The Green Planet (2022) s01e02 Episode Script

1
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.