All language subtitles for PBS.Nature.Living.Volcanoes.1080p.HDTV.x264.AAC.MVGroup.org

♪♪

NARRATOR: We live on
a restless planet.

Every day on Earth,

around 30 volcanoes
violently erupt.

♪♪

By exploring the planet's
most active volcanoes today...

♪♪

DR. MARLOW:
This is amazing.

♪♪

NARRATOR: ...we discover how
they hold the secrets

to the origins of life...

♪♪

...how they continue
to shape our planet...

DR. GIAMANCO: Without volcanoes,
there wouldn't be life on Earth.

NARRATOR:
...and how life has adapted

to thrive in their shadows.

PORTER:
It's a destructive force,

but it's also a force
that makes life possible.

NARRATOR: Volcanoes are not just
forces of destruction.

They are the life blood
of our planet.

♪♪

[ Theme plays ]

♪♪

♪♪

♪♪

♪♪

NARRATOR: Our world is bursting
at the seams.

There are hundreds of
active volcanoes on Earth,

each one capable of exploding
with little warning.

At any one time, up to 30 of
these active volcanoes

are in an eruptive phase.

♪♪

Viewed from space,
patterns begin to emerge.

♪♪

One of the most active volcanoes

is in the southwest corner
of the Pacific,

in the island nation of Vanuatu.

♪♪

This tiny archipelago is home
to a very special volcano.

Producing more poisonous gas
than almost any other volcano

in the world,

Marum is a sight to behold.

And at its heart
is a rare lake of lava.

♪♪

The conditions here
have attracted biologists

Dr. Jeffrey Marlow

and Dr. Jens Kallmeyer

to conduct
a pioneering expedition.

♪♪

DR. MARLOW: So we're in the
Vanuatu island arc.

It's a chain of active
volcanoes, many of them.

We can see some
amazing volcanoes off this way.

We're on an island
that has two very active ones

and we're going up there
right now.

♪♪

NARRATOR: Jeff is going
to descend into the crater

to search for extremophiles,

micro-organisms that are some
of the toughest

forms of life on Earth.

DR. MARLOW: I study life
in extreme environments,

but this is certainly

the most extreme environment
I've been to.

This is my second expedition
to Marum,

but I have no idea
what to expect.

Entire cliffs can fall away
or be created.

The landscape inside the crater
is constantly evolving.

DR. KALLMEYER: Wow.
Holy crap.

♪♪

DR. MARLOW: This lava lake
is going like crazy!

♪♪

DR. KALLMEYER: I'm a geologist
for 20 years,

but I've never seen
anything like that.

♪♪

NARRATOR:
Lava lakes are rare.

Only a handful of volcanoes
in the world

host active pools
of lava like this.

♪♪

Two hundred feet wide,

it's a giant gateway
to the planet's beating heart.

♪♪

What the team finds here
could change the way

we think about the extremes
of life on Earth...

♪♪

...and could also help us
understand

the likelihood of finding life
elsewhere in our universe.

♪♪

DR. KALLMEYER: Heck, this is
where we are about to camp!

NARRATOR: This small camp
is going to be home for the team

for the next few days.

DR. MARLOW:
Home sweet home.

NARRATOR: Meeting the scientists
on the summit

is expedition specialist
Chris Horsley.

Chris is an expert
in rope access and rigging.

He's climbed in some of
the world's

most dangerous environments.

He's been on top of the volcano
for a week,

setting up lines and anchors,

ready for the journey
to the bottom of the crater.

He wastes no time
in getting everyone together

to discuss
the challenges ahead.

HORSLEY: Essentially, guys,
everything up here

is trying to kill you.

We've got volcanic shards of
glass flying through the air,

acid rain, sulphuric clouds,

and a 400-meter vertical cliff

that if you fall off,
there's no return.

Our rigging place
is just over here.

That's going to be
then a 200-meter rappel,

and we can find
our best anchor point

to re-anchor our ropes
that are going to take us

all the way down to the bottom

and to the boulder field
that's located over here.

DR. MARLOW: Our main goal
of being here

is to see if there's
any life inside the crater,

and when we do get down
to the bottom,

how close do you think
it is possible to get?

HORSLEY: If any point,
I think it's too dangerous,

or I'm worried about
your safety,

I'm gonna pull the pin
and take you out of there.

This is one of these rare
examples

of something that is so vicious

and so angry that more people
have been in to space

than have visited
this insanely magical place.

DR. MARLOW: So after
our safety briefing,

I feel a little bit more nervous
than I might have been.

We're going to be sampling
as we kind of approach

the lava lake itself,

and we want to know
when life stops,

when it's too hazardous
for anything to survive.

The samples we're after
are extremely rare

and they're gonna tell us,

hopefully, some really important
things about the way life works

and the possibility
of how life could exist

elsewhere in our solar system.

So I'm hoping
we can do all that.

Do it in a safe way
and kind of meet

the time constraints
that we have.

NARRATOR: The team
settles into camp

and starts preparing
for the descent.

Earth's volcanoes
are not limited

to far-flung tropical islands.

Erupting volcanoes are found
on every continent.

And while Marum continues
to erupt,

one of the planet's
largest volcanoes

rips the Earth into pieces
on the southern edge of Europe.

♪♪

Mount Etna has been erupting for
around half a million years...

...and like Marum,
it might hold precious clues

to how Earth became
a planet fit for life.

♪♪

It ebbs and flows...from periods
of relative peace...

...to catastrophic eruptions

that threaten the lives
of those that live closest.

Yet for some, living here
is a gamble worth taking.

[ Birds chirping ]

The soil created by Etna's
eruptions produces

some of the richest agricultural
land and finest wines

in the whole of Italy.

The unique way of life
on the slopes

of Europe's
most active volcano

is what drew
Dr. Salvo Giamanco here.

It's his job to help predict
Mount Etna's next move.

DR. GIAMANCO: Most of the people
living here

see Etna as a Mother,
and like all mothers,

she gives us life,

through the vegetation,
the plants.

But like all mothers,

she, you know --
sometimes she slaps us

in the face,

and she reminds us of the rules
that are in this environment.

NARRATOR: Most of the year,
Etna de-gasses...

...and the gas offers
precious clues

to what's happening
inside the volcano.

DR. GIAMANCO: You can think
of an eruption

a bit like the opening
of a Spumante bottle.

Before opening it,
you don't see the gas.

It's a liquid that stays there

without showing signs
of any activity.

But once you start
to open the bottle,

You'll see the gas
suddenly forming bubbles,

and those bubbles will give
the final energy to the magma

to rise to the surface
and eventually erupt.

So the gas is the real engine
of eruptions.

NARRATOR: As gas drives
volcanic eruptions,

Salvo and his team are today

trying to determine how much
is coming out of the volcano.

Different types of gas
are released

when the magma rises
to certain depths.

An increase in particular gases

could mean that magma
is racing towards the surface.

♪♪

And this close to the volcano,

even a small eruption
could have deadly consequences.

DR. GIAMANCO: There are many
risks when working here.

The gases,
they are highly corrosive.

♪♪

And also we are on the rim
of the central crater,

where an explosion may occur
at any time.

NARRATOR: It's a race
against time

to get the data and get out.

DR. GIAMANCO: Each time
the gas passes

in between the infrared source
and the sensor,

we get a lot of dips
in our spectrum,

each one corresponding
to a specific gas species

and each one giving us

the concentration
of that specific gas species.

NARRATOR: Today, the team
doesn't see any drastic changes

in the level of gases,
yet there is one gas in the data

that is more important
than nearly any other.

DR. GIAMANCO: So we see
carbon dioxide,

we see chlorine,
we see fluorine,

we see sulphur dioxide.

But the most important one
is water vapor.

From its liquid state
to its vapor state,

it increases its volume
by 1,000 times.

NARRATOR: Water vapor is
a driver of volcanic eruptions,

and on any given day...

Mount Etna releases
hundreds of thousands of tons

of it into the atmosphere.

DR. GIAMANCO: So every time
a volcano erupts,

every time a volcano breathes,

it emits this life-giving gas.

NARRATOR: The origins of water
on Earth have been debated

by scientists
for hundreds of years.

♪♪

Some believe that water
was delivered by comets,

but recently,

there has been mounting evidence
for a different explanation.

♪♪

To explore this theory,

we have to wind the geologic
clock back 4 billion years

to a time when the Earth was hot
and still forming.

The idea is that water
has always been on Earth.

Trapped beneath the crust,
it's locked in liquid magma.

♪♪

But as the Earth's surface began
to cool and harden...

♪♪

...volcanoes acted like a tear
in the fabric of our planet,

allowing the water
to slowly escape.

♪♪

This water vapor then condensed
in our atmosphere

and fell as rain.

♪♪

It rained for so long

that eventually our dry,
barren Earth

turned into a Blue Planet.

♪♪

DR. GIAMANCO: Water that we see
on Earth

mostly comes from volcanoes.

Without volcanoes,
there wouldn't be life on Earth.

Literally.

♪♪

NARRATOR: As the sun sets
in Italy...

it's slowly rising in Hawaii.

One of the most remote island
chains on Earth

is continuing to be transformed
by the raw power of the planet.

It's the perfect place
to explore

how the interior of Earth
shapes life at the surface.

♪♪

Kilauea is the most active
volcano in the United States.

♪♪

Its summit crater is large,
but it's not necessarily

the most
dangerous part of the volcano.

♪♪

♪♪

The giant flank eruption in 2018

was the most devastating
in 200 years.

♪♪

As the volcano's main crater
collapsed,

millions of tons of lava

drained through a series
of underground tunnels...

♪♪

...emerging in the heart
of a residential community.

♪♪

♪♪

Seven hundred homes
were buried beneath molten rock.

♪♪

And 2,000 people
were evacuated.

♪♪

Forests burned and fragile
ecosystems were destroyed.

Amazingly, no lives were lost.

♪♪

♪♪

But the recent outbreak
in Hawaii

is just the latest in a long
line of land-creating eruptions.

♪♪

Hawaii was formed by a hot spot

of magma
beneath the Earth's crust.

As the magma reached
the surface,

volcanoes broke out,
creating islands.

♪♪

Over time, the tectonic plate

on which these islands sit
slowly moved,

and new islands were created
over the hot spot.

The island chain we see today

is 6 million years'
worth of eruptive activity.

♪♪

And it's still creating
new land today.

♪♪

♪♪

Despite the obvious destruction
caused by the volcano,

it may be having surprising,

positive effects
on the ocean ecosystem.

Following the recent eruption,

scientists from
the University of Hawaii

saw giant
phytoplankton blooms,

colored here in blue
on images taken from space.

Could this have been
caused by the volcano?

♪♪

Lava is rich in phosphate
and iron,

elements that act
as fertilizers.

In the enriched waters,
phytoplankton exploded.

♪♪

Phytoplankton is fed on by
larger zooplankton...

♪♪

...which in turn provides
food for larger animals.

♪♪

And nighttime is feeding time.

When plankton abundance is high,

it draws in huge sea creatures.

♪♪

♪♪

Ocean giants...

like manta rays.

They come each night
to feed on plankton

migrating up to the surface
from the depths.

Swimming with their mouths
wide open,

they scoop in water using
their modified front fins

and filter out
the tiny plankton.

♪♪

At the richest feeding sites,

they barrel roll to stay
within these nutritious plumes.

♪♪

♪♪

A single manta can consume up
to 50 pounds of plankton

in a single night.

♪♪

♪♪

♪♪

♪♪

Back in Vanuatu,
rain has started to fall.

It's an unwelcome complication
to the challenges that lie ahead

and bad news for the descent.

DR. MARLOW: So Marum crater
is the world's largest

point source of sulphur dioxide.

That sulphur dioxide mixes
with water in the atmosphere

and makes sulphuric acid.

When that rains down,
you're being bathed by acid.

The same thing that makes
our descent possible,

the idea of this kind of this
nice line down into the crater

is the same thing
that makes it hazardous.

It's where all of the water goes
when it rains.

So you're gonna have acid rain
pushing rock and sediment

down this water course at us,
at our ropes.

We need to wait
for a really good day

to make the full descent.

[ Teakettle whistling ]

♪♪

NARRATOR: Later in the evening,
Jeff uses a thermal camera

to find the best
sampling location in the crater.

DR. MARLOW: Wow.
That is insane.

♪♪

NARRATOR: The imagery
on the camera

gives Jeff information

on where he should be looking
for the extremophiles.

DR. MARLOW: The lava lake there
is off the charts, literally.

It's too hot to actually read
with this camera.

This spot right up here around
that plain

that we've seen
could be really appealing.

There are a lot of rock faces
that are facing the lava lake

and getting a lot of that heat
off of the molten rock.

That's probably a high
priority spot to go to.

♪♪

To imagine that tomorrow
I'm headed down there

is kind of terrifying.

I would say this is probably
one of the most inhospitable

places on the planet, umm...

It would be pretty
remarkable to me

if there's actually life down
inside the crater.

♪♪

NARRATOR: As Marum continues
to light up

the night sky in Vanuatu...

It's the middle of the day
in the heart of Africa,

and it's burning up
with geologic activity.

Three of the planet's
30 erupting volcanoes

are found here.

One of the tallest and most
active volcanoes in the region

is Ol Doinyo Lengai.

But far from
causing devastation,

the eruption here is just
what this ecosystem needs.

♪♪

While most volcanic ash
is full of silicates,

the ash from Ol Doinyo Lengai

is loaded with
carbon and minerals.

♪♪

As the ash rains down,
it transforms the grasslands

into a uniquely rich,
nutritious pasture.

♪♪

After millions of years
of volcanic activity,

the area has become
a vital stage

on the annual
wildebeest migration.

♪♪

The lush pasture is
a giant nursery

that draws in animals from all
over the Serengeti ecosystem.

♪♪

♪♪

♪♪

♪♪

More than a million wildebeest
alone

are nurtured
by the nourishing grass

that grows
in the shadow of the volcano.

♪♪

[ Wildebeest lowing ]

A lot of the planet's volcanoes
can sit dormant for centuries

before explosively erupting.

Life can become desensitized
to the risks they pose.

It's a dangerous game,
considering we live

on a relatively
thin crust of rock

wrapped around a molten
core of magma.

Ecuador is home to a number
of volcanoes

that can erupt
with little warning.

Cotopaxi is one such giant.

♪♪

Rising above 19,000 feet,

it's one of the planet's
highest volcanoes.

♪♪

But finding refuge at its feet
is a very special little frog.

♪♪

This is the Quito Rocket frog.

They were once common
across the Ecuadorian Andes,

but disease and climate change

have pushed them
to the edge of extinction.

♪♪

♪♪

[ Frog chirping ]
The tiny male sends

a high-pitched call
out through the undergrowth.

He's waiting for a response
from a female.

♪♪

Unfortunately,
there's no answer.

♪♪

And that's not too surprising,
as there are only thought to be

around 100 individuals
left in the wild.

♪♪

Like other disappearing species
of frogs,

he's one of rarest animals
in the world.

Along with the rest of his kind,

he now inhabits
just one small creek.

And if finding the last
of his kind isn't hard enough,

the volcano on which
this frog lives has awakened.

Cotopaxi's summit is home
to one of the world's

few equatorial glaciers.

♪♪

A catastrophic eruption here
would create devastating lahars,

boiling flash floods
created by the rapid melting

of snow and ice by the lava.

If the volcano were to erupt,

the stream that is home
to this little frog

would be transformed
into a hot mudslide.

♪♪

Thankfully, the Rocket frog now
has a helping hand

from a team
of scientists from Quito.

Andres and his team
are frog fanatics.

DR. MERINO: This is the last
known location

where this frog can be found.

It's very difficult
to find the frogs.

The best way to do it is try
to make them call to you back.

So we make the sound...
[whistling]

And that's the sound
of the mating call

so they can respond to us.

NARRATOR: The team is now
frantically collecting

the last remaining individuals
for a breeding program.

[ Whistling ]

If successful, they will release
a population back

into a safer stream,
out of the volcano's reach.

♪♪

For now, the fate of a species

is in the hands of Andres
and his team...

and Cotopaxi.

But back in Europe, some of the
animals found around Mount Etna

might have the upper hand when
facing off with a giant volcano.

The Argentata dell'Etna
is a breed of goat

found nowhere else in the world.

♪♪

Each morning, Gaitano herds
his animals out

onto the slopes of the volcano.

♪♪

The goats will eat
just about anything.

But Gaitano knows that
on the upper slopes of Etna,

there are glades
of a yellow flower

that he thinks gives
his goats' milk a unique taste.

♪♪

NARRATOR: Gaitano has been
working on the mountain

his whole life,
and in that time,

he's noticed some
bizarre behavior in his animals.

He believes that the goats
behave erratically,

not just during one of Etna's
eruptions, but before one.

[ Goats bleating ]

A team of scientists
using GPS tags

have now corroborated
Gaitano's theory.

The goats do, in fact,

seem to be moving off
the mountain before an eruption.

[ Bleating ]

It's as if they have
a sixth sense...

an intimate connection
to the Earth.

[ Bleating continues ]

Could it be the vibration
in the ground?

Or the smell in the air?

No one is sure what is
triggering their retreat.

But the next time you see
a humble goat

running in
the opposite direction,

it might pay to follow it.

♪♪

It's dawn in Vanuatu,

and today, the weather
is looking much more promising.

♪♪

In a few hours,
Jeff will come face to face

with the burning heart of Marum.

DR. MARLOW: I think anyone
would be terrified

going into this crater.

My family would think
I'm insane,

my friends would question

why this seems
like a good thing to do.

♪♪

There's an easier way
to do science.

That may be true but the samples
we're after are extremely rare.

So yeah, it's nerve-racking,
but taking these risks

for the science
makes a lot of sense to me.

-HORSLEY: Okay. Ready to rock?
-DR. MARLOW: Ready to rock.

Let's do this.
-HORSLEY: Cool. Awesome.

NARRATOR: The pair's
first challenge

is the 1,300-foot
vertical drop

down to the crater floor.

HORSLEY: The fear
and what's going on

in the back of your mind
there is a vertical cliff,

a lava lake in the background,

and so much lose material
all around you

that it's quite physically
and mentally demanding.

Right now you've got
all your trust in a nylon rope.

There's a lot of loose material
there

so we need to really careful
on where we put our rope,

especially in these stages.
-DR. MARLOW: Yup.

HORSLEY:
This is our biggest concern now.

-DR. MARLOW: Ready to do this?
-HORSLEY: Let's do it.

DR. MARLOW: Okay.

♪♪

HORSLEY: Okay, as soon as you
get to this bottom section

I want us
to get out of this water course

and move out of it
as quick as possible. Okay?

DR. MARLOW: Yeah.
This is the rock-fall zone.

HORSLEY: This is
a rock-fall zone.

Look at every stone
and make sure it's a solid step.

NARRATOR: Once they clear
the wall,

they come face to face
with the boulder field.

HORSLEY: And that's going to be
a nightmare to cross.

This unstable
plateau of boulders.

We're going to have to cut
across here, and then head down.

A tumble here could
certainly mean a fiery death.

As soon as we're on
that black ash plain, I'm happy.

♪♪

♪♪

NARRATOR: Just as Jeff and Chris
make it to the other side,

there's bad news
from the summit.

DR. KALLMEYER: Okay, just
a little weather update,

so it's still okay here

but the clouds
are definitely lowering

so we might be in for quite
a bit of rain pretty soon.

HORSLEY: Obviously it's
extremely acidic down here.

If it does rain,

we want to get out of here
as fast as possible.

NARRATOR: As the team approaches
the lava lake in Vanuatu,

in Hawaii, the eruption
is beginning to slow down.

The lava is starting to cool
and harden.

Despite the hostility
of the landscape,

it doesn't take too long for
life to spring from the ashes.

[ Birds chirping ]

♪♪

The Ohia Lehua is among

the first
to flourish in this new land.

♪♪

It's a tree native to Hawaii

and well adapted to living
on the lava flows.

♪♪

It helps to break down
the hard rock into soil

that will support
an entire ecosystem.

♪♪

It can take 200 years
of struggle for life

to reclaim
what was once its own.

♪♪

Few animals managed
to reach a speck of land

this far out
in the middle of the ocean.

♪♪

Those that did find a way
have been free to evolve

into new ecological niches
created by the volcano.

[ Creatures chirping, calling ]

This is certainly true
of the island's insects.

♪♪

Nearly every species
of caterpillar in the world

is a herbivore,
a plant eater.

♪♪

♪♪

Every species except for

But this caterpillar is not
looking for a leaf to eat.

His claws are better suited
to a more, lively meal.

♪♪

A planthopper.

♪♪

The best way to catch its prey
is to launch an ambush attack.

♪♪

♪♪

To stand a chance,

the caterpillar needs to find
some better camouflage...

♪♪

♪♪

♪♪

And then wait for its prey
to come close.

♪♪

♪♪

Tiny sensitive clasps on the tip
of its abdomen

will trigger the attack.

♪♪

♪♪

♪♪

♪♪

Hawaii is a land of strange
and bizarre creatures.

Isolated out in the Pacific,

ninety percent
of its native species

are found nowhere else
on the planet.

And the continual disturbance
by the volcano

has created a landscape
that can fast-track evolution.

But it's not just
the volcanic forests

that harbor unique
life forms.

♪♪

There is another hidden
ecosystem within the volcano.

♪♪

A secret labyrinth carved
by the flow of molten rock.

♪♪

♪♪

These caves were created
by underground rivers of lava

that have since run dry.

♪♪

♪♪

Annette Engel and Megan Porter
are here to search for creatures

that live in this underworld.

PORTER: The really amazing thing
about lava tubes

is that as soon as
that lava has drained,

and it's cooled,

then there are spaces available
for animals to live in.

NARRATOR: But the lava has left
an obstacle course in its wake.

ENGEL: Well I think I know
what's coming up.

Ugh.

I wish we didn't have to go
through the squeeze.

PORTER: The lava,
because it's so pointy,

you're trying to crawl through
a tube

that is like a porcupine,
it's got spines on it,

so it's catching everything
as you move.

NARRATOR: No sunlight delivers
energy into these caves.

For years, the scientists
were unsure

as to what could possibly
be living down here.

But thanks to a little help
from the surface,

there's an unusual and thriving
ecosystem inside the volcano.

PORTER: The roots come down into
lava tubes looking for water

and then those roots
also structure

the subterranean communities.

NARRATOR: The roots are like
a delivery system.

They provide tiny amounts of
sticky sap for life to live on.

PORTER: Ooo,
I think I found something.

ENGEL: Oh yeah?
What is it?

PORTER: Let's go ahead
and collect it and see.

-ENGEL: Yay!
-PORTER: Excellent.

NARRATOR: Many of these
creatures are descendants

of surface animals

that lost their way in the caves
back through evolutionary time.

♪♪

Like this translucent
thread-legged bug,

a relative
of the praying mantis.

PORTER: It's called
thread-legged

because it has very long thin
spindly legs.

It was first described
from some caves

on the other side of the island,
which is pretty far from here,

so we're pretty sure
that this is a new species.

I think there are so many
new species

in these sorts of environments
because of the volcano,

because it is just
such an active system,

it is both destroying
and creating new habitat,

that opens up space for species
to move underground

and to evolve
and to become very distinct.

NARRATOR: This is a fragile
ecosystem.

It's entirely reliant on the
ecosystem above for its support.

PORTER: If the volcano wiped out
the forest

above where we're standing,

that's gonna wipe out
the nutrient source

for this ecosystem,
because those root systems

are really the life blood
of the ecosystem down here.

But what we see is that
as the forest recovers

eventually then you have insects
that also move underground,

and so it's a cycle.

NARRATOR: And today, the cycle
of death and creation

continues on in Hawaii.

Nowhere on Earth have volcanoes
affected the circle of life

more than a few thousand miles
to the east, in the Galapagos.

This violent, volcanic outpost
is home to an array of animals

unique to these islands.

The giant tortoise
is one such creature.

♪♪

This individual shares
the island of Isabella

with the active vents
of the Alcedo volcano.

Tortoises are cold-blooded
animals,

meaning they rely on heat

from their external environment
to survive.

♪♪

Each year, they migrate up
to the crater

in search of new
feeding grounds.

♪♪

Along the way, they pause

and appear to bask in the warmth
of the active vents.

♪♪

And they snack on small bits of
volcanic rock

rich in minerals
and salts.

♪♪

♪♪

Even in a landscape
riddled with volcanoes,

life manages to find
a way to thrive.

♪♪

The team in Vanuatu
has finally reached

the edge of the lava lake.

The world that meets them
at the bottom

is full of steaming fumaroles
and toxic clouds.

Some of the water here
is as acidic as battery acid...

...but Jeff hopes that extreme
microscopic life forms

are hiding within the sediment.

He also wants to collect rocks
bathed in the radiant heat

and sulphurous clouds
of the lava lake itself.

Getting close enough for that

requires an extra level
of protection.

DR. MARLOW: The lava lake itself
has this magnetic pull.

This extremely deadly feature
makes you keenly aware

of how alive you really are.

NARRATOR: Months of planning
have led to this moment.

Despite the dangers,
Jeff pushes closer.

HORSLEY: Careful!
Really, really careful.

♪♪

♪♪

Watch out.

Please, please, careful.

NARRATOR: If the rocks here
harbor life,

it could be in forms
brand new to science.

For Jeff, the samples
are worth risking his life.

Before leaving,
he takes a temperature reading.

The lava lake is off the scale,

and the rock facing the heat
is over 150 degrees.

With the precious material
bagged and labeled,

Jeff and Chris begin
the long journey back to camp...

♪♪

...thankfully with some help
from motorized ascenders.

♪♪

HORSLEY: Okay.

[ Motors hum ]

DR. MARLOW: Life is found
almost everywhere on Earth.

But where is the line
beyond which life can't go?

What conditions are too much for
even single-celled organisms,

the bacteria and archaea,

or maybe even types of life
we've never seen before?

By sampling here,
we're seeking the very limits

of what life can endure.

♪♪

DR. MARLOW: We're alive!
Made it!

♪♪

We're alive!
Whoo!

NARRATOR: Discovering
microscopic life forms in Marum

could help the team reveal more
about the extremes of life

on Earth...

and could even build a better
picture of how life originated.

Extreme conditions created
by volcanoes

are not limited
to terrestrial environments.

♪♪

At the bottom of the ocean,

where the Earth's
tectonic plates part,

the seafloor comes alive.

Water and minerals,

heated from volcanic activity
beneath the surface,

form giant
hydrothermal vent systems.

It's thought that it was
in these kinds of environments

that life began
3.7 billion years ago.

♪♪

The planet's first
single-celled microbes

needed an energy source.

Harnessing the volcano,
they burst into existence

and ultimately evolved into the
myriad life forms we see today.

DR. MARLOW: And it's that same
process of producing

a lot of energy
and amazing gradients of heat,

and that's what we see down
here.

That's what makes volcanoes
really frightening

in a lot of ways.

They're very dangerous
because of that

but they also can provide that
spark that life needs to begin.

[ Generator rumbles ]

NARRATOR: Back in camp,
Jens and Jeff process

the material
taken from the crater floor,

looking for signs of life
from inside the volcano.

DR. MARLOW: We've stained some
of our samples

with a fluorescent dye

that attaches to
double-stranded DNA,

the genetic material of life.

If anything glows,
that's a positive sign.

-DR. KALLMEYER: Gotcha.
-DR. MARLOW: Yeah?

You found stuff?
-DR. KALLMEYER: Yep.

-DR. MARLOW: It's amazing.
-DR. KALLMEYER: Yeah.

Beautiful.

Nice and shiny.

DR. MARLOW: That's amazing.
There's life down there.

DR. KALLMEYER: Yep, we got
a few cells.

NARRATOR: Jens can see
luminous specs of light,

a telltale sign of cells.

The basic building blocks
of life on Earth.

DR. MARLOW: That fact that life
likely survives

in the crater is amazing.

These microbes can deal
with conditions

that you or I would think is
instantly deadly,

but to them it's home,

and they've managed
to eke out a living,

getting just enough energy
to survive.

What that means in terms
of life's origin

and its possibility
to exist on other planets,

is still up for debate
and we think

that this is a really good place
to start that quest.

NARRATOR: There are now
many months

of in-depth analysis ahead.

The samples collected
from the edge of the lava lake

were photographed
under a more advanced microscope

back in the United States.

♪♪

Further study is still needed,

but based on the team's
observations,

they're confident life
lives within a few feet

of one of the world's
most active lava lakes.

♪♪

If we are to look for life
among the stars,

then we need to know
what we are looking for.

The discovery in Marum builds
a picture of what life

might look like elsewhere
in our universe.

DR. MARLOW: This is the front
lines of astrobiology

and the idea of looking
for life beyond Earth.

NARRATOR: Considering the fact
that almost 30 volcanoes

erupt every 24 hours,
it's remarkable to think

that life has not
only managed to survive,

it thrives
on our violent planet.

♪♪

There's no doubt that life
in the shadow of a volcano

is full of risk.

But is it time for us

to re-align
our perception of volcanoes?

♪♪

We're not here in spite of them.

♪♪

We are here

because

of them.

♪♪

♪♪

♪♪

♪♪

♪♪

♪♪

♪♪

To learn more about what you've
se

en on this "Nature" program,

visit pbs.org.

♪♪

♪♪