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Antarctica.
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00:00:37,180 --> 00:00:42,220
The coldest, the harshest and the
most remote continent on Earth.
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00:00:49,540 --> 00:00:54,300
No human being has ever descended
into the depths that surround it...
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00:00:57,460 --> 00:00:58,940
..until now.
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00:01:01,180 --> 00:01:03,460
INDISTINCT RADIO CHATTER
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00:01:06,100 --> 00:01:10,660
The deep ocean is as challenging to
explore as space.
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00:01:13,820 --> 00:01:17,620
We know more about the surface of
Mars than we do about the
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00:01:17,620 --> 00:01:19,340
deepest parts of our seas.
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00:01:39,780 --> 00:01:41,820
RADIO CHATTER
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00:01:43,020 --> 00:01:47,220
Now we can dive these uncharted
depths to discover
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00:01:47,220 --> 00:01:49,460
what secrets lie beneath.
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00:02:16,660 --> 00:02:20,540
INTENSE CREAKING
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00:02:24,220 --> 00:02:28,620
Sinking down beside the submerged
wall of an iceberg,
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00:02:28,620 --> 00:02:31,060
we enter an unforgiving world.
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00:02:41,300 --> 00:02:44,460
These waters are
the coldest on Earth.
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00:02:49,100 --> 00:02:53,900
As we descend into the deep, the
pressure increases relentlessly.
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00:03:11,380 --> 00:03:14,420
And the light from above
all but disappears.
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00:03:21,860 --> 00:03:23,700
Yet, incredibly...
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00:03:27,300 --> 00:03:29,140
..there is life here.
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00:03:50,820 --> 00:03:54,340
We might have expected that, deep
beneath the surface of
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the polar seas, the waters would be
truly barren.
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00:04:06,620 --> 00:04:11,260
But in fact we find life here in
unimaginable abundance.
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00:04:25,420 --> 00:04:29,660
Nor is such great abundance confined
to Antarctic waters.
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00:04:33,020 --> 00:04:37,260
Currents carry this richness into
the depths of almost every ocean
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00:04:37,260 --> 00:04:39,300
around the world.
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00:04:43,420 --> 00:04:45,580
Astonishingly, in the deep sea,
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there is more life than anywhere
else on Earth.
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00:05:16,700 --> 00:05:20,580
The sunlight fades
and the seas darken.
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00:05:24,500 --> 00:05:27,300
Here in the Pacific,
200 metres down,
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we enter an alien world.
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00:05:32,780 --> 00:05:35,220
The Twilight Zone -
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a sea of eternal gloom.
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00:05:45,860 --> 00:05:47,940
There are strange creatures here.
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00:05:49,620 --> 00:05:50,780
A pyrosome.
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00:05:52,140 --> 00:05:57,940
A tube of jelly two metres long that
dwarfs a visitor from above -
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00:05:57,940 --> 00:05:59,980
an oceanic whitetip shark.
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00:06:08,820 --> 00:06:12,500
Only a tiny amount of light filters
down this far.
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00:06:17,380 --> 00:06:21,900
Survival here means making the most
of every last glimmer.
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00:06:31,540 --> 00:06:32,900
A swordfish.
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00:06:41,740 --> 00:06:44,180
Its eyes are as big as tennis balls,
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to help it see
in the perpetual dusk.
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00:06:52,420 --> 00:06:53,740
A squid,
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00:06:53,740 --> 00:06:56,060
but this is one
that lives only here.
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00:06:57,580 --> 00:07:00,260
Its right eye looks
permanently downwards.
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00:07:02,900 --> 00:07:06,540
But its left eye is much bigger and
trained upwards to detect the
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silhouettes of prey
swimming nearer the surface.
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00:07:12,380 --> 00:07:15,500
No wonder it's nicknamed
"the cockeyed squid".
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00:07:21,860 --> 00:07:23,500
And even stranger.
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00:07:26,060 --> 00:07:27,980
This is barreleye...
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00:07:31,060 --> 00:07:34,500
..a fish with a transparent head
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00:07:34,500 --> 00:07:39,220
filled with jelly so that it can
look up through its skull.
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00:07:56,460 --> 00:08:01,060
We now know that the Twilight Zone
is a refuge for an incredible
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90% of all fish in the ocean.
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00:08:10,380 --> 00:08:15,780
Only at night do vast shoals of
lanternfish migrate to the surface
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00:08:15,780 --> 00:08:17,700
to feed on tiny plankton.
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00:08:29,140 --> 00:08:31,900
By day, they retreat back down here.
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Humboldt squid.
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00:09:02,140 --> 00:09:05,020
Two metres long
and 50 kilos in weight.
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00:09:10,300 --> 00:09:13,420
Like most squid,
they're voracious hunters.
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00:09:20,980 --> 00:09:22,620
There are hundreds of them.
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00:09:33,940 --> 00:09:36,260
They've found a shoal
of lanternfish,
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hiding 800 metres down,
off the coast of South America.
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00:09:52,660 --> 00:09:55,340
Their tentacles are armed with
powerful suckers
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with which they grab their prey.
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00:10:13,660 --> 00:10:16,260
And when there are no more
lanternfish to be found...
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00:10:18,740 --> 00:10:20,980
..they turn on each other.
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00:10:31,860 --> 00:10:35,300
This squid has caught a smaller one
in its tentacles.
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00:10:40,220 --> 00:10:42,420
To hide its capture from the rest,
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it releases a smokescreen
of black ink.
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00:10:57,700 --> 00:11:00,380
But then an even bigger one
challenges it...
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00:11:07,300 --> 00:11:09,140
..and steals its catch.
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00:11:18,380 --> 00:11:22,660
The Twilight Zone is the Humboldt
squid's favoured hunting ground.
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00:11:24,300 --> 00:11:25,900
They seldom go deeper...
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00:11:27,540 --> 00:11:30,700
..into the world of perpetual
blackness below...
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00:11:36,020 --> 00:11:37,780
..The Midnight Zone.
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00:11:48,660 --> 00:11:53,140
Two thirds of a mile from the
surface, beyond the reach the sun.
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00:11:58,940 --> 00:12:01,220
A giant black void,
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00:12:01,220 --> 00:12:05,220
larger than all the rest of the
world's habitats combined.
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00:12:06,780 --> 00:12:09,180
INDISTINCT RADIO CHATTER
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00:12:10,300 --> 00:12:11,820
There's life here...
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..but not as we know it.
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00:12:26,220 --> 00:12:30,180
Alien-like creatures produce
dazzling displays of light.
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00:12:43,180 --> 00:12:47,620
Nearly all animals need to attract
mates and repel predators.
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00:12:50,540 --> 00:12:54,820
This language of light is so
widespread here that these signals
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00:12:54,820 --> 00:12:58,500
are probably the commonest
form of communication
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00:12:58,500 --> 00:13:01,060
on the entire planet.
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00:13:02,620 --> 00:13:05,540
And yet we still know
little about them.
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Hunters illuminate themselves,
and by doing so
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00:13:32,780 --> 00:13:34,700
attract inquisitive prey.
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00:13:47,220 --> 00:13:49,260
This is fangtooth.
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00:13:51,340 --> 00:13:55,060
It has the largest teeth for its
size of any fish.
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00:13:57,820 --> 00:14:01,940
There are pressure sensors all over
its head and body which can detect
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anything moving
in the surrounding water.
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00:14:11,100 --> 00:14:14,500
It's the Midnight Zone's
most voracious fish.
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00:14:16,660 --> 00:14:19,620
But prey use light as a distraction.
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00:14:24,500 --> 00:14:26,940
A decoy of luminous ink.
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00:14:36,420 --> 00:14:38,620
Down here, in this blackness...
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00:14:40,700 --> 00:14:44,020
..creatures live beyond
the normal rules of time.
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00:14:50,940 --> 00:14:54,500
Siphonophores are virtually eternal.
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00:14:54,500 --> 00:14:56,900
They repeatedly clone themselves...
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00:14:58,340 --> 00:15:01,780
..some eventually growing longer
than a blue whale.
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00:15:26,060 --> 00:15:28,580
Down here it snows.
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00:15:37,180 --> 00:15:40,180
Continuous clouds of organic debris
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drift slowly down from above.
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This is food, and a whole variety
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00:15:53,140 --> 00:15:55,860
of filter feeders depend on it.
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00:15:59,260 --> 00:16:00,620
Jellyfish...
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00:16:08,900 --> 00:16:11,460
..and delicate sea cucumbers.
109
00:16:30,500 --> 00:16:33,860
The 1% of marine snow they miss
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00:16:33,860 --> 00:16:36,140
eventually settles on the sea floor.
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00:17:04,180 --> 00:17:08,060
Over millions of years
it forms a layer of mud
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00:17:08,060 --> 00:17:10,100
up to a mile thick.
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00:17:14,620 --> 00:17:16,940
It's an empty plain that covers
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half the surface of our planet.
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00:17:45,220 --> 00:17:49,340
The deep sea bed
may at first appear lifeless...
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00:17:51,580 --> 00:17:55,740
..but it's home to
a unique cast of mud-dwellers.
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00:17:58,660 --> 00:18:00,060
The sea toad.
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00:18:02,940 --> 00:18:06,940
It is an ambush predator
with an enormous mouth...
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00:18:08,660 --> 00:18:10,620
..and infinite patience.
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00:18:21,300 --> 00:18:24,380
This fish has been living
for so long here
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00:18:24,380 --> 00:18:26,140
that its fins have changed
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00:18:26,140 --> 00:18:27,940
into something more useful.
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00:18:33,940 --> 00:18:35,740
Feet.
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00:18:40,300 --> 00:18:43,300
They help it shuffle about
on the sea floor.
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00:19:03,580 --> 00:19:05,500
The flapjack octopus.
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00:19:10,780 --> 00:19:14,900
It hovers just above the surface of
the mud as it delicately sifts
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00:19:14,900 --> 00:19:17,380
through it, searching for worms.
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00:19:20,780 --> 00:19:24,220
But it can jet away at
the first sign of danger.
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00:19:43,220 --> 00:19:46,380
A sixgill shark
as big as a great white.
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00:19:47,900 --> 00:19:51,100
It may not have eaten
for an entire year.
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00:19:57,740 --> 00:19:59,700
It patrols the mud plains
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00:19:59,700 --> 00:20:02,340
using a minimum amount of energy.
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00:20:16,140 --> 00:20:18,940
High above, the carcass of a huge
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00:20:18,940 --> 00:20:21,740
sperm whale is slowly decaying.
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00:20:28,420 --> 00:20:31,460
This will be a bonanza for the
creatures of the deep.
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00:20:32,700 --> 00:20:35,780
Food, 30 tonnes of it.
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00:20:49,020 --> 00:20:52,540
Finally, it settles
on the ocean floor...
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00:20:54,580 --> 00:20:57,060
..and its presence is soon detected.
139
00:21:06,860 --> 00:21:11,700
Sixgill sharks have an
exceptionally acute sense of smell.
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00:21:16,300 --> 00:21:20,140
Just 25 minutes after the whale's
carcass arrives...
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00:21:22,300 --> 00:21:24,180
..a sixgill finds it.
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00:21:45,420 --> 00:21:48,660
Each bite releases blood
into the current.
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00:22:30,060 --> 00:22:33,260
The news that food is here
spreads quickly.
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00:22:41,540 --> 00:22:44,860
Two more ravenous sixgills arrive.
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00:22:53,620 --> 00:22:55,220
Within 12 hours,
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00:22:55,220 --> 00:22:57,140
there are seven enormous sharks
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00:22:57,140 --> 00:23:01,020
jostling with one another as they
compete to tear off mouthfuls.
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00:23:13,340 --> 00:23:15,700
No-one is prepared to back off.
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00:23:59,100 --> 00:24:03,220
24 hours later and a third of the
carcass has gone.
150
00:24:34,860 --> 00:24:38,780
The first arrival has gorged until
it's completely full.
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00:24:43,900 --> 00:24:48,980
This single meal may be enough to
sustain it for a whole year.
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00:24:55,460 --> 00:24:58,460
Now the clean-up team arrives.
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00:25:01,700 --> 00:25:05,380
Spider crabs carrying coral
in their hind legs,
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presumably as makeshift body armour.
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00:25:16,540 --> 00:25:18,260
There are rock crabs here, too.
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00:25:21,180 --> 00:25:25,100
They probably detected the carcass
almost as soon as the sharks...
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00:25:26,820 --> 00:25:28,660
..but they can't move as fast.
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00:25:33,340 --> 00:25:35,620
A month on, and over 30 species of
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00:25:35,620 --> 00:25:38,220
scavenger are clearing away the last
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00:25:38,220 --> 00:25:39,740
edible fragments.
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00:25:42,420 --> 00:25:46,340
But now the scavengers are
attracting their own predators.
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00:25:52,740 --> 00:25:55,940
Scabbardfish,
habitually swimming upright,
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are picking them off one by one.
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00:26:19,020 --> 00:26:22,860
Some of the whale's teeth have been
dislodged as the skeleton starts to
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fall apart.
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00:26:27,620 --> 00:26:32,220
Four months later, there is nothing
left but a few bones.
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00:26:39,940 --> 00:26:41,700
But even they are food...
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..for something.
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00:26:54,140 --> 00:26:55,820
Zombie worms.
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They tunnel into the bones by
injecting acid...
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00:27:04,180 --> 00:27:08,060
..and so reach the tiny amounts of
fat that still remain there.
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00:27:10,460 --> 00:27:12,820
It may take decades, but eventually
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the last of the bones will crumble
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00:27:15,980 --> 00:27:18,460
and the whole 30-tonne carcass
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00:27:18,460 --> 00:27:20,500
will have been recycled.
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00:27:27,700 --> 00:27:30,700
A whale fall is a temporary oasis
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in the desert of the sea floor.
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00:27:36,300 --> 00:27:38,780
But there are permanent
oases here, too.
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00:27:52,940 --> 00:27:55,580
Rocks projecting above the mud
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00:27:55,580 --> 00:27:58,540
provide anchorage
for deep-sea corals.
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As far down as 3.5 miles,
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00:28:20,500 --> 00:28:23,700
there are more species of coral
in the deep
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00:28:23,700 --> 00:28:26,220
than on shallow tropical reefs.
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00:28:34,660 --> 00:28:36,860
Without sunlight,
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00:28:36,860 --> 00:28:39,580
they rely solely
on food drifting in the current.
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00:28:43,420 --> 00:28:48,060
And they grow just
a hair's breadth a year.
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But some of them can live
for 4,000 years.
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00:29:04,140 --> 00:29:07,500
They, like their shallow water
relatives,
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00:29:07,500 --> 00:29:10,420
provide homes for
all kinds of other creatures.
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00:29:35,980 --> 00:29:40,540
Growing among the corals is one of
the most beautiful of sponges.
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00:29:44,260 --> 00:29:47,580
This is Venus' flower basket.
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00:29:55,260 --> 00:29:57,100
These sponges have lodgers.
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00:29:58,340 --> 00:30:00,100
Shrimps.
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00:30:07,980 --> 00:30:10,460
There are plenty of predators
on the reef,
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00:30:10,460 --> 00:30:12,300
so the shrimps are fortunate.
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00:30:16,900 --> 00:30:20,420
Both this male and female were swept
into this sponge
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00:30:20,420 --> 00:30:22,260
when they were tiny larvae,
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00:30:22,260 --> 00:30:24,340
along with the minute particles of
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00:30:24,340 --> 00:30:26,660
food on which the sponge feeds.
200
00:30:30,900 --> 00:30:34,340
They found each other and have been
here ever since.
201
00:30:49,540 --> 00:30:51,380
Now they're full-grown
202
00:30:51,380 --> 00:30:53,860
and the female is carrying eggs.
203
00:31:06,980 --> 00:31:10,940
Once hatched, the larvae will swim
out through the sponge's walls.
204
00:31:17,300 --> 00:31:19,740
But the shrimps will never leave.
205
00:31:21,100 --> 00:31:22,620
They can't.
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00:31:28,860 --> 00:31:32,260
They are now far too big to go out
the way they came in,
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00:31:32,260 --> 00:31:36,100
and no doubt they will live longer
here than they would
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00:31:36,100 --> 00:31:39,980
if they were wandering about on the
reef unprotected.
209
00:31:52,780 --> 00:31:57,260
But how one of the simplest of all
animals, a sponge,
210
00:31:57,260 --> 00:32:00,780
is able to build
such a complex structure,
211
00:32:00,780 --> 00:32:02,980
to the great benefit of the
shrimps...
212
00:32:04,380 --> 00:32:06,620
..is a mystery...
213
00:32:06,620 --> 00:32:08,740
..and surely a marvel.
214
00:32:25,700 --> 00:32:30,220
But today their timeless world is
being reduced to rubble.
215
00:32:38,580 --> 00:32:42,860
As overfishing empties the
surface waters of the seas,
216
00:32:42,860 --> 00:32:46,500
trawlers have started
to ransack the deep.
217
00:32:49,940 --> 00:32:52,660
Now countless numbers of the reefs
218
00:32:52,660 --> 00:32:55,060
that have flourished here
for millennia
219
00:32:55,060 --> 00:32:56,900
lie in ruins.
220
00:33:26,740 --> 00:33:31,220
Over time, organic matter on the sea
floor slowly decays...
221
00:33:32,260 --> 00:33:33,780
..producing methane.
222
00:34:35,260 --> 00:34:37,220
In the Gulf of Mexico
223
00:34:37,220 --> 00:34:41,100
these eruptions also release
a super-salty liquid.
224
00:34:49,100 --> 00:34:50,700
Brine.
225
00:35:01,620 --> 00:35:04,740
Five times heavier than seawater,
226
00:35:04,740 --> 00:35:08,060
it accumulates in great pools
on the sea floor.
227
00:35:13,860 --> 00:35:16,340
It's difficult to make sense
of the sight.
228
00:35:23,660 --> 00:35:28,660
A lake of concentrated saltwater,
15 metres deep
229
00:35:28,660 --> 00:35:30,900
at the bottom of the sea.
230
00:35:39,100 --> 00:35:42,500
Around its margin,
perhaps even more strangely,
231
00:35:42,500 --> 00:35:45,140
there is a profusion of life.
232
00:35:52,140 --> 00:35:56,060
Giant mussels, that can live and
grow for a century or more,
233
00:35:56,060 --> 00:35:58,140
pack tightly together,
234
00:35:58,140 --> 00:36:01,860
dwarfing the shrimps and squat
lobsters that feed around them.
235
00:36:30,660 --> 00:36:33,700
Cutthroat eels, scavengers,
236
00:36:33,700 --> 00:36:37,700
come to the shores of the brine lake
in search of something edible.
237
00:36:46,500 --> 00:36:49,460
Some even venture into the brine.
238
00:37:22,940 --> 00:37:24,780
Spending too long in it
239
00:37:24,780 --> 00:37:27,380
can send an eel into toxic shock.
240
00:37:39,220 --> 00:37:41,860
Its only hope is to rise above it.
241
00:37:56,660 --> 00:37:58,300
It manages to escape.
242
00:38:07,460 --> 00:38:09,140
Others are not so lucky.
243
00:38:16,540 --> 00:38:18,860
The brine embalms their bodies...
244
00:38:20,660 --> 00:38:23,260
..and the casualties of decades
245
00:38:23,260 --> 00:38:25,660
accumulate around the margins.
246
00:38:45,660 --> 00:38:49,100
But parts of the deep are
even more hostile.
247
00:38:56,700 --> 00:39:00,660
In places, gigantic cracks stretch
for many miles
248
00:39:00,660 --> 00:39:02,740
across the ocean floor...
249
00:39:17,660 --> 00:39:21,420
..canyons that plunge towards the
centre of the Earth.
250
00:39:28,860 --> 00:39:33,860
Scans from survey vessels make it
possible to graphically reconstruct
251
00:39:33,860 --> 00:39:36,900
an image of this
vast submarine landscape.
252
00:39:44,740 --> 00:39:47,900
The deepest of all,
at almost seven miles,
253
00:39:47,900 --> 00:39:50,740
is the Mariana Trench
in the Pacific Ocean.
254
00:39:56,700 --> 00:40:00,060
Even Mount Everest
could disappear inside it.
255
00:40:15,260 --> 00:40:18,580
Down here, in these deep ravines,
256
00:40:18,580 --> 00:40:22,580
it was once thought that nothing
whatever could possibly survive.
257
00:40:29,740 --> 00:40:32,300
But there is life even here...
258
00:40:39,140 --> 00:40:40,700
..a kind of sea slug.
259
00:40:48,380 --> 00:40:50,380
A so-called "sea pig".
260
00:40:52,500 --> 00:40:56,700
They, and other simple creatures,
manage to survive on the
261
00:40:56,700 --> 00:41:00,180
minuscule amount of food
that drifts down here.
262
00:41:03,620 --> 00:41:05,340
Like this starfish,
263
00:41:05,340 --> 00:41:09,300
they can withstand pressure
equivalent of 50 jumbo jets
264
00:41:09,300 --> 00:41:11,460
stacked on top of one another.
265
00:41:32,700 --> 00:41:35,060
A remote camera probe reveals
266
00:41:35,060 --> 00:41:37,740
the most extraordinary
discovery of all...
267
00:41:45,260 --> 00:41:48,260
..the ethereal snailfish.
268
00:41:52,140 --> 00:41:54,300
At five miles down,
269
00:41:54,300 --> 00:41:57,940
this is the deepest living fish
so far discovered.
270
00:42:04,220 --> 00:42:07,020
No-one imagined that an animal as
271
00:42:07,020 --> 00:42:09,700
complex as a fish could exist
272
00:42:09,700 --> 00:42:11,700
in such extreme pressures.
273
00:42:23,900 --> 00:42:27,300
From the greatest depths to the
uppermost limit of
274
00:42:27,300 --> 00:42:31,820
the Twilight Zone, it seems that
there is nowhere in the deep sea
275
00:42:31,820 --> 00:42:34,580
where life of some kind
can't survive.
276
00:42:39,420 --> 00:42:42,300
And we now think that the deep sea
may well be
277
00:42:42,300 --> 00:42:44,100
where life on Earth began.
278
00:42:57,980 --> 00:43:00,900
Here, in a world hidden within
279
00:43:00,900 --> 00:43:03,940
the greatest geological
feature on Earth...
280
00:43:07,540 --> 00:43:10,420
..running right down the middle of
the world's oceans,
281
00:43:10,420 --> 00:43:15,140
an underwater mountain range,
spanning the entire globe.
282
00:43:20,260 --> 00:43:21,980
The Mid-Ocean Ridge.
283
00:43:36,140 --> 00:43:37,940
In the South Pacific,
284
00:43:37,940 --> 00:43:40,580
the ocean floor is being torn apart.
285
00:44:53,020 --> 00:44:56,020
Over three quarters of the planet's
volcanic activity
286
00:44:56,020 --> 00:44:57,820
occurs in the deep...
287
00:45:05,180 --> 00:45:08,780
..almost all of it along the
Mid-Ocean Ridge.
288
00:45:12,780 --> 00:45:17,220
But from this titanic violence
come great riches.
289
00:45:26,460 --> 00:45:29,980
Gases and scalding water gush up
through the crevices.
290
00:45:39,340 --> 00:45:43,540
Minerals condensing from these jets
build up great chimneys...
291
00:45:45,260 --> 00:45:46,940
hydrothermal vents.
292
00:45:50,860 --> 00:45:52,900
This one, 30 metres tall,
293
00:45:52,900 --> 00:45:54,980
has been named Godzilla.
294
00:46:03,660 --> 00:46:05,700
Astonishingly, we now know
295
00:46:05,700 --> 00:46:07,660
that they hold as much life
296
00:46:07,660 --> 00:46:09,660
as tropical rainforests.
297
00:46:17,500 --> 00:46:21,380
In places, half a million
individual animals
298
00:46:21,380 --> 00:46:24,460
are crammed into
a single square metre.
299
00:46:36,820 --> 00:46:39,660
They depend entirely for
their food on bacteria.
300
00:46:42,900 --> 00:46:47,660
And THEY feed on chemicals dissolved
in the searingly hot fluid.
301
00:46:54,620 --> 00:46:59,740
Crabs consume the bacterial mats
that coat their shells.
302
00:47:13,580 --> 00:47:16,420
Others maintain bacterial cultures
303
00:47:16,420 --> 00:47:18,820
actually within their bodies.
304
00:47:25,300 --> 00:47:28,300
Shrimps carry such cultures
in their mouthparts,
305
00:47:29,460 --> 00:47:31,940
but that is a strategy
fraught with danger.
306
00:47:36,660 --> 00:47:40,380
To provide sustenance
for these microbes
307
00:47:40,380 --> 00:47:43,940
the shrimps must dash
into the hot vents...
308
00:47:45,860 --> 00:47:48,660
..and that risks being boiled alive.
309
00:48:02,460 --> 00:48:04,380
In the last decade
310
00:48:04,380 --> 00:48:07,940
the number of hydrothermal vents
discovered has doubled.
311
00:48:15,900 --> 00:48:19,580
Every one has its own unique
character and community.
312
00:48:26,620 --> 00:48:30,500
But perhaps the most important one
of all is in the Atlantic.
313
00:48:32,140 --> 00:48:34,660
It has been named "The Lost City".
314
00:48:39,100 --> 00:48:41,860
Within its 60-metre towers,
315
00:48:41,860 --> 00:48:44,980
something truly extraordinary
is taking place.
316
00:48:48,980 --> 00:48:53,860
Under extremes of pressure and
temperature, hydrocarbons -
317
00:48:53,860 --> 00:48:58,860
the molecules that are the basic
component of all living things -
318
00:48:58,860 --> 00:49:01,940
are being created spontaneously.
319
00:49:13,540 --> 00:49:16,700
Indeed, many scientists now believe
320
00:49:16,700 --> 00:49:19,420
that life on Earth may have begun
321
00:49:19,420 --> 00:49:22,140
around a vent like this,
322
00:49:22,140 --> 00:49:24,900
four billion years ago.
323
00:49:43,940 --> 00:49:46,860
We now know that there are deep seas
324
00:49:46,860 --> 00:49:49,780
on the moons of Jupiter and Saturn.
325
00:49:56,700 --> 00:49:58,780
If life can exist under such
326
00:49:58,780 --> 00:50:01,380
extreme conditions down here,
327
00:50:01,380 --> 00:50:03,740
then surely it could exist
328
00:50:03,740 --> 00:50:05,740
somewhere out there.
329
00:50:30,980 --> 00:50:35,180
The team spent more than 1,000 hours
filming in the deep ocean,
330
00:50:35,180 --> 00:50:39,980
mostly from the research vessel
Alucia and her twin submersibles,
331
00:50:39,980 --> 00:50:42,060
Deep Rover and Nadir.
332
00:50:47,460 --> 00:50:50,620
Their most ambitious mission
was to Antarctica,
333
00:50:51,780 --> 00:50:54,780
hoping to film life
two thirds of a mile down,
334
00:50:54,780 --> 00:50:56,620
something never attempted before.
335
00:51:02,140 --> 00:51:04,740
We honestly do not know what we're
going to find down there.
336
00:51:04,740 --> 00:51:08,100
We're going to a place that has
never been explored.
337
00:51:08,100 --> 00:51:10,780
There could be nothing,
there could be a carpet of life,
338
00:51:10,780 --> 00:51:13,620
there could be anything in between.
Who knows?
339
00:51:17,740 --> 00:51:19,980
It's a huge technical challenge.
340
00:51:27,100 --> 00:51:31,940
The water temperature here can reach
minus 1.8 Centigrade.
341
00:51:33,580 --> 00:51:36,180
INDISTINCT RADIO CHATTER
342
00:51:37,220 --> 00:51:40,020
No-one knows for sure
how the subs will cope
343
00:51:40,020 --> 00:51:41,860
with this extreme environment.
344
00:51:47,580 --> 00:51:50,940
OK. Right, I'm going to soak it up.
OK.
345
00:51:50,940 --> 00:51:53,860
Just half an hour into the very
first dive,
346
00:51:53,860 --> 00:51:56,460
a puddle is forming
on the floor of the sub.
347
00:52:00,100 --> 00:52:02,100
Orla confirms it's seawater.
348
00:52:03,700 --> 00:52:07,700
Yeah, Roger. I'm just try to soak up
this puddle of water,
349
00:52:07,700 --> 00:52:09,860
and then see if any more comes.
350
00:52:10,860 --> 00:52:14,620
They must find the leak
and repair it fast.
351
00:52:14,620 --> 00:52:17,140
Are you going to knock that over
my...? Yeah.
352
00:52:17,140 --> 00:52:21,500
You're at 450 metres in a small
bubble and water's coming in.
353
00:52:21,500 --> 00:52:25,220
That's a half an hour straight shot
back up to the surface.
354
00:52:25,220 --> 00:52:27,180
You're kind of thinking about,
355
00:52:27,180 --> 00:52:30,780
"Are we going to fill up with water?
And if we are, there's no way out!"
356
00:52:32,020 --> 00:52:33,580
Yeah.
357
00:52:33,580 --> 00:52:36,660
The sub pilots are well drilled for
emergencies.
358
00:52:36,660 --> 00:52:39,380
INDISTINCT RADIO CHATTER
359
00:52:39,380 --> 00:52:42,020
Just pass them over. Yeah.
360
00:52:42,020 --> 00:52:44,980
Ralph quickly finds the flood
and fixes it.
361
00:52:46,940 --> 00:52:50,180
He made it all seem absolutely
ordinary and normal and,
362
00:52:50,180 --> 00:52:52,580
"I've got this covered,
don't you worry,"
363
00:52:52,580 --> 00:52:54,340
and within 20 minutes, he did.
364
00:52:59,860 --> 00:53:03,380
The waters of the Antarctic Sound
are potentially rich
365
00:53:03,380 --> 00:53:05,140
but also treacherous.
366
00:53:06,580 --> 00:53:10,780
The Sound is ominously known as
"Iceberg Alley".
367
00:53:12,460 --> 00:53:15,380
We've got to find a place where we
can get the submarines down and up
368
00:53:15,380 --> 00:53:18,100
safely without any icebergs coming
along and bowling them over.
369
00:53:18,100 --> 00:53:21,540
I've got a feeling it's going to be
a bit like a game of Space Invaders.
370
00:53:22,900 --> 00:53:25,420
A metre cube of ice weighs a tonne.
371
00:53:25,420 --> 00:53:29,220
You start sort of grinding that
around the sphere, it's delicate.
372
00:53:29,220 --> 00:53:31,100
It's like a big Faberge egg.
373
00:53:33,860 --> 00:53:38,020
One dive brings them right up to the
underside face of an iceberg.
374
00:53:41,140 --> 00:53:44,620
There are icebergs up there that are
the size of a small car, and
375
00:53:44,620 --> 00:53:48,980
then there are icebergs up there
that are the size of Hyde Park.
376
00:53:48,980 --> 00:53:50,380
Enormous.
377
00:53:52,020 --> 00:53:54,580
Conditions here
can change in an instant.
378
00:53:55,820 --> 00:53:57,900
The captain radios down to the subs.
379
00:54:02,500 --> 00:54:03,860
Yeah, Roger that.
380
00:54:05,420 --> 00:54:08,020
We've currently got a couple of big
icebergs coming down
381
00:54:08,020 --> 00:54:11,100
the channel, and it looks like
they're on a collision course.
382
00:54:14,420 --> 00:54:18,700
The impact of two icebergs colliding
overhead is clearly heard.
383
00:54:18,700 --> 00:54:22,060
INTENSE RUMBLE
384
00:54:22,060 --> 00:54:23,540
That is ice.
385
00:54:26,020 --> 00:54:29,700
With icebergs colliding above and
the weather turning fast,
386
00:54:29,700 --> 00:54:31,300
the subs are quickly recalled.
387
00:54:38,980 --> 00:54:41,100
Once again
their efforts are thwarted.
388
00:54:52,180 --> 00:54:55,940
Finally, after two weeks,
conditions are just right.
389
00:54:57,060 --> 00:55:01,820
Once again the team attempt their
1,000-metre dive in Iceberg Alley.
390
00:55:05,700 --> 00:55:09,340
An hour after leaving the surface
they close in on their goal.
391
00:55:13,380 --> 00:55:14,820
999.
392
00:55:18,740 --> 00:55:20,460
Control, control.
393
00:55:20,460 --> 00:55:22,060
This is Nadir
394
00:55:22,060 --> 00:55:27,060
on bottom, depth -
one-zero-zero-zero metres.
395
00:55:27,060 --> 00:55:29,180
Roger. Depth - 1,000 metres.
396
00:55:29,180 --> 00:55:31,380
Control out. New record!
397
00:55:33,660 --> 00:55:37,300
First manned sub dive
to 1,000 metres in Antarctica!
398
00:55:39,340 --> 00:55:42,260
At the bottom of the ocean, at the
end of the world,
399
00:55:42,260 --> 00:55:45,220
the amount of life they find is
astonishing.
400
00:55:50,980 --> 00:55:53,940
But they are equally astonished
to find that,
401
00:55:53,940 --> 00:55:56,340
two thirds of a mile from the
surface,
402
00:55:56,340 --> 00:55:58,260
icebergs are still a danger.
403
00:56:00,260 --> 00:56:03,140
Rocks can drop from them
as they melt,
404
00:56:03,140 --> 00:56:06,140
and one lands
right in front of the sub.
405
00:56:08,780 --> 00:56:11,940
I don't think many people who are
diving subs
406
00:56:11,940 --> 00:56:15,380
ever consider big lumps of rock
landing on them.
407
00:56:16,780 --> 00:56:18,820
It's, it's not your normal risk.
408
00:56:18,820 --> 00:56:20,300
If it had hit the sphere,
409
00:56:20,300 --> 00:56:23,300
there's a good chance it would have
put a nice scratch down it.
410
00:56:23,300 --> 00:56:26,660
If something of ten, 15, 20 tonnes
had hit the sub,
411
00:56:26,660 --> 00:56:28,300
it would completely destroy it.
412
00:56:32,580 --> 00:56:34,660
But over the following dives
413
00:56:34,660 --> 00:56:37,700
the team learns it's these
very drop stones
414
00:56:37,700 --> 00:56:40,500
that enrich the Antarctic
deep sea bed,
415
00:56:41,660 --> 00:56:45,220
creating firm anchor points
for life to thrive.
416
00:56:49,900 --> 00:56:53,580
Proof that the only way to fully
appreciate the complexity and
417
00:56:53,580 --> 00:56:57,900
abundance of life in the deep
is to go there ourselves.
418
00:57:06,420 --> 00:57:09,980
Next time, we travel to bustling
coral reefs.
419
00:57:16,420 --> 00:57:20,740
Here, animals must go to
extraordinary lengths
420
00:57:20,740 --> 00:57:24,500
to get ahead of the competition in
these crowded cities.
31574
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