Original subtitles

The sun giver of light and life

shines most powerfully at the Equator.

Here, it powers an extraordinarily rich zone of life.

Brilliant and bizarre species from 3 continents 3 oceans.

More than a line on a map Equator is a powerful force of nature.

The Galapagos Islands lie on the Equator but they're no tropical paradise.

The Pacific Ocean brings both fortune and famine to these desert islands.

At the Galapagos Islands the ocean has created a strange and improbable realm.

This is a place for dragons.

Marine iguanas live here because they can harness the power of the ocean.

The ocean's power comes from the Equatorial sun.

İt sets in motion great currents that bring food and minerals here

riches to feed many.

But they're not just rich

the ocean currents are cold cold enough for penguins.

Where else but at the Galapagos Islands could a penguin swim at the Equator?

And only here can a lizard graze like a sheep in an underwater meadow.

But sometimes the ocean withdraws the currents and their riches

then there's hardship on these islands of uncertainty.

Even in the face of famine, there's hope

but breeding is a gamble and gamblers often lose.

The riches and desolation that the ocean brings to the Galapagos Islands

are driven by the sun.

Out across the Equatorial Pacific,

the immensely powerful sun heats surface waters to nearly 30 degrees Celsius.

Warm moist air rises in such huge amounts, that from space,

the Equator is visible as a line of boiling cloud.

Cool air drawn in from below is swept west by the spin of the earth.

These are the trade winds

and they collide at the Equator, creating thunderstorms and heavy rain.

Palmyra Atoll is one of the few specks of land in the vast central Pacific

to receive this deluge.

These small islands also lie on the equator.

They are completely different from the Galapagos Islands

yet life on both is shaped by the power of ocean currents.

Although it rains nearly every day in this lush tropical paradise,

it's always hot always summer.

In the well-watered warmth,

Pisonia trees tower to thirty metres

there are very few tropical atolls with a rainforest of giant trees.

And in the damp shade below, giant coconut crabs.

A big male can weigh 13 kilogram, with legs that span more than half a metre.

The crabs' main food is fresh coconuts, that are available all year round.

Coconut crabs are the largest terrestrial invertebrates in the world.

They have massive front claws, strong enough to strip flesh from bone

even so,

it'll take a team of crabs days to husk this coconut.

Apart from coconuts,

there's often not much to eat here

but the crabs eat practically anything.

They thrive on these uninhabited islands and have no predators.

Their only threats come from each other.

Coconut crabs are the undisputed rulers of the forest floor

but the skies and tree tops belong to the seabirds.

Nearly thirty species come here to nest.

Palmyra Atoll is one of only a few islands in the equatorial Pacific

where seabirds can raise their young.

High in a tree,

a red-footed booby chick waits to be fed.

The boobies depend on the tall trees for nesting

but the trees also depend on these birds with spectacular red feet.

To find food for its hungry chick,

a red-footed booby spends most of its time far out at sea,

searching for flying fish

it's a long difficult job

the warm ocean is like a lifeless desert.

Each day,

the adults bring the Pacific's meagre offerings back to the island.

There's only ever enough food for a pair of red-footed boobies to raise one chick.

İf a chick dies,

its parents won't breed again until next year.

Coconut crabs eat anything including dead chicks.

But these eager undertakers aren't the only ones that benefit from what the boobies

'leave behind'.

The boobies give a precious gift to the forest

Their waste is a rich guano fertiliser that Pisonia trees depend on.

The forest needs the seabirds

and also the nearly four and a half metres of rain

that falls on Palmyra Atoll each year.

Though its animals must endure a rainstorm nearly every day,

the island is made of porous coral sand

rainwater quickly drains away.

To get a drink,

a crab collects water dripping off its own body

using a tiny leg that it normally uses to clean its gills.

Even during a storm,

seabirds continue their endless search for flying fish to feed their chicks.

Rain and seabird guano have created

much more than this lush forest garden of coconut crabs and Pisonia trees.

Heavy rain dissolves dried guano off leaves

and washes it down through the porous coral sand.

This liquid is now fertilizer for a very different garden.

Nutrients from the land enrich Palmyra's fringing reef.

Without seabird guano,

these waters would be as barren as the surrounding ocean

but a school of convict surgeonfish graze rich algae,

fertilised from above.

The coral reef looks like a vast garden,

but it's one made up of millions of tiny animals.

Each coral is a colony of polyps,

all filtering food from the passing current.

But the real secret to a coral polyps' success are the minute gardens,

buried inside, in its tissue.

Millions of zooxanthellae, microscopic algae,

make food for themselves and their host coral,

by photosynthesis

by harnessing the power of the equatorial sun.

This incredible relationship, between plants and animals and sun,

has built a great coral fortress.

Yet as fast as the corals build the reef, some inhabitants break it down.

A bumphead parrotfish chews the coral's hard skeleton to get at the polyps inside.

But it's as much a builder as destroyer.

It excretes the coral as sand

sand that helps build the island and its beaches.

Palmyra's reef is home to hundreds of fish species.

Eighteen species of butterfly fish live here,

some so specialised they eat nothing but coral polyps.

With mouths shaped like forceps,

they're precise and careful eaters.

A cleaner wrasse makes its living off other fish -

parasite removal is a thriving business.

At the Equator,

the sun shines for twelve hours every day

but life doesn't stop during the twelve hours of darkness.

Boobies still feed out in the open ocean.

But on the reef, much changes.

A bumphead parrotfish is dressed in drab night colours, to hide as it sleeps.

Swarms of zooplankton rise to the surface to feed

and are fed upon by ghostly figures.

Manta rays with wings spanning nearly three metres swoop and dance

as they suck up the riches available here every night.

The corals have created a rich oasis in the middle of the barren Equatorial Pacific.

But how did so many different fish and corals come to populate this tiny,

isolated atoll in the middle of an empty ocean?

The sun and spin of the earth create trade winds so powerful

they move two great masses of water towards the western Pacific.

The result is a raised sea level, which then flows back downhill,

eastward along the Equator, as a counter-current,

a few hundred kilometres wide.

Palmyra Atoll lies directly in its path.

The counter current brings eggs and larvae of many fish and corals,

from reefs on the edge of Asia

this bounty of young marine life makes Palmyra Atoll much richer than island groups

such as Hawaii, that lie outside the current's flow.

In their turn,

many Palmyra species launch their offspring into the passing current.

On the highest tide of the month

mating surgeonfish release clouds of sperm and eggs.

Many fertilized eggs are swept away from the reef on the outgoing tide,

to face an uncertain journey east,

in the slow-moving counter current.

Within days the eggs hatch into larvae.

After a few weeks they develop into tiny fish.

Within two months of hatching

the hopeful travellers need to settle on a reef.

But the nearest land is the Galapagos Islands,

five months travel to the east.

Their current is too slow

even if predators don't get them, the young fish will run out of time.

Far below the counter current,

the faster Cromwell Current is also flowing east along the Equator.

It carries deep ocean water from as far away as Antarctica.

It finally rises to the surface up the flanks of the western Galapagos Islands

its waters are very cold,

yet they hold the promise of life.

The current is rich in dissolved minerals

and when these nutrients meet the equatorial sun,

a miracle occurs.

The minerals feed microscopic plants, such as diatoms

and in the sunlit surface waters they reproduce,

dividing again and again, in an explosion of life.

These dense plankton blooms

turn the sea into a murky soup that feeds many species,

including an unusual predator - the giant, flightless cormorant.

This small cormorant colony is a busy place

Some pairs have large chicks to feed;

others are just beginning to breed.

There are no land predators on these isolated islands,

so there's nothing here that the cormorants need fly away from

over time, they've lost the power of flight - instead they walk or swim.

There are just a few hundred pairs of cormorants.

They live only where the Cromwell Current wells up, year round,

on the western Galapagos Islands.

All the animals that are prepared to brave these icy waters

dine well.

Marine iguanas are found throughout the Galapagos Island group

but these ones in the west are by far the biggest and fattest.

It's dawn,

and the iguanas are playing their usual waiting game.

These reptiles are now as cold as the long night they've just endured

they need to heat up in the sun before they can feed.

Cold makes the largest males grumpy.

Cool iguanas not only have to wait for hours until the sun warms them enough to feed

- they must also tolerate their busy cormorant neighbours.

Nearly a metre tall,

the cormorants dwarf the basking iguanas.

The warm-blooded birds don't need to wait to get in the cold water

- this courting pair have been dancing since dawn.

This is a great place to be a flightless bird

a male cormorant never needs to travel more than a few hundred metres from his nest.

The cold Cromwell Current provides everything

including the many gifts of fresh algae he must bring to his nest mate.

The female adds the algae gift to the collection she's fashioning into a nest

when complete,

it'll be just high enough to keep her eggs off the hard rock.

By mid-morning,

when the nearby cormorants have already been busy for hours,

the hungry iguanas are only just beginning to show signs of action.

The first big males slowly make their way down to the water's edge.

The vegetarian iguanas have a most unlikely lifestyle,

one that's only possible here, at the Equator

where the heat of the tropical sun allows them to endure the chilly waters.

Just a few hundred metres offshore, nurtured by the cold current,

there are lush algae gardens.

But only the largest males have enough body mass to survive the chill waters

a small iguana would lose heat too quickly and die.

Only big males dive down to feed where the algae is most lush.

But how can even this large male survive water that's just 16 degrees Celsius,

low enough to kill a cold-blooded reptile?

A diving male moves blood away from his body surface,

to help conserve heat in his core organs.

He also drastically lowers his heart rate

By doing this, he can survive a fifteen degree drop in body temperature.

As the morning wears on,

other big iguanas become warm enough to take the plunge.

A male hooks his long claws into the pitted volcanic lava,

as he braces himself against the wave surge.

Iguanas are voracious eaters.

They clip the algae until it looks like a newly mown lawn.

But algae grows fast in these rich waters

- and can be grazed again in just a few days.

A diving iguana must feed quickly.

Being a land animal, he surfaces often to breath.

And he can only survive the cold water for two hours at the most,

before he must head back to shore.

After a long dive,

big males are so chilled, they're barely able to swim.

If they're swept out to sea, they'll face certain death.

Each must fight his way back to the warm shore.

At last

the tide is low enough to expose the shallowest algae beds.

Finally, the smaller females and young iguanas can feed.

But they, too, must hurry

they're in a race against the turning tide.

Marine iguanas share the rich algae gardens with another tropical reptile.

Like the iguanas,

the Galapagos green turtle is slow and sluggish in the cold.

It lacks an iguana's claws to hold on in the swell,

but it's persistent and the fast-growing algae is well worth the effort.

For the inhabitants of the western islands,

the Cromwell Current is a reliable provider.

But what's happening in the less predictable world of the eastern islands?

Right now, in early May,

the sun has heated the surface water to 25 degrees it's clear,

and offers little food.

Galapagos penguins live in both the cold western and warm eastern islands.

In the east, times are hard

but penguins here are gambling on a rich, cold water bonanza arriving soon.

Butterfly fish find the warm waters very much to their liking.

However, unlike Palmyra there's not much coral here to feed on,

so they've changed lifestyles.

Some butterfly fish now eat parasites

they have become cleaner fish.

To survive here you adapt or die.

For some coastal birds,

the warm water around the islands is as much a lifeless desert as the open ocean.

However, like the penguins,

these blue footed boobies are gambling on the arrival of cold water,

rich in food for hungry chicks.

This pair is in the early stages of courtship.

Over the next few days they'll deepen their relationship with ritual displays

and begin the task of choosing a nest site.

This pair is just starting

but others already have chicks.

Throughout the colony pairs are at different stages of breeding

but all are gambling the lives of their offspring on an uncertain future.

This pair nested early

- they'll be winners if the cold water arrives soon.

They have 2 eggs,

others have 3.

They might raise all their chicks or none it all depends on when the food arrives.

A male blue footed booby dives for food, not far from the nest.

But the water is still warm

there's little reward for all his hard work.

He and his mate were among the earliest to breed.

They started with three eggs

but they're only finding enough food for a single chick

and at the moment there's no sign of a change in their fortunes.

This chick's survival depends on the Earth's orbit

and the position of the sun.

As it moves towards the northern hemisphere,

it's bringing trade winds and ocean currents with it

and for the boobies, the promise of plenty.

The boobies are not just gambling on when the change in season will happen.

They have a more immediate problem.

This young frigate bird is already learning to steal food from the hard-working boobies.

Frigatebird success relies heavily on the fortunes of the boobies,

so they've timed their breeding to coincide with them.

By breeding now

frigatebirds will also benefit when the cold water arrives.

If boobies do well, then these pirates will thrive

if the water stays warm, they'll both suffer.

As females fly overhead,

a group of males compete to impress them with the redness of their air sacs,

and the vigorousness of their calling and shaking.

This is a rough neighbourhood.

A red footed booby collecting sticks to build a nest

must run a gauntlet of aerial pirates

as intent on thieving sticks as they are food.

With a wingspan of more than 2 metres, and an amazingly light body,

a frigate bird is an aerobatic thug

able to steal sticks out a booby's beak in mid air.

The booby drops its stick

but the agile frigate bird just swoops it up.

Thievery is a very risky strategy

so much so that this pair will raise just a single chick.

It's an epic job

it will be a year and a half

before their offspring masters the dark art of aerial piracy.

Even an adult frigate bird is a fair target, for an apprentice pirate.

Competition for resources is so intense,

that frigate birds always have to be on guard- even at the nest.

Frigate birds and boobies are gambling that cold water will bring them food

the albatrosses trust it will bring cool weather

hopefully soon.

Although albatrosses are cold climate birds,

the Galapagos Islands are home to waved albatrosses, the only truly tropical species.

This is the only place they breed,

and they're here because it's a safe, predator-free haven.

But it's not so safe for a returning female.

She must run a gauntlet of males, hell-bent on mating with her.

Neither of these males is this female's mate

around a quarter of all chicks are not fathered by the male who raises them.

Among albatrosses,

rape is as unexpected as living at the Equator

but these are the Galapagos Islands,

where strange and improbable things happen.

Like frigate birds,

albatrosses raise just one chick

The task will take a pair nearly eight months.

For weeks before they begin,

they display to each other.

İt's a way of ensuring that, despite all the extra matings,

both birds will be committed to the lengthy task ahead.

The pair's prolonged ritual strengthens their bond,

for the long periods they spend apart.

They feed fifteen hundred kilometres away,

in cold water upwellings off the coast of Peru.

Each bird may be away for two weeks at a time,

but the long journey is well worth it.

The albatrosses' feeding grounds are incredibly rich

and they're the key to what the animals of the Galapagos are waiting for.

The sun not only generates Pacific's ocean currents,

it has the power to move them around.

During May, when the sun is moving north,

the south-east trade winds are gathering strength.

When they're strong enough,

they'll drag the cold Humboldt Current northwards from the coast of Peru.

The arrival of the cold water is marked by a layer of cloud

this is the cool season of plenty known as the 'garua'.

But at the moment,

the eastern islands remain surrounded by warm barren water.

Only the western islands have food,

thanks to the reliable Cromwell Current.

The big male iguana's been feeding in the algae gardens for two hours.

He's now so cold,

he's not even capable of digesting the algae he's just eaten.

It's time to warm up again.

Cold iguanas press themselves against the hot rock for maximum warming.

As the big male absorbs heat,

activity slowly returns to his body.

Only when his temperature reaches 35 degrees can he digest the algae in his stomach.

A young cormorant bothers the sunbathing iguanas,

just because it can.

Despite the annoying neighbours,

the Galapagos Islands have all the conditions to support the iguanas unusual lifestyle.

The black lava, which radiates heat like an oven

and the intense midday sun a blessing

that makes life between two very different worlds possible.

The male cormorant is in and out of the cold water all day collecting algae gifts.

He doesn't notice how hot it's become ashore.

But for some animals,

the merciless midday heat is a curse.

All nesting birds are facing trial by sun.

Ground temperatures in the cormorant colony have climbed into the high thirties

but the adults can't escape.

They're trapped by their eggs and chicks.

As the equatorial sun moves across the sky,

a booby turns to face away from its burning heat

creating a guano sundial around its nest.

It raises the feathers on its back, trying to catch a cool breeze.

A chick shelters in shade cast by its parent,

but there's no shade for the adults.

An incubating albatross pants to lose heat.

İts parental instincts tested to the limit until the cool garua arrives.

Sealions have it easier

- during the hottest part of the day they go surfing.

On the Galapagos Islands climate is unpredictable

conditions change from day to day, year to year.

Creatures deal with the uncertainty as best they can.

A booby chick hatches

- but what will its future hold?

There's food for it today

but will it get fed tomorrow?

When will the cold water arrive?

And what happens if it doesn't arrive at all?

Every few years

the islands remain surrounded by warm empty water

This is called El Nino

All the animals that depend on the coming of the cold water, suffer.

In a severe El Nino,

even the reliable Cromwell Current may fail

the effect is devastating.

Sea lions and seal pups starve to death.

Only scavengers do well.

Many boobies desert their nests,

leaving lava gulls to feast on abandoned eggs.

Death stalks the booby colony.

Only the strongest chicks survive.

In a recent El Nino,

many iguanas died

but others cheated death by shrinking.

Their whole body, including skeleton, shrank by nearly a quarter.

Shrunken survivors could exist on less, poorer quality food.

Iguanas must always be resourceful

it's how they survive on these desert islands.

Each day they walk a thermal tightrope

by mid afternoon, even the iguanas are too hot.

They push their bodies off the hot ground to cool themselves

it's as if they're trying to catch a glimpse of the coming garua.

Clouds on the horizon hint it might be near

- but it's come this close before,

and still failed.

Sunset grants the animals of the Galapagos a temporary reprieve.

The iguanas now risk becoming too cool,

but for the seabirds

the long night will be a blessed relief.

For the sea lions, darkness brings new possibilities.

They can now hunt for sleeping fish on underwater cliffs.

As long hot days turn into weeks,

clouds slowly gather over the islands.

The cold water is almost here.

It's good timing for this year's iguana hatchlings.

This baby iguana has spent days,

digging its way up from where it hatched, deep in the beach gravel.

Above ground for the first time,

it tries to avoid detection while it works out the best place to run.

The hatchling must cross a no-man's land of empty beach,

to reach rocks where it can safely hide.

It makes it.

Instinctively the young iguana knows that it'll find its fortune from the sea

although it'll be many years before it's big enough to dive down

to feed in the rich algae gardens of the Cromwell Current.

Finally,the seasons change

the cold water arrives,

accompanied by its trademark heavy cloud.

This is the season of the garua.

The dense mist forms as the hot equatorial sun interacts with the cold water

of the Humboldt Current.

The garua brings cooler temperatures

- waved albatrosses are more comfortable now.

A weak booby chick is in luck

- there will be food for it this year, after all.

In this nest, both chicks will survive.

It's not just the boobies who prosper so will the frigate birds.

For all the creatures of the sea,

the coming of the garua is the beginning of an incredible time of plenty.

In the west, the Cromwell Current is a reliable year-round provider.

In the east, for a few months each year,

the powerful Humboldt Current brings unimaginable wealth

rich cold water,all the way from Antarctica to the Equator,

here at the Galapagos Islands.

The power of the equatorial sun

and the minerals in the cold current are the sparks

that ignite an explosion of life

plankton grows so quickly and thickly,

it dims the light.

The plankton blooms are so vast,

they can be seen from space blown to the west by the trade winds.

Enormous schools of salimas are the bonanza the penguins of the eastern islands

have been waiting for.

This is a good year for all animals that depend on the sea.

Ocean currents, set in motion by the equatorial sun,

have brought certainty and wealth.

Life prospers on these improbable desert islands in an oasis of cold water,

created by the power of the sun.

And the power of an ocean.