All language subtitles for Coastal Africa - 01x03 - Golden Forest Eng

At the southern tip of Africa...

withstanding the full might
of the Atlantic...

a tiny kelp plant
grows up to take its place

in a forest like no other.

Racing for the sun,

it provides a home

for the secretive animals
of this coast.

From sex-changing fish
and spiky nursemaids

to the show-offs of the forest -

and the ancient hunters
that stalk them.

All coming together to create
one of the most fertile zones

on the planet.

Africa's Golden Forest.

(***)

(***)

(***)

(***)

It's a busy morning
in the kelp forest.

In the canopy,
Cape fur seals play and explore,

safe from the predators
of the open ocean.

Further down,
among the stalks,

Roman fish
patrol their empires.

Among the roots of the forest,

urchins and rock lobster
scour the rocks for food.

Unseen by all of them, new kelp
plants are being born -

a unique species of giant algae.

In this underwater sanctuary,

thousands of tiny spores
are making their way

down to the ocean bed.

Every hour,
each square inch

of these gigantic blades

releases some
65,000 microscopic spores...

Resulting in tens of millions of
spores being launched every day.

Those that survive
will grow into adults,

expanding the forest

that fringes Africa's
south-western shore,

stretching from southern Angola
around the tip of the continent.

The huge extent and abundance
of the kelp forest

seems to contradict the
harshness of this landscape.

On land, life along this
Atlantic coast is a struggle.

And the animals
that live here, like Eland,

Springbok and reptiles,

have learned to get by with
little food and even less water.

The ocean, too, seems brutal.

The Atlantic is unforgiving:

whipped up by oceanic winds,
it breaks onto a rugged coast.

And yet it is these winds
that make the forest

such an abundant place

and allow marine life
to thrive along this shore.

Powerful south-easters

continually blast
the sea surface,

causing an upwelling of water
from the ocean depths.

Millions of years of plant
and animal matter has decayed

and dissolved
into this deep water,

and now it surges up
to the surface,

as an incredibly rich soup
of nutrients.

The compost heap
of the Atlantic is drawn up

and dumped directly
onto this forest.

And the result: enough food to
support a diverse range of life

and huge expanses of seaweed.

For the spores drifting
to the forest floor,

food will not be a problem.

But before they can fight
for a place in the canopy,

they must claim their space
down below.

A tiny new plant
has one job to do:

hold on for dear life.

Once settled,
it grows a holdfast,

a root-like structure that grips
onto the rocky outcrops

of the ocean bed.

But these are
no ordinary roots.

Unlike its earthbound relatives,

this little plant absorbs
no nutrients from the sea bed.

Everything it needs is supplied

by the water
and the sunlight above.

But if it's going to grow
into a giant adult

and reach the surface
it must first focus

all its energy into holding on.

The sturdier the rock
to which it is attached,

the better it can grip against
the sweep of the ocean.

But where the baby kelp
can't anchor, it can't grow

and this forest is dotted
with clearings.

They might look deserted,

but even a forest clearing
is inhabited.

Here, a sandy bottom
provides an ideal home

for one of this ocean's
more elusive predators.

The Short-tail stingray,
the largest in the world.

These solitary hunters
can reach a length of 13 feet

and weigh up to 770 pounds.

Their lethal stinger,
up to 12 inches long,

is easily capable
of killing a human.

Yet despite their size
and vicious blade,

these are docile animals,

quietly scouring the sand
for their favorite meal

of crustaceans
and hard-shelled mollusks.

Clearings on soft sand
are no use to young kelp,

but a clear spot on rocky
substrate is a different matter.

Boosting their chances of
finding the ideal landing zone

are smaller species of seaweed

that endlessly
sweep the forest floor clean.

But this sweeping is not
just good housekeeping.

Their lashing fronds
are also keeping at bay

a pack of particularly
voracious neighbors.

Sea urchins.

Living in large groups,
with as many as 50 urchins

crowding each square yard,

they slowly scour the sea bed,

grazing on young plants
and tasty holdfasts.

Their spikes ward off would-be
predators like starfish

and octopuses.

What's hidden beneath their body
is even more imposing:

a small but ferocious mouth,

ringed with five
self-sharpening teeth

that make short work of kelp.

Left unchallenged,

they can decimate entire
expanses of young forest.

But one plant's predator is
another creature's protector.

While the urchin presents
a life-threatening problem

to the young kelp plant,

they act as nursery nannies
for one rare cold-water snail:

the abalone.

(***)

(***)

(***)

(***)

(***)

(***)

They are part of the fabric
of this forest,

their shells are so overgrown
that they merge into the reef.

Abalones are slow developers.

They're only ready to reproduce
when they're 8 years old.

Scientists believe
that the stimulus to spawn

is a sudden change
in water temperature.

It's a remarkable event.

Males release a cloud
of billions of sperm

into the surrounding waters.

When the cloud
reaches the female,

she gives a dramatic response:

powerful contractions
expel torrents of eggs

into the water.

Within a few minutes, millions
are released to be fertilized.

The numbers are vast, but most
fertilized eggs will perish.

This reproductive overkill
has a vital function.

The odds are so heavily stacked
against survival:

it's the only way to ensure
a few eggs get the chance

to develop into adults.

The larvae swim close
to the ocean floor.

They're incredibly vulnerable;

the perfect snack for filter
feeders like shrimps.

But abalone larvae have
a remarkable alliance

with one forest-dweller:

the urchin.

The larvae are waiting for their
cue to attach to a rock.

Their green light
is a chemical signal.

Encrusting coralline algae
releases an amino acid

into the water,
beckoning the abalone larvae

to settle and start
to form a shell.

And once they are ready
they meet their nursemaids.

Less than a half an inch long,

the abalone creep in under their
nanny's prickly petticoats.

Here they will be protected
from hungry octopuses,

fish, starfish and crustaceans -
and get free nibbles

dropped by the urchin
as it eats.

When the abalone
is strong enough,

they'll venture out from
under their spiny nursemaids

and grow thick,
camouflaged shells.

It's a fragile equilibrium
on the forest floor.

Too many urchins
grazing these rocks

and no young kelp plants
would survive.

Too few urchins
and juvenile abalone

would be exposed to danger.

Nature's system
is kept in balance.

And keeping the urchins in check
is their nemesis:

the rock lobster.

The spiny defense
of the urchin is no match

for its formidable claws
and full-body armor.

The rock lobster has earned
its tough reputation.

And it started young.

While the abalone were
sheltering under their nannies,

this extraordinary animal
was embarking

on one of the most incredible
journeys of the natural world.

As soon as he hatched,
just 1/16th of an inch across,

he floated out
into the open ocean.

Drifting with the currents
for up to seven months,

still no more than
two inches long,

he journeyed in a great loop -

from Africa almost as far
as the South American coast

before he rode the current
back home.

By the time he returned
to the kelp forest,

he had molted 11 times,

shedding his carapace
again and again as he grew,

until he had transformed
into a young adult.

As soon as he arrived
in familiar waters,

he set up camp in a crevice in
one of the vertical rock walls

that define this submerged
landscape.

Here he grew into
a formidable predator,

with thick armor,

a muscular tail
and powerful claws.

He's not alone
in his rocky lair.

Away from the surging sweep
of the forest floor,

the water around this wall
is relatively still

and steeped in microscopic
plant detritus.

This allows filter feeders
to thrive here,

from sea squirts
to anemones...

soft corals to sponges.

They're a convenient snack
for the lobster.

But for him, the main benefit of
this perch is that it offers him

relative safety
from a cunning hunter.

A predator that is not only
agile, quick and dexterous,

but is also considered by many
to be the most intelligent

invertebrate on the planet.

The octopus is a cephalopod,

a word which translates
literally as

"feet around the head".

It's part of the mollusk family,
a distant relative of the snail.

But there's nothing sluggish

about this brilliant master
of camouflage.

It can adapt the color
and texture of its skin

to ambush its prey.

And it has a taste
for rock lobster.

Eight suckered arms
can prize open any shell...

the lobster is wise
to back away...

In the battle between
predator and prey,

animals may vary the
color of their skin,

like the octopus
or their body shape,

like the rock lobster.

But one animal undergoes

the most dramatic transformation
of all:

it changes its sex.

Roman are territorial.

This one's empire could be
up to 32,000 square feet,

but it's worth putting in the
effort to defend its borders.

This fish preys on
crustaceans,

sea urchins
and even octopuses,

and with a patch of this size,

there is plenty of food
on offer.

If it manages to keep
challengers at bay,

it could be a long
and successful reign:

Roman can live up to 30 years.

Like all good emperors,
he protects his subjects,

in this case,
smaller females.

But he wasn't always emperor.

In fact, he wasn't always
a male...

once, he was a she.

Roman are born as females,

growing up under the watchful
eye of a protective male.

Little more than
eight inches long,

they are content to be
members of his harem.

But as soon as they reach
twelve inches,

the stunning change occurs.

Females transform into males
by modifying their sex organs

and suddenly
what was a quiet harem

becomes a serious threat
to his crown.

It's an effective strategy.

Smaller males could never
compete with the emperor

and so by remaining female
they benefit from his protection

while they grow strong enough
to challenge him.

When night falls, this male
will retreat to the rocky wall.

But until then there are borders
to patrol, and worms to hunt.

Sex change is an extreme
survival strategy.

For other species, however,

simply holding on tight
is enough.

In this territorial forest,
the Roman might be an emperor,

but this adult limpet
has its own kingdom to patrol:

the growing stem
of the kelp plant,

covered in the limpet's
staple diet of algae.

Rival limpets are bulldozed
off the stem.

But some neighbors
are tolerated.

Kelp snails are only after
the blades of the plant

and don't compete for the food
on the stem.

The limpet moves imperceptibly,

rippling its muscular foot
hidden beneath its shell.

To eat, it scrapes the algae off
the kelp stem with its radula,

a ribbon-like tongue
with rows of teeth.

The limpet has adapted to live
exclusively on this plant.

The shell of an adult limpet

is shaped to fit
its cylindrical home.

As young ones, they hide
at the base of the fronds

only moving out onto the stem

when they are big enough
to graze and claim ownership.

It's a large kingdom
for a tiny limpet to patrol

and each day his territory
is growing bigger.

Kelp grows at
an incredible rate.

Light powers the Golden Forest

and it needs to get its
chlorophyll-producing fronds

to the surface
as quickly as possible.

As it races towards
the sunlight,

it can shoot up by
half an inch a day.

No wonder this type of kelp
called the bamboo of the ocean.

The little plant
that drifted down here

and locked onto the rocks
has done well.

Now it is well on the way
to growing to a height

of around 39 feet.

Enormously tall in relation
to its narrow trunk...

this forest tree has developed
a unique way to stay upright:

the stems are hollow
and supported by gas bladders

called pneumatocysts.

The blades, too,
are kept afloat.

A floating bulb just beneath
the head of the plant

makes sure that the blades are
held up to the precious light

at all times.

Ultimately all life here owes
its existence to photosynthesis,

from algae to apex predators.

And enjoying life in the middle
of this dynamic food chain

are the forest's most
charismatic creatures.

(***)

(***)

(***)

(***)

(***)

South African fur seals.

The show-offs
of the Golden Forest.

They thrive here
in huge numbers,

living on the same rocky
coastlines carpeted by kelp

and fed by the same bounty that
nourishes the Golden Forest.

For youngsters, identifiable
by their darker pelts,

the forest is a playground.

They're having fun,
but they're also learning skills

that will mean the difference
between life and death.

(***)

(***)

(***)

(***)

(***)

(***)

(***)

Soon they will be old enough to
leave the protection of the kelp

and venture out into the
Atlantic to hunt for fish,

squid and crabs.

When they do, they will be
entering dangerous waters -

the territory of the ocean's
ultimate predator:

the Great White shark.

This abundant ocean provides
plenty of food for the seals;

adult males can grow
to be over six feet long

and weigh up to 660 pounds.

But even the biggest seal
is no match for a 16-foot,

one-ton Great White
swimming at a top speed

of 31 miles an hour.

The super-predators
have perfected

their hunting techniques,

often attacking seals from below
with such force

that they can breach
the surface of the water.

Once a seal is caught,
escape is extremely unlikely.

In many instances,
it takes less than two minutes

from the first impact
until the victim has been eaten.

To survive, these animals
will need agility

and lightning-quick reflexes.

The open water is still too
scary for the youngest pups.

While the teenagers play
in the deeper water,

they hang back in the canopy.

Close to their
low-lying island home,

the seals can use the
upper canopy as day-care

for their pups,
as they go out to hunt.

Baby seals have to
learn how to swim

and this shallow zone
is a safe paddling pool

for the youngsters making
their first tentative outings

into the sea.

But further out,
the forest's dense cover

is a double-edge sword.

If it can hide seals,
it can also hide predators.

Great White sharks tend to avoid

swimming into dense underwater
vegetation.

But there are other hunters
in these waters

that haunt the thick kelp.

Which might explain
this peculiar behavior.

It seems nothing more than
playful vandalism,

but there may
be more to this than fun.

One possible theory is that
this game of cropping kelp

might reduce the chance of
surprise attacks by sharks.

By clearing kelp
from certain areas

and opening up sight-lines,

it is possible that seals
will be able to spot

an approaching predator sooner

and will have precious seconds
to flee.

For now, though,
these seals are safe to play.

A favorite game:
tormenting a potential meal.

The lobster
is wise to play dead.

His sharp claws can give seals
a painful pinch

and they're
handling him with care.

But even with his claws
and tough shell

he's unlikely to
come away from this unscathed.

Not that everything that wanders

into this forest
is edible, though.

This box jellyfish might look
like a treat to the adults

and a toy to the babies,

but all the seals know
that it packs a vicious sting.

It swims on, unharmed.

But the seals must
stay on their guard

because another stealthy
visitor is slipping

into the forest unseen...

Sharks are some of the most
ancient animals in the ocean.

Supremely equipped to survive
in a variety of conditions,

they have changed very little

over hundreds of millions
of years.

And one of the most primitive
of all shark species is this -

the cow shark.

(***)

(***)

(***)

(***)

(***)

With is seven gills
and smoothed features

it would look at home
in ancient seas.

The cow sharks have come here
to hunt seals,

but beyond the
protection of the forest

they, too, are at the mercy
of the Great Whites.

For one, a horrific reminder
of what happens

when predator becomes prey:

most of its tail
has been bitten off.

Without the ability
to maneuver or accelerate,

hunting will be difficult.

It might even starve.

Unlikely to escape larger,
faster sharks,

its next brush
with a Great White

will almost certainly
be its last.

Here, at least, it finds
temporary sanctuary.

Among the soaring stalks,
it is safe.

Kelp is a sun-loving giant.

Photosynthesis is the life blood
of this forest

and up here in the canopy
is where the work is done.

The blades are multi-dimensional
synthesizers:

there is no top
or bottom side.

It makes no difference
how wildly

the ocean waves thrash them;

the entire surface of the fronds
can take part in photosynthesis.

It is an endlessly
renewable engine

that keeps the entire
ecosystem running.

But more than that,
it is a life-saving shield.

The waves that roll in off the
Atlantic are highly destructive.

Each surge is packed with energy

and when they collide
with the shore

they release that power
in an unrelenting bombardment.

But where the kelp forest
thrives,

it creates a huge buffer.

Instead of hitting the rocks
with their full force,

the waves and their energy
are absorbed and diffused.

By the time the Atlantic
reaches the shore,

its destructive power
has been subdued

and instead of wrecking
the coast,

it brings a bonanza of food.

Species that would otherwise be
washed away can flourish

in the intertidal zone.

Marine creatures
are not the only ones

that owe their success
to the kelp.

Evidence suggests that
it was access to shellfish

along southern Africa's coasts

that enabled early humans
to thrive -

A protein-rich diet that helped
to increase their brain power.

Without kelp, the shellfish
might not have flourished

on the rocky shores and without
shellfish to harvest,

our ancestors might
not have developed

their most potent tool:
the human brain.

Kelp is tough, but sometimes
the Atlantic wins.

Pounded to breaking point,

some plants are torn free
and tossed up onto the shore.

But even in death, they support
the life of this coast.

Sand hoppers appear
from underground

to feast on the rotting kelp.

Up to 25,000
of these tiny animals

squeeze into every
square foot of this beach -

all sustained by
the rotting kelp banquet.

There's plenty to go around:

sand hoppers eat up to

700 pounds of kelp
every year.

They're not the only creatures
tucking in.

Once it's dark,
giant isopods emerge.

These large crustaceans,
related to crabs and shrimp,

have lain buried near
the high-tide mark.

Now, they too
join the feeding frenzy -

yet another species kept alive
by this incredible plant.

(***)

(***)

(***)

(***)

(***)

(***)

(***)

(***)

(***)

(***)

(***)

(***)

It's not only the shore
and the kelp that benefit

from the Atlantic upwelling.

Nutrient-rich waters also feed
huge schools of pelagic fish,

such as anchovy.

And a school of anchovy
is a feast for a super-pod

of dolphins.

The Golden Forest
is a world in balance -

a buffer against
the violence of the ocean

and home for fragile animals.

But every year or two,
for a few grim days,

this underwater
heaven transforms into hell.

The oceans are full of algae,
but sometimes

some microscopic
species grow out of control,

reproducing in huge
and unsustainable numbers.

Here on the southwestern coast
of Africa,

these harmful algal blooms

are caused by a sudden lull
in the winds.

With huge volumes
of nutrients in the water,

but no wind
to stir the surface,

algae multiply dramatically,
devouring oxygen.

The murky water
has become anoxic:

the animals of the Golden Forest
are being suffocated to death.

Desperate, they go to the one
place with plenty of air -

but it's the one place
they can't survive.

The seagulls gorge
until they can't eat any more.

Harmful algal blooms
are an apocalyptic event

in the Golden Forest.

And yet, for all
the destruction they cause,

they cannot kill
the forest itself.

The kelp survives;

ready to nurture new life
around its stalks and fronds.

The upwelling continues

and the nutrients
flood the coast once again.

The forest is resilient.

The plant that started
as a tiny spore

is itself flooding
the ocean with spores.

Soon a new kelp plant will
anchor itself onto these rocks.

The Golden Forest
will be renewed.

In the teeth of the south wind

and the pounding waves
of the Atlantic,

kelp is more
than just a plant.

It is a nursery...

a provider...

a hunting ground...

a playground.

Africa's Golden Forest.

A world beneath the waves.