Atlantic: The Wildest Ocean on Earth - From Heaven to Hell

There's an ocean, where giants gather to feast

where people battle the planet's roughest seas.

It stretches nearly 10,000 miles from Arctic, to Antarctic

from tropical shallows, to mysterious depths

It's an ocean of extremes.

The engine room for storms a thousand miles across

Yet also, a sanctuary for the vulnerable.

People and animals brave this unpredictable ocean.

Risking it all for rich rewards.

This is the Atlantic, the wildest ocean on Earth.

It's January in the far north of the Atlantic off the coast of Arctic Norway.

The air temperature is ten degrees below freezing.

The land is lifeless, locked in ice.

But beneath the surface of the ocean, the water is stirring.

Billions of Herring have arrived from the open ocean to spawn

and their presence attracts giants.

Humpback whales...

massive fin whales...

hundreds of orcas.

Animals travel hundreds, even thousands of miles

for this once a year event.

A feast that will last for just a few weeks.

This extraordinary gathering is only possible

because of one of the planet's most powerful forces

A force whose origin lies half a world away from these Norwegian waters...

... the Gulf Stream.

An underwater current of warm water

fifty miles wide

that cuts through the ocean for thousands of miles.

The Gulf Stream shapes all life in the North Atlantic.

From the Arctic, to the Caribbean.

The Gulf Stream is driven by winds and it begins here

where the open ocean meets the reefs of the Caribbean Sea.

Sheltering here are animals that will soon travel to the Arctic

On the same journey as the great current.

Every winter, these reefs north of the Dominican Republic

are filled with the song of humpback whales.

HUMPBACK WHALE SINGS

This female humpback came here this time last year to mate.

Eleven months later, she's returned because these waters are warm, and calm

sheltered by the surrounding reefs.

The perfect place to have her baby.

This calf was born just a few days ago, weighing in at a healthy one ton.

For now, while his mother rests, the calf explores his new world.

But he's so young that he tires easily.

He'll need to be a much stronger swimmer before he can leave this sanctuary.

His mother lifts him to the surface to breathe.

There is very little food here for the mother to eat

so she won't be able to produce milk for much longer.

Soon, they will have to leave.

There are many dangers ahead. Orca attack, collisions with ships.

His mother's back is lined with scars from a boat propeller

but the young calf faces an even more immediate threat

from a very dangerous animal.

Male humpbacks come here every year looking for a chance to mate.

They compete amongst themselves for access to the females.

Their rivalry can be very dangerous.

Some females in these waters are looking for a mate

but not this mother with her vulnerable young calf.

If she doesn't shake off the testosterone charged males

her calf can be crushed to death in a scrum of thirty—ton bodies.

The males chase her down

jostling to get into position to try and mate with her.

The calf struggles to keep up.

The mother guides her calf up for a breath

and uses her body as a block to protect him from the males.

The males become more aggressive as they battle for access.

Their five metre long fins, edged with sharp barnacles, are swung like clubs

Their bodies can be weapons too.

A breach could severely wound a rival

or crush a calf caught up in the fight.

The calf is exhausted.

but finally, his mother, who's bigger and stronger than the males

gets her message across.

The males move on.

The calf is now six weeks old

his mother has done well to keep him safe this far

but her energy supplies are dwindling.

She needs to leave the breeding grounds and head north.

Fortunately, her baby's diet of around two hundred litres of milk a day

coupled with lots of playtime, have built his strength.

Now he too, is strong enough to breach.

He's ready to face the open ocean.

His mother leads him away from the nursery.

They're headed to the fertile waters of Norway's distant shores.

It's a journey they must embark on.

The great Gulf Stream will help carry them on their way.

The Gulf Stream is driven by winds

which blow across the ocean, pushing water before them.

From the Caribbean and the Gulf of Mexico, the winds blow north

driving the current towards the United States.

Off the Florida coast, the Gulf Stream grows in strength

as it's squeezed against the land.

Just off shore from the beaches of Miami, flows a current

one hundred times greater than all the world's rivers combined

and it's a busy highway, packed with giants.

Thousands of three metre long bluefin tuna hitch a ride every spring

travelling north from the Gulf of Mexico to their summer hunting grounds.

Swordfish, marlin and their cousins, sailfish, also jump on board.

The sailfish's thousand mile summer migration takes about a month

but unlike the whales, they find something to eat along the way

This floating mat of sargassum seaweed is a perfect place to find food.

Sargassum gives its name to a nearby sea, the Sargasso

a huge region at the heart of the Atlantic

where sailors fear to travel

because of stories of ships trapped forever, in huge mats of the weed.

In reality, these floating islands provide food and shelter

for hundreds of small fish, and that makes them a rich hunting ground.

Sailfish can sprint at up to sixty miles an hour, able to chase down the fastest prey.

How they catch their prey has only recently been discovered.

The sailfish uses its long bill to flick a fish out from the shawl

throwing it off balance, before striking.

The Gulf Stream and the winds that blow it, aren't just relied upon by wildlife.

People have used the Gulf Stream winds for hundreds of years.

When Christopher Columbus set foot on the New World in 1492

he opened up a world of opportunities.

For hundreds of years, treasures and natural riches

were shipped back and forth across the Atlantic

driving the colonisation of America and changing the course of human history.

And none of that could have happened without the Gulf Stream winds.

From the Caribbean, the winds push the current north and then east towards Europe

with such consistency that sailors could rely on them to cross thousands of miles of ocean.

Even today, sailors use this ancient trading route.

The crew of this Dutch ship use the winds to ship rum, chocolate and coffee beans

from the Caribbean back to Amsterdam.

The Tres Hombres has no engine. She's entirely reliant on winds and currents.

so the crew have to respond to every change in the breeze.

We're ready to wear ship.

Standby on the braces, standby on the main.

The crew work in shifts, twelve hours out of every twenty—four.

It's hard work, but it has its rewards.

You feel very connected to nature

because you constantly feel the waves on the ship.

And you feel the wind on your own back.

It's the dolphins visiting you.

You feel exactly what your ancestors felt.

The same waves, the same winds.

So, it's, it's beautiful.

But as in ancient times, harnessing the Atlantic's natural power

means putting your life on the line.

Over the centuries, more than six hundred ships have been wrecked

along just one short stretch of America's Atlantic coast

Where the Gulf Stream flows perilously close to land.

The treacherous sandbanks off the Barrier Islands off North Carolina

are known as the graveyard of the Atlantic.

But there may have been some survivors from the wrecks here.

No one's certain how they got here, but many believe that their ancestors

made it to shore from shipwrecked galleons of Spanish conquistadors.

For the last five hundred years, horses descended from Spanish stock

have lived completely wild on these islands

Today, the fertile grasses of the salt marshes support over a hundred horses.

Once domesticated, now completely wild.

They live in small groups of mares and foals, over which stallions battle for access.

With these horses, there's a critical challenge.

The water that surrounds them, is too salty to drink.

To quench their thirst, they must first dig.

These horses are survivors.

They'll even swim between islands in search of fresh grazing.

Marooned for centuries on this Atlantic outpost

these Spanish horses are a living reminder

of the role the Gulf Stream has played in human history.

Off shore from the Barrier Islands

the Gulf Stream has helped to carry these humpbacks

for over a thousand miles from the Caribbean.

This mother and calf have joined forces with a male

perhaps to give them some protection against the increasing threat from orcas.

They have done well to make it this far

but the mother may not have eaten for six months

and her milk won't last much longer.

Luckily, the Atlantic is about to deliver salvation.

As the Gulf Stream passes the northern United States

a meeting of the waters helps to drive an extraordinary transformation.

A cold current pushes down from the Arctic along the coast

carrying icebergs with it.

The mingling of the two currents helps to bring nutrients to the surface

sowing the seeds for an explosion of life.

Bluefin tuna are one of many Gulf Stream travellers

that end their summer migration off New England and eastern Canada

some of the richest seas on Earth.

This rich stretch of ocean also supports seabirds in their millions

and huge numbers of marine mammals.

Crab seals travel together on the hunt for fish.

Every spring, these fertile seas turn into a rich green soup

across hundreds of miles as billions of tiny plants burst into life.

A plankton bloom.

Individually, these plants are too small for the naked eye to see.

But in such huge numbers, they are the basis for these incredibly rich seas.

Tiny animals feed on the tiny plants.

These in turn are preyed on by even larger animals

and so on, up the food chain.

Any animal or plant that can't swim against the current is called plankton.

Most of these are tiny

but this fertile region can provide enough food for the colossus of the planting world.

This is a lion's mane, the largest jellyfish in the world.

Its body alone can be wider than a man is tall.

Its stinger covered tentacles can be longer than a blue whale

catching anything from tiny shrimps, to fish, to other jellyfish.

This is a creature most would go out of their way to avoid.

But one remarkable animal swims all the way from the Daribbean

to southern Canada in search of it.