All language subtitles for Our Planet 2019 - 1x07 - Fresh Water.WEB.en

[radio static]

[radio beeps]

[indistinct chatter over radio]

[narrator] Just 50 years ago,

we finally ventured to the moon.

For the very first time,

we looked back at our own planet.

Since then, the human population
has more than doubled.

This series will celebrate
the natural wonders that remain

and reveal what we must preserve

to ensure people and nature thrive.

Fresh water.

Everything that lives on land,
animal or plant,

depends upon it.

Yet only one percent of it
is within reach.

The desert of central Australia.

One of the hottest, driest places
on Earth.

Virtually nothing can live here
for any length of time.

Yet once a decade,
this vast, empty desert is transformed.

For that to happen,
a chain reaction has to be triggered

two thousand kilometers to the north.

There, each year,
the moisture-laden clouds of the monsoon

begin to build.

[thunder rumbling]

Eventually they burst,
and the process begins.

Riverbeds that have been dry for years
suddenly fill.

[birdsong]

The torrents join together
and race towards the interior

and the lowest land on the continent.

Here, they flood over the desert
and create Australia's largest lake,

Kati Thanda, Lake Eyre.

Huge numbers of fish
swim down these wide waterways

and into the growing lake.

Pelicans arrive from Australia's coasts,
hundreds of kilometers away.

Many will only see the lake fill
once in their entire lives,

so how they know the lake has formed,
and in which direction to reach it,

is still a mystery.

[pelicans cawing]

These new waters now contain so much food
that the birds start to breed.

But the clock is ticking.

The pelicans feed...

and feed...

and feed.

The chicks must grow quickly,

for they have to be strong enough
to leave within a matter of weeks.

But time is short,

for the parents
will only be able to find food

while the water remains.

The young pelicans set off
on their first long journey.

It will be a demanding one, to the coast,

and the nearest is 500 kilometers away.

The lake will soon dry,

and water may not return here
for another decade.

This boom to bust transformation
is an exceptional event.

But everywhere,
the availability of fresh water

is becoming increasingly unpredictable
and uncertain.

Much of the planet's fresh water,
however, is locked away.

Almost two-thirds of it
lies frozen around the poles.

This ice is several kilometers thick

and may have been lying here
for millions of years.

Every summer, some of it melts

and carves its way
into the heart of the glaciers.

These great caves
are beautiful and romantic,

but they're also dangerous places,
for glaciers are always on the move.

[glacier creaking]

Even away from the poles,

much of the land's fresh water
freezes each winter.

But when spring arrives,
this vast snowy reservoir melts

and a great journey begins.

Racing down the steep mountain slopes,

the ice-cold waters
collect a life-giving ingredient...

oxygen.

Here, on the rivers of the Andes
in South America,

there is a living to be made

for those that can cope
with the powerful currents.

And torrent ducks can.

[ducks squawking]

These chilly headwaters
may be oxygen-rich,

but they contain few nutrients.

The torrent ducks collect
what little food there is

from below the surface.

Stonefly and mayfly larvae have gills,

with which they extract oxygen
from the water.

Their flattened bodies
resist the relentless pull of the current.

Black fly larvae.

One of the ducks' favorite prey.

Their specialized mouthparts
filter out the tiny particles of food

as they race by.

Hooks at the rear end
anchor them to the rocks,

but the current
is sometimes irresistible.

However, they have a special safety line,
with which they can pull themselves back.

Every year, visitors come
to these rushing, oxygen-rich waters.

Salmon.

They have spent most of their lives
in the Pacific Ocean.

Now, fully grown, they're returning
to the particular rivers in North America

where they will now lay their eggs.

Salmon have an extraordinary ability
to leap up waterfalls,

but even they cannot, unaided,
cross the dams that we have built.

Today, Pacific salmon number less than
one percent of the numbers they used to,

and that's causing problems
for many other animals.

Alaskan brown bears
wait for them at the waterfalls.

Without these fish,

the bears cannot build up
the fat reserves they need

to sustain themselves
through their long winter hibernation.

There is fierce competition
for the best fishing spots.

[growling]

[gulls cawing]

Where water flows over hard rock,
it collects few nutrients,

so few plants can grow in it.

Here, in South America, however,

this plant, Macarenia,
manages to flourish.

For a few months each year,

when the water level is low enough
for sunlight to reach the bottom,

the Macarenia bursts into bloom.

This is the Caño Cristales,
Colombia's rainbow river.

Sometimes, however,
water disappears underground,

beyond the reach of light,

and there, no plants can live.

Thirty percent of the planet's fresh water
lies beneath the surface of the land,

either within the substance
of porous rocks

or as subterranean lakes and rivers.

Made slightly acid by rain,

it slowly dissolves limestone,
creating great caves.

A labyrinth of such passages and chambers
underlies much of the state of Florida.

For the most part, they're barren.

But where the water comes to the surface,
it's full of life.

Fish are abundant.

And so are fish eaters.

Otters.

All over the state,
fresh water bubbles to the surface

from the greatest concentration of springs
on Earth.

They feed rivers and pools,
in which all kinds of life flourish,

including one of Florida's specialities...

manatees.

Many spend the summer in the sea,

but when winter approaches,
they swim up the rivers,

which are relatively warm.

And there they graze
on an abundance of freshwater plants.

But human beings are now taking
so much water from these springs,

and polluting many of the others,

that the manatees
are losing their winter homes.

Rivers, being comparatively shallow,
warm quickly,

and in spring, across Europe,

the rising temperatures
trigger a sudden surge of life.

[tweets]

On Hungary's Tisza River,
giant mayfly are starting to emerge.

For three years,
they've lived underwater as larvae.

Now, in just three hours,

millions of the winged adults
dance together and mate before they die.

This extraordinary spectacle
was once common in Eastern Europe,

but so many rivers
now have stabilized banks

and are badly polluted

that the mayflies
have largely disappeared.

But when the rivers are clean,
wildlife is quick to return.

The kingfisher,
the most glorious of divers.

The osprey, the most skillful of graspers.

Iguazu, on the frontier
between Brazil and Argentina.

These are
the largest waterfalls on the planet.

Thousands of tons of fresh water
thunder over them every second.

Much of Iguazu's water
comes from the Amazon rainforest,

a thousand kilometers away.

There, it rose as vapor
from the surface of the jungle canopy.

A single tree can give off
a thousand liters a day.

As the vapor rises into the sky,
it condenses into clouds.

Twenty billion tons of water
leave the forest each day,

more than travels
down the Amazon River itself.

If the rainforest is destroyed,

this life-giving cycle will be broken.

As the clouds travel across the continent,
they shed their water,

irrigating farmland and forest alike.

And on the plains of Brazil,

they create
the largest tropical wetland on Earth,

the Pantanal.

Each year, however,
seasonal changes reduce the river's flow,

and the Pantanal shrinks
to just a few river channels.

This suits the top predator very well.

The jaguar.

It's a competent swimmer, but in water,

it can't make the killing pounce
which makes it such a fearsome hunter.

[mewls]

Now, in the dry season,

the banks can get somewhat crowded.

But the jaguar has spotted prey
on the river's edge.

Capybara.

It must get close to be successful.

Two capybara incautiously
are standing in the shallows.

They have seen one another.

Which will run first?

[barks]

Farther along the river,
dense vegetation provides better cover,

but the bank here is quite high.

Capybara have acute hearing.

-One noisy footfall...
-[branch snaps]

...and the chance is lost.

Another failure.

[barks]

Perhaps it's time to try a different prey.

Tackling one of these would be risky,

but the jaguar is really hungry.

If a jaguar is to catch a caiman,

it must bite its neck and then hold on
to prevent the caiman striking back.

It has to get into a position
directly above its prey.

This is dangerous.

The caiman rolls
to try and drown the jaguar.

Predator and prey seem evenly matched.

The jaguar won't let go.

After 20 minutes, and near to exhaustion,
the jaguar wins.

Sometimes, a river's downward journey
is interrupted by lakes.

Together, they contain 40 times more water
than all the world's rivers combined.

Africa's Lake Tanganyika

holds almost a fifth
of all accessible fresh water on Earth.

But, considering its great size,
Tanganyika contains little life.

It's almost a kilometer and a half deep,

but at the bottom the water barely moves
and there is no oxygen.

It's only close to the surface,
in its top 150 meters,

that the water contains enough oxygen
for life to exist.

But here, it flourishes in abundance.

Two hundred and fifty species
of cichlid fish have evolved here,

many of which are found nowhere else.

Competition in these crowded waters
is intense.

A male callipterus cichlid
collects shells.

The more shells a male has,
the more females he will attract.

And this one is doing very well.

His neighbor has a rather smaller mound.

And the neighbor is a thief.

As soon as he turns his back,

the thief swoops in...

and steals a shell.

The hardworking owner of the larger mound
doesn't seem to notice.

So, the thief commits the crime again...

and again...

until he has built the largest mound.

The shells are not just for display.

They will be used by the females
as cradles.

One arrives.

She's tiny, only a tenth of his size.

She's so small,
she can slip inside a shell.

There, she lays her eggs,
and the male quickly fertilizes them.

She will then stay inside protecting them
for up to a fortnight until they hatch.

The emperor,

the largest of all the cichlids
in Tanganyika.

At almost a meter long, this female
must raise her young in the open.

Guarding them is therefore
a full-time job for both parents.

But the future for all these fish
is uncertain.

As global temperatures rise,
Lake Tanganyika is warming.

Its waters are no longer mixing as well
as they once did,

so the top oxygenated layer is reducing.

The Mekong River in Southeast Asia.

Four thousand kilometers long
and with the widest falls anywhere.

Today, over 60 million people
depend upon it for their livelihood.

The monsoon rains create
such a colossal surge of water

that the falls themselves
almost disappear.

The water is loaded with sediment,

collected during the Mekong's long journey
from the Tibetan Plateau.

Even before the flood,
the water covers a vast area of land.

These exposed roots are evidence

of the great rise in water level
that is to come.

When the main flood does arrive,

the trees are submerged
up to their branches.

For a few months, the floodwaters create
the planet's greatest breeding grounds

for freshwater fish.

One species
has a particularly ingenious solution

to the problems of living
in shallow, oxygen-poor water.

The Siamese fighting fish.

The male breathes
by gulping air from the surface,

and during the breeding season

he uses that ability
to build a raft of bubbles.

Day after day he labors.

A female, waiting nearby,
rises to inspect the raft.

They wrap themselves around one another
in a tender embrace.

This union encourages her
to release her eggs.

As they sink downwards,
the male fertilizes them.

Both carefully collect them,

and then blow them, one by one,
into the bubble nest.

Oxygen is scarce in these stagnant waters,

but the eggs
will get enough from the bubbles

to allow them to develop.

The climax of the flood is still to come.

Eventually,
so much water surges down the Mekong

that the Tonlé Sap Lake expands
to five times its dry-season size.

Vast numbers of fish now swim
into these new feeding grounds.

People have harvested this seasonal event
for millennia.

They set nets across half of the river,

leaving the other half free

for the rest of the fish
to swim on and breed.

The Mekong, in fact, supports
the largest inland fishery in the world.

One-fifth of all the freshwater fish
caught by people worldwide

comes from this one river system.

But the future of the Mekong,

like that of so many other rivers
around the world,

is increasingly at risk.

We have changed the natural flow

of more than two-thirds
of the planet's longest rivers

by, amongst other things,
building dams across them.

So now, many rivers across the world
no longer flow.

Here in East Africa, in Ruaha, Tanzania,

these elephants are searching for water.

Each needs to drink 200 liters every day,
and there doesn't seem to be any here.

But the elephants know that baobab wood
contains a lot of moisture.

And in an emergency,
they eat it in great quantities.

Lions also need water.

And conveniently for the lions,
water is where their prey will gather.

So both predators and prey
head for the rivers.

Until 30 years ago,

rivers in this part of Africa
never ran dry.

Now, agriculture upstream
is taking great quantities,

and during the dry season,
the rivers shrink into isolated pools.

Hippos rely on flowing water
to keep themselves cool during the day,

but now they have to make do with mud.

As the water level falls still further,
they cram together.

Tempers begin to fray.

[roaring]

Each day, the mud pools shrink further,
and the hippos' plight worsens.

Buffalo, in the urgent search for water.

The lions are already here
at this water hole.

However, the buffalo are driven on
by their desperate need for fresh water.

They need to drink every day.

Every drink is now a risk,

but the buffalo have no choice.

As the drought continues,
the buffalo begin to weaken.

The odds are changing,
in the lions' favor.

The elephants have reached their river.

Nothing else is here because it's dry.

But elephants can find water
where others can't.

They use their trunks to dig holes
in the sand of the riverbed.

The extraordinary sense of smell

that enables them to detect open water
from kilometers away

also helps them
to locate places underground

where it lies closest to the surface.

In severe droughts,
the wells they dig can be their lifeline.

The hardships of the dry season
have always been part of life

on East Africa's plains,

but as the planet warms,

and we ourselves take so much water
for our own purposes,

the droughts are becoming more frequent
and more severe.

The Platte River,
in Nebraska, North America.

Each year, sandhill cranes arrive here
as they travel north across America

on one of the last great migrations
made by any animal.

It's one of their crucial staging posts.

The river once flooded the prairie
for a mile in all directions.

This was a perfect place
for them to feed and rest.

Now, we have dammed the river

and taken so much of its water
for our own use

that there is little space left
for the cranes.

But conservationists
now manage the river's flow in such a way

that it still creates the sandbanks
the cranes need.

We are not alone in our need for water,

but we have the ability to ensure
the fresh waters of the world do flow,

and we alone can determine
how they are shared.

Please visit ourplanet.com
to discover what we need to do now

to ensure fresh water keeps flowing.

♪ I can hear the whole world
Singing together ♪

♪ I can hear the whole world
Say it's now or never ♪

♪ 'Cause it's not too late
If we change our ways ♪

♪ And connect the dots to our problems ♪

♪ I can hear the whole world
Say we're in this together ♪

♪ We're in this together ♪