Far beneath the ocean's surface,
thousands of feet down in the pitch black,
lies the world of inner space.
It's our planet's last great unexplored frontier,
a realm of strange, haunting creatures.
Alien landscapes,
and unexpected beauty.
Join us as we take the plunge into the deep ocean.
The journey to the deep begins in a small, acrylic sphere.
Its five-inch-thick walls
protect the pilot and our cameraman
from the enormous pressure
as they begin the dive to nearly 3,000 feet.
By 1,000 feet, it's already very dark,
and the water temperature is dropping fast.
For marine biologist turned film maker Mike deGruy,
there's no experience on Earth quite like it.
Down and down you go.
Now, mind you, there's no connection to the surface.
You're completely on your own.
You go up, down, sideways, backwards, spin around.
Man, that's when the fun begins.
It's got an acrylic sphere that you're sitting in,
about a seven-foot-diameter glass ball, and it vanishes.
If you're a claustrophobic person,
that's the sub to dive in.
You don't feel like there's metal around you.
It's a fantastic view.
Depth is 1,755.
The temperature is 7 degrees.
Around 2,000 feet down,
we enter the twilight zone,
a dim and featureless world
dominated by ghostly creatures like this tomopterid.
In a realm with little light and no hard surfaces,
animals like this squid have developed translucent bodies
with neither bones nor shells.
This giant schistosoma is five inches long
and almost completely see-through.
Inside its head,
two huge eyes strain to detect miniscule prey.
A relative, phronima,
inspired the monster in the 'Alien' movies.
But for now, this tiny huntress has taken shelter with her eggs
in the stolen body of a tunicate.
The twilight zone is home to an array of unusual creatures
found nowhere else in the ocean.
Some are at the mercy of the ocean currents,
but comb jellies have thousands of tiny rainbow-coloured cilia
to steer their course.
Sea gooseberries unfurl long, sticky nets to fish for prey.
But it's the siphonophore
that sets the ocean's most extensive death trap.
Attached to a single pulsating bell
are millions of stinging cells strung together
like Christmas lights.
Mesmerizing and deadly.
Down here, there's only a vestige of sunlight.
Human eyes can't see it, but others can.
Like this winteria
whose large, tubular eyes
can detect the faintest glimmer in the gloom.
Survival in the twilight zone
is all about seeing without being seen,
and hatchet fish are masters of hide-and-seek.
Head on, their slim bodies are barely visible,
and as soon as their mirrored sides catch the light,
they disappear completely.
Hatchet fish have also evolved an effective technique
for eluding predators stalking them from below.
Their bellies contain light-producing cells,
called photophores,
which change colour to match the shade of light from far above.
This counter shading breaks up its silhouette,
making it almost invisible from below.
Almost.
The tube eyes' vision is so sophisticated
it can distinguish between sunlight
and light produced by photophores.
One survival tactic outdone by another.
But escape and evasion techniques
may not be enough to protect the rare creatures of the deep,
as marine biologist Richard Lutz has come to realize.
Each and every dive that we go on,
we find something we've never seen before
and perhaps something someone will never see again.
We know in tropical rainforests
just how many species no longer exist.
We want to make sure in the deep sea
that we take a lesson from those actions
and make sure we don't do the same thing.
Descend to 3,000 feet
and we enter the bleak alien realm
beyond the reach of sunlight.
The dark zone.
Where the water is as cold as ice
and some of the most frightening creatures on the planet
are waiting to greet you.
3,000 feet down,
the dark zone is a dangerous realm.
The water is pitch black, near freezing,
and home to some of the most monstrous-looking creatures
on Earth.
Relative to body size,
these are the largest teeth in the ocean.
So big their owner can't even close its mouth.
They belong to the fang tooth,
a powerful, muscular fish.
It's an unusually aggressive hunter.
And with food in such short supply down here,
dark-zone predators can't afford to be finicky.
This fish, captured on film for the first time,
is a hairy angler.
Its highly sensitive antennae
can detect the slightest movement
of any prey careless enough to stray too close.
But one of the strangest fish yet discovered
is this nearly six-foot-long denizen.
The gulper eel.
Like a monster made from spare parts,
its whip-like tail hangs down from a massive head.
Gulper eels can unhinge their enormous jaws
to swallow a meal as big as themselves.
The gulper is a patient fisherman.
Hanging motionless in mid-water,
it waits for an unsuspecting victim
to approach its gaping maw.
And then...
it's lights out.
This world may be alien, but it's not without beauty.
Caught in the lights of the submersible,
a deep-sea jelly puts on an impressive display.
Oceanographer Craig Smith continues to marvel
at this astonishing world.
If you turn off the lights,
you see this amazing light show,
just this amazing light show of bio luminescence.
As the submersible goes down,
it hits jellyfish and other kinds of animals that luminescence,
and so it's like a meteor shower as you're going down.
It's just extraordinary.
Bio luminescence
is light generated by living organisms.
And for deep-sea angler fish,
it makes for some tempting lures.
This squid is intrigued by the glimmer of light.
It might just be food.
A satisfying meal
for a fish with a highly extendible stomach.
Other hunters, like this flash light fish,
use bio luminescence to search out prey in the darkness.
Most deep-sea bio luminescence is blue or green.
But a handful of predators, like this black dragonfish,
glow red.
Normally, red prey appears completely black
in the deep zone.
But under the predator's search light,
that cover is blown.
Unable to detect red light,
this cope pod never saw it coming.
Bio luminescence is useful in escape as well as attack.
A shrimp senses a threat.
It spins in the water,
releasing bio luminescent glue
that sticks to the pursuer.
Suddenly illuminated,
the attacker is now on the defensive,
vulnerable to its own predators.
These twinkling lights are produced by cope pods.
They probably flash like this to communicate with one another
and confuse predators,
like this pea-sized gigantocypris.
But when flashing doesn't work,
cope pods have another evasion strategy.
They discharge a shot of bio luminescent liquid
that's delayed.
Like a depth charge.
Spinning, confused,
gigantocypris chases after the flashes
while the cope pod slips away into the darkness.
With its inhospitable habitat and bizarre creatures,
these dark waters may seem like the last outpost
for life on Earth,
but we're about to go deeper still.
Straight down to the ocean floor.
Miles below the surface of the ocean,
there exists a fascinating frontier
rarely seen, barely explored.
The ocean floor.
To reach such extreme depths requires an extreme craft.
Unlike the Plexiglas sphere used before,
this titanium submersible, called Alvin,
can plunge nearly three miles below the ocean's surface.
A deep dive is just another day at the office for Mike deGruy.
Alvin takes three passengers and you're very cramped
and it's got small windows, but it's a workhorse.
It has done so many diverse dives.
A typical dive in Alvin might last 8 hours, 10 hours.
Something in that range.
Less than 12 hours, so you go down early in the morning
and you come up before sunset.
About 150 miles from the coast,
the ocean floor slopes downward
to an average depth of around 12,000 feet.
Without Alvin's lights,
this world would be completely dark.
Its waters are crystal clear
because organic matter rarely gets this far down.
This magical place has held several surprises
for oceanographer Craig Smith.
As you come down in a submersible
and get near the sea floor,
you gradually get some inkling that there's a bottom there.
And at first it just looks like
a Gray or brownish featureless area,
but when you get right down close and it gets well lit up,
all this structure leaps out at you.
It's just an incredible experience.
I expected to go down and see very little life on the bottom.
We got down there, and there was life all over the place.
These animals would die immediately
once out of this deep-water habitat,
so they're best studied through the porthole of a submersible.
Rocky outcrops provide good anchorage
for animals that rely on drifting food particles.
These crinoids, or sea lilies, look like plants,
but are, in fact, animals.
Long stalks allow their feeding tentacles
to reach into the current and sweep food into their mouths.
Coral reefs are not supposed to exist in total darkness.
But a new species has been discovered 6,000 feet down
in the icy waters of a Norwegian fjord.
This rare colony gets no energy from the sun.
So it has to be far more efficient in finding food
than shallow-water species.
To that end, the polyps of this deep-sea mushroom coral
have tentacles more than an inch long.
All the better to hunt with.
In this watery desert,
species have developed new survival tactics.
Unlike most tunicates, which are filter-feeders,
this one has become a predator
with a giant mouth-like trap.
Sea cucumbers usually stay firmly on the bottom,
but not this extraordinary species.
Its skirts of skin allow it to swim in search of nourishment.
This has to be the most extraordinary animal design
of all.
Most polychaete worms make their home in the sediment.
But on the ocean floor,
immobility can mean doom.
Propelling itself with its frill,
this unusual worm swims in open water
searching for food
while trying to keep from becoming someone else's lunch.
This chimaera is a close relative of the shark.
Sensory pits on its chin help it hunt prey along the ocean floor.
The chimaera's surprisingly large eyes
may help spot bio luminescent prey.
Large fish are rare down here.
There's simply not enough live prey to sustain them,
so most are scavengers.
A dead tuna has attracted two deep-sea monsters,
the conger eel
and a six gilled shark.
Six gills are living fossils.
This species has stalked these depths virtually unchanged
for 150 million years.
Very few people have ever even glimpsed these sharks,
and we know almost nothing about their behaviour.
A tuna is a substantial meal,
but on rare occasions, something much, much bigger
drifts down to the deep sea floor,
and when that happens,
an incredible cast of characters comes together
to feast on the bounty.
The carcass of a 30-ton Gray whale
has drifted thousands of feet down to the ocean floor.
An army of slimy-skinned hag fish
has already begun gorging on this bounty.
They attach their sucker-like mouths
to the side of the carcass
then rasp off the flesh with tooth like plates.
The next guest at the feast
was a surprise to oceanographer Craig Smith.
When we returned to the whale,
it had been on the bottom for about six weeks,
and one of the really exciting finds was giant sleeper sharks.
They get large, up to four or five meters long,
or at least 15 feet.
And this is an animal that no one had ever filmed
at the sea floor before.
It was really dramatic.
Unlike the hag fish,
the sleeper's powerful jaws
allow it to rip off huge chunks of meat.
Preserved by the icy water,
the flesh will feed this community of scavengers
for months to come.
A year and a half later,
it's almost as if a museum specimen
has been placed on the sea floor.
At first, the whale carcass seems to be stripped bare,
but there's still some flesh left in the head.
Hag fish are so flexible
they can tie themselves in knots for better leverage.
They'll stay until the bones are picked clean,
and after that,
microscopic colonies of bacteria
will start to consume the bones themselves.
I went down and was looking at this community of animals
living on a whale skeleton,
and I suddenly realized
that there are thousands and thousands of these animals
living on every square inch of the whale bones,
and there were potentially hundreds of species,
and this just blew me away.
This is quite a revelation to me.
It's very exciting.
To discover a new kind of habitat,
a new kind of community is really remarkable.
Around 10,000 feet down,
the continental slope flattens out
and joins the abyssal plain
which covers over half the Earth's surface.
Mostly it's flat,
but in places it's gashed by massive trenches
hundreds of miles wide.
The deepest of these is the Mariana Trench,
which drops to over seven miles below sea level.
Deep enough to swallow Mt. Everest.
There are just five manned submersibles worldwide
that can reach the abyssal plain.
Combined, they have explored less than 1% of it.
Fish have been found
right down to the bottom of the deepest trenches.
Most come from one family.
The aptly named rat tails.
They forage near the ocean floor
using their keen sense of smell
to follow odour trails from rotting carcasses.
Rat tails can travel long distances
across the abyssal plain
in search of food,
but other fish prefer to sit and wait.
This tripod fish supports itself
on two specially-adapted fin rays
and can rest motionless for hours.
Virtually blind,
it relies on a pair of highly-sensitive fins
behind its head
to detect the motion of potential prey.
Every dive to this unexplored frontier
produces incredible new discoveries,
and that's what keeps film maker Mike deGruy
coming back again and again.
From my perspective,
the beauty and the reason
that I enjoy diving in these submersibles
is because there are always surprises.
So, yes, I found surprises.
We found lots of surprises.
One of the things that I personally wanted to see
and film was a dumbo octopus.
I knew they existed and I knew where they lived,
but I'd never seen one.
And so that was a goal, a little personal goal of mine,
and we got it.
With its extraordinary flapping ears,
the dumbo octopus hovers effortless over the sea floor
in search of prey.
Right in the middle of the abyssal plain
lie the largest geological structures on our planet.
The mid-ocean ridges.
They extend for over 30,000 miles.
The longest mountain chain on Earth.
And on the other side of this sublime landscape,
a newly discovered world.
The mid-ocean ridge system
forms the longest continuous mountain range on Earth.
If the Andes, Rockies, and Himalayas
were strung together, they'd still be dwarfed
by this incredible underwater range.
The mid-ocean ridge is actually a series of volcanic mountains
rising from a seam in the Earth's plates.
As the plates slowly move apart,
magma rises from the Earth's core,
creating a surreal landscape.
Throughout the ridge,
towering volcanic chimneys pour out sulphide-rich water
as hot as molten lead.
Marine scientist Richard Lutz is a veteran of the vents.
We saw many spectacular chimneys,
some of which were 30 feet high.
They're the mountain peaks.
They're the small Everests on the bottom of the sea.
And herein lie the oases of life.
Those little islands of life that are down on the bottom.
Phenomenal life-forms that were beyond our wildest imagination.
But it's a dangerous place to explore.
One of the biggest fears that we have on the bottom
is with regard to the integrity of the sub,
given the 3,800 pounds per square inch on the outside.
The Plexiglas windows of Alvin will melt
at a little over 200 degrees Fahrenheit.
We have water temperatures at the vents
of up to 750 degrees Fahrenheit.
Should those windows get in contact with that hot water,
the implosion would be instantaneous,
and you would not even have time to kiss that sweet tush goodbye.
Despite this hostile backdrop,
life flourishes around the volcanic vents.
Pompeii worms make their home on the chimneys.
Few animals on Earth can tolerate such high temperatures.
And they aren't the only creatures living here.
The hydrothermal vent community is like nothing you've seen.
If you want to see an alien planet,
if you want to see something
that just is absolutely mind-blowing
in its diversity, in its magnitude,
in its vast number of creatures living
where nothing else is around,
go to the hydrothermal vents.
Whole communities of different organisms
have taken hold in the chimneys, like these gardens of mussels.
Swarms of white crabs
and hundreds of 3-foot-long tube worms
thrive near the vents.
Until these creatures were discovered,
it was believed that all life on Earth was dependent on the sun.
But these tube worms are packed with a kind of bacteria
that derives energy from the sulphides
pouring from the vents.
Just as green plants are the basis of life
for animals living in the sun,
these bacteria and other microbes
provide the foundation of life
for many specialized vent species.
Crab and shrimp feed off bacteria
and even try to snip off pieces of tube worm plumes.
Since biologists first visited the vents in 1979,
hundreds of new species have been identified.
And today, this extraordinary habitat
is giving researchers new insights
into the basis of life.
The vents have generated
a tremendous quantity of excitement
over the last number of years in the scientific community.
They've given us a window into really believing
that life itself may have originated
in these kind of environments.
And perhaps most significantly, they've given us a real belief
that there is a tremendous possibility
that life itself may exist on extraterrestrial bodies
within our own solar system.
But hot vents aren't the only hot ticket
in the deep ocean.
In the Gulf of Mexico,
there's a newly discovered weirdness that's so unearthly
it seems to defy all laws of nature.
Thanks to deep-sea submersibles like Alvin,
scientists have discovered astounding new worlds
at the bottom of the ocean.
They've been amazed that such a diversity of life could exist
in the extreme conditions
of this vast and seemingly barren plain.
Life on this planet started in the sea,
and here may lie some of the clues to its origins.
One of the strangest places on the ocean's floor
was only just discovered in the 1990s.
And Mike deGruy is one of a handful of people
to ever see it in person.
Without a doubt,
one of the most amazing things that I have ever seen
in the bottom of the ocean.
It was while filming for 'Blue Planet.'
It was in the Gulf of Mexico.
I noticed there's something out in the distance.
Couldn't tell exactly what, but it looked like a dark band.
And as we approached it, the dark band became a doughnut.
I saw this doughnut. It was black in the centre.
'What the heck is that?'
And so as we get closer and closer to it,
I noticed that the black band
had what appeared to be kind of steam over it.
And then I looked,
and there was water lapping against the shoreline.
This band was a ring of mussels.
And inside the ring of mussels was a lake.
And it's like, 'Wait a minute. I'm already underwater.'
We went out over the water in this lake
and tried to descend in it and bounced off.
It was so super saline and dense
that the submarine couldn't go down in it.
We literally bounced off.
And as we bounced off,
we sent ripples heading back to the shoreline.
It was insane.
I've never seen anything like it.
Scientists realized the lake itself,
bubbling with methane,
was actually a thick soup of salty brine
far heavier than the surrounding seawater.
An entire community lives on its shores.
Shrimp...
weird squat lobsters...
and bright red polychaete worms
make their homes in this unearthly habitat.
These methane leaks are called cold seeps
and are surprisingly similar to the hot vents.
Closely related animals flourish in both extreme environments.
There were just giant mounds of bivalves.
Clams and worms.
These beautiful tube worms. Just forests of them.
It was just this mound of life
with all sorts of associated creatures living in it.
Crabs and fish
and swarms of amphipods and cope pods.
Just a giant, giant community.
Amazingly, these tube worms
are over 200 years old.
Whereas the hot-vent habitat
can experience dramatic changes from year to year...
life here is slow and stable.
Unlocking this biological paradox
could be the key to solving many of our planet's other mysteries.
The deep ocean remains incredibly unexplored.
I guess this is an often-used phrase,
but we know more about the surface of the moon
than we do about much of the deep-sea floor.
I'm convinced there are all kinds of discoveries to be made.
New kinds of communities.
Remarkable species with undreamed-of adaptations.
The take-home message to the young future generation
is that you're just embarking
upon the age of exploration and discovery.
The most exciting discoveries have yet to be made.
They get to make them.
They get to go down to the vents and really figure out
whether life itself did originate at those vents.
They get to isolate those novel compounds
that may find cures
for many of the deadliest diseases that we have on Earth.
So far we have explored
just 1% of the deep-ocean floor.
Who knows what's still out there waiting to be discovered?
Craig, you have permission to surface.
One of the problems in doing deep dives and filming
is that these submersibles that we're using
were built for research, not film making.
They've had our two best lights...
the HMI's way up on the top... next to a big xenon spotlight.
And that works great for science.
Gives you nice flat light. Lot of information in the frame.
But that's not what we're interested in.
We want to get shadows and detail and darks and lights.
I had these guys build big booms that I could spread out
and put the lights way away from the camera.
It is ink blackness out there.
And I wanted to show what it looked like with lights.
Oh-ho-ho!
We had two submersibles.
And we would have one sub as a lighting ship.
And that was the big guns.
It would just fire up lights and back light these areas.
And I would be in a second sub.
In lighting the foreground, I could see detail,
but that second sub gave depth to it.
I saw views of these areas that I had never seen before.
Those are the sorts of subtleties
that we were going after...
a style of filming that I hadn't done before
and I don't think anyone had done prior to this.