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00:50I am at the very center of the great white continent, Antarctica.
00:56The South Pole is about half a mile away.
00:59For 1,000 miles in all directions, there is nothing but ice.
01:05And in the whole of this continent,
01:071.5 times the size of the United States,
01:10and larger than Europe,
01:12there's a year-round population of no more than 800 people.
01:19This is the loneliest and the coldest place on Earth,
01:24the place that is most hostile to life.
01:28And yet, in one of two places, it is astonishingly rich.
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01:46Penguins come here by the million
01:49and endure temperatures of minus 70 degrees centigrade
01:53and winds of 120 miles an hour.
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02:07Other birds fly right to the heart of the continent,
02:10even though they have to dig away snow
02:12in order to find a place to nest.
02:15And here is the nursery for over half the world's seas.
02:21Antarctica is remote from all other continents,
02:25surrounded by the vast Southern Ocean
02:27and smothered by a blanket of ice so immense
02:30that it contains over three-quarters of the world's fresh water.
02:35All life in the Antarctic is dominated by the ice.
02:40All but 2% of the continent is covered by it.
02:44Its very whiteness reflects back what little heat there is
02:48in the sun's feeble rays,
02:50and snow, when it falls, remains permanently frozen,
02:54so that now, after accumulating for millions of years,
02:58it has formed this gigantic ice cap,
03:01and the ice beneath my feet is three miles thick.
03:06Submerged beneath it are mountain ranges as high as the Alps.
03:11Only their summits project through it.
03:16Rivers of ice spill down from the ice cap as great glaciers
03:22and creep slowly towards the edge of the continent and the sea.
03:31When you get beneath the snout of one of these huge glaciers,
03:36you begin to appreciate the immense power and size
03:40of the Antarctic ice machine.
03:43The ice here towers 100 feet above me,
03:47and the whole front of the glacier is about two miles across.
03:51But this is a small glacier.
03:54The largest glacier in Antarctica and in the world
03:57is the Lambert Glacier, and that's 25 miles across.
04:02But this is not a place where you want to linger.
04:05The glacier moves slowly,
04:07but it's not a place where you want to linger.
04:10The glacier moves forward at the rate of about two-thirds of a mile a year,
04:14and the front end is continually breaking away to form icebergs.
04:19And if one came down now,
04:21well, the surge could easily overturn a small boat.
05:08These icefalls disintegrate into brash ice,
05:12but when a large chunk of a glacier or an ice sheet breaks away,
05:16it floats off as an iceberg.
05:21At first, these bergs are slab-like,
05:24but winds and waves above water and currents below
05:28slowly carve them into the loveliest of shapes.
05:38A large berg can survive for up to ten years
05:42before it ultimately breaks up and melts.
05:50Only one-fifth of an iceberg is above the surface.
05:54The rest is hidden beneath the water.
05:58Streams of minute air bubbles, released from the melting berg,
06:02carve grooves in its submerged flanks.
06:09The icebergs are so thin,
06:11they can only hold up to three-quarters of the weight of an iceberg.
06:16But they're so thin,
06:18they can only hold up to three-quarters of the weight of an iceberg.
06:23The icebergs are so thin,
06:25they can only hold up to three-quarters of the weight of an iceberg.
06:29The rest is hidden beneath the water.
06:32Streams of minute air bubbles, released from the melting berg,
06:36carve grooves in its submerged flanks.
06:42Huge though bergs may be, they are nonetheless usually on the move.
06:54The Iceberg
07:01As winter progresses, so more and more of the sea freezes,
07:06spreading out from the margins of the land like an immense skirt,
07:10so that, in effect, the continent doubles in size.
07:14When the ice reaches its farthest extent,
07:16you have to travel hundreds of miles from the edge of the continent
07:20before you reach open water.
07:23The annual formation of the sea ice
07:26is the greatest seasonal change that takes place on this planet,
07:30and it completely dominates the lives of Antarctic animals.
07:34Practically all of them are directly dependent upon the sea for their food,
07:39so year-round access to it is essential for their survival.
07:43In the summer, when the sea ice melts,
07:45they can reach the islands that were trapped in the ice
07:48and eventually the continent itself.
07:51But when the ice reforms, they have to retreat north.
07:55So now, in winter, with the sea ice at its fullest extent,
08:00it's in the sea that we must look for life.
08:19The Southern Ocean is extremely rich in food.
08:23Millions of penguins and seals and thousands of whales feed here.
08:29The Atlantic Ocean
08:42The majority of them rely on just one source of food, krill.
08:48Krill are small, shrimp-like creatures about six centimetres long.
08:53In winter, they're dispersed widely, mostly under the ice,
08:57but in summer, they assemble in vast swarms,
09:00some of which may contain a billion individuals.
09:07They are the most numerous animals on Earth.
09:10They're close to the surface of the ocean,
09:13They are the most numerous animals on Earth.
09:16Their total weight far exceeds that of the total human population.
09:31Humpback whales.
09:33During the brief summer, they gorge themselves on krill.
09:44Humpback whales
09:50When the krill swarms are near the surface,
09:52the humpbacks collect them by lunging.
10:04They simply open their cavernous mouths and scoop it up.
10:14Often, the whales cooperate, working together as fishing boats do.
10:19Humpback whales
10:40When the krill is more dispersed, the whales have to dive deeper.
10:46After a while, lines of bubbles appear on the surface.
10:54The bubbles gradually form a pattern that spirals inwards.
11:04Then suddenly, in its centre, the whales appear.
11:15Humpback whales
11:18Time and again, the pair dive.
11:21When they reach the bottom of the dive, they start releasing bubbles
11:25and continue to do so as they swim upwards, spiralling around one another.
11:31These curtains of bubbles rise through the water,
11:34creating a ring on the surface.
11:37Humpback whales
11:42Underwater, the curtains drive the krill into the centre of the spiral,
11:46and the humpbacks then surge up through the middle, jaws agape.
11:50Humpback whales
12:08The humpbacks that visit Antarctica only feed during the brief southern summer,
12:14building their reserves for a winter that will be spent in less productive northern waters.
12:19And so, for hour after hour throughout the long Antarctic day,
12:23these 40-tonne creatures perform a splendidly synchronised
12:28and very productive underwater ballet.
12:38Seabirds
12:40Other creatures benefit from the whales' industry.
12:43Seabirds forage in their wake.
12:53As the whales drive the krill closer to the surface,
12:56it comes within reach of birds that are not particularly skilled at diving.
13:01Cape petrels
13:04Cape petrels, about the size of pigeons, can only duck dive a few feet down.
13:12But that is enough to give them a share.
13:32Ocean
13:39360 million seabirds constantly scour the southern ocean for food.
13:45They only go to land to breed.
13:48Most of their lives are spent on the wing, far out at sea.
13:52Howling gales
13:57This ocean is rich in nutrients and very rough.
14:01Howling gales whip it into huge waves.
14:04These, with so few islands to interrupt and break them,
14:08grow and grow into some of the most mountainous seas to be found in any ocean.
14:23Ocean
14:31Birds, dispersed over its vast surface, face a huge problem in finding food,
14:37for it is by no means uniformly spread throughout the ocean.
14:41The nutrients occur in patches,
14:43and so the krill, which is sustained by those nutrients, is patchy too.
14:49But once the birds find a swarm, there is a frenzy of feeding.
15:02Krill typically spends the day in deep water, rising nearer to the surface at night.
15:08But sometimes a swarm rises during the day, and then the birds get their chance.
15:15But getting to the krill is still a major problem to all birds except penguins.
15:20Albatrosses, such as the black-browed, whose diet is about 40% krill,
15:25can only dive down a couple of meters at the most.
15:45Fur seals also feed out in the open ocean,
15:49but they are able to dive to 100 meters or more.
16:14Krill
16:17Albatross
16:40The patchiness of the krill requires those that live on it to spend a great deal of time searching,
16:46and an albatross will fly hundreds, sometimes thousands of miles on a single foraging trip.
16:53Out here, birds can't afford to be fussy and must take whatever food they can find,
16:59almost all of them scavenged to some extent.
17:04These birds have found the remains of a small whale.
17:10They are the crumbs left behind after a catch by killer whales.
17:16Albatross
17:35Giant petrels, the vultures of the Antarctic, soon dominate the feast.
17:47Albatross
17:58The biggest of all these scavengers is the wandering albatross.
18:02With a wingspan of over three meters, this bird can range over greater distances than any other.
18:10It needs the updraft created by waves in order to fly,
18:14and only these stormy southern waters provide that in such abundance.
18:22Throughout the winter, wandering albatross remain in the south,
18:26for although the continent is trapped in ice,
18:29there are a few outer islands that always remain beyond its grasp,
18:33and these provide the albatross with their nesting sites.
18:37South Georgia
18:42Three thousand pairs of wandering albatross nest on one of them, here in South Georgia.
18:49Albatross
19:05An adult wanderer may travel five thousand miles, sometimes to Brazil and back,
19:11in order to collect squid for its young.
19:18Albatross
19:48Seabird
19:54This enormous chick weighs ten kilos, as much as a full-grown swan.
20:00It's the biggest of any seabird chick.
20:04Although it's a couple of months before it has to face its first flight,
20:09it's now at its maximum weight.
20:11In fact, it's heavier even than the adult.
20:19The spring snows are now beginning to melt,
20:22but the chick has already faced the worst of the winter weather.
20:26Hatched last March, it has sat here on its nest mound,
20:30unprotected and unshielded, for eight months,
20:33while the temperatures may have fallen to minus ten degrees,
20:37and terrible storms rage round it.
20:39It's so big that it can't possibly grow to this very huge size in the short summer season.
20:46So, the parents have to come to feed it every three or four days for ten months,
20:53and in order to do that, they have to be able to reach the open sea.
20:59Seabird
21:03King penguins
21:07King penguins
21:26Only one other animal breeds throughout the year on the outer islands, king penguins.
21:32They also need continuous access to the ocean to collect food for their chicks.
22:02Seabird
22:25Throughout the winter, adults come and go from their traditional breeding colonies.
22:33Antarctica is home to two million kings.
22:37In this one colony alone, there are 600,000 of them.
22:45These engaging chicks are so inquisitive that you only have to sit down to their own level
22:52for them all to gather around you to try and discover what sort of creature you are.
22:58They were hatched last summer, and like the albatross chicks,
23:02they're just coming to the end of their first winter.
23:06During that period, their parents were out at sea catching food for them,
23:10but each chick was only fed about once every three weeks.
23:15Left to themselves for so long, they've all gathered together to form immense creches.
23:22This one contains about 50,000 chicks.
23:26You might think that this huge congregation would make it almost impossible
23:31for a parent returning with food to find its own chick, but not so.
23:36The fact is that parent and chick can recognise one another's voice.
23:49A returning adult may spend hours looking for its chick among such a crowd,
23:54for the young are inclined to wander.
24:00The chick will respond to its parent's call and the parent to the chick's whistle.
24:10Eventually, they meet.
24:16But instead of feeding the chick straight away, the adult leads it through the rookery
24:21as if to test the bond between them.
24:27At last, in response to its chick's plaintive entreaties,
24:31the parent regurgitates a meal of squid.
24:35CHICKS SQUAWK
24:49A king penguin chick takes more than 12 months to rear.
24:53That means that the adults can't breed annually.
24:56At best, they raise two chicks every three years.
25:00Because of this, the breeding cycle of any one pair slides out of phase with the seasons.
25:06So now, late in winter, there are chicks both young and old,
25:10and adults at different stages in their cycle.
25:14Some of the adults are going through their pre-breeding molt
25:18before going to sea to fatten up for courtship.
25:22Others are already courting, parading back and forth with a special ritualised walk.
25:30CHICKS SQUAWK
25:53The male usually leads.
25:57If the female is sufficiently impressed,
26:00the pair seal their relationship with a vocal duet.
26:04CHICKS SQUAWK
26:07CHICKS SQUAWK
26:18CHICKS SQUAWK
26:23King penguin rookeries are very busy places.
26:27Every morning at about six o'clock, the adults leave their chicks,
26:31cross the glacier stream and march down to the sea.
26:37CHICKS SQUAWK
26:42They like to take an early morning bath,
26:45getting rid of the smelly mud and grime of the crowded colony.
26:49CHICKS SQUAWK
26:52CHICKS SQUAWK
27:22For an hour or so, they wash in the surf.
27:39CHICKS SQUAWK
27:46These penguins seem to have a fairly easy time of it,
27:49surrounded by an ocean laden with food
27:51and with year-round access to their breeding beaches.
27:54But they are one of the few of Antarctica's inhabitants
27:57that have achieved independence
27:59from the factor that governs almost everything else,
28:02the advance and retreat of the sea ice.
28:06King penguin and albatross live only on the frontier of the Antarctic.
28:11They never go closer to the pole than the edge of the sea ice.
28:15Next week, we will.
28:17As spring really takes hold, we will follow the retreating sea ice
28:21to the shores of the continent and then go up onto the Great Ice Cap,
28:25to the very heart of the Antarctic,
28:27where life in the freezer faces its greatest challenge.