All language subtitles for BBC.The.Green.Planet.2of5.Water.Worlds.1080p.HDTV.x265.AAC.MVGroup.org.eng

Plants cover much of the
land surface of our planet.

But there is another
extraordinary green world

that is often hidden from us.

It's one where plants
have overcome huge challenges

in order to survive.

The world of fresh water.

At first sight, a lake like this
would seem to have everything

that life needs in order to thrive.

Clear, oxygen-rich water,

plenty of dissolved nutrients
and minerals

and lots of sunlight.

But, in fact, life in fresh water

presents plants with huge problems.

To succeed, plants have had to
abandon many of the adaptations

that served them so well on land

and evolve something
quite new and, doing that,

they have created some of the most
beautiful and bizarre

and important habitats on Earth.

There are few places where
it's more difficult to make

a permanent home than a freshwater
torrent like this one.

Violent currents
drip across the riverbed,

scouring it clean...

..whipping land plants
from their margins

and drowning them.

How could any plant survive
in a place like this?

Yet, even here, some do manage to,

quite literally, hold on.

They can grasp the bare rock
with remarkable strength.

This ability allows plants to thrive

in these otherwise
hostile environments.

This is the Cano Cristales
river in Colombia.

These plants are red Macarenia,

sometimes called the
Orchid of the Falls.

They cling to the riverbed,
not with their roots,

but with their stems, glued
to the rock surface by one

of the most powerful
adhesives in nature.

The rock itself will break

before these anchors
lose their grip.

These feathery filaments
are their modified leaves,

and they do what roots normally do -

gather the minerals and
nutrients they need

that are dissolved in the water.

With such spectacular colours,
it's hardly surprising

that the Cano Cristales
is sometimes called

the most beautiful river on Earth.

But being rooted to the spot
is not always the best strategy

for living in a water world.

This is a water lettuce,

and it has some
remarkable adaptations.

Its roots hang free,

so it's not anchored to the ground,

and its leaves are thick and spongy

and covered in fine hairs.

So the plant itself
is more or less unsinkable.

This combination of characteristics
enable the water lettuce

to do something that almost
no land plant can do.

It can travel.

It is an ability that
becomes invaluable when,

during the wet season, flooded
rivers become great highways,

as they do here in South America.

This is the largest inland
water world on Earth.

The Pantanal.

For a few months every year,
it provides water plants

with ideal conditions,

but, all too soon,
it becomes a battleground.

Plants are racing to claim
their space on the surface.

The water lettuce rapidly expands
its network of hanging roots

so that it starts
absorbing nutrients

before other competitors arrive.

Water hyacinth appears.

Its leaves are carried
on stalks filled with air

that also make it
virtually unsinkable.

The race for space intensifies.

A new competitor arrives, Ludwigia.

It spreads by developing
a chain of tiny rafts.

And jostles for space with
the densely packed leaves

of mosaic plants.

All are racing to claim
as much sunlight as possible.

They flower quickly before
the floodwaters recede.

And these surface dwellers
also have competitors.

Including one that has been
waiting in the depths

and is now stirring.

It's a monster.

It's well armed.

It clears space for itself

by wielding one of its buds.

Like a club.

And now it dominates the surface.

This is a leaf of the
giant water lily.

It expands by over
20 centimetres a day

and eventually measures

more than two metres across.

Its immense leaves are supported
by a network of air-filled struts

and protected by spines
two centimetres long.

The leaves float high in the water
and their surfaces are dotted

with tiny holes, drains, that
help them ensure that rainwater

doesn't accumulate and sink them.

Nutrients from the fertile mud
below are carried up by tubes

in its stem to fuel
the leaf's expansion.

Over the next few months,
the lily will produce

some 40 or so of these
gigantic leaves.

And as each one reaches the surface
and expands, more and more light

is taken from those plants
that are trying to grow beneath.

Competitors are pushed aside.

Some are crushed,

or skewered.

Eventually, its immense
leaves press their margins

against one another,

totally cutting off the light
from the plants beneath them.

The battle is over.

And victory is total.

The frozen water world of
Lake Akan in northern Japan.

Home to one of the strangest
and most primitive of plants.

It's an alga, like those that appear
so mysteriously in our ponds.

But this one is truly extraordinary.

Each spring, the melting ice
releases soft, velvety balls

of interwoven threads
called Marimos.

This one is small.

No bigger than a walnut.

But there are lots of them here.

They attract the attention
of visiting whooper swans.

But there is one way for the
Marimo to escape from the danger,

and it depends on a change
in the weather.

Fortunately, in the spring,
winds sweep across the lake...

..creating currents that carry some
of the Marimos beyond the reach

of hungry swans.

It's the start
of a remarkable journey.

They are gently carried back
and forth by the currents

so that the Marimos become
more and more spherical.

And, slowly, they travel
into deeper water.

Here, there are great numbers
of them, certainly many millions.

Some are the size of basketballs.

They're safe from swans,

and the water is still
shallow enough

for some sunlight to reach them.

It seems a perfect home.

And so it is...

..almost.

The snag is that these waters
also carry a fine sediment

that can clog the Marimo's surface,

cutting off the all-important light.

But the Marimos are not
entirely immobile.

They dance.

The winds blowing over the
lake's surface create currents

beneath that are sufficiently
strong to move the Marimos.

They rub against each other.

And in just a couple of hours
of gentle movement,

they're all clean once more.

As they spin, every part
of their surface

gets enough time in the sunlight
to keep growing.

This is the heart of the Amazon.

There are water worlds here that
are so remote that, even today,

few people have ever seen them.

This barely explored tributary
is the Rio Claro.

And here, when conditions
are just right, it's possible

to witness a rare
and remarkable spectacle.

The river is so crystal clear
that its bed is bathed in sunlight.

A magical landscape of miniature
mountains and valleys.

It's carpeted by pipewort, fanwort

and star grasses.

As the sun climbs in the sky...

..bubbles of gas appear.

Evidence of photosynthesis.

Deep inside the plant cells,

tiny structures called chloroplasts

move towards the light.

They absorb carbon dioxide
and use the sun's power

to synthesise the sugars
that the plant needs to grow.

And as a by-product,
they release oxygen.

The gas that we and all
other animals must have

in order to breathe.

Now, in late afternoon, bubbles
of oxygen make the river water

fizz like champagne.

The plants can become
so buoyant with gas

that they rise to the surface,

even carrying the bedrock with them.

Only in this remote water world

can this spectacular
natural wonder be seen.

Eastern Venezuela.

Here, rectangular table mountains
known as tepuis

stand above the tropical forest.

There are more than 50 such
isolated mountain plateaus here,

each home to a unique
community of plants.

Downpours are so torrential
that no soil can accumulate

on their broad, rocky summits,

and some plants living up here
have to find their nutrients

from another source.

These are Bromeliads.

Their leaves are shaped like
a funnel and collect rainwater,

which accumulates in the centre.

This small pond is colonised
by all kinds of tiny animals.

And it is their bodies,
when they die, that provide

some of the nutrients
the Bromeliads need.

This makes a good partnership
in which both parties can thrive.

But...

..it can be exploited

by a plant predator.

This probing stem belongs to a plant
called a bladderwort.

It, too, is in need of nutrients.

And a well-stocked Bromeliad pool
is just the place to find them.

This one is full of aquatic animals.

The bladderwort begins to change...

..into a hunter.

It develops bladders

and removes sufficient
of the water within them

to create a partial vacuum.

Each bladder has a trap door
beside it with trigger hairs.

Now all the bladderwort has to do...

..is to bide its time.

It only takes one touch

for the trap door to snap open...

..and suck in its prey.

It's all over in a millisecond.

And after it has fed, a bladderwort
has enough energy

to produce another tendril

to search for another
Bromeliad pool.

Swamps and bogs are also
poor in nutrients.

So several plants that live in
such places catch insects too,

if they can.

The leaves of Sundews are
covered with long, red hairs,

each tipped with a droplet.

These glistening globules are,

in fact, glue.

Once the Sundews detect the taste
of their victim's body,

they flood it with
digestive enzymes.

The little body disintegrates.

And the Sundew gets
the nutrients it needs.

Another plant has
an even more elaborate way

of catching a meal.

The Venus Flytrap has leaves
that are lined

with interlocking teeth.

It attracts insects by producing
a sweet perfume,

just as a flower does.

It, too, has a hair trigger.

And another insect is caught.

But the technique is more complex
than it might seem.

The Venus Flytrap has a problem.

It needs to avoid false alarms,

snapping shut on something
inedible, like a raindrop

or a little bit of twig.

That would be a waste
of both time and energy.

So how does it avoid that?

Well, it does it by counting.

If I touch this one,

sensitive hair just there...

..no reaction.

That could be a false alarm,
but the plant remembers that

for 20 seconds.

And if I touch it a second
time within that time,

then that's much more likely
to be worth eating.

And so...

..it closes.

So far, so good, but now it
needs to be absolutely certain

that it's got something
worth eating,

so it continues counting.

Only after it has totted up five
separate touches to those hairs

will it give the final squeeze
and then begin to produce the liquid

from the surface of the leaf,
which will dissolve the body

of its unfortunate victim.

The Flytrap now has enough
energy to produce flowers

and attract pollinating insects.

Wind and insects between them
pollinate virtually all land plants,

but neither method can be used
by plants that live

entirely underwater.

So some lead double lives.

A chalk stream in southern England,
and swaying in the current

is a plant for which these rivers
are famous.

This is water-crowfoot,
a kind of aquatic buttercup.

For most of the year,
it is underwater.

And if I take this
underwater camera...

..you can see its floppy stems
grow horizontally.

That reduces the risk of being
swept away by the current.

But each spring, when it's
time to flower, it produces

something crucially different...

..a stem that is stiff enough
to resist the current

and lift its flowers
into the air above.

And now, of course,
they can get help from insects.

So every year, in part, at least,

water-crowfoot becomes
a land plant...

..and provides us with one of
the loveliest natural spectacles

of the early English summer.

Water-crowfoot is not the only
water plant to lift its flowers

above the surface.

Plants do so all around the world.

From the swamps of the Pantanal...

..to the lakes of Thailand,

they all burst
into spectacular bloom.

Once they've been pollinated,
they produce seeds.

And now their flowers
have done their job,

some return to a life under water.

Now they must ensure
that some of their seeds

will find suitable places
in which to germinate.

Bullrushes every year produce
these long, brown, velvety objects.

Look what happens
when I break one open.

It contains almost
a quarter of a million seeds.

Each seed is attached
to a delicate parachute.

Even the slightest breeze
will lift it and may carry it

for very long distances indeed.

So even though suitable
stretches of fresh water are few

and far between, there's
a good chance that at least one

will end up in a place
where it can grow.

Much bigger seeds, of course,
can't travel by air.

A river can provide transport,

but it's a one-way
journey downstream

that often ends up in the sea.

And that's not ideal.

So how can any riverside plant
avoid this and travel upstream?

Here, along the Bonito River
in Brazil,

a variety of trees manage
to do exactly that.

They embed their seeds in the middle
of soft, sweet fruit.

Monkeys, such as these capuchins,

make a meal of them
just as soon as they're ripe.

But monkeys are very
wasteful feeders.

And what's not eaten
ends up in the river

and is washed away.

But not all.

In the fruiting season,
hundreds of Piraputanga fish

gather beneath these trees.

But the Piraputanga want more
than the monkeys' leftovers.

The brightly coloured fruits are
clearly visible, even to the fish

in the water below.

And some manage to claim them

even before a monkey does.

This isn't a skill mastered
by just one particularly

successful acrobatic fish.

Many of the Piraputanga can do this.

Nor is this a disaster for the tree.

Far from it.

These Piraputanga are migratory,

heading many miles upriver to spawn.

The trees, by enticing
the fish to eat their fruits,

have a perfect means of transport
for their seeds.

With luck, the seeds will be
deposited many miles upstream.

The ability to colonise new habitats

has allowed one group of flowering
plants to venture out of fresh water

and into a world that
may look the same to us,

but for a plant
is crucially different.

The much greater, saltier world...

..the sea.

This is a fruit from one of the most
important plants on the Earth today.

Seagrass.

This particular one is floating
off the coast of Formentera

in the Mediterranean.

100,000 years ago,
a seagrass seed like this

sank to the sea floor just here.

And, eventually, it produced...

..a great meadow.

A meadow that is still
flourishing today.

It did so by cloning itself.

Now over ten miles across,

it's not only one
of the largest living

organisms on Earth,

it's also one of the oldest.

And it supports a rich community
of many kinds of animals.

It's become a kind of
marine savannah.

Over 1,000 species now live here.

Some, like these elegantly
camouflaged pipe fish,

live nowhere else but
amongst the seagrass.

Seagrass fringes
many of the world's coasts.

Turtles depend upon it, too.

And so do Dugong - animals
that are sometimes called,

very appropriately, sea cows.

Today, seagrass plays a critical
role in maintaining the health

of our planet.

It creates stores of carbon
around its roots

at an enormous rate.

35 times faster, in fact,
than plants that live on the floor

of a tropical rainforest.

Here in Formentera,

it's possible to see,
beneath the living seagrass,

layer upon layer of trapped carbon

that the plants have accumulated
over the past 2,000 years.

Seagrass, however, is easily
destroyed by human disturbance.

A third of the world's underwater
meadows have already been lost,

and many more are in decline.

Biologists are now striving to not
only protect the remaining meadows,

but to restore them.

One plant at a time.

Seagrass could be a valuable ally

in our fight against climate change.

Today, water worlds everywhere
are under threat.

Many of their inhabitants
are disappearing

without us even being aware
of their existence.

The plants that grow in water
are probably the least noticeable.

They're certainly the least studied.

But the more you know about
the problems of living in that way,

the greater the wonder
of their success.

Surely they deserve
more of our attention

and, most importantly,

our care.

This vast wetland is the Pantanal.

The Water World's team are heading
to a plant battlefield.

The home of Brazil's
giant water lily.

This is like seeing
the end of a war.

There are leaves growing
on top of each other,

flowers going through leaves.

Unbelievable!

To capture this story in all
its detail would take over a year

and require a unique Green Planet
approach, both filming here,

and, in a parallel mini Pantanal,

in deepest, darkest Devon.

This is the unique world of
specialist time lapse cameraman

Tim Shepherd.

Tim has the reputation of being
able to think like a plant.

It's absolutely crucial that
you get the plant really happy.

And to make the giant lily
feel totally at home,

Tim must build a little piece
of Brazilian wetland.

First, a 10,000 litre tank.

Hundreds of bricks,
almost 1,000 kilos of soil

and countless cups of tea later,

the foundations are complete.

So far, so good.

Now time to prepare for the
new green pellet camera system.

We're trying to assemble
the main gantry framework

so that we can mount the
moving rig on top of it.

So it's a bit of a fiddle
to get all the screws

in all the right places, basically.

After a few weeks,
the building works are complete.

The flood can now begin.

Tim needs to be sure
everything in the room is heated

to tropical temperatures...

..before the star of the scene
can move in.

Carefully grown at the Royal Botanic
Gardens at Kew, especially for us.

Everything depends
on this one plant.

There will be no time
for a second attempt.

And even more important for Tim

to keep his guest happy and healthy.

This big monster need a lot
of feeding.

We found we need about
five sand bags full of compost

every two or three weeks,
so we just sort of lower them in

and stick them down by the roots.

There you go.

Whilst the Devon giant settles in,

the Pantanal crew are continuing
to get their shots.

Time to see some giant
water lilies underwater.

And I hope there's no anaconda.

Ooh! Mission accomplished!

The pressure is now on Tim.

After months of pampering, the
giant lily is ready for action.

First thing to film is a leaf spike
rising up from the depths.

Luckily, there are
no anacondas here.

The special camera
weighs over 40 kilos.

It's suddenly become less heavy,
which is good.

The new rig means Tim
will be able to follow

the emerging plant in any direction.

Wow, fancy!

The technology is working well,

but nature is starting
to derail Tim's plans.

We're tangled up in all these weeds.

What happens is we've got a bit
of an ecosystem developing here

and, before you know it,
you get masses and masses of algae

growing in amongst it all.

Cor!

Think I've just released
some anaerobic gases there.

No, not me, the algae!

State of the art tools
help keep the algae at bay.

Eurgh!

Just in time for Tim
to film lift-off.

That's quite nice coming out
of the water, look at that!

Tim's focus can now shift to the
battle that's starting to take place

on the surface.

I'm trying to film this new bud
coming out on this lily leaf.

Give or take about three days
to grow from where it is now.

Somewhere in this zone between
these two other leaves.

I want that to last
about ten seconds.

Ten seconds is about 250 frames.

That works out about
one frame every 20 minutes.

But plants don't read scripts.

It's nature, it doesn't always do
what you think it's going to do.

We've had a few false starts where
the leaf has swung out of shot

and gone somewhere else.

Or it just grows a lot quicker
than you thought.

It's a challenge
to get things right.

But with the combination of Tim's
expertise and the new camera system,

results are starting to look good.

I think the difference now
with this series is we can bring

the plants much more to life
as characters and tell their story

in a much more dynamic way.

It's great to be able to follow them
around much more with the way

you'd film an animal behaving.

These rigs have given us a whole
new realm of possibilities.

After over a year
of filming and recording

100,000 separate images,

the secret life of the giant water
lily and the battle of the Pantanal

has been revealed.

Next time on The Green Planet,

the ever changing seasonal world,

full of hunters, tricksters

and unlikely alliances.

Plants here are in a race
against the clock.

Timing is everything.

The Open University
has produced a poster

that explores the vital role
that plants have for our planet.

To order your free copy, call...

..or go to...

..and follow the links
to the Open University.