The Rite of Passage (Mała matura 1947)

Antarctica.

The coldest, the harshest, and the most remote continent on Earth.

No human being has ever descended into the depths that surround it...

...until now.

The deep ocean is as challenging to explore as space.

We know more about the surface of Mars

than we do about the deepest parts of our seas.

Now we can dive these uncharted depths,

to discover what secrets lie beneath.

Sinking down beside the submerged wall of an iceberg,

we enter an unforgiving world.

These waters are the coldest on Earth.

As we descend into the deep,

the pressure increases relentlessly.

And the light from above all but disappears.

Yet, incredibly...

there is life here.

We might have expected

that deep beneath the surface of the Polar seas,

the waters would be truly barren.

But, in fact, we find life here in unimaginable abundance.

Nor is such great abundance confined to Antarctic waters.

Currents carry this richness

into the depths of almost every ocean around the world.

Astonishingly, in the deep sea,

there is more life than anywhere else on Earth.

The sunlight fades,

and the seas darken.

Here, in the Pacific, 200 metres down,

we enter an alien world.

The Twilight Zone,

a sea of eternal gloom.

There are strange creatures here.

A pyrosome.

A tube of jelly two metres long that dwarfs a visitor from above,

an oceanic whitetip shark.

Only a tiny amount of light filters down this far.

Survival here means making the most of every last glimmer.

A swordfish.

Its eyes are as big as tennis balls to help it see in the perpetual dusk.

A squid, but this is one that lives only here.

Its right eye looks permanently downwards.

But its left eye is much bigger and trained upwards

to detect the silhouettes of prey swimming nearer the surface.

No wonder it's nicknamed the "cock-eyed squid".

And even stranger,

this is barreleye,

a fish with a transparent head,

filled with jelly,

so that it can look up through its skull.

We now know that the Twilight Zone is a refuge

for an incredible 90% of all fish in the ocean.

Only at night, do vast shoals of lanternfish

migrate to the surface to feed on tiny plankton.

By day, they retreat back down here.

Humboldt squid.

Two metres long and 50 kilos in weight.

Like most squid, they're voracious hunters.

There are hundreds of them.

They found a shoal of lanternfish

hiding 800 metres down, off the coast of South America.

Their tentacles are armed with powerful suckers

with which they grab their prey.

And when there are no more lanternfish to be found,

they turn on each other.

This squid has caught a smaller one in its tentacles.

To hide its capture from the rest,

it releases a smokescreen of black ink.

But then, an even bigger one challenges it

and steals its catch.

The Twilight Zone

is the Humboldt squid's favourite hunting ground.

They seldom go deeper

into the world of perpetual blackness below.

The Midnight Zone.

Two-thirds of a mile from the surface,

beyond the reach of the sun.

A giant black void

larger than all the rest of the world's habitat's combined.

There's life here,

but not as we know it.

Alien-like creatures

produce dazzling displays of light.

Nearly all animals need to attract mates

and repel predators.

This language of light is so widespread here,

that these signals are probably the commonest form of communication

on the entire planet.

And yet, we still know little about them.

Hunters illuminate themselves,

and by doing so

attract inquisitive prey.

This is fangtooth.

It has the largest teeth for its size of any fish.

There are pressure sensors all over its head and body

which can detect anything moving in the surrounding water.

It's the Midnight Zone's most voracious fish.

But prey use light as a distraction.

A decoy of luminous ink.

Down here, in this blackness,

creatures live beyond the normal rules of time.

Siphonophores are virtually eternal.

They repeatedly clone themselves,

some eventually growing longer than a blue whale.

Down here, it snows.

Continuous clouds of organic debris

drift slowly down from above.

This is food,

and a whole variety of filter feeders depend on it.

Jellyfish.

And delicate sea cucumbers.

The 1% of marine snow they miss

eventually settles on the sea floor.

Over millions of years,

it forms a layer of mud up to a mile thick.

It's an empty plain

that covers half the surface of our planet.

The deep seabed may, at first, appear lifeless,

but it's home to a unique cast of mud dwellers.

The sea toad.

It is an ambush predator with an enormous mouth

and infinite patience.

This fish has been living for so long here

that its fins have changed into something more useful.

Feet.

They help it shuffle about on the sea floor.

The flapjack octopus.

It hovers just above the surface of the mud

as it delicately sifts through it searching for worms.

But it can jet away at the first sign of danger.

A sixgill shark, as big as a great white.

It may not have eaten for an entire year.

It patrols the mud plains

using a minimum amount of energy.

High above,

the carcass of a huge sperm whale

is slowly decaying.

This will be a bonanza for the creatures of the deep.

Food.

Thirty tonnes of it.

Finally it settles on the ocean floor

and its presence is soon detected.

Sixgills sharks

have an exceptionally acute sense of smell.

Just 25 minutes after the whale's carcass arrives,

a sixgill finds it.

Each bite releases blood into the current.

The news that food is here spreads quickly.

Two more ravenous sixgills arrive.

Within 12 hours, there are seven enormous sharks

jostling with one another

as they compete to tear off mouthfuls.

No one is prepared to back off.

Twenty-four hours later,

and a third of the carcass has gone.

The first arrival has gorged

until it's completely full.

This single meal

may be enough to sustain it for a whole year.

Now, the clean up team arrives.

Spider crabs carrying coral in their hind legs,

presumably as makeshift body armour.

There are rock crabs here too.

They probably detected the carcass almost as soon as the sharks,

but they can't move as fast.

A month on, and over 30 species of scavenger

are clearing away the last edible fragments.

But now, the scavengers are attracting their own predators.

Scabbardfish, habitually swimming upright,

are picking them off one by one.

Some of the whale's teeth have been dislodged

as the skeleton starts to fall apart.

Four months later, there is nothing left but a few bones.

But even they are food

for something.

Zombie worms.

They tunnel into the bones by injecting acid

and so reach the tiny amounts of fat that still remain there.

It may take decades,

but eventually, the last of the bones will crumble,

and the whole 30-tonne carcass will have been recycled.

A whale fall is a temporary oasis

in the desert of the sea floor.

But there are permanent oases here too.

Rocks projecting above the mud

provide anchorage for deep sea corals.

As far down as three and a half miles,

there are more species of coral in the deep

than on shallow tropical reefs.

Without sunlight, they rely solely on food

drifting in the current.

And they grow

just a hair's breadth a year.

But some of them can live for 4,000 years.

They, like their shallow water relatives,

provide homes for all kinds of other creatures.

Growing among the corals,

is one of the most beautiful of sponges.

This is Venus' flower basket.

These sponges have lodgers.