All language subtitles for Great.Blue.Wild.S03E04.WEBRip.x264-ION10

Narrator: The ocean sprawls
across 70% of our planet.

It's home to as many
as one million

known species of
plants and animals.

From tiny, cunning critters,

to some of the largest,
most feared predators.

But it's the smallest of
oceancreatures that underpins

the world's largest food web:

Plankton.

These tiny organisms
drift through

the ocean's diverse habitats,

triggering a feeding
cycle in their wake.

Woman: The zooplankton is what
most fish feed on.

So it really starts
with the nutrients

and basically you see effectsall
the way up the food chain.

Narrator: Plankton may be the
most important creatures on
earth.

In the dead of night,
two tinymandarin fish find one another,

engaging in one of nature's
mostelegant mating rituals.

They rise together,
cheek to cheek

and simultaneously
release sperm and eggs,

which float away in the current,

on the start of an
incredible journey.

It's a journey that could
takethem to coral reefs,

to coastlines, to
the open ocean,

or to settle on the
deep ocean floor.

Along the way they will fuel
an oceanic food chain,

on which much of the human
racedepends for its survival.

These fish eggs aren't on
this journey alone.

Masses of tiny organisms
drift in the ocean

at the mercy of the currents.

They're called plankton,
Greek for "drifter".

Any animal incapable of
moving through the water

without the aid of currents
isdefined as plankton.

Some are phytoplankton.

Tiny algae and some kinds
of bacteria

smaller than the
diameter of a human hair.

Or zooplankton,

tiny living animals,
no largerthan a grain of rice.

Other soft, bodied animals
likejellyfish are much larger.

Though because they're
weak swimmers

that rely primarily on
driftingwith the current

they're still classified
as plankton.

But it's the tiniest of
planktonic organisms

that are the most important.

Without them,
life in the oceanwould cease to exist.

Just one teaspoon of ocean water

contains more than amillion
microscopic organisms.

Their green hue can be seen
from outer space.

Phytoplankton require
sunlight to grow, as such,

they occupy the top
35 feet of the ocean.

Like land-based plants,

phytoplankton use
photosynthesis.

They absorb carbon dioxide,
and release oxygen.

Producing nearly two-thirds
ofthe atmospheric oxygen

on our planet.

More than all rainforests

and other terrestrial
plants combined.

Phytoplankton is a source of
food for slightly larger

zooplankton like crab larvae,
amphipods and copepods.

Copepods are the most
abundantcreatures on the planet.

With an estimatedpopulation
of one quintillion,

a billion-billion.

Though plankton can fill
stretches of water,

it isn't evenly distributed
throughout the ocean.

The vast seas can be a
wastelandfor hungry travelers.

There can be nothing to
eat forhundreds of miles.

Until a plankton bloom takes
shape.

When currents from two
separatewater systems collide,

they push nutrients, on
which the plankton feed,

up the water column,

drawing the tiny organisms to
one densely packed area

on the water's surface.

Small fish race in to feed
on the plankton.

This creates the base for
a micro food chain,

in the middle of the sea.

A pod of dolphins detects the
sounds of schooling fish

from hundreds of feet away
and homes in for a feast.

The shoal of sardines feels
the vibrations

of approaching hunters.

They huddle into a ball
for protection.

Any individual that stays out
ofthe group is an easy target.

But within the bait ball,
there's a fighting chance

they'll survive the
onslaught to come.

Dolphins hunt as a team.

They use sonar to locate theirprey,
making clicking sounds,

that travel through the
open ocean.

The sound waves bounce off of
potential prey

and echo back to the dolphin,

revealing the size,
shape and location of a meal

as far as 250 feet away.

It's a sophisticated method
that's taken the dolphin

more than 20 million
years to perfect.

Dolphins prefer to hunt
where the odds are stacked

in their favor.

A school of sardines feeding
on plankton,

offers the perfect opportunity.

The entire pod can feed inone place.

The dolphins corral the
sardinesinto a tightly packed ball

and take turns fishing.

The commotion alerts one of
the ocean's greatest hunters,

the copper shark.

It detects the vibrations
emitted by the panicked shoal

of sardines.

The trail leads the predator
directly to its prey.

A second shark joins the hunt.

But its sights are set on
a target much larger

than the sardines, a manta ray.

Sharks prefer to hunt
in murky waters,

using stealth to stalk their
target from behind.

Filter feeders, like
this manta ray

can fall victim to the
shark's cunning.

Like the schooling fish,
mantarays feed close to the surface,

where plankton is most abundant.

A pair of specialized fins
unrolls to guide plankton

into its enormous mouth.

But the manta's throat is no
larger than a human fist,

and as a result,

its diet is restrictedalmost
exclusively to plankton.

Because they're so big, manta
rays don't make an easy meal

for a shark.

Many survive an attack,
but thescarring and bite marks remain,

evidence of the manta having
been in the wrong place

at the wrong time.

The ocean's largest fish,
alsofeeds on its tiniest organisms.

As if skimming the cream
off milk,

a whale shark slurps
up the sheets of plankton,

that collect on the surface.

In a single day, one whale
sharkwill filter nearly enough water

to fill two olympic-sized
swimming pools.

A mouth as wide as a bathtub
sucks in the plankton.

A set of gills, fitted
with filters,

traps the tiny organisms.

When they've devoured enough
plankton, the animals leave,

in search of the next pulse
of life in the open ocean.

Dead plankton fall
to the seabed,

where they form the basis
of adifferent food chain.

Survivors continue their voyageas
passengers on the current,

their fate in the ocean's hands.

An ocean surge carries the
tiny organisms

through marine corridors.

Sometimes,
their epic journey isinterrupted by land.

Pinnacles and peaks, rise fromthe ocean,

powerful currentssmash
against the summit walls,

bringing in nutrients
that sustain plankton,

which in turn feed and
populate the reef.

Here,
a new group of creaturesrelies on plankton,

including corals,
the architectsthat built this reef.

Each coral is made up of tiny,
transparent animals

called polyps, that are
invisible to the naked eye.

Similar to these soft corals,
polyps use their tentacles

to catch plankton,
that drift by.

Polyps hide their
soft, delicate bodies

in the limestone
skeletons we know as corals.

Polyps connect to one another,
to create colonies.

Over millions of years, these
tiny engineers lay down

the foundation of the reef.

The plankton that feeds the
builders of this coral city,

also feeds its residents.

For those firmly planted,

the current acts as a
food delivery service.

A sea apple cucumber extends
itstentacles into the stream,

to collect passing plankton.

Like arms,
the tentacles bringfood to its mouth.

But for many, life on the
reef is a daily fight,

against the current.

Larger residents, like
these angel fish,

swim on their side to
combat the surge.

Crustaceans and smaller fish
tuck into nooks and crannies

seeking protection
from the current,

and from lurking predators.

Eventually, the smaller fish,
like these juvenile catfish,

must come out of hiding
to feedon the plankton.

When they do, ambush
hunters, like moray eels,

will be waiting to feed on them.

The moray eel will
typically stay in its den

and wait for prey to come to it.

Other hunters are more active
in their pursuit.

One of the most venomous
animals on earth

slithers through the water.

A sea snake, ten times more
toxic than a cobra,

the sea snake can paralyze
itsprey and swallow it whole.

This ribbon eel is a favored
food of the snake.

He quickly tucks back inside
before he's discovered.

As the snake surfaces for
a breath of air

it fills a lung that extends

nearly the entire length of
its body.

A single breath will
supply enough air

for two hours of
underwater hunting.

Plankton, feeding fish and
crustaceans

would be wise to
postpone their dinner

while this predator is
on the prowl.

Larger reef fish, have
their sights set on

a substantial meal.

They're targeting a nest of
freshly laid eggs

attached to the reef.

Left unattended,
the nest is aneasy meal for the reef fish.

This protective
male sergeant major

won't let the same fate happento his brood.

He stands guard to fend off
hungry predators,

and hovers over a purple
bed of fertilized eggs,

darting at incoming intruders.

The barber fish and king
angelfish are relentless

in their pursuit.

Eventually the persistent
sergeant major

repels the attackers.

Not every fish is a threat.

Some, like parrotfish,
feed oncoral instead.

The parrotfish uses its
large, beak-like mouth

to scrape micro-algae
from the coral surface,

maintaining the
health of the reef.

A hawksbill turtle, renders a
similar service.

She uses her narrow,
hooked beakto fetch her favorite snack,

sea sponge.

Smaller fish stick close
by tonibble at her leftovers.

The hawksbill prunes
this coral garden,

preserving the reef's
delicate balance.

By picking off sponge, she
clears some much-needed

real estate for
fresh coral growth.

Though coral reef covers
lessthan one percent of the ocean,

it's the most diverse of any
ecosystem on earth.

Coral reefs are home to
more than a quarter

of all known ocean species.

In one way or another,
each ofthose species is influenced by,

and dependent on, plankton,
as their nutrients move

through the food chain.

Of all the creatures on
the coral reef,

fish are by far the most
diverseand plentiful.

Many species, like
these glass-fish,

feed directly on zooplankton.

The tiny animal-based
organismsthat drift in the current.

The larger reef fish,
like theselionfish, feed on them.

A vivid variety of shapes
and colors,

helps the fish to hunt and hide.

Every bright color and bold
pattern serves a function

in the highly organized world
centered on the reef.

In this way, reef fish are
strikingly different

from the silvery sheentypically
associated with fish

in the open ocean.

A pancake-shaped body allowsreef fish,
like this Angelfish,

to maneuver between crevices in
the coral.

A specialized set of fins
further enhances

a flattened frame.

A paddle-like tail and
distinctive pectoral fins

help filefish to make sharp
turns through the coral

to out-swim predators.

Other fish, like yellow snapper,

travel in shoals to
confuse hunters.

But where there is life,
energized by plankton,

predation follows.

Sharks.

Hundreds of sharks.

White tips scour the
outskirtsof this coral city.

Hammerheads circle overhead.

The hammerhead shark, is one
of the most skillful hunters

in these waters.

Its mallet-shaped head
providesa panoramic view,

allowing the shark to see
preyboth above and below.

While it cruises mid-water.

Rays hunt under the very eyes
of their predator.

This blue spotted stingray
usesspecialized sensors

to detect tiny electrical
pulses emitted by shellfish

buried under the sand.

But this ray has lost its
greatest weapon.

A shark bit off its tail
and theray's stinger with it.

Now completely defenseless,
theray needs to be extra cautious

in these waters.

But for now, the hammerheadsshow
little interest in hunting,

which they tend to do at night,
and alone.

Most of the reef's
larger predators

are also nocturnal hunters,
likethese white tip reef sharks,

which spend most of the
daylying still to conserve energy.

Under the cover of darkness,
life on the reef gives way

to a new cast of characters.

Docile filter feeding of
plankton is eclipsed

by the frenetic pursuit of
the predators

at the top of the food chain.

White tip reef sharks force
their narrow bodies

through openings in the reef.

Pushing their heads into each
nook and cranny,

as they rummage the seabed.

One of the sharks bullies a
small fish out of its home.

But an agile black
jack scoopsit up instead.

Despite a body tailor-made
formaneuvering through coral,

The white tip reef shark is a
sluggish hunter.

It has bad eyesight,
and must rely

on a strong sense of smell to
locate its prey.

Once a shark makes a catch,
sharing is out of the question.

Though the jacks do their best
to muscle in.

Each shark fends for
itself ina feeding frenzy

that will continue
through the night.

As the sun pierces the
water's surface,

the mighty ocean
welcomes a new day.

It's the calm after the storm,
the night's hunters are resting.

The reef's residents come out
ofhiding and new visitors arrive.

Currents fuel the reef with
fresh plankton,

enticing millions of thimble
jellyfish with an easy meal.

They have no brain.

They have no blood.

And are made up almost entirelyof water.

Even though they can swim to
some degree,

jellyfish are consideredplankton
due to their soft body,

which limits their mobility.

These ocean drifters may be low
on the evolutionary scale.

And even lower on the food
chain.

But as their numbers show,

simplicity can be
effective in survival.

A much larger ocean wanderer
turns up with the current.

A loggerhead turtle.

The largest of all
hard-shelled sea turtles,

loggerheads carnivores.
are carnivores.

It's come to feast on crabs
and shellfish

hiding out in the seabed,

and on the planktonicjellyfish
that ride the current.

But a hungry visitor approaches.

The tiger shark has just one
thing on its mind.

Food.

The tiger shark is one of
theocean's most-feared predators.

At 15 feet long, it's also one
of the largest.

Tiger sharks live in both
the open ocean,

and the coastal areas
of tropical

and subtropical waters.

Often called the trashcan
of the sea,

the tiger shark is known
for itsvoracious appetite.

From stingrays and
smaller sharks,

to car tires and license plates,

the tiger shark will eat
just about anything.

No creature is safe.

The loggerhead takes a
short recess from feeding

to catch a breath of air.

But she's spotted.

The shark strikes from below.

A death like this is commonplaceat
the top of the food chain.

But would not be possible
without plankton

providing the base for all
life in the sea.

This ocean wanderer's journeyhas
come to an end on the reef.

But for another, it's just
beginning.

A Puddingwife wrasse releases
her eggs into the current,

and a frantic race ensues.

Males release a cloud of sperm,

in an attempt to
fertilize the eggs.

It's a spawning frenzy
that's over in seconds.

The fertilized eggs join the
spawn of thousands of

other fish species in the
plankton mass

floating through the sea.

Urchins, starfish and
some crustaceans,

also start their
lives as plankton.

Drifting through the ocean.

They're at the mercy of the
wind, the currents

and coastal upwellings,

which may bring the tiny
drifters close to shore.

Here, plankton sustains a new
chapter of life in the ocean.

In shallow coastal water,
phytoplankton,

or microscopic algae,

thrives in the warm
embrace of the sun.

Much like terrestrial plants,

phytoplankton harness energy from the sun

and convert it to food.

As the sun hits the water, it
nourishes the phytoplankton

and the grassy seabed below it.

Crustaceans feed on the
plankton.

And larger animals like the
stingray, feed on them.

One of the largest feeders
foundalong tropical coastlines

is the manatee.

This docile herbivore will
graze on the sea meadow

for as long as 12 hours
each day.

It's no wonder the manatee is
often called the "sea cow".

In deeper coastal waters, the
scene is far less peaceful.

Here, the sea lions
takesadvantage of the schooling fish

brought to their doorstep by the
fresh influx of plankton.

Agile and flexible, sea lions
are master swimmers.

This young hunter whizzes
pastafter a school of jack fish.

Methodical, and relentless in
its pursuit.

From hundreds of fish,
its focusbelongs to just one.

But the sea lion's presence
invites another hunter.

A great white shark.

Nearly 20 feet in length.

Weighing as much as a rhino,
with an appetite to match.

It's the world's largest
predatory fish.

A hunter, 400 million years inthe making.

The great white shark is one
ofevolution's greatest triumphs.

The shark advances slowly.

Though its torpedo-shaped
bodyand powerful tail

can propel it through the water,

at speeds of
more than 20 miles an hour.

The sea lion colony appears
to be on high alert.

But the determined sea lion
continues its chase.

At last, it's rewarded with
a meal.

The sea lion swims off
with its catch,

unaware of impending danger.

The great white homes in.

In these deeper coastal waters,

predatory sea lions
quickly become prey.

The journey of plankton
throughthe ocean is an infinite cycle.

But the isolated journeys
of each organism

have a beginning and an end.

Like bus routes,
currents maketheir way around the ocean.

Picking up and dropping off
passengers as they push on.

But much of the plankton
at some point

will drop out of the watercolumn
and sink to the seabed,

where once again it is
theplatform that supports all life.

Down here, away from coral
reefs or seagrass beds,

food and shelter can be
hard to come by.

Plankton drops into the
waitingmouths and claws

of hungry bottom dwellers,
like this porcelain crab.

It spreads the bristles
of itsclaws to catch

and comb through
falling plankton.

The crab takes shelter in
an anemone sprouting

from the ocean floor.

Its stinging tentacles serve
asprotection against predators.

A special coating of mucous,
protects the porcelain crab from

the stinging appendages of
its host.

Fish and crustaceans scour
the seabed,

sifting through sand to find
leftover scraps

of detritus and plankton

that may have settled
on the bottom.

But they're not the only
ones looking for a meal

on this seemingly
barren ocean floor.

An urchin crab, carries its
living armor on its back.

The crab is well protected,
andthe urchin gets a free ride.

Denizens of the muck

that haven't made protective
arrangements with others

seek shelter with
what's available.

Because these plankton feeders

are tasty meals for
other creatures.

When there's nowhere left to
remain unseen.

The only option is to hide in
plain sight.

Wispy strands of algae sway inthe current.

With a closer look,
the seaweedgrows arms and legs.

It's a decorator crab
camouflaged by debris.

What appears to be sea grass,
isactually two ghost pipefish.

The ocean floor is abattlefield,
where the smartest,

rather than the strongest
survive.

Those who can't outwit the
predator, are done for.

This is the fastest bite
in theanimal kingdom.

It belongs to one of the
ocean'sstrangest creatures,

the frogfish.

It uses a lure, like a fishingrod,
to catch other fish.

When nothing bites, the
frogfishwalks elsewhere to try its luck.

The ocean floor hides
many suchcunning hunters.

If you can spot them.

They're among the most
bizarrecreatures on the planet.

A master of illusion floats inthe water.

Its skin sparkles like a
starry night.

Its three hearts pump blue
blood.

Its eight arms grow out of itshead.

This is the cuttlefish, an
alien-like creature

in the muck.

The cuttlefish hunts along theocean floor,
using camouflage

to surprise its prey.

And hide from predators.

Beyond the coastal seafloor,

in the trenches of the
seemingly endless ocean,

is a world even more
mysterious, more alien.

It's a graveyard.

As plankton dies, it sinks
to the ocean floor.

The falling plankton,
nourishes a world

beyond the realm of sunlight.

With no light, resources
are scarce.

Organisms must work together
to survive.

What may look like one animal,

is in fact a colony
of marine organisms,

called zooids,
attached to one another.

Each one captures the
falling plankton.

They travel and hunt, as one.

Together, they form one
string-like organism,

called a siphonophore,

that can grow to
be longer than a blue whale,

Although it's one of the
world's longest animals,

it is incapable of
independent movement.

It drifts in the black stillnessinstead.

As such, the siphonophore is
thelargest planktonic organism

in the world.

As oceans churn and currents
surge upward,

they carry withthem a
rich supply of nutrients

that come from dead plankton

and the remains of other decayed
organisms on the seabed.

The upwelling thrusts these
nutrients toward the surface,

where they nourish new
blooms of plankton,

and start the cycle once again.

A cycle without which,
life onour planet would cease to exist.

Without plankton, the
entire marine food chain

would collapse.

Plankton feeders
and smaller fish

would be wiped off the face
of the earth.

Without these smaller fish,
oceanic mega fauna like sharks,

dolphins and rays would
disappear.

Coastal mammals like sea lionswould perish.

As would billions of people

that depend directly on
marine resources.

There are seven-and-a-half
billion people in the world.

And every second, there are
four more mouths to feed.

Nearly half need food from
the ocean.

For thousands of years
fishinghas been a way of life,

passed down for generations
as a means to feed families.

Today, seas are overfished by
commercial boats.

And corals are destroyed when
fishermen drop explosives

in the water.

Wiping out reefs and killing
far more fish

than are ever harvested.

Each day, more than four
millionfishing boats set out to sea,

to feed a growing
human population.

In 2009, Americans alone
consumed 4.8 billion pounds

of seafood.

Researchers around the world
are trying to understand

how to protect our oceans

from the ever-increasing
demands of people.

As a conservation biologist,
I have two different jobs.

One of them is to learn
more about the biology

and ecology of animals.

But at the same time as
you're out every day

you're almost on patrol.

Basically you're going up
and down the coast

literally looking for dead
animals on the beach,

nets, people poaching
these animals.

And then you're reporting
back to authorities.

So you're almost acting as a
ranger at the same time

as you're acting as a biologist.

and that's, it's really
sobering.

A lot of people have the
mentality

that the oceans are just huge,

vast pools of resources.

But those resources are limited.

For a lot of different
fisherieswe are reaching

that critical point were
we're at that limit

of what it can actually handle.

Dr. Marshall: Over the yearsshark
populations have declineddramatically.

and that's largely due to the
gill nets that occur along

the coastline and also
targetedfishing for sharks.

Chinese syndicates have
formed along the coastline

that are buying shark fins.

So local fishermen respond by
actually killing sharks.

Narrator: Recent estimates
suggest that populations of
large sharks

have declined by 90% or more.

Smukall: The biggest threats
tosharks in general is humans.

In certain areas they're
doing large beach nets

to protect surfers and swimmers.

In other areas it's the sharkfinning
and just a misconception

about what type of fishing these
animals can withstand.

And then the role and the
importance of these animals

in the environment.

Narrator: Sharks are the
ocean's apex predator.

Without them, the entire food
chain collapses.

They're efficient,
opportunistic hunters.

They prey on old, sick,
and weak fish,

maintaining the overall
health of the population.

Losing sharks would be a
tragedy in itself.

But the impact of human
influence is felt

at every level of
the food chain.

Down to the tiny plankton
thatunderpins all oceanic life.

Humans dominate the ocean's
food chain.

We are the last link.

There is no greater predator.

As ocean temperatures rise
due to climate change,

the cycling of chemicals
in water is disturbed.

Creating a difficult
environmentfor plankton growth.

Dr. Marshall: The zooplankton
iswhat most fish feed on.

A lot of planktonic fish and
even things like manta rays

and whale sharks,

when there's a lot of
biomass of fish of course

you're going to have a lot
of predatory fish.

So it really starts with the
nutrients being driven up

the coastline and
basically you see effects

all the way up the food chain.

Narrator: More than marine
lifeneeds plankton to survive,

terrestrial life does too.

Most of all, humans.

We owe every other breath
we take to phytoplankton.

The producer of nearly
two-thirds of all oxygen

on our planet.

The absence of plankton
wouldmark the end of life on earth.

And yet we've only
scratched the surface

when it comes to learning
aboutthese essential life forms.

From copepods, to snails
and crab larvae

a remarkable diversity of
tinydrifters floats on the current.

Triggering a feeding cycle
in every habitat.

We may know little about them.

But there's one thing we
do know.

These tiny microscopic
organismsare the unsung heroes

of our oceans.

And their epic journey is
perhaps the most important

of any creature on earth.

♪