Planet Earth (2006) s01e11 Episode Script

1
Away from all land
the ocean.
It covers more than half
the surface of our planet,
and yet for the most part
it is beyond our reach.
Much of it is virtually empty
a watery desert.
All life that is here is locked
in a constant search to find food
a struggle
to conserve precious energy
in the open ocean.
The biggest of all fish
30 tons in weight,
12 meters long
a whale shark.
It's huge bulk is sustained by mere
microscopic creatures of the sea —
Plankton.
Whale sharks cruise on
regular habitual routes
between the best feeding grounds.
In February, that takes them
to the surface waters
far from the coast of Venezuela.
Others are already here.
Baitfish have come for the same
reason to feed on the plankton.
The whale shark has timed
it's arrival exactly right.
Oddly, the tiny fish swarm around it.
They're using it as a shield.
Other predatory fish
are lurking nearby.
Yellowfin tuna.
They seem wary of the giant.
The shark dives, as if to
escape from such overcrowding.
Now the tuna have a chance to
attack the unprotected baitfish.
But then
back comes the giant.
It has taken a vast mouthful
of the baitfish itself.
Plankton, it seems, is not the
only food for a whale shark.
Both shark and tuna feast together,
but the tuna must be wary.
Even they can end up in
the whale shark's stomach.
Predators here must grab
what they can, when they can,
for such events do not last long.
The dense shoals
on which so many depend,
gather only when water
conditions are perfect.
Many predators spend much of their
time cruising the open ocean
endlessly searching.
Plankton feeding rays do so,
gliding with minimum effort.
The oceanic whitetip shark —
another energy efficient traveler.
It specializes in locating prey in the
emptiest areas of the open ocean
patrolling the top 100 meters of water.
Taste in water, is the
equivalent of smell in the air.
An oceanic whitetip is able to
detect even the faintest trace.
Small pilot fish swim with it.
The shark can find prey
far more easily than they can,
and they'll be able to collect
the scraps from it's meals.
It's long, fixed pectoral fins
enable it to soar through the water,
with the least expenditure of energy.
This shark has found a school
of rainbow runners.
It would eat one, given the chance,
but rainbow runners are swift
and agile and not easily caught.
So, it bides it's time.
There's a chance that, eventually,
it may spot a weakened fish
that's catchable.
The hunter
endlessly waiting.
Excitement far from land.
A school of dolphin 500 strong.
They've sensed there's food around,
and they're racing to catch up with it.
The news has spread. Now a number
of schools are on their way.
They're heading towards the Azores,
volcanic islands a thousand
miles west of Portugal.
The dolphin scan the water ahead
with their sonar.
They're close to their target.
This is it.
Scad mackerel.
It's difficult for a single dolphin
to catch the fish.
To avoid wasting energy,
they work as a group.
They drive the fish upwards,
trapping them against the surface,
and there,
other predators await them.
Cory's shearwaters.
They're waiting for the dolphin to
drive the prey closer to the surface.
Now the shearwaters
can dive down on them,
descending to 20 meters or more
and the dolphins block
the baitball's retreat.
The dolphins leave as soon as
they've had their fill
and, at last, the mackerel sink below
the diving range of the birds.
As the Sun disappears, a profound
change takes place in the ocean.
Deep water plankton start
to rise from the depths,
and another hungry army
prepares to receive it.
Every night,
wherever conditions are right,
countless millions of creatures
from the deep
migrate to the surface,
seeking food.
A baby sailfish, 15 centimeters long,
snaps up everything in it's path.
In 3 years' time, it'll be one of the
oceans most formidable hunters
weighing 60 kilos.
Just now, however,
it's very vulnerable.
These manta rays are giants.
8 meters across
and weighing over 2 tons.
The blade-like projections
on either side of the head,
help to steer plankton
into the manta's mouth.
Dawn returns, and the plankton
sinks back into the depths.
If we are to follow,
we must use a submarine.
As we descend into the darkness, the
pressure builds, the temperature falls.
Below 500 meters, new,
mysterious animals appear.
Their bizarre shapes help them to
remain suspended in the dark space.
Some resemble creatures
familiar from shallower waters,
others defy classification.
All around, organic particles
drift downwards.
Marine snow, detritus from the creatures
swarming in the sunlit waters above.
The snow is food for many animals
here, like the sea spider,
a small relative
of shrimps and crabs.
Those strange leg-like appendages are
feathered, to stop it from sinking.
They can also enmesh marine snow,
which it wipes carefully
into it's jaws.
A sawtooth eel
hangs upright and motionless.
Gazing ever upwards, it watches for prey,
silhouetted against the faint
glimmerings of light
from the surface.
Days may pass before prey swims
close enough for it to strike.
Farther down still,
the blackness is complete.
No vestige of sunlight
can penetrate as far as this.
Food is very scarce and nothing
can afford to waste any energy.
A dumbo octopus simply flaps a fin,
no need for the jet propulsion used by
it's shallow water relatives above.
The weirdest, in this world of
the strange, vampyroteuthis,
the vampire squid from hell.
Disturb it. and it only retreats
a little distance.
Go after it,
and it has a special defense.
To see what it does,
you must switch off the lights.
The vampire squid
has lights of it's own.
Bioluminescent bacteria shine
from pockets on it's arms
to confuse it's predators.
Are those eyes?
In fact they're spots
at the end of it's mantle.
A bite there,
would leave the head unscathed.
The threat diminishes, and
vampyroteuthis disappears
into the blackness.
At last, the sea floor.
Over 2 miles down, the pressure here
is 300 times that at the surface.
It takes several months for marine
snow to drift down as far as this.
As you travel away from the
rocky margins of the continents,
an immense plain stretches ahead.
It extends for thousands of miles,
gradually sinking downwards.
There are faint trails in the ooze,
signs that even here there is life.
These are what made some of them —
sea urchins sifting
the accumulating drifts.
Shrimps standing on elegant tiptoe,
fastidiously select the particles
that appeal to them.
But, in the deep sea, as everywhere else,
if there are grazers, there are hunters.
A monkfish, almost indistinguishable
from the sand on which it lies.
Why waste energy chasing around, if you
can attract prey towards you with a lure?
Maybe that one was a bit big.
The monkfish can wait, for days if necessary,
until the right sized meal turns up.
Scavengers on the other hand, have
to move around to find their food.
Crabs can detect
the faintest of tastes in the water,
and that helps them locate the latest
body to drift down from above.
Eels are already
feeding on the corpse.
Isopods, like giant marine woodlice
a third of a meter long,
are ripping into the rotting flesh.
Over the next few hours, there'll
be frenzied competition
between scavengers of all kinds
to grab a share.
Just occasionally,
there is a gigantic bonanza.
The remains of a sperm whale.
It died 5 months or so ago.
There's little left but fatty
blubber clinging to it's bones.
It's flesh has nourished life
for miles around,
but now the feast is almost over.
Spider crabs, a meter across,
still pick at the last putrid remains.
A few weeks more, and nothing
will be left, but bare bones.
The crabs will have to fast,
until the next carcass drifts down.
But not all food comes
from the sunlit world above.
The floor of the Atlantic Ocean
is split in two
by an immense volcanic
mountain chain
that winds unbroken for
45,000 miles around the globe.
In places, it's riven by great fissures,
from which superheated water
loaded with dissolved minerals
blasts into the icy depths.
Clouds of sulfides solidify into towering
chimneys, as tall as a 3-story house.
At 400 degrees, this scalding
cocktail of chemicals
would be lethally toxic
to most forms of life,
but astoundingly, a particular
kind of bacteria thrives here,
and feeding on the bacteria,
vast numbers of shrimps.
So, beyond the farthest reach
of the Sun's power,
a rich independent community exists,
that draws all it's energy
directly from the Earth's molten core.
On the other side of the planet, in
the western Pacific bordering Japan,
the dragon chimneys, another series
of hot vents, erupting in the darkness.
Here, more, but different bacteria
thrive in a similar way.
And here, too, more crustaceans,
but quite different species
from those around the hot vents
in the Atlantic.
These are squat lobsters,
clad in furry armor,
jostling with one another beside
the jets of superheated water
for the best places,
from which to graze on bacteria.
These vents, too, like those in the
Atlantic, are isolated oases
so widely separated,
that each community is unique.
Cross to the other side of the Pacific,
to the deep near the Galapagos Islands,
and there are yet other fissures
venting superheated water.
One and a half miles down,
at a site known as "Nine North",
towering chimneys support a spectacular
display of giant tubeworms.
These vents give off so much energy,
that some of the worms reach
3 meters in length.
They're the fastest growing
marine invertebrates known.
All told, over 50 different species
have so far been found living here.
The inhabitants of these bustling
communities may grow at speed,
but their existence can also be short,
for the vents do not erupt indefinitely.
Suddenly, unpredictably,
they may become inactive.
9 months have passed at "Nine North".
What were only recently chimneys
teeming with life,
have turned into cold,
sterile mineral monuments.
Some eddy,
deep in the Earth's crust,
diverted the volcanic
energy elsewhere,
and, an entire microworld
was extinguished.
In places, volcanoes have erupted to
build great submarine mountains.
There are thought to be around
30,000 such volcanoes,
some, measured from the sea floor,
are taller than Everest.
Sheer cliffs soaring to
drowned volcanic peaks.
Powerful currents sweep up
the mountains' flanks
transporting nutrients from
deep water towards the summits.
The hard rock provides
excellent anchorage
for communities of great variety
and stunning color.
Soft corals, several meters across,
collect the marine snow as it drifts past.
Whip corals stretch
out into the current.
Giant sponges filter nourishment
from the cold water.
A richly varied community
flourishes here,
sustained by the nutrients and
detritus in the icy currents
that flow around the peak.
Yet it is all blossoming
on an extinct volcano
a mile below the reach of the Sun.
A nautilus. It spends it's days
hiding 400 meters down,
But as night falls, it ascends
up to the reefs, to look for food.
It's graceful shell contains
gas-filled floatation chambers,
that control it's depth.
It's powered by a jet of water,
squirting from a siphon,
but it travels shell first, so it
can't see exactly where it's going.
It's nearest living relatives
are squid and octopus
which, over evolutionary time,
have both lost their shells,
and the octopus has become one
of the nautilus' major predators.
It's a master of disguise.
The nautilus keeps
well clear of them.
It's small tentacles carry highly
developed chemical sensors
which can detect traces
of both predators and prey.
It uses it's water jet
to dig in the sand.
Because it devotes so little
energy to swimming,
it only needs a meal
once a month.
Got something. And just as well.
Dawn is approaching and it
has to puff it's way
back, to deeper waters.
30 miles away, shoals of squid are
jetting upwards towards the surface.
By night, they seek small fish among
the plankton, but they're cautious.
Pacific spotted dolphin.
They're guided by their sonar.
The dolphin, as so often, are working as
a team, synchronizing their attacks
to confuse their prey.
As dawn approaches, squid and fish
and plankton retreat downwards,
to shelter in the darkness.
Some of these isolated volcanoes
rise as much as 9,000 meters from the
sea floor, reaching close to the surface.
Around these peaks,
invigorated by daily sunshine,
marine life flourishes
in spectacular abundance.
Fish crowd here, because the volcano
forces nutrients to the surface
encouraging the plankton to bloom.
An oceanic wanderer,
a Mola mola
stops by to be cleaned by reef fish,
at the sea mount edge.
Butterfly-fish pluck string-like
parasites from it's flanks.
The huge fish lives on jellyfish
over a thousand meters down
where the water is
20 degrees colder,
so, a brush-up near the surface,
allows it to warm up
before making more
deep water forays.
The summit of this volcanic mountain
rises above the surface of the sea.
It's Ascension Island,
800 miles from any other land, a welcome
vital haven for long distance travelers.
Frigatebirds spend months
continuously airborne at sea,
but at nesting time, they come to
Ascension from all over the ocean.
The island's barren slopes
of volcanic ash and lava
might seem to offer
perfectly good sites for a nest,
but the frigates choose
an even more isolated site,
Boatswain Bird Island, a lonely
pillar, just of Ascension's coast.
Frigates are the world's lightest
bird, relative to their wingspan,
and they can soar for weeks
on end with minimal effort.
They seem much more at home in the
skies, than in a crowded colony on land,
but nest, they must.
They come from all over the Atlantic
to this, their only colony.
There are boobys here, too.
To raise their young, seabirds
worldwide seek such remote islands.
Swimmers also come
to Ascension to breed.
A female green turtle
approaches the coast.
She's not eaten once, in 2 months.
She may have traveled 1,000 miles
from her feeding grounds,
the greatest journey of her kind.
Many others are here, too,
resting on the sandy sea floor
awaiting the darkness of night, when
it'll be safer to visit the beaches.
Eggs that were laid a few weeks ago,
at the start of the season,
are beginning to hatch.
Most hatchings happen at night.
Now, in the light of day,
the young are extremely vulnerable.
They must get to the sea
as soon as possible,
but their trials have only just begun.
Many will drown in the pounding waves.
During the next 20 years, the
vast majority will inevitably die,
but those that survive will, eventually,
as their mothers did before them,
return to the very same beach
where they were hatched.
How they find their way back
across thousands of miles of
open ocean, we still have no idea.
A frigate soars.
Somewhere, beneath
the surface below,
there is the food it must have.
But where?
Those that fly above the ocean
must be able to read the signs
of fresh supplies, or perish.
A 100 miles from the Mexican coast,
and keen eyes have spotted movement.
Sailfish, 3 meters long,
are closing in on prey.
They will only use just enough
energy to make their kill,
never wasting a fin stroke.
Nearly a hundred sailfish have
surrounded a single school of baitfish.
It's very rare to see so many
of these hunters in one place.
To herd their prey, the predators
raise their huge dorsal fins.
A mistimed strike by one sailfish,
could fatally damage another,
but each continually changes it's color,
from blue, to striped, to black,
that warns it's companions of it's
intentions and also confuses the prey.
As the shoal is driven nearer the surface,
it comes within the range of the seabirds.
Out here, in the open ocean, there
is nowhere for the baitfish to hide.
Sailfish live a high octane life.
To survive,
they must find prey daily,
so their entire existence
will be spent on the move.
Over 90% on the living space for
life on our planet, is in the oceans,
home to the biggest
animal that exists,
or has ever existed —
the blue whale.
Some weigh nearly 200 tons,
twice the size
of the largest dinosaur.
Despite their great size,
we still have little idea
of where they travel
in the vast oceans,
and none at all
of where they go to breed.
The largest animal on Earth
feeds almost exclusively
on one of the smallest
krill, shrimp-like crustaceans.
They take many tons of water into their
ballooning throats in a single gulp,
and sieve out what it contains.
Every day, each one swallows
some 4 million krill.
Such gargantuan harvests depend on the
continuing fertility of the oceans.
But global changes now threaten
the great blooms of plankton
on which the whales depend.
Once, and not so long ago,
300,000 blue whales
roamed the oceans,
now, less than 3%
of that number remains.
Our planet is still full of wonders.
As we explore them, so we gain
not only understanding, but power.
It's not just the future of the whale
that today lies in our hands,
it's the survival of the natural world
in all parts of the living planet.
We can now destroy,
or we can cherish.
The choice is ours.