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Antarctica.
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00:00:39,291 --> 00:00:44,963
The coldest, the harshest,
and the most remote continent on Earth.
3
00:00:52,137 --> 00:00:56,808
No human being has ever descended
into the depths that surround it...
4
00:01:00,354 --> 00:01:01,647
...until now.
5
00:01:09,363 --> 00:01:14,326
The deep ocean is as
challenging to explore as space.
6
00:01:17,371 --> 00:01:20,082
We know more about the surface of Mars
7
00:01:20,165 --> 00:01:23,210
than we do about
the deepest parts of our seas.
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00:01:47,859 --> 00:01:51,697
Now we can dive
these uncharted depths,
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00:01:51,780 --> 00:01:54,283
to discover what secrets lie beneath.
10
00:02:30,777 --> 00:02:35,115
Sinking down beside
the submerged wall of an iceberg,
11
00:02:35,240 --> 00:02:37,909
we enter an unforgiving world.
12
00:02:48,628 --> 00:02:52,007
These waters
are the coldest on Earth.
13
00:02:56,762 --> 00:02:58,889
As we descend into the deep,
14
00:02:58,972 --> 00:03:01,850
the pressure increases relentlessly.
15
00:03:20,035 --> 00:03:23,205
And the light from above
all but disappears.
16
00:03:30,879 --> 00:03:32,464
Yet, incredibly...
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00:03:36,802 --> 00:03:38,637
there is life here.
18
00:04:01,034 --> 00:04:02,494
We might have expected
19
00:04:02,577 --> 00:04:05,747
that deep beneath
the surface of the Polar seas,
20
00:04:06,832 --> 00:04:09,835
the waters would be truly barren.
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00:04:17,509 --> 00:04:22,556
But, in fact, we find life here
in unimaginable abundance.
22
00:04:37,195 --> 00:04:41,741
Nor is such great abundance
confined to Antarctic waters.
23
00:04:45,078 --> 00:04:47,289
Currents carry this richness
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00:04:47,372 --> 00:04:51,543
into the depths of almost
every ocean around the world.
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00:04:55,714 --> 00:04:58,216
Astonishingly, in the deep sea,
26
00:04:58,300 --> 00:05:02,220
there is more life
than anywhere else on Earth.
27
00:05:30,749 --> 00:05:32,834
The sunlight fades,
28
00:05:33,293 --> 00:05:34,961
and the seas darken.
29
00:05:38,924 --> 00:05:42,260
Here, in the Pacific, 200 metres down,
30
00:05:42,344 --> 00:05:45,180
we enter an alien world.
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00:05:47,641 --> 00:05:50,060
The Twilight Zone,
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00:05:50,143 --> 00:05:52,979
a sea of eternal gloom.
33
00:06:01,029 --> 00:06:03,323
There are strange creatures here.
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00:06:04,950 --> 00:06:06,284
A pyrosome.
35
00:06:07,619 --> 00:06:12,666
A tube of jelly two metres long
that dwarfs a visitor from above,
36
00:06:13,792 --> 00:06:16,002
an oceanic whitetip shark.
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00:06:24,970 --> 00:06:29,224
Only a tiny amount of light
filters down this far.
38
00:06:34,062 --> 00:06:39,234
Survival here means making the most
of every last glimmer.
39
00:06:48,702 --> 00:06:49,995
A swordfish.
40
00:06:59,337 --> 00:07:04,843
Its eyes are as big as tennis balls
to help it see in the perpetual dusk.
41
00:07:10,390 --> 00:07:14,394
A squid, but this is one
that lives only here.
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00:07:15,770 --> 00:07:19,065
Its right eye
looks permanently downwards.
43
00:07:21,443 --> 00:07:24,779
But its left eye is much bigger
and trained upwards
44
00:07:24,904 --> 00:07:29,034
to detect the silhouettes of prey
swimming nearer the surface.
45
00:07:31,244 --> 00:07:34,623
No wonder it's nicknamed
the "cock-eyed squid".
46
00:07:41,212 --> 00:07:43,256
And even stranger,
47
00:07:45,550 --> 00:07:47,886
this is barreleye,
48
00:07:50,805 --> 00:07:53,642
a fish with a transparent head,
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00:07:54,392 --> 00:07:56,311
filled with jelly,
50
00:07:56,394 --> 00:07:59,564
so that it can look up
through its skull.
51
00:08:17,248 --> 00:08:20,627
We now know that
the Twilight Zone is a refuge
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00:08:20,752 --> 00:08:25,757
for an incredible 90%
of all fish in the ocean.
53
00:08:31,763 --> 00:08:36,017
Only at night,
do vast shoals of lanternfish
54
00:08:36,101 --> 00:08:40,271
migrate to the surface
to feed on tiny plankton.
55
00:08:51,282 --> 00:08:54,953
By day, they retreat back down here.
56
00:09:10,885 --> 00:09:13,012
Humboldt squid.
57
00:09:25,692 --> 00:09:28,862
Two metres long
and 50 kilos in weight.
58
00:09:34,242 --> 00:09:37,662
Like most squid,
they're voracious hunters.
59
00:09:45,920 --> 00:09:47,338
There are hundreds of them.
60
00:09:58,850 --> 00:10:01,269
They found a shoal of lanternfish
61
00:10:01,352 --> 00:10:05,356
hiding 800 metres down,
off the coast of South America.
62
00:10:18,369 --> 00:10:21,206
Their tentacles are armed
with powerful suckers
63
00:10:21,289 --> 00:10:23,416
with which they grab their prey.
64
00:10:40,266 --> 00:10:43,478
And when there are
no more lanternfish to be found,
65
00:10:45,605 --> 00:10:47,899
they turn on each other.
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00:10:59,285 --> 00:11:03,081
This squid has caught
a smaller one in its tentacles.
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00:11:07,919 --> 00:11:10,088
To hide its capture from the rest,
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00:11:10,171 --> 00:11:12,924
it releases a smokescreen of black ink.
69
00:11:26,271 --> 00:11:29,315
But then, an even
bigger one challenges it
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00:11:36,197 --> 00:11:38,616
and steals its catch.
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00:11:47,792 --> 00:11:49,168
The Twilight Zone
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00:11:49,294 --> 00:11:52,380
is the Humboldt squid's
favourite hunting ground.
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00:11:54,299 --> 00:11:55,800
They seldom go deeper
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00:11:57,343 --> 00:12:00,805
into the world
of perpetual blackness below.
75
00:12:06,227 --> 00:12:08,229
The Midnight Zone.
76
00:12:19,324 --> 00:12:22,118
Two-thirds of
a mile from the surface,
77
00:12:22,201 --> 00:12:24,495
beyond the reach of the sun.
78
00:12:30,001 --> 00:12:32,503
A giant black void
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00:12:32,587 --> 00:12:36,549
larger than all the rest
of the world's habitat's combined.
80
00:12:42,013 --> 00:12:43,681
There's life here,
81
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but not as we know it.
82
00:12:58,529 --> 00:13:00,281
Alien-like creatures
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produce dazzling displays of light.
84
00:13:16,130 --> 00:13:19,300
Nearly all animals
need to attract mates
85
00:13:19,384 --> 00:13:20,927
and repel predators.
86
00:13:23,888 --> 00:13:27,433
This language of light
is so widespread here,
87
00:13:27,558 --> 00:13:32,105
that these signals are probably
the commonest form of communication
88
00:13:33,231 --> 00:13:34,899
on the entire planet.
89
00:13:36,442 --> 00:13:39,112
And yet,
we still know little about them.
90
00:14:04,429 --> 00:14:06,305
Hunters illuminate themselves,
91
00:14:06,431 --> 00:14:07,807
and by doing so
92
00:14:07,932 --> 00:14:10,309
attract inquisitive prey.
93
00:14:23,114 --> 00:14:25,366
This is fangtooth.
94
00:14:27,326 --> 00:14:31,205
It has the largest teeth
for its size of any fish.
95
00:14:33,791 --> 00:14:37,378
There are pressure sensors
all over its head and body
96
00:14:37,462 --> 00:14:41,007
which can detect anything
moving in the surrounding water.
97
00:14:47,972 --> 00:14:51,642
It's the Midnight Zone's
most voracious fish.
98
00:14:53,686 --> 00:14:57,023
But prey use light as a distraction.
99
00:15:01,903 --> 00:15:04,822
A decoy of luminous ink.
100
00:15:14,248 --> 00:15:16,709
Down here, in this blackness,
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00:15:18,836 --> 00:15:22,548
creatures live beyond
the normal rules of time.
102
00:15:29,388 --> 00:15:32,934
Siphonophores are virtually eternal.
103
00:15:33,017 --> 00:15:36,938
They repeatedly clone themselves,
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00:15:37,105 --> 00:15:40,942
some eventually growing
longer than a blue whale.
105
00:16:05,925 --> 00:16:09,095
Down here, it snows.
106
00:16:17,562 --> 00:16:20,606
Continuous clouds of organic debris
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00:16:20,731 --> 00:16:23,442
drift slowly down from above.
108
00:16:30,825 --> 00:16:33,119
This is food,
109
00:16:33,244 --> 00:16:37,415
and a whole variety
of filter feeders depend on it.
110
00:16:40,626 --> 00:16:41,961
Jellyfish.
111
00:16:50,761 --> 00:16:53,598
And delicate sea cucumbers.
112
00:17:13,284 --> 00:17:16,120
The 1% of marine snow they miss
113
00:17:16,829 --> 00:17:19,457
eventually settles on the sea floor.
114
00:17:48,319 --> 00:17:50,071
Over millions of years,
115
00:17:50,154 --> 00:17:54,867
it forms a layer of mud
up to a mile thick.
116
00:17:59,247 --> 00:18:01,165
It's an empty plain
117
00:18:01,249 --> 00:18:04,252
that covers half
the surface of our planet.
118
00:18:31,195 --> 00:18:35,533
The deep seabed may,
at first, appear lifeless,
119
00:18:37,743 --> 00:18:42,373
but it's home to a unique
cast of mud dwellers.
120
00:18:45,126 --> 00:18:46,711
The sea toad.
121
00:18:49,588 --> 00:18:53,634
It is an ambush predator
with an enormous mouth
122
00:18:55,594 --> 00:18:57,722
and infinite patience.
123
00:19:08,733 --> 00:19:12,236
This fish has been
living for so long here
124
00:19:12,320 --> 00:19:15,823
that its fins have changed
into something more useful.
125
00:19:22,288 --> 00:19:23,581
Feet.
126
00:19:28,586 --> 00:19:31,922
They help it shuffle about
on the sea floor.
127
00:19:52,943 --> 00:19:55,446
The flapjack octopus.
128
00:20:00,451 --> 00:20:03,079
It hovers just above
the surface of the mud
129
00:20:03,162 --> 00:20:07,291
as it delicately sifts through it
searching for worms.
130
00:20:10,795 --> 00:20:14,965
But it can jet away
at the first sign of danger.
131
00:20:34,318 --> 00:20:37,488
A sixgill shark,
as big as a great white.
132
00:20:39,073 --> 00:20:42,701
It may not have eaten
for an entire year.
133
00:20:49,375 --> 00:20:51,502
It patrols the mud plains
134
00:20:51,585 --> 00:20:54,380
using a minimum amount of energy.
135
00:21:08,519 --> 00:21:09,728
High above,
136
00:21:09,854 --> 00:21:12,398
the carcass of a huge sperm whale
137
00:21:12,523 --> 00:21:14,692
is slowly decaying.
138
00:21:21,282 --> 00:21:24,702
This will be a bonanza
for the creatures of the deep.
139
00:21:25,744 --> 00:21:27,037
Food.
140
00:21:27,621 --> 00:21:29,290
Thirty tonnes of it.
141
00:21:42,887 --> 00:21:46,974
Finally it settles on the ocean floor
142
00:21:48,642 --> 00:21:51,729
and its presence is soon detected.
143
00:22:01,405 --> 00:22:03,324
Sixgills sharks
144
00:22:03,407 --> 00:22:06,285
have an exceptionally
acute sense of smell.
145
00:22:11,248 --> 00:22:15,419
just 25 minutes
after the whale's carcass arrives,
146
00:22:17,630 --> 00:22:19,590
a sixgill finds it.
147
00:22:41,612 --> 00:22:45,032
Each bite releases
blood into the current.
148
00:23:28,242 --> 00:23:31,662
The news that food
is here spreads quickly.
149
00:23:40,170 --> 00:23:43,841
Two more ravenous sixgills arrive.
150
00:23:52,766 --> 00:23:56,478
Within 12 hours,
there are seven enormous sharks
151
00:23:56,562 --> 00:23:58,105
jostling with one another
152
00:23:58,188 --> 00:24:01,025
as they compete to tear off mouthfuls.
153
00:24:13,412 --> 00:24:16,081
No one is prepared to back off.
154
00:25:00,959 --> 00:25:02,795
Twenty-four hours later,
155
00:25:02,920 --> 00:25:05,923
and a third of the carcass has gone.
156
00:25:38,205 --> 00:25:40,541
The first arrival has gorged
157
00:25:40,624 --> 00:25:42,668
until it's completely full.
158
00:25:47,715 --> 00:25:49,466
This single meal
159
00:25:49,550 --> 00:25:53,220
may be enough to sustain it
for a whole year.
160
00:25:59,643 --> 00:26:03,021
Now, the clean up team arrives.
161
00:26:06,233 --> 00:26:09,695
Spider crabs carrying coral
in their hind legs,
162
00:26:10,320 --> 00:26:13,407
presumably as makeshift body armour.
163
00:26:21,832 --> 00:26:24,001
There are rock crabs here too.
164
00:26:26,587 --> 00:26:31,008
They probably detected the carcass
almost as soon as the sharks,
165
00:26:32,426 --> 00:26:34,595
but they can't move as fast.
166
00:26:39,224 --> 00:26:42,811
A month on,
and over 30 species of scavenger
167
00:26:42,895 --> 00:26:46,273
are clearing away
the last edible fragments.
168
00:26:48,734 --> 00:26:52,905
But now, the scavengers
are attracting their own predators.
169
00:26:59,369 --> 00:27:02,706
Scabbardfish, habitually
swimming upright,
170
00:27:02,790 --> 00:27:05,250
are picking them off one by one.
171
00:27:26,897 --> 00:27:29,566
Some of the whale's teeth
have been dislodged
172
00:27:29,650 --> 00:27:32,402
as the skeleton starts to fall apart.
173
00:27:35,906 --> 00:27:40,911
Four months later,
there is nothing left but a few bones.
174
00:27:48,752 --> 00:27:50,754
But even they are food
175
00:27:55,175 --> 00:27:56,468
for something.
176
00:28:03,475 --> 00:28:05,310
Zombie worms.
177
00:28:09,439 --> 00:28:13,110
They tunnel into the bones
by injecting acid
178
00:28:13,986 --> 00:28:18,115
and so reach the tiny amounts of fat
that still remain there.
179
00:28:20,492 --> 00:28:22,119
It may take decades,
180
00:28:22,202 --> 00:28:26,373
but eventually,
the last of the bones will crumble,
181
00:28:26,456 --> 00:28:31,128
and the whole 50-tonne carcass
will have been recycled.
182
00:28:38,468 --> 00:28:41,889
A whale fall is a temporary oasis
183
00:28:41,972 --> 00:28:44,057
in the desert of the sea floor.
184
00:28:47,561 --> 00:28:50,397
But there are permanent oases here too.
185
00:29:05,203 --> 00:29:07,623
Rocks projecting above the mud
186
00:29:07,706 --> 00:29:11,168
provide anchorage for deep sea corals.
187
00:29:29,853 --> 00:29:33,690
As far down
as three and a half miles,
188
00:29:33,774 --> 00:29:36,693
there are more species of coral
in the deep
189
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than on shallow tropical reefs.
190
00:29:48,372 --> 00:29:52,292
Without sunlight,
they rely solely on food
191
00:29:52,376 --> 00:29:54,044
drifting in the current.
192
00:29:57,422 --> 00:29:59,049
And they grow
193
00:29:59,216 --> 00:30:02,552
just a hair's breadth a year.
194
00:30:08,266 --> 00:30:12,229
But some of them
can live for 4,000 years.
195
00:30:19,069 --> 00:30:22,239
They, like their
shallow water relatives,
196
00:30:22,406 --> 00:30:25,909
provide homes for all kinds
of other creatures.
197
00:30:52,310 --> 00:30:54,229
Growing among the corals,
198
00:30:54,312 --> 00:30:57,149
is one of the most beautiful of sponges.
199
00:31:00,777 --> 00:31:04,614
This is Venus' flower basket.
200
00:31:12,289 --> 00:31:14,541
These sponges have lodgers.
201
00:31:15,459 --> 00:31:16,710
Shrimps.
202
00:31:25,635 --> 00:31:27,846
There are plenty
of predators on the reef
203
00:31:28,305 --> 00:31:30,307
so the shrimps are fortunate.
204
00:31:34,895 --> 00:31:37,022
Both this male and female,
205
00:31:37,147 --> 00:31:40,317
were swept into this sponge
when they were tiny larvae,
206
00:31:40,525 --> 00:31:43,361
along with the minute particles of food
207
00:31:43,487 --> 00:31:45,489
on which the sponge feeds.
208
00:31:49,534 --> 00:31:53,538
They found each other
and have been here ever since.
209
00:32:08,929 --> 00:32:11,056
Now, they're full-grown
210
00:32:11,181 --> 00:32:13,767
and the female is carrying eggs.
211
00:32:27,114 --> 00:32:31,535
Once hatched, the larvae will swim
out through the sponge's walls.
212
00:32:38,041 --> 00:32:40,752
But the shrimps will never leave.
213
00:32:42,087 --> 00:32:43,296
They can't.
214
00:32:50,053 --> 00:32:54,057
They're now far too big
to go out the way they came in.
215
00:32:54,724 --> 00:32:56,893
And, no doubt,
they will live longer here
216
00:32:56,977 --> 00:33:01,731
than they would if they were
wandering about on the reef unprotected.
217
00:33:14,953 --> 00:33:18,248
But how one
of the simplest of all animals,
218
00:33:18,415 --> 00:33:23,086
a sponge, is able to build
such a complex structure
219
00:33:23,587 --> 00:33:25,589
to the great benefit of the shrimps
220
00:33:27,340 --> 00:33:28,592
is a mystery.
221
00:33:29,593 --> 00:33:31,928
And, surely, a marvel.
222
00:33:49,196 --> 00:33:50,322
But today,
223
00:33:50,447 --> 00:33:54,367
their timeless world
is being reduced to rubble.
224
00:34:02,667 --> 00:34:07,464
As over-fishing empties
the surface waters of the seas,
225
00:34:07,547 --> 00:34:11,134
trawlers have started
to ransack the deep.
226
00:34:14,471 --> 00:34:17,390
Now, countless numbers of the reefs
227
00:34:17,474 --> 00:34:20,018
that have flourished here for millennia
228
00:34:20,143 --> 00:34:22,145
lie in ruins.
229
00:34:52,717 --> 00:34:53,927
Over time,
230
00:34:54,010 --> 00:34:57,722
organic matter on the sea floor
slowly decays
231
00:34:58,598 --> 00:35:00,016
producing methane.
232
00:36:04,331 --> 00:36:06,541
In the Gulf of Mexico,
233
00:36:06,624 --> 00:36:10,628
these eruptions also release
a super salty liquid.
234
00:36:19,095 --> 00:36:20,263
Brine.
235
00:36:31,775 --> 00:36:34,611
Five times heavier than sea water,
236
00:36:35,278 --> 00:36:38,656
it accumulates in great pools
on the sea floor.
237
00:36:44,621 --> 00:36:47,457
It's difficult to make sense
of the sight.
238
00:36:54,798 --> 00:36:58,009
A lake of concentrated salt water,
239
00:36:58,134 --> 00:36:59,969
fifteen metres deep,
240
00:37:01,012 --> 00:37:02,680
at the bottom of the sea.
241
00:37:10,855 --> 00:37:14,567
Around its margin,
perhaps even more strangely,
242
00:37:14,651 --> 00:37:17,320
there is a profusion of life.
243
00:37:24,577 --> 00:37:28,873
Giant mussels that can live
or grow for a century or more,
244
00:37:28,998 --> 00:37:30,583
pack tightly together,
245
00:37:30,667 --> 00:37:34,838
dwarfing the shrimps and squat lobsters
that feed around them.
246
00:38:04,701 --> 00:38:07,954
Cutthroat eels, scavengers,
247
00:38:08,037 --> 00:38:10,373
come to the shores of the brine lake
248
00:38:10,457 --> 00:38:12,375
in search of something edible.
249
00:38:21,259 --> 00:38:24,262
Some even venture into the brine.
250
00:38:59,130 --> 00:39:03,760
Spending too long in it
can send an eel into toxic shock.
251
00:39:16,105 --> 00:39:19,150
It' only hope
is to rise above it.
252
00:39:34,332 --> 00:39:36,000
It manages to escape.
253
00:39:45,510 --> 00:39:47,470
Others are not so lucky.
254
00:39:55,144 --> 00:39:57,564
The brine embalms their bodies,
255
00:39:59,482 --> 00:40:04,696
and the casualties of decades
accumulate around the margins.
256
00:40:25,383 --> 00:40:29,178
But parts of the deep
are even more hostile.
257
00:40:37,020 --> 00:40:38,187
In places,
258
00:40:38,271 --> 00:40:43,359
gigantic cracks stretch for many miles
across the ocean floor.
259
00:40:58,791 --> 00:41:02,879
Canyons that plunge
towards the centre of the earth.
260
00:41:10,553 --> 00:41:12,722
Scans from survey vessels
261
00:41:12,805 --> 00:41:16,434
make it possible to graphically
reconstruct an image
262
00:41:16,559 --> 00:41:19,145
of this vast submarine landscape.
263
00:41:27,070 --> 00:41:30,406
The deepest of all,
at almost seven miles,
264
00:41:30,490 --> 00:41:33,493
is the Mariana Trench
in the Pacific Ocean.
265
00:41:39,499 --> 00:41:43,252
Even Mount Everest
could disappear inside it.
266
00:41:58,851 --> 00:42:02,397
Down here, in these deep ravines,
267
00:42:02,480 --> 00:42:06,984
it was once thought that
nothing whatever could possibly survive.
268
00:42:13,950 --> 00:42:16,869
But there is life even here.
269
00:42:23,626 --> 00:42:25,545
A kind of sea slug.
270
00:42:33,386 --> 00:42:35,805
A so-called sea pig.
271
00:42:37,724 --> 00:42:40,184
They, and other simple creatures,
272
00:42:40,309 --> 00:42:45,732
manage to survive on the minuscule
amount of food that drifts down here.
273
00:42:49,235 --> 00:42:50,945
Like this starfish,
274
00:42:51,028 --> 00:42:55,199
they can withstand pressure
equivalent of 50 jumbo jets
275
00:42:55,324 --> 00:42:57,577
stacked on top of one another.
276
00:43:19,557 --> 00:43:21,434
A remote camera probe
277
00:43:21,517 --> 00:43:25,062
reveals the most
extraordinary discovery of all.
278
00:43:32,570 --> 00:43:35,948
The ethereal snailfish.
279
00:43:39,744 --> 00:43:41,829
At five miles down,
280
00:43:41,913 --> 00:43:46,042
this is the deepest living fish
so far discovered.
281
00:43:52,381 --> 00:43:54,050
No one imagined
282
00:43:54,133 --> 00:43:57,136
than an animal as complex as a fish
283
00:43:57,220 --> 00:44:00,389
could exist in such extreme pressures.
284
00:44:12,944 --> 00:44:14,695
From the greatest depths
285
00:44:14,779 --> 00:44:17,782
to the uppermost limit
of the Twilight Zone,
286
00:44:17,907 --> 00:44:21,285
it seems that there is
nowhere in the deep sea
287
00:44:21,410 --> 00:44:24,330
where life of some kind can't survive.
288
00:44:29,168 --> 00:44:30,336
And we now think
289
00:44:30,419 --> 00:44:34,131
that the deep sea may well be
where life on Earth began.
290
00:44:48,604 --> 00:44:49,730
Here,
291
00:44:49,814 --> 00:44:54,777
in a world hidden within the greatest
geological feature on Earth,
292
00:44:57,989 --> 00:45:01,784
running right down the middle
of the world's oceans,
293
00:45:01,868 --> 00:45:04,287
an underwater mountain range
294
00:45:04,370 --> 00:45:06,622
spanning the entire globe.
295
00:45:11,794 --> 00:45:13,713
The mid-ocean ridge.
296
00:45:28,311 --> 00:45:29,937
In the South Pacific,
297
00:45:30,021 --> 00:45:32,982
the ocean floor is being torn apart.
298
00:46:48,432 --> 00:46:51,686
Over three quarters
of the planet's volcanic activity
299
00:46:51,769 --> 00:46:54,063
occurs in the deep.
300
00:47:01,070 --> 00:47:04,949
Almost all of it along
the mid-ocean ridge.
301
00:47:09,078 --> 00:47:11,956
But from this titanic violence
302
00:47:12,081 --> 00:47:14,083
come great riches.
303
00:47:23,342 --> 00:47:27,096
Gases and scalding water
gush up through the crevices.
304
00:47:36,772 --> 00:47:39,358
Minerals condensing from these jets
305
00:47:39,442 --> 00:47:41,360
build up great chimneys.
306
00:47:42,862 --> 00:47:44,780
Hydrothermal vents.
307
00:47:48,784 --> 00:47:51,162
This one, 30 metres tall,
308
00:47:51,287 --> 00:47:53,330
has been named "Godzilla
309
00:48:02,048 --> 00:48:04,425
Astonishingly, we now know
310
00:48:04,508 --> 00:48:08,679
that they hold as much life
as tropical rainforests.
311
00:48:16,729 --> 00:48:20,649
In places, half a million
individual animals
312
00:48:20,733 --> 00:48:23,736
are crammed into a single square metre.
313
00:48:36,665 --> 00:48:40,419
They depend entirely
for their food on bacteria.
314
00:48:43,005 --> 00:48:45,382
And they feed on chemicals
315
00:48:45,508 --> 00:48:48,260
dissolved in the searingly hot fluid.
316
00:48:55,267 --> 00:48:58,979
Crabs consume the bacterial mats
317
00:48:59,063 --> 00:49:01,065
that coat their shells.
318
00:49:15,037 --> 00:49:17,915
Others maintain
bacterial cultures,
319
00:49:18,040 --> 00:49:20,584
actually within their bodies.
320
00:49:27,216 --> 00:49:30,886
Shrimps carry such cultures
in their mouth parts.
321
00:49:31,554 --> 00:49:34,557
But that is a strategy
fraught with danger.
322
00:49:39,103 --> 00:49:43,315
To provide sustenance
for these microbes,
323
00:49:43,482 --> 00:49:46,735
the shrimps must dash
into the hot vents,
324
00:49:48,737 --> 00:49:51,991
and that risks being boiled alive.
325
00:50:06,088 --> 00:50:07,631
In the last decade,
326
00:50:07,756 --> 00:50:11,802
the number of hydrothermal vents
discovered has doubled.
327
00:50:20,019 --> 00:50:24,356
Every one has its own unique
character and community.
328
00:50:31,197 --> 00:50:35,451
But, perhaps, the most important
one of all is in the Atlantic.
329
00:50:36,952 --> 00:50:40,623
It has been named "The Lost City".
330
00:50:44,210 --> 00:50:46,962
Within its 60-metre towers,
331
00:50:47,046 --> 00:50:50,716
something truly extraordinary
is taking place.
332
00:50:54,511 --> 00:50:57,514
Under extremes
of pressure and temperature,
333
00:50:57,806 --> 00:50:59,725
hydrocarbons,
334
00:50:59,808 --> 00:51:04,313
the molecules that are the basic
component of all living things,
335
00:51:05,147 --> 00:51:08,359
are being created spontaneously.
336
00:51:20,037 --> 00:51:23,457
Indeed, many scientists now believe
337
00:51:23,540 --> 00:51:29,380
that life on Earth
may have begun around a vent like this
338
00:51:29,838 --> 00:51:32,091
four billion years ago.
339
00:51:51,860 --> 00:51:54,738
We now know
that there are deep seas
340
00:51:54,863 --> 00:51:58,033
on the moons of Jupiter and Saturn.
341
00:52:05,207 --> 00:52:09,878
If life can exist under
such extreme conditions down here,
342
00:52:10,212 --> 00:52:14,800
then surely it could exist
somewhere out there.
343
00:52:27,771 --> 00:52:31,066
Next time, we travel
to bustling coral reefs.
344
00:52:38,282 --> 00:52:42,119
Here, animals must go
to extraordinary lengths
345
00:52:43,662 --> 00:52:47,499
to get ahead of the competition
in these crowded cities.
28641
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