The Bountiful Sea Life in the Freezer

I am at the very centre of the great white continent, Antarctica.

The South Pole is about half a mile away.

For a thousand miles in all directions, there is nothing but ice.

And in the whole of this continent, which is 1.5 times the size of the US and larger than Europe,

there is a year-round population of no more than 800 people.

This is the loneliest and the coldest place on earth,

the place most hostile to life,

and yet, in one or two places, it is astonishingly rich.

RAGING WIND

Penguins come here by the million,

enduring temperatures of -70 degrees Centigrade and winds of 120 mph.

Other birds fly right to the heart of the continent,

digging away snow to find a nesting place.

And here is the nursery for over half the world's seals.

Antarctica is remote from all other continents,

surrounded by the vast southern ocean

and smothered in ice that contains over 75% of the world's fresh water.

ALL life in the Antarctic is dominated by the ice.

All but 2% of the continent is covered by it.

Its whiteness reflects back what heat there is in the sun's feeble rays.

Fallen snow becomes permanently frozen,

so that now, after accumulating for millions of years, the ice beneath my feet is three MILES thick.

Submerged beneath it are mountain ranges as high as the Alps.

Only their peaks project through it.

Rivers of ice spill down from the ice-cap as great glaciers

and creep slowly towards the end of the continent and the sea.

When you get beneath the snout of these huge glaciers,

you begin to appreciate the immense power and size of the Antarctic ice machine.

The ice towers 100 feet above me and the front of the glacier is about two miles across.

But this is a small glacier.

The largest glacier in Antarctica,

the Lambert Glacier, is 25 miles across.

This is not a place to linger.

The glacier moves forward at the rate of about 2/3 of a mile a year

and the front end is continually breaking away to form icebergs.

If one came down now, the surge could easily overturn a small boat.

These icefalls disintegrate into brash ice,

but when a large chunk of a glacier or an ice sheet breaks away, it floats off as an iceberg.

At first, these bergs are slab-like,

but winds and waves above water and currents below

slowly carve them into the loveliest of shapes.

A large berg can survive for up to 10 years before it ultimately breaks up and melts.

Only one-fifth of an iceberg is above the surface.

The rest is hidden beneath the water.

Streams of minute air bubbles released from the melting berg

carve grooves on its submerged flanks.

Huge though bergs may be,

they are usually on the move.

But come the winter, sea ice forms around them and locks them solid.

As winter progresses, so more and more of the sea freezes,

spreading out like an immense skirt so that, in effect, the continent doubles in size.

When the ice reaches its farthest extent,

you have to travel hundreds of miles before you reach open water.

The annual formation of the sea ice is the greatest seasonal change that takes place on this planet

and it completely dominates

the lives of Antarctic animals.

Most of them depend on the sea for their food, so year-round access to it is vital for their survival.

In summer, when the ice melts, they can reach the islands that were trapped in the ice

and eventually the continent itself.

But now, in winter, with the sea ice at its fullest extent,

it's in the sea that we must look for life.

The southern ocean is extremely rich in food.

Millions of penguins and seals and thousands of whales feed here.

The majority of them rely on just one source of food - krill.

Krill is a small, shrimp-like creature

about six centimetres long.

In winter, they disperse widely,

but in summer they assemble in vast swarms, some of which may contain a billion individuals.

They are the most numerous animals on earth,

their total weight far exceeding that of the total human population.

Humpback whales - during the brief summer, they gorge themselves on krill.

When the krill are near the surface, the humpbacks collect them by lunging.

They simply open their huge mouths and scoop it up.

Often the whales co-operate, working together as fishing boats do.

When the krill is more dispersed, the whales have to dive deeper.

After a while, lines of bubbles appear on the surface.

The bubbles gradually form a pattern that spirals inwards.

Then suddenly, in its centre,

the whales appear.

Time and again the pair dive.

When they reach the bottom of the dive,

they start releasing bubbles

and continue to do so as they swim upwards,

spiralling around one another.

The bubbles rise and create a ring on the surface.

Underwater, the bubble curtains

drive the krill to the centre of the spiral

and the humpbacks surge through the middle, jaws agape.

The humpbacks that visit Antarctica only feed during the brief southern summer,

building their reserves for a winter that will be spent in less productive northern waters.

And so, for hour after hour, throughout the long Antarctic day,

these forty tonne creatures perform a splendidly synchronised and very productive underwater ballet.

Other creatures benefit from the whales' industry.

Sea birds forage in their wake.

As the whales drive the krill closer to the surface,

it comes within reach of birds that are not particularly skilled at diving.

Cape petrels, about the size of pigeons,

can only duck dive a few feet down,

but that is enough to give them a share.

360 million sea birds constantly scour the Southern Ocean for food.

They only go to land to breed.

Most of their lives are spent on the wing, far out at sea.

This ocean is rich in nutrients and VERY rough.

Howling gales whip it into huge waves.

With so few islands to break them,

these grow and grow into some of the most mountainous seas to be found on any ocean.

Birds, dispersed over its vast surface,

face a huge problem in finding food, for it is not uniformly spread throughout the ocean.

The nutrients occur in patches,

and so the krill, which is sustained by these nutrients, is patchy too.

But once the birds find a swarm, there's a frenzy of feeding.

Krill typically only rise to the surface at night.

But sometimes a swarm rises during the day and then the birds get their chance.

But getting to the krill is still a problem for all birds except penguins.

Albatrosses, whose diet is about 40% krill, can only dive down a couple of metres at the most.

Fur seals also feed in the open sea,

but they are able to dive to a hundred metres or more.

The patchiness of the krill requires those that live on it to spend a great deal of time searching.

An albatross will fly hundreds, sometimes thousands of miles, on a single foraging trip.

Out here, birds can't afford to be fussy.

Almost all of them scavenge.

These birds have found the remains of a small whale,

the crumbs left behind after a catch by killer whales.

Giant petrels, the vultures of the Antarctic, soon dominate the feast.

The biggest of these scavengers is the Wandering Albatross.

With a wingspan of over three metres, this bird can range over greater distances than any other.

It needs the updraught created by waves in order to fly,

and only the stormy southern waters provide that in such abundance.

Throughout the winter,

Wandering Albatross stay in the south,

for there are a few outer islands that remain beyond the ice's grasp.

These provide the albatross with their nesting sites.

3,000 pairs of Wandering Albatross nest on one of them, here in South Georgia.

An adult Wanderer may travel 5,000 miles -

sometimes to Brazil and back -

in order to collect squid for its young.

This enormous chick weighs 10 kilos, as much as a full-grown swan.

It's the biggest of all sea-bird chicks.

Although it's a couple of months before it takes its first flight, it's now at its maximum weight.

In fact, it's heavier even... ah-ha...! Yeah... ..than the adult.

The spring snows are melting, but the chick has already faced the worst of the winter weather.

Hatched last March, it has sat here unprotected and unshielded for eight months

with temperatures as low as minus 10 and terrible storms raging round.

It's so big that it can't possibly grow to its full size in the short summer season,

so the parents have to come to feed it every three or four days for TEN months.

In order to do that, they have to be able to reach the open sea.

Only one other animal breeds throughout the year on the outer islands - king penguins.

They also need access to the ocean

to collect food for their chicks.

Throughout the winter, adults come and go from their traditional breeding colonies.

Antarctica is home to two million kings.

In this one colony alone,

there are 600,000 of them.

These engaging chicks are so inquisitive

that you only have to sit down at their level for them to gather round to investigate you.

They were hatched last summer

and, like the albatross chicks, are just ending their first winter.

During that time, their parents were out at sea catching food for them,

but the chicks were only fed

about once every three weeks.

Left to themselves for so long, they gathered together to form immense creches.

This one has about 50,000 chicks.

You might think it would be almost impossible for a returning parent to find its own chick, but not so.

The fact is that parent and chick can recognise one another's voice.

A returning adult may spend hours looking for its chick

among such a crowd,

for the young are inclined to wander.

The chick will respond to its parents call

and the parents to the chick's whistle.

Eventually, they meet.

But instead of feeding the chick straight away,

the adult leads it through the rookery as if to test the bond between them.

At last, responding to its pleas,

the parent regurgitates a meal of squid.

A chick takes more than 12 months to rear, so adults can't breed annually.

At best they may raise two chicks every three years.

So the breeding cycle of any one pair slides out of phase with the seasons.

So now, late in winter, there are chicks both young and old and adults at different stages in their cycle.

Some adults are moulting before they go to sea

to fatten up for courtship.

Others are already courting, parading with a ritualised walk.

The male usually leads.

If the female is sufficiently impressed, the pair seal the relationship with a vocal duet.

TRUMPETING CRIES

King penguin rookeries

are very busy places.

Every morning at about 6 o'clock,

the adults leave their chicks and march down to the sea.

They like to take an early bath, getting rid of the smelly mud and grime of the crowded colony.

For an hour or so, they wash in the surf.

These penguins seem to have a fairly easy time of it,

surrounded by an ocean laden with food and with year-round access to their breeding beaches.

But they are one of the few of Antarctica's inhabitants

to achieve independence from the sea ice.

Subtitles by Chas Donaldson BBC Scotland 1993

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