.

It's the world's largest reptile and
it's common on the lagoon's islands

because it's at home
in saltwater and fresh,

sometimes swimming far out at sea.

So it's not unusual to find one
hauled out on an island beach.

Salties, though, start life
with more modest dimensions.

This one-year-old is no more
than 30 centimetres long

and it's hiding amongst
the plants at the edge of the sea.

Hunting at the junction
between air and water

means there's a good choice of food.
Like mud skippers.

He'll have to improve as a hunter

if he's going to grow
into a six-metre giant.

And he'd best better watch his back.

There's a bird about that could
easily take a baby crocodile.

This is a white bellied sea eagle.

It's the second largest eagle
in Australia

and it's fantastic to be this close.

This is the closest I've ever been
to any eagle anywhere in the world.

They can be seen just about anywhere
around the lagoon.

You're as likely to spot one
amongst the trees,

as you are over the reef.

So an island is a perfect base.

They may be specialised
to catch fish,

but like the goannas and crocodiles
they're adaptable too.

This is a range of items taken
from beneath a killing tree

of a white bellied sea eagle
on a continental island.

The killing tree is where the
sea eagle will take apart, dismember,

and eat its prey.

It's a very good representation
of what these animals eat

and indeed their strategy
for hunting.

You've got a parrot fish here,
which is a deeper swimming fish.

you've got things like
these long toms

which actually swim right
on the surface,

you've even got birds here.

Most remarkable of all
you've got these freshwater turtles,

that don't exist on the island.

They are on the mainland
so that eagle has flown the mainland

taken these turtles
and brought them back to the nest.

It's an excellent representation
of the strategy of these animals.

If a food item is short locally
in short supply on the island,

they'll actually seek alternatives.

This generalist approach
makes them very, very successful

in the limited environment
that an island represents.

Even so,
fish make up half of its diet.

To catch them it uses huge talons.

They're also weapons it can use
to have a crack at these...

fruit bats.

Spectacled fruit bats are big.

They have a wingspan of about a metre

and they roost in island forests
as well as those on the mainland.

Babies have to cling on tight.

But that's the least
of a mother's worries.

Diving into the tangle of branches

and grabbing a bat
hanging at its roost site

is not an option for a large bird.

For the eagle to have any chance,
the bats needs to be airborne.

These are little red fruit bats.

During the day, they gather
in roosts of up to a million

so they're not hard to find.

An eagle's appearance creates panic.

Bats are agile flyers

but the eagle's powerful claws
gave it the edge.

The continental islands
are magnets for wildlife,

providing shelter,
lookout points and hunting grounds.

They're oases for life
but they're not the only ones.

Below the surface of the lagoon is
an island of a very different kind.

A shipwreck.

This is the SS Yongala.

She sank during a cyclone in 1911

and now sits on the seabed
at a depth of thirty metres.

122 people lost their lives.

But out of this human tragedy
has come an opportunity.

100 years underwater has created
something very, very special.

The Yongala is regarded by many as
the greatest wildlife wreck on earth.

And looking around me
it is very hard to disagree.

The wreck provides shelter
on the featureless plain

for more than 120 fish species.

This concentration of life

is sustained by food swept in
by the exceptionally strong currents.

The living is so good,

many of the young fish
stay here for their entire lives,

rather than move to the outer reef
when they grow up.

There are sea turtles down here too.

This one's a loggerhead.

And the wreck's a favourite hangout
for another species.

This is a hawksbill turtle

and he's here to feed on
the soft coral that coats the wreck.

The soft corals are one of
the main reasons that all this life

is attracted to the Yongala.

Almost every available space
on its once smooth hull

is covered with them.

The soft corals are a refuge
for millions of small fish

but they must dart out
from time to time

to feed on the plankton
in the current.

And wherever small fish gather,

it's not long before something
bigger turns up to eat them.

A grouper!

This is a Queensland grouper,

it's the largest bony fish
that lives on the Great Barrier Reef.

Queensland groupers are real giants.

This Yongala resident
is known as the VW,

because he's the same
size as the car.

His mouth's so big,

he's quite capable of swallowing
sharks and rays whole.

But another resident
has an even deadlier bite.

Sea snakes have more potent venom

than many of their
land-living relatives

and they put it to good use.

The olive sea snake doesn't really
look as though it's hunting,

but when its small head
disappears into a hole,

it can trap and paralyse
any fish hiding there.

It's unusual for so many predators to
be swimming so close to each other,

but there's so much to eat here.

Most of the action
is on top of the wreck,

where the strongest currents
sweep in the most food.

The waters within the immediate
vicinity of the wreck

is an area of incredibly intense
and violent predatory activity.

For the small fish
that call the Yongala their home,

to venture into this blue water
is a huge gamble

but they've got to do it,
to seek out food.

And if they get it wrong
and go too far,

the difference between life and death
on this wreck

can be a matter of
millimetres or seconds.

The amount of marine life
to be found in the 100 metres

of the wreck of the Yongala
is truly staggering.

Arguably it's a greater concentration

than on any spot
on the Barrier Reef itself.

In contrast to the middle,

the landward edge of the lagoon
is relatively shallow.

Here, bright sunlight can reach
all the way to the sandy bottom,

where conditions are right
for plants to grow.

This is not seaweed, but a marine
relative of the water lily,

known as "sea grass".

It grows and flowers in vast meadows
in clear water around islands

and along the shore of the mainland.

And it supports a creature

that ancient mariners
once mistook for mermaids.

Gathering in herds of a hundred
or more are dugongs or "sea cows".

They're relatives of elephants.

Each one can weigh nearly
half a tonne

and munch through 40 kilos
of sea grass a day.

Dugongs were once abundant

but they've had a difficult
relationship with people.

Nowadays they're trapped
accidentally in fishing nets

and shark protection barriers

and traditionally aboriginal hunters
targeted them

because they taste good,
like prime beef.

And recovery of a population is slow.

A single baby is born
every three to seven years.

And this baby dugong

may not be old enough to breed
until she's 17 years old.

A combination of all these factors
means the population

in the southern part of the reef
has halved in the last decade.

Now there are just 11,000 left in
the entire Great Barrier Reef region,

yet there are still more dugongs
in Australian waters

than any other place on Earth.

Dugongs are not the only animals
to feed on sea grass.

Young green turtles like it too.

He's after the most tender shoots

and this is his exclusive patch.

He's very choosy
about what he likes

and what he doesn't.

Like your lawn,

sea grass needs to be constantly
cut short for healthy growth,

so he's actually farming his
own little plot

that he'll tend for several months
before moving on.

Sea grass meadows are also nurseries
for baby fish,

like these domino damselfish.

They won't stay here forever.

When they're bigger,

they won't be able to hide
amongst the slender stems,

and they'll look for a better hiding
place, maybe one even closer to land.

Where the sea meets the coast,
saltwater meets the freshwater

from rivers and streams.

But one doesn't suddenly
become the other.

The water mixes slowly,
creating a world unlike either,

but connected to both.

It's here that you'll find
a special group of plants.

Fringing the coast of the mainland

is a habitat that has a profound
impact on the ecosystem of the reef.

They're plants that have cracked
a neat evolutionary trick.

They can live in brackish
environments,

which is a combination
of salt and fresh water.

They're the mangroves.

They grow where no other trees
are able to.

Twice a day, the tide floods
their roots with saltwater.

At the same time, water from rivers
flows through the mangroves

and their lattice of roots
acts like a giant tea strainer,

slowing it down so that any sediments
washed off the land can settle out.

Bacteria break down the trapped
sediment and other organic material

helping create tonnes and tonnes
of sticky mud.

A whole new home for wildlife.

In a perfect world
mud should be thick,

glutinous and as rich
as dark chocolate.

And it should also stink
to high heaven.

But this is extremely important stuff
to the Great Barrier Reef.

One teaspoon full of this mud
contains ten million bacteria.

All those bacteria
are potential food.

And although there aren't many
species that eat mud directly,

those that do,
operate in large numbers.

Legions of creatures perform
the unglamorous but crucial task

of breaking down the gloop.

Mud whelks and fiddler crabs
both eat the mud

and their waste is the vital product
that spawns an entire food chain.

Once it's in the water,
clouds of shrimp devour it.

The nutrients that started in the mud
are now swimming around

in small, easy to catch parcels.

All this food makes the mangrove
a great place for fish,

small residents, as well as
youngsters that will one day move out

to the Barrier Reef.

Reef species like these rabbit fish
may look big

but they're still only one
third of their adult size.

These snappers also have some
growing up to do before they leave.

And these young trevally
will grow up one day

and be major predators on
the outer reef.

The mangroves, sea grass meadows
and the soft coral oases

are vital nurseries for
so many fish on the reef,

and they all provide two things,

food and shelter.

The complexity of the mangrove
root system

makes it a perfect haven
for small and juvenile fish.

The reason is, the latticework
of the roots as they cross

means it's a very difficult
for large predators to manoeuvre

and actually get at the smaller fish.

But predators like these young
blacktip reef sharks hide here too.

They hunt at the edge
of the mangroves,

but they can't get deep
into the tangle of roots.

So the young reef fish are safe,
for now.

So, it's a great environment for the
small fish to actually grow up in,

to get big and strong,

before they make the big move
to open sea and the reef beyond.

But when they leave
the safety of the mangroves

they must cross that sandy desert

and the many hazards waiting
for them in the lagoon.

This is a mantis shrimp.

From his neatly kept burrow,
he surveys the world

with the most complex visual system
known to science.

He's about the size
of a man's forearm.

And he's got quite a reach.

Even if a young fish avoids
the dangers on the seabed,

there are plenty more predators
floating above.

Patrolling these inshore waters

is probably the most dangerous
animal in the lagoon.

The box jellyfish,

whose stinging tentacles are quite
capable of killing a person.

This creature is much more
than a passive drifter.

It can move has as fast
as an Olympic swimmer

and it has 24 eyes,

each complete with a lens
that can form a detailed image.

It uses its tentacles
like a trawl net,

when a fish makes contact, thousands
of microscopic stinging capsules

explode into the prey's body,
flooding it with paralysing venom.

The fish is killed quickly,

and then hauled into the mouth on
the underside of the bell.

All of the habitats
we've seen so far

have an obvious connection
to the lagoon,

but there's one place
that couldn't be more different

from the underwater world,
that's critically important

to the vigour of the
Great Barrier Reef ecosystem.

It's the tropical rainforest.

The Queensland rainforest
is the oldest in the world,

it's older even than the Congo
and even the Amazon.

And this is one of the most
impressive trees in it.

This giant fig has strangled
its original host

and now dominates
this immediate environment.

It's an ecosystem in its own right.

But you might be asking yourself,

"What has this tree got in common
with the reef?"

But, in fact, it's directly linked.

The rainforest all around me
and indeed swamps and mangroves

are critical
for the health of the reef.

These huge tracts of rainforest
close to the Queensland coast

are essential because
they regulate the flow of water

and the sediment it contains.

That's important, because
there's an awful lot of water here.

Hot, humid tropical air gives rise
to vast amounts of rainfall.

It pours for at least 120 days a year

and as much as 60 centimetres
can fall in a single day.

It's one of the wettest places
on Earth.

Left unchecked by the forest

the water would wash out sediments
and smother marine life,

but the waterways flowing off the
rainforest are relatively clear,

and many are spectacular.

When sediments are released slowly,
the nutrients in them

help sustain life in the lagoon,
so everything flourishes.

Where conditions are just right,

corals manage to grow
right next to the coast.

Here, pristine tropical rainforest

grows right down to the waters edge,

a stone's throw from a coral reef.

It's a place where two worlds meet

and animals from the reef
and the rainforest

can be found
right next to each other.

These footprints belong to one of the
biggest land animals in Australia.

The cassowary.

A flightless bird
that's almost as tall as a person.

Its claws wouldn't look out of place
on a dinosaur.

And its kick is so violent,

that the cassowary is said to be
the world's most dangerous bird.

A parent is particularly dangerous
when rearing a chick.

In fact, the cassowary is shy,

and is rarely seen in the wild.

But it's a key animal here.

It feeds on the fruits
of rainforest trees and shrubs,

it's one of the few animals
that spread their seeds.

The seeds of many forest trees
can't germinate

without animals like the cassowary.

As the forest is directly linked
to the reef

by regulating sediments
entering the lagoon,

the cassowary contributes to
the health of the reef itself.

But there are now less than 2000
living here

and they're becoming
rarer all the time.

Before European settlers arrived

much of the coast here
was covered in forest

and a lot of that was jungle
just like this,

this is a vibrant ecosystem
in its own right.

It's full of reptiles and birds,
as you can hear all around me.

But today things
have changed significantly.

Much of coastline that abuts
the great Barrier Reef,

80% of it, in fact,
has been cleared for agriculture

and much of that has been
totally cleared for sugar cane.

Obviously this has a dramatic impact
on the terrestrial environment,

but it also has a significant
effect on the reef itself.

And it's not only crops.

Cattle ranches, fish farms,
six large coastal cities

and many holiday resorts
along the coast

all have an impact
on the reef system.

Without the natural vegetation
controlling the movement of water

and the sediment it carries,

heavy rain now washes millions
of tonnes of silt,

often laced with damaging fertilisers
and pesticides

straight into the lagoon.

Sediment plumes can be so extensive,

they sometimes spread all the way to
the outer reef.

In the sea grass meadows,

the fine silt shrouds
the light-dependant plants,

and fertilizers feed algal blooms
that choke the life from them.

When the meadows die,
the turtles, dugongs

and baby fish that depend on them
die too.

Near the shore,
the water can be so murky

that less light reaches the corals,

so most fringing reefs
have also disappeared.

All of these habitats
are interdependent.

If you ruin one, it can have
an impact on many others.

And that includes
the outer reef itself.

To look after all of these habitats,
the Great Barrier Reef Marine Park

sits at the heart of a network
of protected areas.

All interconnected
and covering a vast area.

After all, the reef is an inspiration
to people all over the world.

It attracts one and a half million
visitors each year

who come to see
the largest coral reef on earth.

Together with divers,
yachtsmen and anglers,

they inject seven billion dollars
a year into the local economy.

But the value to Australia
is even greater than that.

Towns and cities along much
of the Queensland coast

are not washed into the Pacific Ocean
because the reef protects them.

It means the Barrier Reef is
so much more than just a coral reef.

And there are vast tracts of
rainforests, mangrove swamps,

sea grass meadows and soft coral
oases in a deep-water lagoon.

It's truly an extraordinary place.

And, the reef's influence goes
far beyond Australian waters.

It's vital to wildlife from many
other parts of the world.

Wave after wave of voyagers
arrive here from across the ocean.

From the islands
of the South Pacific,

from the Asian mainland...

And from as far away as
the icy seas of Antarctica.

These wildlife visitors create

some of the most impressive
natural spectacles

on the Great Barrier Reef.

And all this is the subject
of the next programme.

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