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DAVID ATTENBOROUGH:
A Perfect Planet.
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All life in the oceans depends
on the continuous movement of water.
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00:00:56,060 --> 00:00:58,340
There are not five separate oceans
on Earth...
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00:00:59,900 --> 00:01:01,460
..but just one...
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00:01:01,460 --> 00:01:05,820
..whose parts are linked by
powerful, unceasing currents.
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00:01:08,060 --> 00:01:12,300
Every drop of seawater on Earth
rides these currents,
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taking a thousand years
to complete a single circuit.
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And where there are currents...
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..there is life.
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Off the coast of South Africa,
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dolphins are on the hunt.
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They have found a cold-water current
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and are now travelling along it
looking for food.
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00:02:05,740 --> 00:02:08,100
Gannets follow them.
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00:02:09,900 --> 00:02:13,660
They know that doing so
is the fastest way to a meal.
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A shoal of mackerel...
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..just what the dolphins
have been looking for.
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They encircle the fish,
driving them into a bait ball,
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and then trap them against
the surface
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to prevent them from escaping
to deeper water.
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Now, the fish are within range
of the dive-bombing gannets,
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who hit the water at 50mph.
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A sudden gathering of thousands
of predators brought together
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by the flow of currents.
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Last to the feast are sharks.
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00:04:02,740 --> 00:04:05,340
In these vast, open waters,
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00:04:05,340 --> 00:04:09,620
finding food would be all but
impossible without currents...
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00:04:10,660 --> 00:04:14,300
..the highways of the seas
that bring this life together.
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00:04:19,180 --> 00:04:22,260
When the bait ball
has been dispersed,
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all that is left are scales
drifting downwards.
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They are part of a slow,
never-ending blizzard
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of organic waste that eventually
settles on the sea floor.
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But it doesn't stay here forever.
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The currents sweep it back up
into the sunlit surface waters...
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..where it nourishes
clouds of phytoplankton...
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..simple microscopic plants
that are the pastures of the seas.
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00:05:11,900 --> 00:05:14,740
There are thousands
of different kinds,
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and together they produce half of
all the oxygen in the atmosphere...
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..more than all our forests
and jungles combined.
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And, by absorbing carbon,
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they are our greatest ally
in combating climate change.
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Plankton are the foundation
of almost all life in the ocean,
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for, in those places where
the currents bring nutrients
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to the surface, they multiply
in astonishing numbers...
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..turning the ocean green.
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The currents travelling through our
oceans bring life to seas
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that would otherwise
be marine deserts.
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The Galapagos Islands lie
in the path of one of them,
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the deep-flowing Cromwell Current
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that runs for 6,000 miles
across the Pacific.
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As it approaches Fernandina Island,
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it rises and delivers nutrients
into its shallows.
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And it also brings life
to this otherwise barren island.
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Iguanas.
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There are thousands of them.
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And yet there's nothing on the
island for these vegetarians to eat.
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Or...
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..almost nothing.
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Cormorants bring seaweed ashore
with which to make their nests.
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00:07:41,100 --> 00:07:44,020
But what is building material
for a cormorant
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is food for an iguana.
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SQUAWKS
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Both these species evolved here,
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but that doesn't necessarily
make them good neighbours.
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No matter.
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He knows where there's
more elsewhere.
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He's a marine iguana...
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..the only lizard in the world
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that gets its food from the sea.
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The seaweed on which
he totally relies
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only grows in abundance here
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because of the nutrients
brought by the Cromwell Current.
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Once in the water, he has just
30 minutes to find food.
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00:09:01,020 --> 00:09:02,900
Any longer than that,
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00:09:02,900 --> 00:09:05,820
and his muscles will seize up
and he'll drown...
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00:09:07,220 --> 00:09:11,180
..for, like most reptiles,
he can't handle the cold.
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Chilly water isn't a problem
for a warm-blooded cormorant.
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She can swim in it all day,
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but can only hold her breath
for a few minutes.
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He, on the other hand,
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completes his whole half-hour trip
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on one single breath.
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His flat face and sharp teeth
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make him an efficient
seaweed-cropping machine,
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but with the clock ticking,
he must eat fast.
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The cormorant, having caught
its fish...
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..goes back to the surface.
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One last mouthful,
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00:10:09,060 --> 00:10:12,180
and it's also time for the iguana
to head for home.
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00:10:15,620 --> 00:10:19,220
But to stop his muscles from seizing
up in the cold water,
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he must get back quickly.
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So he could do without
the attentions
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of an inquisitive sea lion.
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Dry land is now just 30 metres away,
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but the biggest hurdle
is still to come.
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00:11:09,580 --> 00:11:12,540
The surging water now fights
against him.
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00:11:19,700 --> 00:11:23,500
He's out, but he's stayed
in the cold so long
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that he's lost his strength.
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And he's made it.
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00:12:11,100 --> 00:12:14,980
Few reptiles on the planet have
to work harder for a meal
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than he does.
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00:12:19,180 --> 00:12:22,860
And, tomorrow, he'll have to
do it all over again...
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..unless next time...
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..he can outwit his neighbour.
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Over 100,000 marine iguanas
live on Fernandina...
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00:12:40,940 --> 00:12:44,780
..and each owes its existence
to the Cromwell Current
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that brings nutrients
to these shores.
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00:12:49,460 --> 00:12:53,100
But there is another,
much bigger, current
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which carries water from the Pacific
into the Indian Ocean.
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00:13:00,620 --> 00:13:05,500
On this great journey, it travels
through the islands of Indonesia,
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bringing together life
from both oceans.
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00:13:15,700 --> 00:13:19,900
A third of all the world's
reef fish live here.
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00:13:23,660 --> 00:13:26,740
Some call it the Coral Triangle,
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the most diverse marine region
on Earth.
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00:13:38,180 --> 00:13:41,980
The variety here is dazzling,
not just of coral,
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but of animals of all kinds.
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Few are stranger than
the flamboyant cuttlefish.
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This is a male,
just five centimetres long.
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Swimming against the current
isn't easy when you're small,
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so, instead, he prefers to walk...
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..very, very slowly.
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He's a master of camouflage.
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00:14:29,380 --> 00:14:32,020
But, right now,
he wants to be noticed.
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He's looking for a mate.
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His potential partner
is a giant, by comparison,
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four times his size.
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When it comes to courtship,
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being flamboyant isn't enough.
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To win her over, he must dazzle.
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His aim is to deposit
a packet of sperm
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inside her mouth.
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Close...
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..but no cigar.
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He'll have to turn up the dazzle.
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Take two.
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Bingo!
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His job is done.
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00:15:57,020 --> 00:16:00,180
Now she must find somewhere
to lay their eggs.
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00:16:03,340 --> 00:16:06,220
An old shell will do nicely
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00:16:06,220 --> 00:16:09,020
if she can slip past
the present occupant.
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00:16:14,220 --> 00:16:17,860
She fastens her eggs to
the underside of the shell,
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00:16:17,860 --> 00:16:19,980
where they'll be safe
from predators.
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00:16:33,700 --> 00:16:38,300
The current that brings so much life
to the Coral Triangle
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now washes the eggs with clean,
oxygenated water.
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After just three weeks,
they start to hatch.
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Smaller than a human fingernail,
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the hatchlings are now carried
by the current
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to other parts of the reef.
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00:17:12,580 --> 00:17:15,020
And, in just a few months,
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00:17:15,020 --> 00:17:19,140
this young male will be ready
to find a female of his own.
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00:17:25,180 --> 00:17:28,140
By a stroke of cosmic good fortune,
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the Earth has a satellite...
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..the moon, which orbits our planet
every 27 days.
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Its gravitational pull drags
our oceans across the planet...
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..and so gives us the tides.
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Unlike currents that stir
the open ocean,
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the tides have their greatest impact
on the coasts,
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flushing them with nutrients
from both sea and land.
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00:18:07,540 --> 00:18:10,980
And nowhere are they more violent
and dramatic than here...
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..Norway's Saltstraumen strait.
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Every six hours,
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nearly half a billion tonnes
of water
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are forced through a channel
just 150 metres wide.
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Its very narrowness accelerates
the water...
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..making this the strongest
tidal pull in the world.
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Most animals caught here
would be swept away.
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But not these tidal specialists.
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00:19:02,100 --> 00:19:05,140
Eiders are one of the few ducks
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that depend totally on the ocean
for their survival.
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And they're the only kind
strong enough
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to live permanently
in these racing waters.
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00:19:25,140 --> 00:19:28,380
But there is food here,
and in great quantity,
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for any that can gather it...
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..mussels.
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They filter out particles of food
brought to them by the tide.
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And eider ducks love mussels.
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The challenge is reaching them.
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Eiders seem to be the only creatures
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that can hold their own
in the fast-flowing water...
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..so they have the mussels
all to themselves.
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They swallow them whole,
shell and all.
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00:20:27,180 --> 00:20:31,020
Each eider duck eats
hundreds of mussels a day...
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..a year-round feast
that no others can reach.
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The tides here owe their power
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to the unique geography
of the coastline.
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But, elsewhere in our oceans,
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the lay of the land influences tides
in a very different way.
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Here in the Bahamas,
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wide, shallow sandbanks
mean the tide moves gently
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00:21:10,660 --> 00:21:13,420
over the sea floor...
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..turning what would be
a sandy desert
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into a rich underwater habitat.
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00:21:22,060 --> 00:21:26,380
This is the home of garden eels
and razorfish.
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00:21:30,660 --> 00:21:35,340
And fresh food arrives for them
from deeper waters twice a day.
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Life seems unhurried and gentle...
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..but there is trouble in paradise.
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WHISTLING AND CLICKING
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These bottlenose dolphins
eat razorfish,
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00:21:52,780 --> 00:21:55,860
and they're not so easily fooled
by vanishing tricks.
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00:22:01,620 --> 00:22:05,580
They scan the sand
with echolocating clicks
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to discover exactly
where the razorfish are hiding.
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CLICKING CONTINUES
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00:22:25,940 --> 00:22:29,180
But knowing where they are
is not the same as catching them.
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00:22:35,500 --> 00:22:38,100
The more the dolphins dig,
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00:22:38,100 --> 00:22:40,140
the deeper the razorfish burrow.
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00:22:43,780 --> 00:22:46,420
But it's clearly not deep enough.
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00:22:55,980 --> 00:22:59,020
Blowing jets of water into the sand
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00:22:59,020 --> 00:23:02,900
exposes even the most
hard-to-reach razorfish.
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00:23:06,540 --> 00:23:10,700
Before long, the dolphins
have had enough and they move on.
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00:23:13,060 --> 00:23:15,900
It looks as if they have picked
the sand clean...
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..but here, at least,
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there really are
plenty more fish in the sea.
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Closer to the land, the same tides
bring nourishment
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00:23:40,260 --> 00:23:43,660
to one of the most threatened
of coastal habitats...
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00:23:44,660 --> 00:23:46,540
..mangrove forests.
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00:23:48,060 --> 00:23:50,220
Part land...
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00:23:50,220 --> 00:23:52,020
..part sea.
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00:23:53,860 --> 00:23:56,700
Mangroves are the only trees
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00:23:56,700 --> 00:23:59,780
capable of surviving in salt water
220
00:23:59,780 --> 00:24:03,980
and are specially adapted to it
coming and going twice every day.
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00:24:11,580 --> 00:24:14,980
As sea water floods in,
fish come with it.
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00:24:16,380 --> 00:24:18,460
Here in the flooded forests,
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00:24:18,460 --> 00:24:21,900
they can find both food and shelter.
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00:24:28,420 --> 00:24:31,860
Stingrays ride on the incoming tide.
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00:24:39,300 --> 00:24:42,580
Other commuters follow.
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00:24:42,580 --> 00:24:45,980
Young lemon sharks,
still far from full-grown,
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00:24:45,980 --> 00:24:47,900
are looking for food.
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00:25:02,940 --> 00:25:05,340
When the tide is at its highest,
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00:25:05,340 --> 00:25:07,580
even adult lemon sharks
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00:25:07,580 --> 00:25:09,420
can get into the mangroves.
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00:25:12,500 --> 00:25:16,380
A three-metre female
moves cautiously into the shallows.
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00:25:19,580 --> 00:25:22,020
She can't stay here for long,
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00:25:22,020 --> 00:25:24,660
but, then, she hasn't come here
to hunt.
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00:25:31,100 --> 00:25:33,860
She's come to give birth...
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00:25:35,380 --> 00:25:38,060
..returning to the very place
where she was born.
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00:25:41,940 --> 00:25:45,340
She has nourished the pups
inside her body
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00:25:45,340 --> 00:25:47,620
with a placenta, as we do.
238
00:25:54,460 --> 00:25:57,980
The mangroves provide
an ideal nursery for them,
239
00:25:57,980 --> 00:26:01,220
and placing them here gives them
an excellent start,
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00:26:01,220 --> 00:26:04,300
but that is the end of her
parental care.
241
00:26:06,300 --> 00:26:10,380
She has to return to deeper water
before the tide goes out.
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00:26:14,700 --> 00:26:17,460
Her young must now fend
for themselves.
243
00:26:21,140 --> 00:26:25,620
The pups instinctively take refuge
among the roots of the mangroves.
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00:26:28,700 --> 00:26:32,220
They're so small, they can swim deep
245
00:26:32,220 --> 00:26:34,100
into this tangled labyrinth.
246
00:26:45,580 --> 00:26:47,740
With the tide fast receding,
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00:26:47,740 --> 00:26:49,780
even they need to find a place
248
00:26:49,780 --> 00:26:52,020
where they won't be left
high and dry.
249
00:26:53,740 --> 00:26:55,540
A place like this...
250
00:26:56,900 --> 00:27:00,740
..a permanent pool in the heart
of the mangrove forest.
251
00:27:07,500 --> 00:27:10,180
Only the smallest sharks
can get here,
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00:27:10,180 --> 00:27:12,540
and only at the highest tides.
253
00:27:19,700 --> 00:27:22,700
The pups will spend
the next two years here
254
00:27:22,700 --> 00:27:26,340
perfecting the skills that make them
one of the ocean's top hunters.
255
00:27:31,380 --> 00:27:33,660
And it seems...
256
00:27:33,660 --> 00:27:35,460
..that there's a lot to learn.
257
00:27:42,060 --> 00:27:43,500
Got one!
258
00:27:49,540 --> 00:27:54,260
All life at the coasts has to move
to the daily rhythm of the tides,
259
00:27:55,620 --> 00:27:58,660
but tides are not the same
throughout the year.
260
00:28:04,540 --> 00:28:10,380
Every month, when our planet, the
moon and the sun are all aligned,
261
00:28:10,380 --> 00:28:12,980
the increased gravitational pull
262
00:28:12,980 --> 00:28:15,900
produces particularly high tides.
263
00:28:17,500 --> 00:28:21,100
And this triggers
a truly extraordinary event
264
00:28:21,100 --> 00:28:23,660
on one particular reef
in the central Pacific.
265
00:28:30,500 --> 00:28:33,460
Thousands of resident surgeonfish
266
00:28:33,460 --> 00:28:36,820
begin to assemble
on these high tides.
267
00:28:41,300 --> 00:28:45,540
And they are being followed by one
of the largest fish in the sea...
268
00:28:52,260 --> 00:28:54,100
..manta rays.
269
00:29:03,580 --> 00:29:08,500
The rays spend their year
moving between coral islands.
270
00:29:10,940 --> 00:29:15,060
But it's only now, when the tide
is at its highest
271
00:29:15,060 --> 00:29:17,860
and the surgeonfish have gathered,
that they appear
272
00:29:17,860 --> 00:29:19,980
on this particular reef.
273
00:29:23,580 --> 00:29:25,860
Their timing is so perfect
274
00:29:25,860 --> 00:29:28,620
that they rarely have to wait
more than an hour
275
00:29:28,620 --> 00:29:30,460
for the event to begin.
276
00:29:56,900 --> 00:30:01,340
At the precise moment
when the tide is at its highest,
277
00:30:01,340 --> 00:30:03,540
the surgeonfish begin to spawn.
278
00:30:06,220 --> 00:30:09,260
They release billions of eggs
and sperm into the water.
279
00:30:14,460 --> 00:30:17,180
Breeding in this way
gives their fertilised eggs
280
00:30:17,180 --> 00:30:20,340
the best chance of being
carried on the tide
281
00:30:20,340 --> 00:30:22,860
away from predators
that haunt the reef.
282
00:30:26,580 --> 00:30:28,140
All except one.
283
00:30:31,820 --> 00:30:33,820
The mantas move in.
284
00:30:51,540 --> 00:30:54,140
They gorge on the eggs,
285
00:30:54,140 --> 00:30:57,060
filtering them out
using specially adapted gills.
286
00:30:59,500 --> 00:31:02,700
If the mantas had arrived
just an hour later,
287
00:31:02,700 --> 00:31:05,260
there would have been nothing here
for them to eat.
288
00:31:12,700 --> 00:31:16,300
No-one knows how the mantas
are so perfectly in tune
289
00:31:16,300 --> 00:31:18,140
with the rhythm of the tides.
290
00:31:24,340 --> 00:31:28,460
But they appear without fail
whenever the surgeonfish spawn.
291
00:31:36,780 --> 00:31:38,620
Most of the eggs, however,
292
00:31:38,620 --> 00:31:41,260
are carried out into the open ocean
293
00:31:41,260 --> 00:31:43,900
before the mantas
are able to eat them all.
294
00:32:00,260 --> 00:32:06,020
The rhythms of coastal life are
influenced by another ocean force.
295
00:32:09,740 --> 00:32:14,180
Winds blowing over the sea
so batter the surface
296
00:32:14,180 --> 00:32:17,020
that it begins to rise and fall.
297
00:32:19,060 --> 00:32:20,860
These swells may travel far
298
00:32:20,860 --> 00:32:23,940
and reach the shores
of even the most sheltered bays.
299
00:32:25,540 --> 00:32:27,820
As they approach shallower water,
300
00:32:27,820 --> 00:32:29,620
they turn into waves.
301
00:32:34,100 --> 00:32:36,700
A shoal of hardyheads,
302
00:32:36,700 --> 00:32:40,100
close to the beach
of Australia's Lizard Island.
303
00:32:42,020 --> 00:32:46,980
The clearness of these glassy waters
shows that they lack nutrients.
304
00:32:48,540 --> 00:32:52,420
But the gentle waves
expose food hidden in the sand,
305
00:32:52,420 --> 00:32:54,980
and that's what the hardyheads
are looking for.
306
00:33:10,900 --> 00:33:13,420
Packs of trevally are on the hunt.
307
00:33:22,060 --> 00:33:24,460
The hardyheads stick together.
308
00:33:25,460 --> 00:33:27,100
There's safety in numbers.
309
00:33:28,580 --> 00:33:30,740
But they're vulnerable, nonetheless.
310
00:33:41,900 --> 00:33:44,820
They're so small, they can swim
in the shallowest waters...
311
00:33:53,300 --> 00:33:56,540
..even in the body
of the waves themselves,
312
00:33:56,540 --> 00:33:58,780
out of the reach of their enemies.
313
00:34:03,900 --> 00:34:06,700
But trevally aren't their
only concern.
314
00:34:16,180 --> 00:34:18,260
Blacktip reef sharks.
315
00:34:19,740 --> 00:34:23,780
They are bigger and more powerful
than trevally...
316
00:34:25,580 --> 00:34:27,860
..but not as fast or as agile.
317
00:34:32,940 --> 00:34:35,740
The hardyheads are well aware
of them,
318
00:34:35,740 --> 00:34:38,380
but, so long as they stay
just out of reach,
319
00:34:38,380 --> 00:34:39,820
they have little to fear.
320
00:34:54,300 --> 00:34:57,780
But now the sharks
and the trevally join forces.
321
00:35:02,940 --> 00:35:05,780
Together, they enter the shallows,
322
00:35:05,780 --> 00:35:07,860
each looking for a chance to attack.
323
00:35:25,900 --> 00:35:27,780
The trevally make the first move...
324
00:35:29,580 --> 00:35:33,420
..and the hardyheads take refuge
again in the waves.
325
00:35:34,500 --> 00:35:36,900
And this is what the sharks
have been waiting for.
326
00:35:41,380 --> 00:35:45,620
Surging forwards, they chase
the hardyheads out of the water...
327
00:35:46,660 --> 00:35:50,900
..beaching themselves in a daring
bid to hoover up their prey.
328
00:35:55,420 --> 00:35:57,820
The hardyheads that escape
the sharks
329
00:35:57,820 --> 00:35:59,660
swim back out to deeper water...
330
00:36:01,860 --> 00:36:04,140
..but into the mouths
of the trevally.
331
00:36:15,300 --> 00:36:18,740
Now the receding waves
help to pull the sharks back
332
00:36:18,740 --> 00:36:20,580
into deeper water.
333
00:36:51,260 --> 00:36:54,740
In the chaos, the sea birds
get their chance.
334
00:36:59,820 --> 00:37:02,220
It's a feeding frenzy...
335
00:37:02,220 --> 00:37:04,860
..in only ten centimetres of water.
336
00:37:17,820 --> 00:37:21,900
The power of waves
is dramatically evident
337
00:37:21,900 --> 00:37:23,540
when they crash onto our shores.
338
00:37:26,860 --> 00:37:32,260
But the biggest of all start far
away from land, out at sea.
339
00:37:32,260 --> 00:37:34,740
THUNDER CRASHES
340
00:37:34,740 --> 00:37:38,660
Great storms blowing over
the surface of the ocean
341
00:37:38,660 --> 00:37:41,300
raise towering walls of water.
342
00:37:44,900 --> 00:37:48,940
Such giant swells can travel
for thousands of miles.
343
00:37:51,460 --> 00:37:53,580
As they approach land,
344
00:37:53,580 --> 00:37:58,180
the shallowing sea floor begins
to drag on their undersides,
345
00:37:58,180 --> 00:38:00,300
and they topple forward...
346
00:38:00,300 --> 00:38:01,740
..and break.
347
00:38:05,580 --> 00:38:09,820
This stirring of the ocean
produces great riches.
348
00:38:13,620 --> 00:38:15,740
The Falkland Islands are surrounded
349
00:38:15,740 --> 00:38:17,980
by some of the stormiest
waters on Earth...
350
00:38:22,060 --> 00:38:26,500
..ideal hunting grounds
for rockhopper penguins.
351
00:38:28,300 --> 00:38:30,380
It's the breeding season
352
00:38:30,380 --> 00:38:32,020
and, for the last two weeks,
353
00:38:32,020 --> 00:38:34,820
the males have been incubating
the eggs by themselves.
354
00:38:37,740 --> 00:38:40,700
They're confined to the nest
with nothing to eat,
355
00:38:40,700 --> 00:38:43,300
while the females are out at sea
collecting food.
356
00:38:48,060 --> 00:38:51,940
All across the colony,
eggs are starting to hatch.
357
00:38:53,940 --> 00:38:57,540
This male now has two youngsters
to care for.
358
00:39:00,860 --> 00:39:05,100
But he has no food to give them,
and he can't leave them unprotected.
359
00:39:06,700 --> 00:39:09,180
He can do nothing but wait.
360
00:39:23,180 --> 00:39:26,740
are now heading for home
with food in their crops.
361
00:39:30,700 --> 00:39:32,300
There's just one problem.
362
00:39:33,620 --> 00:39:36,580
The colony sits at the top
of huge cliffs.
363
00:39:39,700 --> 00:39:43,100
The waves that make feeding
so good here
364
00:39:43,100 --> 00:39:46,100
have now become major obstacles.
365
00:39:48,380 --> 00:39:50,420
Timing is vital.
366
00:40:04,620 --> 00:40:06,260
Go too early...
367
00:40:07,300 --> 00:40:09,780
..and they could be smashed
against the rocks.
368
00:40:16,020 --> 00:40:18,940
Too late...
369
00:40:18,940 --> 00:40:21,060
..and they will be carried
back out to sea.
370
00:40:27,380 --> 00:40:29,780
Hooked claws now help
to get purchase
371
00:40:29,780 --> 00:40:31,420
on the slippery rocks.
372
00:40:34,900 --> 00:40:36,740
But they're not out of trouble yet.
373
00:40:41,700 --> 00:40:44,820
Success depends on both judgment...
374
00:40:44,820 --> 00:40:46,260
..and luck.
375
00:41:06,380 --> 00:41:10,220
Time and again,
the waves drag her back in.
376
00:41:16,540 --> 00:41:18,540
She has to persevere.
377
00:41:18,540 --> 00:41:23,060
The lives of her chicks
depend on her safe return.
378
00:41:55,060 --> 00:41:57,140
Finally...
379
00:41:57,140 --> 00:41:59,140
..she's made it.
380
00:42:08,540 --> 00:42:11,300
They're not called rockhoppers
for nothing.
381
00:42:16,940 --> 00:42:19,180
With one more jump, she's home.
382
00:42:22,620 --> 00:42:24,380
And just in time.
383
00:42:29,540 --> 00:42:31,900
Her chicks are desperately hungry.
384
00:42:39,660 --> 00:42:42,700
This is their first proper meal.
385
00:42:42,700 --> 00:42:44,700
CHICK CHEEPS
386
00:42:52,660 --> 00:42:56,940
The oceans have sustained life
on our planet for millions of years.
387
00:43:01,740 --> 00:43:06,260
But, today, there's growing evidence
that this is changing.
388
00:43:12,300 --> 00:43:14,340
As our climate warms,
389
00:43:14,340 --> 00:43:17,860
polar ice sheets are melting
at an alarming rate.
390
00:43:21,900 --> 00:43:26,460
In the Arctic alone,
14,000 tonnes of fresh water
391
00:43:26,460 --> 00:43:29,580
are emptying into the sea
every second.
392
00:43:37,500 --> 00:43:40,900
This is slowing the flow of currents
around the globe.
393
00:43:43,820 --> 00:43:47,020
And, if the atmosphere
continues to warm,
394
00:43:47,020 --> 00:43:50,700
ocean circulation could eventually
stop altogether.
395
00:43:59,740 --> 00:44:02,860
Our seas would then stagnate,
396
00:44:02,860 --> 00:44:05,620
threatening the life within them.
397
00:44:09,380 --> 00:44:12,060
And there are places
in the oceans today
398
00:44:12,060 --> 00:44:14,820
where this is already
beginning to happen.
399
00:44:23,620 --> 00:44:25,420
The Gulf of Thailand.
400
00:44:32,740 --> 00:44:35,780
Eden's whales have lived here
for generations.
401
00:44:39,380 --> 00:44:41,900
But the world around them
is changing.
402
00:44:51,220 --> 00:44:54,820
Today, agricultural pollution
flowing from the land...
403
00:44:57,540 --> 00:45:00,340
..is beginning to suffocate
this sea.
404
00:45:10,540 --> 00:45:13,780
Many fish now stay closer
to the surface,
405
00:45:13,780 --> 00:45:17,660
where the waters still contain
enough oxygen to survive.
406
00:45:22,140 --> 00:45:25,580
Eden's whales depend on these fish.
407
00:45:27,540 --> 00:45:30,060
They swallow huge
quantities of water
408
00:45:30,060 --> 00:45:32,220
before filtering out their prey.
409
00:45:37,540 --> 00:45:41,580
It takes a lot of energy
to drive their 15-tonne bulk
410
00:45:41,580 --> 00:45:43,420
through the water.
411
00:45:46,180 --> 00:45:48,500
And, with so few fish,
412
00:45:48,500 --> 00:45:51,460
the rewards from feeding like this
are barely worth it.
413
00:45:54,060 --> 00:45:56,580
So, to survive here,
414
00:45:56,580 --> 00:45:59,660
the whales have developed
a new hunting technique...
415
00:46:04,420 --> 00:46:07,620
..one that requires almost
no effort.
416
00:46:10,780 --> 00:46:13,660
They simply open their mouths...
417
00:46:13,660 --> 00:46:15,060
..and wait.
418
00:46:20,420 --> 00:46:22,860
The panicked fish jump right in.
419
00:46:30,380 --> 00:46:32,300
Swimming alongside,
420
00:46:32,300 --> 00:46:35,780
another whale scares even more
into the open jaws.
421
00:46:47,820 --> 00:46:50,700
With this ingenious new technique,
422
00:46:50,700 --> 00:46:54,420
Eden's whales have found a way
to survive the pressures
423
00:46:54,420 --> 00:46:55,740
they now face.
424
00:46:58,220 --> 00:47:02,260
All across the planet,
animals are having to adapt
425
00:47:02,260 --> 00:47:04,100
to a changing world.
426
00:47:05,980 --> 00:47:09,580
But the speed of these changes
will be too fast for many.
427
00:47:14,980 --> 00:47:20,340
If we could only halt our
unrestrained plunder of the ocean,
428
00:47:20,340 --> 00:47:22,940
its habitats and species
would recover.
429
00:47:25,820 --> 00:47:28,460
And, at a time when our
overexploited lands
430
00:47:28,460 --> 00:47:30,700
are already failing us,
431
00:47:30,700 --> 00:47:33,700
this has never been more important
for humanity.
432
00:47:54,660 --> 00:47:58,300
The volcanic island of Fernandina
in the Galapagos
433
00:47:58,300 --> 00:48:01,060
is home to two incredible lizards...
434
00:48:03,420 --> 00:48:07,660
..the land iguana
and the marine iguana.
435
00:48:09,460 --> 00:48:12,180
There are two parts to their story
436
00:48:12,180 --> 00:48:14,940
that cameraman, Richard Wollocombe,
has wanted to film
437
00:48:14,940 --> 00:48:18,620
since he first came to
these islands 25 years ago,
438
00:48:19,860 --> 00:48:22,900
and, on A Perfect Planet,
he got his chance.
439
00:48:27,620 --> 00:48:29,820
Driven by powerful currents,
440
00:48:29,820 --> 00:48:34,140
the cold Pacific Ocean
slams into Fernandina's shores.
441
00:48:40,780 --> 00:48:44,220
The marine iguanas must brave
these waters every day.
442
00:48:49,100 --> 00:48:52,100
Their journey through the big surf
is what Richard and the team
443
00:48:52,100 --> 00:48:54,340
are here to film...
444
00:48:54,340 --> 00:48:56,220
..but from underwater.
445
00:48:57,220 --> 00:48:59,580
It looks fairly benign
from the surface here,
446
00:48:59,580 --> 00:49:02,300
but, underneath,
it's really shallow,
447
00:49:02,300 --> 00:49:06,140
and there's all these really sharp
rocks with lots of jagged edges.
448
00:49:06,140 --> 00:49:08,580
So if we were taken by the wave,
449
00:49:08,580 --> 00:49:11,460
it would cut us up really badly,
I think.
450
00:49:16,140 --> 00:49:17,980
Whose idea was this?
451
00:49:17,980 --> 00:49:19,740
Ha-ha, ha-ha.
452
00:49:20,780 --> 00:49:23,020
I'm a glutton for punishment,
did you know?
453
00:49:26,860 --> 00:49:29,940
The waves are certainly punishing.
454
00:49:30,940 --> 00:49:33,220
With these dangerous conditions,
455
00:49:33,220 --> 00:49:37,420
extra protection is clearly needed
for Richard and dive buddy Rafael.
456
00:49:38,340 --> 00:49:41,100
So what better than surf helmets?
457
00:49:49,420 --> 00:49:53,740
It isn't long before Richard
realises what he's up against.
458
00:49:56,740 --> 00:49:59,780
The relentless churning
of the water makes it difficult
459
00:49:59,780 --> 00:50:02,220
to stay the right way up...
460
00:50:02,220 --> 00:50:03,860
..let alone film the iguanas.
461
00:50:09,540 --> 00:50:13,180
In between the waves,
the iguanas briefly appear.
462
00:50:17,860 --> 00:50:20,740
But Richard barely has time
to line up a shot...
463
00:50:21,860 --> 00:50:24,980
..before the iguana disappears
behind another wave.
464
00:50:32,460 --> 00:50:34,100
In the violent surge,
465
00:50:34,100 --> 00:50:36,940
the iguanas have learned
to hang on to the rocks...
466
00:50:38,380 --> 00:50:42,620
..a trick Richard is quick to copy
to avoid being swept away.
467
00:50:44,500 --> 00:50:47,460
That, however, only leaves
one hand to film with.
468
00:50:56,460 --> 00:50:59,260
But, with adrenaline
carrying him through,
469
00:50:59,260 --> 00:51:03,220
Richard is able to get the perfect
shots of iguanas in the surf.
470
00:51:09,580 --> 00:51:14,140
And to achieve that totally
unscathed is a great relief.
471
00:51:15,140 --> 00:51:17,780
I don't need to go to the gym
for months after that!
472
00:51:20,100 --> 00:51:22,300
Well done, mate. Good job.
473
00:51:25,460 --> 00:51:30,340
On the shore, land iguanas have
to battle a very different force.
474
00:51:33,020 --> 00:51:38,540
Each year, they migrate up to the
top of Fernandina's active volcano,
475
00:51:38,540 --> 00:51:42,900
a journey of ten days
across razor-sharp lava
476
00:51:42,900 --> 00:51:45,940
before descending into its heart
to lay their eggs
477
00:51:45,940 --> 00:51:47,780
in the ashy floor.
478
00:51:52,740 --> 00:51:57,020
It's this behaviour Richard
and the team plan to film,
479
00:51:57,020 --> 00:52:00,860
and the scale of the expedition
is one that's rarely been attempted
480
00:52:00,860 --> 00:52:02,660
in the Galapagos.
481
00:52:07,340 --> 00:52:11,620
To reach the top takes the crew
ten gruelling hours.
482
00:52:21,540 --> 00:52:23,980
When they finally arrive on the rim,
483
00:52:23,980 --> 00:52:26,020
the experience doesn't disappoint.
484
00:52:28,300 --> 00:52:30,260
I can't believe it.
485
00:52:30,260 --> 00:52:32,820
It's absolutely awe-inspiring.
486
00:52:35,020 --> 00:52:38,220
I just can't believe the iguanas
actually manage
487
00:52:38,220 --> 00:52:42,740
to navigate down these slopes
into the bowl of this volcano.
488
00:52:44,540 --> 00:52:47,620
More people have been into space
than to the bottom
489
00:52:47,620 --> 00:52:49,820
of Fernandina's crater.
490
00:52:49,820 --> 00:52:53,260
But that is exactly where Richard
and the team must go
491
00:52:53,260 --> 00:52:55,900
if they are to film
the nesting iguanas.
492
00:53:00,780 --> 00:53:03,700
From their campsite
at the edge of the volcano,
493
00:53:03,700 --> 00:53:07,060
it's an extremely dangerous journey
down to the crater floor,
494
00:53:07,060 --> 00:53:11,540
and assistant producer Toby wants
to be clear with everyone
495
00:53:11,540 --> 00:53:13,380
what is at stake.
496
00:53:31,420 --> 00:53:34,740
There's only one passable
route down,
497
00:53:34,740 --> 00:53:38,780
and, as the team enter the lip
of the volcano,
498
00:53:38,780 --> 00:53:41,740
the sound of rock fall
is all around.
499
00:53:41,740 --> 00:53:43,740
THUNDEROUS SOUND
500
00:53:44,780 --> 00:53:46,300
WOMAN SHOUTS OUT
501
00:53:50,700 --> 00:53:54,620
Regular earthquakes make
the crater walls very unstable.
502
00:53:59,700 --> 00:54:02,140
Just keeps getting better.
503
00:54:02,140 --> 00:54:06,380
Not far away, some iguanas
are making their own descent,
504
00:54:06,380 --> 00:54:08,820
disturbing the loose surface
as they go.
505
00:54:20,420 --> 00:54:23,580
If a creature only a sixth
the size of a person
506
00:54:23,580 --> 00:54:27,180
can start a deadly avalanche
of razor-sharp rocks,
507
00:54:27,180 --> 00:54:29,820
what can a whole film crew do?
508
00:54:29,820 --> 00:54:31,780
RUMBLE OF FALLING ROCKS
509
00:54:36,460 --> 00:54:40,860
It's clear the crew are going
to have to be extremely cautious.
510
00:54:40,860 --> 00:54:42,780
ROCK FALL DROWNS OUT WORDS
511
00:54:45,660 --> 00:54:48,420
On the steepest slopes,
the equipment needs to be
512
00:54:48,420 --> 00:54:50,020
lowered with ropes.
513
00:54:58,180 --> 00:55:02,260
With rocks falling all around,
the longer they're on the slopes,
514
00:55:02,260 --> 00:55:04,740
the greater the risk of an accident.
515
00:55:09,020 --> 00:55:11,820
But, when one misstep
can start an avalanche,
516
00:55:11,820 --> 00:55:13,620
hurrying is impossible.
517
00:55:16,740 --> 00:55:20,380
Finally, the prize of
the crater floor is in sight.
518
00:55:20,380 --> 00:55:24,140
Look, just below there is
where the iguanas are nesting.
519
00:55:24,140 --> 00:55:28,060
We're very close to it now,
about an hour's walk.
520
00:55:28,060 --> 00:55:31,700
All that lies between them
is a stretch of loose lava
521
00:55:31,700 --> 00:55:34,940
that has cascaded down the slopes
after the last eruption.
522
00:55:37,060 --> 00:55:40,300
FALLING ROCK RUMBLING
523
00:55:48,740 --> 00:55:51,180
We're actually in the crater now,
524
00:55:51,180 --> 00:55:54,020
surrounded by these vertical walls.
525
00:55:55,780 --> 00:55:59,060
I just can't believe that
we really made it down here.
526
00:56:00,100 --> 00:56:03,820
Sometimes I doubted that, you know,
we would actually make it.
527
00:56:07,060 --> 00:56:11,300
And there they were, iguanas,
using the warm volcanic ash
528
00:56:11,300 --> 00:56:13,180
to incubate their eggs.
529
00:56:17,900 --> 00:56:22,860
For Richard, after 25 years
living in the Galapagos,
530
00:56:22,860 --> 00:56:26,940
filming this unique behaviour
is a lifelong dream come true.
531
00:56:29,300 --> 00:56:32,420
My, God, what an incredible place
this is!
532
00:56:32,420 --> 00:56:37,100
It's such a vivid feeling
to be constantly challenged
533
00:56:37,100 --> 00:56:39,060
by the forces of nature like that.
534
00:56:40,380 --> 00:56:44,220
But they have to do this every year
in order to survive.
535
00:56:44,220 --> 00:56:47,820
I'll never forget,
for as long as I live.
536
00:56:47,820 --> 00:56:49,940
What an adventure!
What an adventure!
537
00:56:54,180 --> 00:56:55,860
Next time...
538
00:56:55,860 --> 00:56:57,820
..a new force...
539
00:56:57,820 --> 00:56:59,500
..humans.
540
00:56:59,500 --> 00:57:01,260
Now so dominant...
541
00:57:02,380 --> 00:57:04,500
..we're disrupting
the forces of nature...
542
00:57:06,540 --> 00:57:10,460
..and the vital habitats
life needs to survive.
543
00:57:12,020 --> 00:57:14,860
This is the most important story...
544
00:57:14,860 --> 00:57:16,700
..of our time.
545
00:57:16,700 --> 00:57:18,820
Whose future? Our future.
546
00:57:19,980 --> 00:57:23,220
The Open University has produced
a free poster
547
00:57:23,220 --> 00:57:25,460
exploring our perfect planet.
548
00:57:25,460 --> 00:57:27,060
To order, please call...
549
00:57:31,140 --> 00:57:32,700
Or go to...
550
00:57:35,820 --> 00:57:38,420
..and follow the links to
the Open University.
43706
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