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00:00:36,453 --> 00:00:40,082
Dwarfed by the vast expanse
of the open ocean,
2
00:00:40,249 --> 00:00:43,961
the biggest animal
that has ever lived on our planet.
3
00:00:50,550 --> 00:00:56,160
A blue whale, 30 meters long
and weighing over 200 tons.
4
00:00:56,320 --> 00:01:00,040
It's far bigger
than even the biggest dinosaur.
5
00:01:01,750 --> 00:01:04,540
Its tongue weighs
as much as an elephant.
6
00:01:04,710 --> 00:01:07,190
Its heart is the size of a car,
7
00:01:07,610 --> 00:01:10,250
and some of its blood vessels
are so wide
8
00:01:10,410 --> 00:01:12,500
that you could swim down them.
9
00:01:14,170 --> 00:01:15,960
Its tail alone
10
00:01:16,130 --> 00:01:19,590
is the width
of a small aircraft's wings.
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00:01:37,570 --> 00:01:40,840
Its streamlining,
close to perfection,
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00:01:41,010 --> 00:01:43,420
enables it to cruise at 20 knots.
13
00:01:43,590 --> 00:01:46,920
It's one of the fastest animals
in the sea.
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00:01:51,390 --> 00:01:53,480
The ocean's largest inhabitant
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00:01:53,650 --> 00:01:56,990
feeds almost exclusively
on one of the smallest -
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00:01:57,160 --> 00:02:01,050
krill, a crustacean
just a few centimeters long.
17
00:02:05,380 --> 00:02:08,720
Gathered in a shoal, krill stain the sea red,
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00:02:08,890 --> 00:02:13,560
and a single blue Whale in a day
can consume 40 million of them.
19
00:02:22,570 --> 00:02:25,700
Despite the enormous size
of blue whales,
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we know very little about them.
21
00:02:28,120 --> 00:02:30,440
Their migration routes
are still a mystery,
22
00:02:30,610 --> 00:02:33,860
and we have absolutely no idea
where they go to breed.
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They are a dramatic reminder
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00:02:40,850 --> 00:02:42,840
of how much we still have to learn
25
00:02:43,010 --> 00:02:46,550
about the ocean and the creatures
that live there.
26
00:02:49,800 --> 00:02:52,200
Our planet is a blue planet.
27
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Over 70 percent of it
is covered by the sea.
28
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The Pacific Ocean alone
covers half the globe.
29
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You can fly across it non-stop
for 12 hours
30
00:03:05,150 --> 00:03:08,450
and still see nothing more
than a speck of land.
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This series Will reveal
32
00:03:11,930 --> 00:03:14,870
the complete natural history
of our ocean planet
33
00:03:15,040 --> 00:03:19,460
from its familiar shores to
the mysteries of its deepest seas.
34
00:03:31,890 --> 00:03:33,710
By volume, the ocean makes up
35
00:03:33,880 --> 00:03:36,890
97 percent of the earth 's
inhabitable space,
36
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and the sheer quantity
of its marine life it contains
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far exceeds that
which inhabits the land.
38
00:04:07,090 --> 00:04:11,130
But life in the ocean is not
evenly spread. It's regulated
39
00:04:11,300 --> 00:04:13,630
by the path of currents
carrying nutrients,
40
00:04:13,800 --> 00:04:16,070
and the varying power of the sun.
41
00:04:18,020 --> 00:04:21,900
In this first program, we will
see how these two forces interact
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to control the distribution of life
43
00:04:24,320 --> 00:04:28,260
from the coral seas
to the polar wastes.
44
00:05:25,280 --> 00:05:28,260
The sheer physical power
of the ocean
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dominates our planet.
46
00:05:46,780 --> 00:05:50,580
It profoundly influences
the weather of all the world.
47
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Water vapor rising from it forms
the clouds and generates the storms
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00:05:55,800 --> 00:05:58,380
that ultimately
will drench the land.
49
00:06:18,360 --> 00:06:21,490
The great waves that roar in
towards the shores
50
00:06:21,660 --> 00:06:24,790
are dramatic demonstrations
of its power.
51
00:06:40,220 --> 00:06:43,050
Waves originate far out at sea.
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There, even gentle breezes
can cause ripples,
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and ripples grow into swells.
54
00:06:59,440 --> 00:07:02,460
Out in the open ocean,
unimpeded by land,
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00:07:02,620 --> 00:07:05,460
such swells can become gigantic.
56
00:07:28,480 --> 00:07:32,450
It's only when an ocean swell
eventually reaches shallow water
57
00:07:32,620 --> 00:07:34,710
that it starts to break.
58
00:07:42,250 --> 00:07:45,720
As it approaches the coast,
the water at the bottom of the swell
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00:07:45,890 --> 00:07:48,560
is slowed by contact
with the seabed.
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The top of the swell,
still traveling fast,
61
00:07:51,520 --> 00:07:55,140
starts to roll over
and so the wave breaks.
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00:08:27,800 --> 00:08:32,390
The ocean never rests. Huge currents,
such as the Gulf Stream,
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00:08:32,550 --> 00:08:36,480
keep its waters constantly
on the move all round the globe.
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00:08:36,640 --> 00:08:39,270
It's these currents
more than any other factor
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00:08:39,440 --> 00:08:43,770
that control the distribution
of nutrients and life in the seas.
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A tiny island lost
in the midst of the Pacific.
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It's the tip of a huge mountain
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that rises from the sea floor
thousands of meters below.
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00:09:03,050 --> 00:09:06,390
The nearest land is 300 miles away.
70
00:09:10,100 --> 00:09:12,890
Isolated sea mounts like this one
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00:09:13,060 --> 00:09:15,710
create oases
where life can flourish
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00:09:15,880 --> 00:09:19,590
in the comparatively empty expanses
of the open ocean.
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00:09:29,060 --> 00:09:32,720
But all the creatures that swim
beside it would not be here
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00:09:32,890 --> 00:09:35,140
were it not for one key factor -
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00:09:36,350 --> 00:09:38,230
the deep ocean currents.
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00:09:43,820 --> 00:09:47,790
Far below the surface,
they collide with the island's flanks
77
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and are deflected upwards,
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bringing with them from the depths
a rich soup of nutrients.
79
00:09:56,840 --> 00:10:01,340
Such up-wellings attract
great concentrations of life.
80
00:10:09,600 --> 00:10:12,530
Most of the fish here
are permanent residents
81
00:10:12,700 --> 00:10:15,960
feeding on plankton -
tiny floating plants and animals
82
00:10:16,120 --> 00:10:19,250
nourished by the richness
brought up from the depths,
83
00:10:19,420 --> 00:10:22,920
and they attract visitors
from the open ocean.
84
00:10:24,760 --> 00:10:26,130
Tuna.
85
00:10:52,830 --> 00:10:55,960
The plankton feeders
are easy targets.
86
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All this action attracts
even larger predators.
87
00:11:13,810 --> 00:11:15,230
Sharks.
88
00:11:20,020 --> 00:11:21,900
Hundreds of sharks.
89
00:11:24,690 --> 00:11:28,720
These silky sharks
are normally ocean-going species,
90
00:11:28,890 --> 00:11:31,410
but the sea mounts
in the eastern Pacific
91
00:11:31,570 --> 00:11:34,520
like Cocos, Mapelo
and the Galapagos,
92
00:11:34,690 --> 00:11:39,020
attract silkies in huge groups
up to 500 strong.
93
00:11:42,940 --> 00:11:46,550
Silkies seem to specialize
in taking injured fish
94
00:11:46,710 --> 00:11:48,770
and constantly circle sea mounts
95
00:11:48,930 --> 00:11:51,770
on the lookout for the chance
to do so.
96
00:11:56,900 --> 00:11:59,490
But silkies are not
the only visitors.
97
00:12:03,450 --> 00:12:07,560
Hammerheads gather
in some of the largest shark shoals
98
00:12:07,730 --> 00:12:09,980
to be found anywhere in the ocean.
99
00:12:10,150 --> 00:12:14,150
Sometimes, thousands will circle
over a single sea mount.
100
00:12:18,910 --> 00:12:21,760
But these sharks are not here
for food.
101
00:12:22,180 --> 00:12:24,430
They have come for another reason.
102
00:12:27,930 --> 00:12:32,140
Some of the locals
provide a cleaning service.
103
00:12:35,400 --> 00:12:37,670
Following the last El Niño year,
104
00:12:37,840 --> 00:12:42,700
when a rise in water temperatures
gave many sharks fungal infections,
105
00:12:42,860 --> 00:12:45,330
the number of hammerheads
visiting the sea mounts
106
00:12:45,500 --> 00:12:47,380
reached record levels.
107
00:12:58,760 --> 00:13:01,440
Nutrients also well up
to the surface
108
00:13:01,610 --> 00:13:04,030
along the coasts of the continents.
109
00:13:05,400 --> 00:13:09,410
This is Natal
on South Africa 's eastern seaboard.
110
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It's June,
111
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and just off-shore,
strange black patches have appeared.
112
00:13:18,890 --> 00:13:22,480
They look like immense oil slicks
up to a mile long.
113
00:13:25,110 --> 00:13:27,650
But this is a living slick:
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00:13:27,820 --> 00:13:31,850
millions and millions of sardines
on a marine migration
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00:13:32,020 --> 00:13:34,010
that in terms of sheer biomass,
116
00:13:34,170 --> 00:13:38,090
rivals that of the Wildebeest
on the grasslands of Africa.
117
00:13:42,470 --> 00:13:46,830
These fish live mostly
in the cold waters south of the Cape,
118
00:13:47,250 --> 00:13:50,160
but each year
the coastal currents reverse.
119
00:13:50,330 --> 00:13:54,060
The warm Agulhas current
that flows down from the north
120
00:13:54,230 --> 00:13:57,440
has been displaced
by cold water from the south,
121
00:13:57,850 --> 00:14:00,340
and that has brought up
rich nutrients.
122
00:14:00,510 --> 00:14:03,770
They in turn have created
a bloom of plankton,
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00:14:03,850 --> 00:14:06,610
and the sardines
are now feasting on it.
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As the sardines travel north,
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a whole caravan of predators
follow them.
126
00:14:25,690 --> 00:14:29,020
Thousands of Cape gannets
track the sardines.
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00:14:29,190 --> 00:14:31,640
They nested off the Cape
and timed their breeding
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so that their newly-fledged chicks
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00:14:33,850 --> 00:14:36,440
can join them
in pursuing the shoals.
130
00:14:44,280 --> 00:14:49,030
Below water, hundreds of sharks
have also joined the caravan.
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00:14:52,240 --> 00:14:54,700
These are bronze Whaler sharks,
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a cold water species that
normally lives much further south.
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These three-meter sharks
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cut such great swathes
through the sardine shoals
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that their tracks
are visible from the air.
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00:15:14,060 --> 00:15:16,050
Harried by packs of predators
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00:15:16,220 --> 00:15:18,640
and swept in
by the action of the waves,
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the sardine shoals are penned
close to the shore.
139
00:15:40,830 --> 00:15:45,340
Common dolphin are coming in
from the open ocean to join the feast.
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There are over a thousand of them
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00:16:02,490 --> 00:16:04,570
in this one school.
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00:16:12,710 --> 00:16:17,750
When they catch up with the sardines,
the action really begins.
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Working together, they drive
the shoal towards the surface.
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00:16:34,230 --> 00:16:38,520
It's easier for the dolphins
to snatch fish up here.
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00:16:52,830 --> 00:16:56,190
Now the sardines have no escape.
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00:17:07,950 --> 00:17:09,340
Thanks to the dolphins,
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the sardines have come within
the diving range of the gannets.
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00:17:25,790 --> 00:17:28,910
Hundreds of white arrows
shoot into the sea,
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leaving long trails of bubbles
behind each dive.
150
00:17:44,920 --> 00:17:48,130
Next to join the frenzy
are the sharks.
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00:18:01,020 --> 00:18:04,220
Sharks get very excited
when dolphins are around.
152
00:18:04,380 --> 00:18:07,050
They can feed particularly well
153
00:18:07,220 --> 00:18:09,300
once the dolphins
have driven the sardines
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00:18:09,460 --> 00:18:12,340
into more compact groups
near the surface.
155
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As the frenzy continues,
walls of bubbles drift upwards.
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They are being released
by the dolphins
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working together in teams.
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00:18:30,890 --> 00:18:32,090
They use the bubbles
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to corral the sardines
into ever tighter groups.
160
00:18:38,970 --> 00:18:41,810
The sardines seldom cross
the wall of bubbles
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and crowd closer together.
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00:18:47,820 --> 00:18:49,500
Bubble netting in this way,
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enables the dolphins to grab
every last trapped sardine.
164
00:19:06,300 --> 00:19:09,130
Just when the feasting
seems to be almost over,
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a Bryde's Whale.
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00:19:15,680 --> 00:19:18,100
The survivors head on northwards,
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00:19:18,270 --> 00:19:21,190
and the caravan of predators
follows them.
168
00:19:30,110 --> 00:19:33,790
Nutrients can also be brought up,
though less predictably,
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00:19:33,960 --> 00:19:36,040
by rough weather.
170
00:19:40,920 --> 00:19:45,320
Particularly near the poles,
huge storms stir the depths
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00:19:45,480 --> 00:19:47,200
and enrich the surface waters,
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and here, in the South Atlantic,
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the seas are the roughest
on the planet.
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And very rich seas they are, too,
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00:19:57,990 --> 00:20:00,950
for here, the cold Falklands
current from the south
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00:20:01,120 --> 00:20:03,860
meets the warm Brazil current
from the north,
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00:20:04,030 --> 00:20:07,120
and at their junction
is food in abundance.
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00:20:09,960 --> 00:20:13,850
These black-brewed albatross
are duck-diving for krill
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00:20:14,020 --> 00:20:16,820
that has been driven up
to the surface.
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00:20:20,280 --> 00:20:21,450
Like all albatross,
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black-brows are wanderers
across the face of the open ocean.
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A feeding assembly on this scale
is a rare sight.
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00:20:44,950 --> 00:20:49,010
Most of the time, the birds
of the open see are widely dispersed,
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00:20:49,170 --> 00:20:53,440
but these feeding grounds are close
to an albatross breeding colony,
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00:20:53,610 --> 00:20:55,530
and a very special one.
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00:21:05,750 --> 00:21:08,130
This is Steeple Jason,
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00:21:08,300 --> 00:21:11,310
a remote island
in the far west of the Falklands.
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00:21:11,480 --> 00:21:14,990
It has the largest albatross colony
in the world.
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00:21:23,370 --> 00:21:26,630
There are almost
half a million albatross here,
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an astonishing demonstration
of how fertile the ocean can be
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00:21:31,380 --> 00:21:32,770
and how much food it can give
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even to creatures
that do not actually live in it.
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00:22:03,090 --> 00:22:04,770
Nutrients by themselves
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00:22:04,940 --> 00:22:08,320
are not enough to generate
these vast assemblies.
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00:22:08,490 --> 00:22:12,500
The heat and light from the sun
is also essential
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00:22:12,660 --> 00:22:15,530
for the growth of the microscopic
floating plants -
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00:22:15,690 --> 00:22:17,950
the phytoplankton.
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00:22:22,320 --> 00:22:27,290
And it's the phytoplankton that is
the basis of all life in the ocean.
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00:22:33,710 --> 00:22:37,680
Every evening, the disappearance
of the sun below the horizon
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00:22:37,850 --> 00:22:40,370
triggers the largest
migration of life
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00:22:40,540 --> 00:22:42,620
that takes place on our planet.
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00:22:50,590 --> 00:22:54,050
One thousand million tons
of sea creatures
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00:22:54,220 --> 00:22:58,590
ascend from the deep ocean to
search for food near the surface.
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00:23:05,840 --> 00:23:10,010
They graze on the phytoplankton
under cover of darkness.
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00:23:10,180 --> 00:23:12,890
Even so, they are far from safe.
206
00:23:13,560 --> 00:23:15,390
Other marine hunters follow them,
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00:23:15,560 --> 00:23:18,940
some traveling up
from hundreds of meters below.
208
00:24:20,540 --> 00:24:21,630
At dawn,
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00:24:21,790 --> 00:24:26,310
the whole procession returns
to the safety of the dark depths.
210
00:24:32,980 --> 00:24:37,620
The moon, too, has a great
influence on life in the oceans.
211
00:24:39,040 --> 00:24:40,830
Its gravitational pull
212
00:24:41,000 --> 00:24:44,780
creates the daily advances
and retreats of the tide.
213
00:24:56,960 --> 00:25:00,090
But the moon has more
than a daily cycle.
214
00:25:00,510 --> 00:25:04,730
Each month, it waxes and wanes
as it travels round the earth,
215
00:25:04,900 --> 00:25:09,600
and this monthly cycle
also triggers events in the ocean.
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00:25:13,230 --> 00:25:15,460
The Pacific coast of Costa Rica
217
00:25:15,620 --> 00:25:17,710
on a very special night.
218
00:25:18,120 --> 00:25:21,900
It's just after midnight
and the tide is coming in.
219
00:25:26,280 --> 00:25:28,610
The moon is in its last quarter,
220
00:25:28,780 --> 00:25:31,990
exactly half way
between full and new.
221
00:25:34,990 --> 00:25:37,290
For weeks,
the beach has been empty,
222
00:25:37,450 --> 00:25:39,540
but that is about to change.
223
00:25:39,710 --> 00:25:43,960
At high tide, turtles
start to emerge from the surf.
224
00:25:49,880 --> 00:25:53,010
At first, they come
in ones and twos,
225
00:25:53,180 --> 00:25:54,680
but Within an hour,
226
00:25:54,850 --> 00:25:57,970
they are appearing
all along the beach.
227
00:26:04,230 --> 00:26:07,320
They are all female
Ridley's turtles,
228
00:26:07,480 --> 00:26:09,570
and over the next six days or so,
229
00:26:09,730 --> 00:26:12,640
400,000 will visit this one beach
230
00:26:12,810 --> 00:26:14,890
to lay their eggs in the sand.
231
00:26:23,320 --> 00:26:28,030
At the peak time, 5,000
are coming and going every hour.
232
00:26:28,450 --> 00:26:30,720
The top of the beach
gets so crowded
233
00:26:30,890 --> 00:26:34,340
that they have to clamber
over one another to find a patch
234
00:26:34,510 --> 00:26:36,600
where they can dig a nest hole.
235
00:26:41,890 --> 00:26:45,930
A quarter of the world 's population
of Ridley's turtles
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00:26:46,100 --> 00:26:49,810
come to this one beach
on a few key nights each year.
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00:26:50,480 --> 00:26:51,760
The rest of the time,
238
00:26:51,930 --> 00:26:55,140
they are widely distributed
through the ocean,
239
00:26:55,520 --> 00:26:57,600
most, hundreds of miles away.
240
00:26:58,520 --> 00:27:01,460
This mass nesting is called
an arribada.
241
00:27:01,900 --> 00:27:04,360
How it's coordinated is a mystery,
242
00:27:04,660 --> 00:27:06,950
but we do know that arribadas start
243
00:27:07,120 --> 00:27:10,660
when the moon is either
in its first or last quarter.
244
00:27:19,590 --> 00:27:23,680
Forty million eggs are laid
in just a few days.
245
00:27:23,840 --> 00:27:27,840
By synchronizing their nesting,
the females ensure
246
00:27:28,010 --> 00:27:31,040
that six weeks later,
their hatchlings will emerge
247
00:27:31,210 --> 00:27:32,990
in such enormous numbers
248
00:27:33,160 --> 00:27:35,660
that predators are overwhelmed,
249
00:27:35,830 --> 00:27:42,000
and a significant proportion of baby turtles
will get past them and make it to the water.
250
00:27:44,250 --> 00:27:47,170
But Why do the females
use a cue from the moon
251
00:27:47,330 --> 00:27:49,750
to help synchronize their nesting?
252
00:27:50,170 --> 00:27:51,650
Part of the answer to that
253
00:27:51,820 --> 00:27:55,160
becomes clear at dawn
on the following morning.
254
00:28:17,100 --> 00:28:21,600
The day shift of predators
are arriving for their first meals.
255
00:28:26,730 --> 00:28:28,720
Vultures have learnt
256
00:28:28,880 --> 00:28:33,300
that the returning tide can wash
freshly laid eggs out of the send.
257
00:28:36,310 --> 00:28:39,080
The risk of eggs being exposed
by the surf
258
00:28:39,240 --> 00:28:42,750
may be partly why
turtle arribadas tend to occur
259
00:28:42,920 --> 00:28:46,050
around the last or first quarter
of the moon.
260
00:28:50,260 --> 00:28:54,530
It's on such days as this when
the moon is neither full nor new,
261
00:28:54,690 --> 00:28:58,700
that the tides are weakest
and the sea is likely to be calmer.
262
00:29:13,710 --> 00:29:19,180
So it's easier for the female turtles
to make their way through the surf,
263
00:29:19,350 --> 00:29:22,580
and there's less chance of their
eggs being washed out of the sand
264
00:29:22,740 --> 00:29:24,660
and taken by vultures.
265
00:29:36,680 --> 00:29:40,850
The moon '3 monthly cycle
and its influence on the tides
266
00:29:41,010 --> 00:29:43,250
triggers many events in the ocean,
267
00:29:43,420 --> 00:29:46,170
from the spawning of the corals
on the Great Barrier reef
268
00:29:46,340 --> 00:29:48,420
to the breeding cycles of fish,
269
00:29:48,840 --> 00:29:50,790
but there '3 an even longer rhythm
270
00:29:50,960 --> 00:29:53,670
that has the most profound effect
of all -
271
00:29:53,840 --> 00:29:56,120
the annual cycle of the sun.
272
00:29:59,830 --> 00:30:02,040
The sun '3 position
relative to the earth
273
00:30:02,210 --> 00:30:03,690
changes through the year,
274
00:30:03,860 --> 00:30:06,570
and it's this
that produces the seasons.
275
00:30:06,990 --> 00:30:09,270
In the north, spring comes
276
00:30:09,430 --> 00:30:12,390
as the sun begins to rise
higher in the sky.
277
00:30:13,980 --> 00:30:16,020
Off the coast
of north west America,
278
00:30:16,190 --> 00:30:20,850
the seas are transformed by
the increasing strength of the sunshine.
279
00:30:25,230 --> 00:30:28,940
Here in Alaska,
the coastal waters turn green
280
00:30:29,100 --> 00:30:31,690
with a sudden bloom
of phytoplankton.
281
00:30:35,570 --> 00:30:38,480
Herring that have spent the winter
far out to sea
282
00:30:38,650 --> 00:30:42,600
time their return to the shallow
waters to coincide with this bloom.
283
00:30:42,770 --> 00:30:44,790
They come in vast numbers
284
00:30:44,960 --> 00:30:49,560
and initiate one of the most productive
food chains in all the oceans.
285
00:31:05,360 --> 00:31:08,980
Humpback whales
are at the top of that food chain.
286
00:31:09,140 --> 00:31:10,430
They have spent the Winter
287
00:31:10,600 --> 00:31:13,660
breeding in the warmer
tropical waters off Hawaii,
288
00:31:13,820 --> 00:31:15,910
but there was little food there.
289
00:31:16,080 --> 00:31:18,060
This herring bonanza
290
00:31:18,230 --> 00:31:21,850
provides the majority of their food
for the year.
291
00:31:43,790 --> 00:31:46,490
Stellar and Californian sea lions
292
00:31:46,660 --> 00:31:51,370
also return from the open ocean
each year to feast off the herring.
293
00:32:02,170 --> 00:32:06,090
The herring, however,
have not come here for food.
294
00:32:06,260 --> 00:32:09,630
They are about to breed.
Nothing deters them
295
00:32:09,790 --> 00:32:13,090
as they head
for even shallower waters.
296
00:32:14,800 --> 00:32:16,690
Now the waters are so shallow that
297
00:32:16,850 --> 00:32:18,610
glaucous-winged gulls are able to
298
00:32:18,780 --> 00:32:21,950
snatch live fish
from just below the surface.
299
00:32:33,790 --> 00:32:37,610
In spite of these attacks,
the herring swim on
300
00:32:37,780 --> 00:32:39,390
until they reach the vegetation
301
00:32:39,560 --> 00:32:42,310
that the females need
if they are to lay.
302
00:32:48,690 --> 00:32:52,590
Each female produces
around 20,000 eggs,
303
00:32:52,750 --> 00:32:55,170
and they're very sticky.
304
00:32:58,720 --> 00:33:01,880
The males arrived soon after
the females have spawned
305
00:33:01,880 --> 00:33:05,330
and release their sperm
in vast, milky clouds.
306
00:33:10,210 --> 00:33:14,220
Soon, the excesses
of the herrings' sexual spree
307
00:33:14,380 --> 00:33:18,010
creates a thick white scum
on the surface.
308
00:33:19,720 --> 00:33:20,810
Through the season,
309
00:33:20,980 --> 00:33:24,520
curds of sperm clog the shares
for hundreds of miles
310
00:33:24,690 --> 00:33:28,720
from British Columbia in the south
to Alaska in the north.
311
00:33:36,150 --> 00:33:40,110
After a few days, this gigantic
spawning comes to an end,
312
00:33:40,280 --> 00:33:42,810
and the herring
head back out to deeper waters,
313
00:33:42,970 --> 00:33:45,170
leaving behind them fertilized eggs
314
00:33:45,340 --> 00:33:48,720
plastered on every rock
and strand of vegetation.
315
00:34:01,270 --> 00:34:05,890
They time the spawning so that two
weeks later, when these eggs start to hatch,
316
00:34:06,060 --> 00:34:10,360
the annual plankton bloom will be
at its height, and the fish fry
317
00:34:10,520 --> 00:34:12,110
will have plenty to eat.
318
00:34:12,280 --> 00:34:15,000
But in the meantime,
all these eggs provide food
319
00:34:15,160 --> 00:34:19,920
for armies of different animals
both below and above the surface.
320
00:34:27,680 --> 00:34:32,270
Millions of birds arrive to collect
a share of the herrings' bounty.
321
00:34:32,440 --> 00:34:34,020
Some of it is easily gathered,
322
00:34:34,190 --> 00:34:37,900
for millions of eggs have been
washed up onto the shore.
323
00:34:39,070 --> 00:34:41,150
This encapsulated energy
324
00:34:41,320 --> 00:34:45,120
is particularly valuable
to migrating birds.
325
00:34:45,780 --> 00:34:47,850
These surfbirds are on their way
326
00:34:48,020 --> 00:34:52,390
to their breeding grounds in
the Arctic and come down to refuel.
327
00:34:52,560 --> 00:34:55,770
Stranded herring eggs
are just What they need.
328
00:34:57,400 --> 00:34:59,520
Bonaparte gulls collect the eggs
329
00:34:59,690 --> 00:35:01,980
just below the surface
of the water.
330
00:35:05,570 --> 00:35:09,330
Further out in the bay,
huge flocks of ducks have gathered.
331
00:35:09,500 --> 00:35:11,240
They're mostly surf scoters -
332
00:35:11,410 --> 00:35:15,580
diving ducks that can feed
off the bottom several meters down.
333
00:35:20,330 --> 00:35:22,560
There are such huge quantities
of eggs,
334
00:35:22,730 --> 00:35:25,120
that even a big animal like a bear
335
00:35:25,280 --> 00:35:27,740
finds it worthwhile
to collect them.
336
00:35:31,450 --> 00:35:34,120
The spawning of the herring
is a crucial event
337
00:35:34,280 --> 00:35:37,490
in the lives of many animals
all along the coast.
338
00:35:37,660 --> 00:35:40,820
The whole event coincides
with the plankton bloom,
339
00:35:40,990 --> 00:35:44,570
and within three short weeks,
it's all over.
340
00:35:50,320 --> 00:35:54,790
The migratory birds leave
to continue their journey north.
341
00:36:02,380 --> 00:36:06,550
They will not come back until
the herring also return next year.
342
00:36:13,260 --> 00:36:15,600
As the herring spawning finishes,
343
00:36:15,770 --> 00:36:19,200
other migrants
are starting to arrive offshore.
344
00:36:21,450 --> 00:36:23,330
Gray Whales.
345
00:36:28,000 --> 00:36:29,960
They have followed the sun north,
346
00:36:30,120 --> 00:36:32,260
and they too are seeking the food
347
00:36:32,420 --> 00:36:35,550
generated by the bloom
of the phytoplankton.
348
00:36:38,600 --> 00:36:43,100
Krill are feeding off it, and these
Whales are feeding on the krill,
349
00:36:43,270 --> 00:36:46,860
skimming it from the surface
with the filter plates of baleen
350
00:36:47,020 --> 00:36:49,190
that hang from their upper jaws.
351
00:36:52,440 --> 00:36:54,970
Gray whales make
one of the longest migrations
352
00:36:55,140 --> 00:36:57,180
undertaken by any marine mammal -
353
00:36:57,350 --> 00:37:00,220
a round trip of 12,000 miles or so
354
00:37:00,630 --> 00:37:02,660
from their breeding grounds
off Mexico
355
00:37:02,830 --> 00:37:07,270
along the entire coast of North
America, right up to the Arctic Ocean.
356
00:37:10,100 --> 00:37:12,290
They travel close to the coast,
357
00:37:12,460 --> 00:37:16,290
with the males and non-breeding
females leading the way.
358
00:37:16,460 --> 00:37:19,960
The last to start are cows
that have just given birth.
359
00:37:20,120 --> 00:37:23,990
They have to wait until their calves
are sufficiently big and strong
360
00:37:24,160 --> 00:37:26,290
to tackle such an immense journey.
361
00:37:29,290 --> 00:37:32,010
Their progress is necessarily slow.
362
00:37:32,180 --> 00:37:34,640
The mothers stay with their young,
363
00:37:34,810 --> 00:37:38,440
and even a strong calf
only travels at a couple of knots.
364
00:37:40,320 --> 00:37:42,240
They stick even closer
to the shore,
365
00:37:42,400 --> 00:37:44,890
often Within just 200 meters.
366
00:37:49,390 --> 00:37:50,890
Killer Whales.
367
00:37:51,050 --> 00:37:55,220
They have learnt that gray whales
follow traditional routes.
368
00:37:56,140 --> 00:37:57,630
The killers have no trouble
369
00:37:57,790 --> 00:38:01,550
in overtaking the calf
and its devoted mother.
370
00:38:05,340 --> 00:38:08,340
Normally, they continually call
to one another,
371
00:38:08,500 --> 00:38:10,880
but now they have fallen silent.
372
00:38:11,300 --> 00:38:13,180
The gray Whale and her calf
373
00:38:13,350 --> 00:38:16,480
have no idea
that they've been targeted.
374
00:38:38,290 --> 00:38:41,760
Catching up with the gray whales
is the easy part for the killers.
375
00:38:41,930 --> 00:38:43,300
They have to be cautious
376
00:38:43,460 --> 00:38:46,800
for they are only
about half the size of the grey whale mother.
377
00:38:50,930 --> 00:38:54,270
She can inflict real damage
with her tail.
378
00:39:03,110 --> 00:39:05,540
But the killers are after her calf.
379
00:39:05,960 --> 00:39:10,910
As long as the mother can keep it
on the move, it will be safe,
380
00:39:11,070 --> 00:39:14,030
and she does her best
to hurry it along.
381
00:39:16,780 --> 00:39:22,030
At first, the killers avoid getting
too close but just keep pace alongside.
382
00:39:22,440 --> 00:39:27,450
They know that the calf, going at
this speed, will eventually tire.
383
00:39:37,130 --> 00:39:39,520
After three hours of being harried in this way,
384
00:39:39,690 --> 00:39:43,050
the calf becomes too exhausted
to swim any further.
385
00:39:43,210 --> 00:39:45,300
The mother has to stop.
386
00:39:45,970 --> 00:39:48,810
This is the moment the killers
have been waiting for.
387
00:39:48,810 --> 00:39:53,480
They start to try and force
themselves between mother and calf.
388
00:40:15,130 --> 00:40:19,550
A calf separated from its mother
will not be able to defend itself.
389
00:40:19,720 --> 00:40:22,450
Time and again,
the black fins of the killers
390
00:40:22,610 --> 00:40:25,710
appear between the mottle
backs of the gray Whales.
391
00:40:36,930 --> 00:40:39,410
At last the killers succeed,
392
00:40:39,580 --> 00:40:42,010
and now they've got the calf
on its own,
393
00:40:42,170 --> 00:40:43,860
they change their tactics.
394
00:40:44,030 --> 00:40:48,070
They leap right onto the calf,
and try to push it under.
395
00:40:59,960 --> 00:41:02,040
They are trying to drown it.
396
00:41:11,640 --> 00:41:14,770
The calf snatches
a desperate breath.
397
00:41:28,860 --> 00:41:31,390
The mother becomes
increasingly agitated.
398
00:41:31,560 --> 00:41:34,780
Frantically, she tries to push
her calf back to the surface
399
00:41:34,940 --> 00:41:37,030
so that it can breathe.
400
00:41:40,450 --> 00:41:42,450
But now it's so exhausted
401
00:41:42,620 --> 00:41:45,830
that it has to be supported
by its mother's body.
402
00:42:03,390 --> 00:42:05,370
The killers won't give up.
403
00:42:05,540 --> 00:42:09,710
Like a pack of wolves, they take
turns in harassing the whales.
404
00:42:31,320 --> 00:42:34,290
Now, the Whole pod is involved.
405
00:42:45,380 --> 00:42:48,130
One of them takes a bite.
406
00:43:00,480 --> 00:43:03,800
Soon, the sea is reddened
with the calf's blood,
407
00:43:03,970 --> 00:43:07,090
and the killers close in
for the final act.
408
00:43:29,320 --> 00:43:31,200
The calf is dead.
409
00:43:35,910 --> 00:43:38,000
After a six-hour hunt,
410
00:43:38,170 --> 00:43:41,500
the killer whales
have finally won their prize.
411
00:43:47,680 --> 00:43:49,640
The mother, bereft,
412
00:43:49,810 --> 00:43:53,400
has to continue her migration north
on her own.
413
00:43:57,740 --> 00:44:00,460
She leaves behind
the carcass of a calf
414
00:44:00,630 --> 00:44:04,130
that she cherished for 13 months
in her womb,
415
00:44:04,290 --> 00:44:07,840
for which she delayed
her own journey to find food.
416
00:44:11,380 --> 00:44:16,420
The 15 killer whales spent over
six hours trying to kill the calf,
417
00:44:16,840 --> 00:44:18,850
but having succeeded,
418
00:44:19,010 --> 00:44:23,380
they've eaten nothing more
than its lower jaw and its tongue.
419
00:44:31,430 --> 00:44:35,680
Valuable food like this
will not go to waste in the ocean.
420
00:44:36,100 --> 00:44:39,440
Before long, the carcass
will sink to the very bottom
421
00:44:39,610 --> 00:44:41,260
of this deep sea,
422
00:44:41,430 --> 00:44:44,960
but even there its flesh
will not be wasted.
423
00:44:47,380 --> 00:44:51,680
Over a mile down, in the total
darkness of the deep ocean,
424
00:44:51,850 --> 00:44:53,840
the body of another gray Whale,
425
00:44:54,010 --> 00:44:55,550
a 30-tonne adult.
426
00:44:55,970 --> 00:44:59,140
It settled here
only a few weeks ago.
427
00:45:01,140 --> 00:45:04,480
Already, it has attracted
hundreds of hagfish.
428
00:45:11,320 --> 00:45:15,550
These scavengers, over half a meter
long and as thick as your arm,
429
00:45:15,720 --> 00:45:18,250
are only found in the deep sea.
430
00:45:18,420 --> 00:45:21,500
They have been attracted
by the faint whiff of decay
431
00:45:21,670 --> 00:45:25,010
suffusing through the water
for miles around.
432
00:45:28,930 --> 00:45:31,880
With their heads buried
in the Whale's flesh,
433
00:45:32,050 --> 00:45:35,880
they breathe through gill openings
along their sides.
434
00:45:36,800 --> 00:45:38,520
They're very primitive creatures -
435
00:45:38,690 --> 00:45:41,810
not even true fish
for they lack jaws.
436
00:45:42,230 --> 00:45:44,220
They feed, not by biting,
437
00:45:44,380 --> 00:45:48,340
but by rasping off flesh
with two rows of horny teeth.
438
00:45:50,260 --> 00:45:51,860
In just a few hours,
439
00:45:52,020 --> 00:45:56,280
a hagfish can eat several times
its own weight of rotting flesh.
440
00:46:00,280 --> 00:46:01,880
Next to arrive,
441
00:46:02,040 --> 00:46:04,130
a sleeper shark.
442
00:46:10,050 --> 00:46:13,290
It moves so slowly
to conserve energy -
443
00:46:13,450 --> 00:46:16,150
an important strategy
for so large an animal
444
00:46:16,320 --> 00:46:18,570
surviving in such a poor habitat.
445
00:46:26,080 --> 00:46:29,000
Sleeper sharks live
over a mile down,
446
00:46:29,160 --> 00:46:31,620
and grow to over seven meters long.
447
00:46:34,500 --> 00:46:39,500
They can go for months without food,
slowly cruising along the bottom,
448
00:46:39,670 --> 00:46:41,470
waiting for rare bonanzas
449
00:46:41,640 --> 00:46:42,720
such as this one
450
00:46:42,880 --> 00:46:44,760
to arrive from above.
451
00:46:51,930 --> 00:46:55,470
A whole range of different
deep-sea scavengers
452
00:46:55,640 --> 00:46:58,070
will feast on this carcass
for a long time
453
00:46:58,230 --> 00:47:01,570
before all its nutriment
has been consumed.
454
00:47:03,650 --> 00:47:05,020
18 months later,
455
00:47:05,190 --> 00:47:09,530
all that is left is a perfect
skeleton stripped bare.
456
00:47:12,320 --> 00:47:15,960
The sun's energy, that was captured
and turned into living tissue
457
00:47:16,130 --> 00:47:17,910
by the floating phytoplankton,
458
00:47:18,080 --> 00:47:21,390
has been transferred
to another link in the food chain,
459
00:47:21,560 --> 00:47:26,240
and has ended up as far away from the sun
as it is possible to be on this planet -
460
00:47:26,410 --> 00:47:28,500
at the bottom of the deep sea.
461
00:47:29,910 --> 00:47:34,000
But some energy
also returns from the deep.
462
00:47:39,550 --> 00:47:44,390
Millions of opalescent squid
are on their way to the shallows.
463
00:47:45,800 --> 00:47:47,850
They've come up here to mate.
464
00:47:48,010 --> 00:47:52,390
As the males grab the females,
their tentacles flush red.
465
00:47:54,230 --> 00:47:55,240
For most of the year,
466
00:47:55,410 --> 00:47:58,560
these squid live
at a depth of around 500 meters.
467
00:47:58,730 --> 00:48:02,610
They are part of these breeding
schools for a few weeks.
468
00:48:03,020 --> 00:48:06,360
Just one school was estimated
to contain animals
469
00:48:06,530 --> 00:48:09,250
that weigh around 4,000 tons.
470
00:48:21,260 --> 00:48:23,510
Wave after wave
rise from the depths,
471
00:48:23,680 --> 00:48:25,410
and soon the seabed
in the shallows
472
00:48:25,580 --> 00:48:30,170
is strewn with dense patches of
egg capsules several meters across.
473
00:48:36,460 --> 00:48:39,680
As each female
adds another capsule to the pile,
474
00:48:39,840 --> 00:48:43,180
the males fight
to fertilize its contents.
475
00:48:59,650 --> 00:49:02,450
The squid make their huge journey
into the shallows
476
00:49:02,620 --> 00:49:06,540
because their eggs will develop
faster in the warmer water here,
477
00:49:06,700 --> 00:49:09,380
and when the young emerge,
they will find more food
478
00:49:09,550 --> 00:49:12,890
more easily than they would
in the ocean depths.
479
00:49:18,390 --> 00:49:20,270
Dawn the next morning,
480
00:49:20,440 --> 00:49:24,900
and the seabed for miles around
is covered in egg capsules.
481
00:49:25,070 --> 00:49:28,890
The squid have all gone.
Many have died,
482
00:49:29,060 --> 00:49:32,400
but some will have returned
to their home in the deep.
483
00:49:32,570 --> 00:49:35,000
They will not return
to the light of the sun
484
00:49:35,160 --> 00:49:39,990
until the next time they are
driven up by the urge to spawn.