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MUSIC

The oceans, seemingly limitless, invoking us a sense of awe

and wonder, and also sometimes fear. They cover 70% of the

surface of our planet, and yet they are still the least

explored. Hidden beneath the waves, right beneath my feet,

there are creatures beyond our imagination.

MUSIC

With revolutionary technology, we can enter new worlds... SCREAMS

..and shine a light on behaviours in ways that were impossible just a generation ago.

We've also recognised an uncomfortable fact. The health of

our oceans is under threat. They're changing at a faster

rate than ever before in human history.

Never has there been a more crucial time to reveal

what is going on beneath the surface of the seas.

SCREAMS In this first episode... ..we will journey

across the globe from the warm waters of the tropics...

..to the coldest around the poles...

..to bring us a new understanding of life beneath the waves.

SCREAMS This is Blue Planet 2.

SCREAMS The surface of the ocean conceals the many creatures that live beneath.

But not all.

Bottlenose dolphins.

They are extremely intelligent.

And with this intelligence comes playfulness.

They surf. And as far as we can tell, they do so for the sheer joy of it. SCREAMS

SCREAMS

But to properly appreciate their true character,

you have to travel with them into their world.

A pod of bottlenose dolphins is visiting a coral reef in the

Red Sea. For the youngsters, there are things to be learned

here.

The adults lead a calf to a particular bush-like coral called a gorgonian.

And here the adults behave rather strangely.

They deliberately rub themselves through the fronds.

SCREAMS Their calf seems reluctant to do so.

SCREAMS By watching his elders, he may be

realising that this is something he ought to do.

Gorgonian fronds, in fact, are covered with a mucus that

can have anti-inflammatory and anti-microbial properties.

So maybe the adult dolphins are doing this to protect themselves from infection.

The dolphins' intimate knowledge of the reef is

spurring us to search for new medicines here too.

Tropical coral reefs occupy only a tenth of one percent of

the ocean floor. But their shallow, warm waters and stable

year-round conditions support some of the most crowded

and varied communities to be found anywhere in the oceans.

And there are new discoveries to be made on every one of them.

One creature on Australia's Great Barrier Reef is

challenging our understanding of fish intelligence. A

tuskfish. And you can see why it gets its name.

He does something few would have believed a fish could do.

Every morning, he travels to the edge of the reef.

He's searching for something special to eat amongst the coral rubble and sand.

Here's one. A small clam.

But how to crack it open and get to the meat?

He takes it all the way back to his special kitchen.

A bowl-shaped coral that has a particular bump on the inside that he always uses.

It's not easy if you have no hands.

Oops. There he goes again.

But he's got great determination...

and surprising accuracy.

At last.

So here is a fish that uses tools. Some fish

are much cleverer than you might suppose.

The density of the animals on tropical reefs makes

competition inevitable and extreme. Not only for those that

live within the reefs, but for the birds that fly above them.

During the dry season, over half a million terns are caught

in the water. Terns crowd onto this remote atoll in the

Indian Ocean.

Their chicks are still in their dark juvenile plumage.

They vary in age.

Whilst the more advanced chicks take to the air...

others aren't quite ready yet.

Those just starting to learn to fly use the shallow lagoon

that occupies the centre of the atoll as their training

ground. It's difficult for some of them to stay aloft for long.

Giant trevallies.

Usually, they are solitary hunters. But they are very smart.

But about 50 of them have come here from neighbouring reefs,

attracted by this abundance of potential prey.

The fledglings stay out of the water if they can. They even drink on the wing.

If the trevallier to catch one now, they have to up their game.

So there is a fish here that, amazingly, has a brain and

a mind of its own. Capable of calculating the airspeed,

altitude and trajectory of a bird.

The time comes when every fledgling has to

take to the air and collect food for itself.

Their parents lead them to the training grounds.

If they are to survive, they must learn quickly.

After a month of practising over and over again, the

youngsters start to leave and take their chances out over

the open sea.

The oceans hold 97% of all the water in the world. As the

sun warms their surface, water evaporates. The vapour rises

into the sky until it cools and condenses into

towering clouds. And they generate huge storms.

The spin of the earth deflects these storms north and south into cooler latitudes.

As they travel across the sea, storm-driven winds create huge swells.

When the swells reach shallower water, they rise again. They rise into gigantic waves.

In its lifetime, a large storm can release energy

that is the equivalent of 10,000 nuclear bombs. ...

These are the seasonal seas.

And when they warm in spring, they can suddenly explode with life.

Mobular rays have gathered in Mexico's Sea of Cortez in vast numbers.

Why do they leave?

Is it to tell others that they're here?

No one knows.

They feed mostly at night, for that is when

vast swarms of plankton rise from the depths.

The disturbance in the water stimulates many of the

planktonic creatures to luminesce. Only now do we have the

technology to record their faint glow.

The feasting rays swim through them, creating

an extraordinary ballet of life and death.

The richness of these waters is based on microscopic plants,

phytoplankton, which bloom on such a massive scale they

benefit us all.

They, together with seaweeds and sea grasses, produce as

much oxygen as all the forests and grassy plains on land.

Every spring off New Zealand, the seasonal bounty draws in rare visitors.

False killer whales.

They are relatives of the orca, six meters long and weighing over a ton.

They appear to be searching for dolphins.

And there are many in these coastal waters.

Here, bottlenose dolphins stick together,

constantly chattering with whistles and clicks.

Such a din carries some miles underwater.

The false killers have detected them.

Traveling at 10 knots, the killers quickly close in on them.

But then something truly extraordinary happens.

The dolphins turn as if to greet their pursuers.

They seem to change their calls. Could it be that they're attempting to communicate?

Scientists studying this annual encounter now

think that individuals may recognize one another.

Almost unbelievably, it seems that these different species appear to be old friends.

Together, they're gathering as one unified army, up to a thousand strong.

This formidable hunting party now harvests

the riches that come with New Zealand summer.

All across the higher latitudes, seasonal seas flourish under the summer sun.

Here in Alaska, sea otters lounge in the canopy of great submarine forests.

Giant kelp, the biggest seaweed of all, is home to all

kinds of life. On the forest floor, spiny sea urchins munch

through the kelp. Elsewhere, there are continuously hungry sea cucumbers.

And in the tangled undergrowth, wonderfully camouflaged sea dragons.

In the underwater forests of northern Japan, the residents

of this sunken wreck are waiting for the summer temperatures

to reach 16 degrees Celsius.

That, for some, is the time for mating.

A kind of giant wrasse called a kobodai.

This is a male.

And in female terms, he's particularly handsome.

He's a meter long and weighs 15 kilos.

Much larger than the diminutive female.

And he is ready to breed.

He attempts to mate with her and with any of the other dozen

or so females that live in his territory. Whenever he gets

the chance.

But females from around 10 years old take little notice of his advances.

This is because, when any life is in danger, he is ready to

mate with any of the other 10 females. When a large female

reaches a critical body size, she can begin a dramatic transformation.

Over just a few months, particular enzymes inside her

body cease to work. And male hormones start to circulate.

As time passes, her head expands and her chin gets longer.

As she has changed into a he.

And with this comes a change in temperament.

The old male who ruled all the females here is challenged to a face off.

The more bulbous the head, the more it intimidates an opponent.

The territory has a new ruler.

Only the largest females transform themselves in this way.

But the change enables them to have more mates, so they

will have many more offspring carrying their genes.

But a new male can't afford to be complacent. Inside

the body of every kobudai female, there is a new male in

waiting.

The closer we travel towards the poles, the colder the seas become.

Icebergs appear, huge slabs that have broken away from

glaciers that are sliding into the sea. And then the surface

starts to freeze.

While the lights of the aurora play above, even in the

depths of midwinter, there are a few places well north of

the Arctic Circle that are still open.

The fjords of northern Norway remain ice free because a

giant current, the Gulf Stream, flows up here from the

south, bringing warmth all the way from the Caribbean.

And every winter, billions of herring come here for shelter.

And following them,

walker.

There are up to a thousand of them. It's possibly

the greatest gathering of walker on the planet.

The herring may be plentiful, but in these winding

fields, they're not always easy to track down.

These particular walker, however, are fish hunting specialists.

They work as a team, coordinating their approach by calling loudly to one another.

They heard the herring into tighter and tighter shoals.

They swim below them, trapping them against the surface of the sea.

And now the walker deploy their special weapon.

They beat their tails with such force that the shock waves

stun the herring. And then the senseless victims are easily

collected.

But all this underwater noise attracts others.

Humpback whales. They move in on the action.

They approach the shoal from beneath and then lunge upwards.

Gathering up to a hundred kilos of herring in a single mouthful.

The humpbacks are competitive newcomers. They

only started coming here within the last decade.

But these polar seas are so rich that there appears to be enough food for everyone.

Nonetheless, few, if any, of these riches

would be here were it not for the Gulf Stream.

Ocean currents, in fact, are crucial to the well-being of our planet.

They distribute the sun's heat towards the poles all the way

from the equator. Maintaining a climate favorable for life

almost everywhere.

From creating the weather to producing oxygen, the seas keep our world healthy.

But there are now worrying signs that conditions in the

oceans that have remained relatively stable for millennia

are changing radically.

Nowhere is this more evident than in the Arctic. Here in

the past 30 years, the extent of the ice in summer has been

reduced by 40 percent. This sudden warming, most likely a

consequence of human activity, is having a profound impact

on its wildlife.

Walruses are among those that are seriously affected.

Every adult female needs to find a safe place where her 80 -kilo pup can rest.

The sea ice is retreating from much of the walruses'

traditional range, so they now have to haul out on dry land.

But a herd of hundreds of quarrelsome mothers, some

weighing almost a ton, is not an ideal nursery.

Walruses on land stick together for good reason. Polar bears.

A full-grown male walrus is gigantic, too big for even a

polar bear to tackle. So the bear is looking for a walrus

baby.

The scent of the bear spreads along through the colony.

The walruses retreat into the sea.

The bear knows it won't be able to catch them there.

But she, too, has young ones to feed.

What is a mother to do?

The mother walrus still needs to find a place where her young can rest.

A melting iceberg might do, but she is not the first to find this one.

Suitable places are already taken.

The mother walrus is looking for a place where her young can rest.

Other mothers don't want to share.

They, too, need a patch of ice where they can protect their young.

A desperate mother has no choice but to barge her way in.

So this time, everyone loses.

Finding the right place on these melting shores gets harder

and harder. The mother walrus is looking for a place where

she can

rest.

Solving these problems together helps create a bond so

strong that the mother will stay in contact with her young

for the rest of her life.

But who knows now what their future will be?

As we understand more about the complexity of the lives of

sea creatures, so we begin to appreciate the fragility of

their home, our blue planet.

Blue Planet 2 has been four years in the making. The teams

have explored every ocean, seeking extraordinary untold

stories, many new to science,

bringing a new understanding of life beneath the waves.

The latest diving technology, producing no bubbles or

noise, has allowed our teams longer and closer encounters.

To explore our final frontier, the deep, we have spent a

thousand hours in submersibles over half a mile below the

surface.

Innovative new camera technology makes it possible to film moments never seen before.

Low-light cameras capture magical events almost invisible to the naked eye.

We don't see anything. We're filming in

total absolute darkness. We're totally blind.

Probe cameras give a completely fresh perspective into the

lives of tiny creatures, while suction cameras take us on a

giant's eye view of the ocean.

But the sea is an unpredictable and dangerous place to work,

nowhere more so than the so-called wild coast of South Africa,

home to surfing dolphins.

The team's mission here is to ride alongside the dolphins

and record their surfing behavior in closer detail than ever

before.

These are treacherous seas, so the film crew

enlist local professional surfers to guide them.

But this year, the waves are bigger than anyone had

anticipated. A daunting prospect for surf cameraman Chris

Bryan. Yeah, I'm feeling pretty nervous. It's a big swell

out there. Really big swell, like there's 20-foot waves out

there. Yeah, this will probably be the biggest seas I think

I've ever been out in. No risk, no reward, I guess. Chris

has a high-speed camera to shoot super slow-motion action in the waves.

The challenge is to get as close to the wave-riding dolphins as possible.

The good news is that the dolphins have been spotted on the horizon.

They said this was going to be the biggest swell of the

year, and hey, I've never seen anything like this. This is

much bigger than I'd possibly imagined.

In these waves, the only way to get out the dolphins is with

a jet ski. There's going to be enough of a challenge for

them just to kind of weave their way out.

At last, the driver's detailed knowledge gets

them safety through the massive breakers.

But the dolphins are nowhere to be seen,

leaving the crew to face the hair-raising task of getting back to shore.

That was pretty wild, yeah. The wave actually hit the back

of the sled, and I was like, go, go, get out of here, Jase,

get out of here. I hit a big bump and almost bounced off

trying to hold the camera, and Jase rode out of there, but

yeah, it was hectic. Just another day at the office.

The next day brings a sudden change in conditions.

Plenty of dolphins, but a calmer sea. But the complete

lack of any wave at all. Look out, look out, look out.

As so often in the ocean, if you know you're in the right

place, you just need the patience to wait for the perfect

moment.

A week later, and a storm is once again brewing off the

wild coast, and surf is building. Kind of like a nervous

excitement. The conditions are absolutely perfect. This is

completely what we've been waiting for. And the dolphins

seem to know it. But Chris is struggling to get a steady shot.

Hey. Hi, gentlemen. A little tricky on the jet ski, just

trying to get the right angle, so I'm going to have a go on

the Zodiac and hopefully have better luck on that one.

The inflatable boat gives Chris a larger, more stable filming platform.

At last, he's in exactly the right place at exactly the right time.

And the results are spectacular. That's amazing!

Mission accomplished.

And this intimate footage is now available as part of wider scientific studies.

Supporting evidence that dolphins surf to strengthen

friendships, develop social skills, and for the sheer

exhilaration of it.

Next time, the deep. A world richer than we ever thought

possible. Where creatures thrive in the most extreme

conditions on Earth.

Thanks for watching! Thanks for watching!