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These images, taken
less than five years ago,
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were the first ever recorded
of that almost mythical inhabitant
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of the deep sea, the giant squid.
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Its body is over twice
the height of a man,
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its tentacles four
times that length.
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No-one before had seen it alive
in its natural habitat.
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Filming it was a historic triumph.
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Now, the scientists and cameramen
who captured this amazing pictures
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have teamed up once again to explore
still further the least-known part
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of our planet.
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They're armed with the latest
in deep-sea technology...
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..and a new highly sensitive camera
that can record pictures
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in near total darkness.
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The team is heading for a deep sea
gorge off the coast of California.
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And this time, they hope to reveal
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another of the ocean's
astonishments.
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Creatures that glow in the deep.
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It's so rich.
It's so bright.
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It's so thick.
It's so dense.
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It's so many different kinds
of luminous displays.
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And with them, the bizarre
animals that prey on them.
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This is a journey to the Earth's
darkest frontier...
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..to try and unravel some of the
secrets
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of these extraordinary living
lights.
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On the West Coast of California,
200km south of San Francisco,
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lies Monterey Bay.
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World famous for the richness
of its marine life.
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Cold Pacific currents bring
an abundance of nutrients
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into the bay, which support
great numbers of sea mammals.
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Whales.
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Seals.
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And, drifting among the floating
kelp, sea otters, floating leisurely
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on their backs, cracking open
shellfish on their stomachs.
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Beneath the surface of the sea lies
the largest underwater canyon
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off the coast of North America.
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Over 3,000 metres deep, and
rivalling in size the Grand Canyon.
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The jagged walls of the Monterey
Canyon drop down steeply,
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and create a unique underwater
landscape.
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The cold, sheltered waters provide
a home for many deep-sea animals,
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and new species are still
continually being discovered.
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Between 200 and 1,000 metres deep,
light gradually diminishes
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into blackness.
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This is the twilight zone,
where little sunlight penetrates.
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Many of the creatures that live
here produce their own light.
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The expedition plans to dive
down into this zone,
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guided by Dr Bruce Robison,
who's worked in Monterey Bay
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for many years and is a world expert
on deep-sea animals.
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We have been studying
this place for 25 years.
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And yet, we still find new animals.
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It is like treasure hunting.
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And you never know
the nature of the treasure.
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Robison himself has made many
discoveries in Monterey Bay
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over the years.
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But he knows well that exploration
here has only just begun,
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and all kinds
of astonishments may await.
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Now, the team will deploy his
specially designed research
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submersible for their first
exploratory dive.
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It's unmanned, but it carries
a camera that sends pictures
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to the surface by a cable.
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Three...
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Here we go.
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A pair of inquisitive seals come
to check out the strange machine.
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It slowly descends into deeper
waters.
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200 metres.
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Now, it's entered the twilight zone.
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So little light from the surface
reaches these depths that,
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to our eyes, it's
virtually pitch-black.
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It's time to turn
on the sub's lights.
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What is that?
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It's a strange, ribbon-like worm.
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We call them wiggle worms.
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And they are... They are really fun
to watch.
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Because they go through all
of these contortions,
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and they make spirals and circles
and loops.
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Well, they seem never to tie
themselves into a knot
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that they can't get out of.
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And then, another strange creature.
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Oh, it's a salp.
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Oh.
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The salp is, in fact,
not one individual,
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but a chain of nearly
50 linked together.
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Sea salps are jelly-like filter
feeders that suck water
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in through their tubular mouths
and filter out tiny food particles.
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DJ, let's stop on that.
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Robison has spotted something
else in the darkness.
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It's a kind of
comb jelly called beroe.
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Rows of tiny beaking hairs run
the entire length of its body.
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It's a magical sight,
but it's not bio-luminescence.
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The shimmer is merely reflected
from the light coming
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from the submersible.
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A small squid appears
in the headlights.
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It hangs in the water,
waiting for prey to get caught
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on its long tentacles.
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And it has a remarkably large eye
for such a small animal.
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Many creatures here have huge eyes.
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They need to be able to follow prey,
or pick out the shape of a predator
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in the near-darkness.
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And there are plenty of those
around.
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In the open ocean,
there is no place to hide.
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The submersible is now halfway
into the twilight zone.
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600 metres.
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They're hoping to see one
still little-known creature
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that lives at this particular depth.
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And here it is.
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A fish called the barreleye.
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Its extraordinary head is encased
in a transparent dome
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so that you can look right inside.
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Its eyes within the transparent
shield are enormous
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and point upwards.
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Robison first encountered
this bizarre animal
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over a decade ago.
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At this point, we were
very, very excited.
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Because no-one had ever seen one
of these alive before.
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Only specimens that
had been caught in nets.
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And as we watched it,
we realised that it looked
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very different than all
the specimens that had been
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collected by nets.
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This transparent dome over the eyes
had never been seen before.
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When you catch these in the nets,
that's all scraped off.
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It was an extraordinary discovery.
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And the strange fish
with a see-through head
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would make the headlines.
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While the transparent shield
was thought to protect
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the eyes, it was a puzzle
as to how the fish could catch prey
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with its forward-facing
mouth if it can't see
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what it's feeding on.
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It was a mystery that Robison
would also solve, some years later.
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Many of the creatures in the deep,
like the barreleye fish,
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defy imagination.
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And here's another.
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The black sea devil.
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It's a kind of angler fish,
with a bony rod and a luminous lure
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hanging from it, perched
on the top of its head.
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Every dive down to these depths
brings new discoveries.
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There's a black fish.
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Where? Oh, right there.
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Ooh!
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Ooh! It's an excellent dragon.
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Ooh!
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It's a deep-sea dragon fish.
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I thought that was
its red luminescence.
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Oh, really?
Yeah, yeah, yeah.
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The red spot just below
the eye is a photophore,
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a light-emitting organ.
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Even Robison has never seen
it in action before.
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Looks better to me. Good. Let's do
it.
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The sub has a special suction device
with which they might catch it.
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Oh! Ooh!
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But it's not easy.
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Oh, dear!
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Argh!
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Robison wants to bring
it to the surface so that he can
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study it closely.
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You got him!
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Got him! There we go!
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All right!
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Now, he'll have to act quickly.
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With the enormous pressure change,
the fish may not be able
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to produce its light for long.
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The deep-sea dragon is only ten
centimetres in length.
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But Robison is keen to find out how
its light-producing organ works.
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I think there's enough water in
there,
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unless you feel like you'd like
more?
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No. OK.
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To see the photophore in action,
they'll need some
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highly specialised equipment.
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The red light emitted
by the photophore is too weak
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to register on an ordinary camera.
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But the team has developed one that
is 600 times more sensitive.
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Tested outside on a clear night,
it produces an astonishingly sharp
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image of the stars.
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So, it should be able to detect the
light produced
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by bioluminescent animals.
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The team have set up a filming tank
in a darkroom with water
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that's kept at the same
temperature as the deep ocean.
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With any luck, the dragon fish
should behave relatively naturally
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in these conditions.
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Under normal lights, the fascinating
creature lives up to its name.
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It looks truly fearsome.
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And the two photophores are clearly
visible under each eye.
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But in the dark,
the photophores light up.
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They glow in unison.
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One red and the other blue.
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And then, a surprise.
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Ooh! Wow!
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This is something that no-one
has ever seen before.
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That's unexpected.
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And it's interesting.
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Ooh!
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It's a spectacular display.
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But what is its function?
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It could be to frighten
off a predator.
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But no-one knows.
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We may not find the answer
for many years yet.
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Bioluminescence isn't
limited to the ocean.
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It's found in creatures on land.
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Even in the air.
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Fireflies flash their lights
to attract a mate.
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Some woodland fungi glow bright
green, attracting insects,
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00:15:41,760 --> 00:15:44,440
maybe to distribute their spores.
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And at certain times of the year,
beetle larvae emerge from termite
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mounds and illuminate them
like Christmas trees.
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But in the deep ocean,
90% of the creatures produce light.
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And we still know very little
about why they do so.
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The only way to find
them in the pitch-black
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is to shine our own lights on them.
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00:16:14,840 --> 00:16:18,240
But when we do that,
it's impossible to see the much
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00:16:18,240 --> 00:16:22,560
weaker living lights
that the animals themselves produce.
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So, studying the phenomenon
is extremely difficult.
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The mysteries are how they use it.
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00:16:37,680 --> 00:16:40,720
What are they saying
to each other with that light?
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00:16:40,720 --> 00:16:43,760
The problem was that we never
had a camera that we could take
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00:16:43,760 --> 00:16:46,520
down and use to record
bioluminescence.
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00:16:46,520 --> 00:16:49,560
And that's why it was so important
for me to go down and see
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00:16:49,560 --> 00:16:51,000
it with my own eyes.
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Now, Robison and his team
have an opportunity to use
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00:16:57,640 --> 00:17:00,000
the latest technology
to tackle the problem.
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00:17:02,240 --> 00:17:06,440
They'll be working from the Alucia,
the same research vessel that helped
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00:17:06,440 --> 00:17:08,960
the film team find the giant squid.
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00:17:11,640 --> 00:17:13,160
Nice to meet you. I'm Toby.
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00:17:13,160 --> 00:17:14,520
Hi, Toby. Nice to meet you.
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00:17:14,520 --> 00:17:15,800
Felix. Felix, hi.
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00:17:15,800 --> 00:17:18,520
Hi, I'm Mark Taylor. Mark.
Yeah. Pleased to meet you.
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I've heard about you.
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00:17:21,200 --> 00:17:25,800
The high-sensitivity camera system
that took two years to develop
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will now be really tested.
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The crew carry out last-minute
checks on the submersible
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before its dive into
the Monterey submarine canyon.
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At the kind of depths
at which they'll be operating,
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every precaution has to be taken.
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The camera is carefully
installed on a mount attached
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to the outside of the submersible.
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At last, everything is in place,
and they're ready to go.
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I'm excited like a boy!
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I know I'm going
to have a lot of fun.
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00:18:16,120 --> 00:18:19,880
Robison has spent a good part
of his career exploring the ocean
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depths, but he still gets
excited before each dive.
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Welcome! Why, thank you!
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THEY LAUGH
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00:18:34,400 --> 00:18:38,200
After his submersible, the Nadir,
has been lowered into the water,
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00:18:38,200 --> 00:18:42,280
a second sub, the Deep Rover,
is also launched.
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RADIO BUZZES
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00:18:51,320 --> 00:18:52,920
Roger. Thank you.
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00:18:52,920 --> 00:18:54,960
Copy? Yes.
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00:18:54,960 --> 00:18:56,600
Good. OK, here we go.
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00:19:03,680 --> 00:19:05,280
We're ready.
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And the dive begins.
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00:19:12,640 --> 00:19:17,560
Their aim is to descend to a depth
of 600 metres into the middle
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00:19:17,560 --> 00:19:19,600
of the twilight zone.
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Sent to try me.
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00:19:26,600 --> 00:19:29,760
Soon, the light levels start to
fall,
252
00:19:29,760 --> 00:19:33,080
and they enter a dark blue world.
253
00:19:51,040 --> 00:19:52,720
Control, control.
254
00:19:52,720 --> 00:19:55,400
At a depth of 200 metres,
descending. Over?
255
00:19:57,600 --> 00:19:59,440
There's something upfront. Yeah.
256
00:19:59,440 --> 00:20:01,920
There's quite a long one there,
isn't there? Yes.
257
00:20:04,880 --> 00:20:08,560
This may look like a piece
of string, but in fact,
258
00:20:08,560 --> 00:20:12,400
it's a huge colony of living
creatures linked together.
259
00:20:12,400 --> 00:20:16,280
They're called siphonophores, and
are relatives of the jellyfish.
260
00:20:18,200 --> 00:20:21,640
Siphonophores are very unusual
creatures.
261
00:20:21,640 --> 00:20:27,240
They are a colony of individuals
all connected to one another.
262
00:20:27,240 --> 00:20:32,280
We have found individuals
that were 40 metres long.
263
00:20:32,280 --> 00:20:33,800
Longer than a blue whale -
264
00:20:33,800 --> 00:20:36,760
the longest creature on Earth.
265
00:20:39,440 --> 00:20:43,440
The individuals at the front
contract and expel water
266
00:20:43,440 --> 00:20:47,160
simultaneously, so slowly
moving the colony forward
267
00:20:47,160 --> 00:20:48,480
by jet propulsion.
268
00:20:50,680 --> 00:20:54,240
The rest of the chain
extend hairlike tentacles
269
00:20:54,240 --> 00:20:55,840
to catch passing prey.
270
00:20:58,280 --> 00:21:02,520
There may be hundreds,
if not thousands, of individuals
271
00:21:02,520 --> 00:21:04,240
in a single chain.
272
00:21:14,400 --> 00:21:18,800
Each one performs a particular
function and occupies a particular
273
00:21:18,800 --> 00:21:20,800
place within the colony.
274
00:21:20,800 --> 00:21:23,840
Much like the organs in our bodies.
275
00:21:23,840 --> 00:21:28,880
This super-colony works as a team,
but how individuals communicate
276
00:21:28,880 --> 00:21:32,520
with each other and coordinate
their movements is still a mystery.
277
00:21:38,400 --> 00:21:39,520
Ooh!
278
00:21:39,520 --> 00:21:40,600
There's a colobonema.
279
00:21:40,600 --> 00:21:43,320
Very, very pretty Medusa.
280
00:21:45,720 --> 00:21:50,600
Colobonema is a small jellyfish,
just five centimetres long.
281
00:21:50,600 --> 00:21:52,720
But it's a strong swimmer.
282
00:21:52,720 --> 00:21:56,360
And as the sub gets closer,
it puts on a turn of speed.
283
00:21:57,920 --> 00:21:59,840
See? He just dropped his tentacles.
284
00:21:59,840 --> 00:22:01,640
Oh!
285
00:22:01,640 --> 00:22:03,440
Cool. You got it!
286
00:22:07,160 --> 00:22:11,080
The small jelly sheds his
tentacles on purpose.
287
00:22:11,080 --> 00:22:13,400
It's a ploy to confuse predators.
288
00:22:13,400 --> 00:22:16,520
While our eyes follow
the discarded appendages,
289
00:22:16,520 --> 00:22:18,680
colobonema makes its escape.
290
00:22:27,200 --> 00:22:31,120
Control, control,
Nadir passing 570 metres.
291
00:22:31,120 --> 00:22:32,680
Descending. Over.
292
00:22:34,600 --> 00:22:37,840
The sub is nearing
the 600-metre mark.
293
00:22:41,280 --> 00:22:42,760
Oh! Stop.
294
00:22:42,760 --> 00:22:44,400
See that fish! Yeah, yeah.
295
00:22:51,000 --> 00:22:52,600
Slow, slowly.
296
00:22:56,400 --> 00:22:57,920
That's an owlfish.
297
00:23:00,920 --> 00:23:04,080
It seems to be scared
of the sub's bright lights.
298
00:23:10,440 --> 00:23:13,440
So the crew decide
to switch them off.
299
00:23:14,800 --> 00:23:20,000
They turn on a much weaker light,
adjust the sensitivity of the camera
300
00:23:20,000 --> 00:23:22,880
and the fish comes into view again.
301
00:23:22,880 --> 00:23:24,920
Wow! Nice.
302
00:23:24,920 --> 00:23:25,960
Wow!
303
00:23:28,040 --> 00:23:32,000
Like many deep-sea creatures,
the owlfish has a huge eyes,
304
00:23:32,000 --> 00:23:35,400
which can detect the faintest trace
of light, including the living
305
00:23:35,400 --> 00:23:37,480
light of its prey.
306
00:23:37,480 --> 00:23:41,040
The fish uses the very minimum
of energy and simply hangs
307
00:23:41,040 --> 00:23:43,600
in the water, waiting
for prey to swim by.
308
00:23:47,280 --> 00:23:52,680
You know, having a camera with
this sensitivity is very exciting
309
00:23:52,680 --> 00:23:56,160
because of the things it may
reveal - things that we don't even
310
00:23:56,160 --> 00:24:00,960
know are here, that may appear
for the first time, and again
311
00:24:00,960 --> 00:24:03,920
because we can work
with very low light.
312
00:24:05,200 --> 00:24:06,640
Oh!
313
00:24:09,960 --> 00:24:11,400
Oh, and here's a...
314
00:24:13,640 --> 00:24:16,560
It's the beroe comb jelly again.
315
00:24:17,760 --> 00:24:22,440
In the submersible's headlights,
it shimmers with refracted colours.
316
00:24:25,160 --> 00:24:28,560
But what would it look
like if the lights were off?
317
00:24:28,560 --> 00:24:29,760
Sure.
318
00:24:37,920 --> 00:24:41,480
In the dark, beroe produces
the most astonishing,
319
00:24:41,480 --> 00:24:44,800
intricate pattern of light
all along its body.
320
00:24:44,800 --> 00:24:47,240
This is bioluminescence.
321
00:24:55,960 --> 00:24:57,200
Oh, look at that! Ahh!
322
00:24:57,200 --> 00:24:59,160
Just here.
323
00:24:59,160 --> 00:25:00,880
Wow! That's a big one.
324
00:25:00,880 --> 00:25:02,520
That's a huge one. Holy cow!
325
00:25:02,520 --> 00:25:04,040
What a beauty!
326
00:25:05,800 --> 00:25:10,200
The striking red torpedo
is a periphylla jellyfish.
327
00:25:10,200 --> 00:25:14,240
It's a voracious hunter that uses
stiff tentacles to catch its prey.
328
00:25:18,240 --> 00:25:21,040
But it also has another
trick up its sleeve.
329
00:25:24,080 --> 00:25:29,200
That's a very luminescent animal
when it is stimulated.
330
00:25:34,320 --> 00:25:36,160
OK.
331
00:25:36,160 --> 00:25:39,720
So as not to scare it,
they switch to a red light
332
00:25:39,720 --> 00:25:41,200
which the jelly can't detect.
333
00:25:51,200 --> 00:25:55,080
And then, it starts a totally
different performance.
334
00:26:00,640 --> 00:26:04,600
It starts to eject
the tiny blue particles.
335
00:26:04,600 --> 00:26:09,000
They drift away, leaving a trail
of twinkling blue lights.
336
00:26:09,000 --> 00:26:10,320
What is going on?!
337
00:26:12,720 --> 00:26:13,880
No!
338
00:26:13,880 --> 00:26:17,600
Stay away, stay away, stay away,
stay away...
339
00:26:17,600 --> 00:26:18,880
Ahh!
340
00:26:20,040 --> 00:26:23,120
The crew try to keep away
from the jelly, but the currents
341
00:26:23,120 --> 00:26:25,560
created by the submersible
have disturbed it.
342
00:26:26,920 --> 00:26:30,680
Its response is to eject
its living lights.
343
00:26:44,840 --> 00:26:48,440
It seems that, if threatened,
periphylla tries to trick
344
00:26:48,440 --> 00:26:52,480
a predator into following
the glowing trail, and so enable
345
00:26:52,480 --> 00:26:54,440
the jelly itself to escape.
346
00:26:59,120 --> 00:27:02,760
Ooh, there's a tomopterid worm.
347
00:27:02,760 --> 00:27:04,480
Yes!
348
00:27:04,480 --> 00:27:08,800
The transparent worm seems
to crawl through the water
349
00:27:08,800 --> 00:27:10,440
with its bristly legs.
350
00:27:12,480 --> 00:27:16,880
But, when disturbed,
it also ejects glowing lights.
351
00:27:25,760 --> 00:27:29,480
Many other bioluminescent
creatures make an appearance,
352
00:27:29,480 --> 00:27:33,080
and the crew are able to capture
their displays with the new camera.
353
00:27:39,240 --> 00:27:43,800
Living in this twilight zone
depth range is very challenging
354
00:27:43,800 --> 00:27:48,880
for the animals that choose to live
here, because there are no rocks
355
00:27:48,880 --> 00:27:52,840
or trees or holes in the ground
where animals can hide.
356
00:27:52,840 --> 00:27:55,680
It's a truly three-dimensional
space,
357
00:27:55,680 --> 00:27:57,880
without boundaries or borders.
358
00:27:57,880 --> 00:28:02,520
Light is an extremely important way
that the animals deal
359
00:28:02,520 --> 00:28:04,680
with the challenges of living here.
360
00:28:15,840 --> 00:28:20,320
The team have been underwater
for nearly eight hours.
361
00:28:20,320 --> 00:28:22,320
It's time to come up to the surface.
362
00:28:31,400 --> 00:28:35,800
It's two days into the expedition,
and they're awaiting the arrival
363
00:28:35,800 --> 00:28:37,280
of a visitor.
364
00:28:46,160 --> 00:28:50,600
Dr Edith Widder is a world
expert on bioluminescence.
365
00:28:50,600 --> 00:28:52,800
Don't step on that! No! Thank you.
366
00:28:52,800 --> 00:28:54,960
How are you? I'm good, fine.
367
00:28:54,960 --> 00:28:58,000
She's worked with Robison
many times over the years.
368
00:28:58,000 --> 00:28:59,720
I can't believe this!
369
00:28:59,720 --> 00:29:01,400
Yes!
370
00:29:01,400 --> 00:29:04,480
Anyway, I'm glad you're here. I'm
glad to be here!
371
00:29:04,480 --> 00:29:06,280
I need all the help I can get.
Oh, yeah!
372
00:29:08,200 --> 00:29:13,040
Widder was part of the giant
squid exhibition in 2012.
373
00:29:13,040 --> 00:29:17,160
She had developed an electric
jellyfish that emitted flashing
374
00:29:17,160 --> 00:29:20,760
light, similar to that used
by deep-sea creatures.
375
00:29:20,760 --> 00:29:23,800
That had helped the team
to attract a giant squid
376
00:29:23,800 --> 00:29:27,120
so that they could film it alive
for the very first time.
377
00:29:27,120 --> 00:29:29,240
THEY CHEER
378
00:29:29,240 --> 00:29:30,760
Ooh! Oh!
379
00:29:32,960 --> 00:29:37,120
Now, Widder has brought along some
new gadgets that she's developed
380
00:29:37,120 --> 00:29:38,880
specially for this expedition.
381
00:29:41,640 --> 00:29:43,000
This is one of them.
382
00:29:43,000 --> 00:29:45,320
She calls it a "splat screen".
383
00:29:48,000 --> 00:29:51,560
If deep-sea creatures
unknowingly swim into it,
384
00:29:51,560 --> 00:29:54,920
she thinks they'll produce
bioluminescence, and their special
385
00:29:54,920 --> 00:29:57,040
camera should then
be able to film it.
386
00:29:57,040 --> 00:29:59,520
Oh, I think it's going to be
an incredible dive.
387
00:29:59,520 --> 00:30:01,800
I can't wait to try out
the new splat screen.
388
00:30:01,800 --> 00:30:04,840
And so, to be able to see now what
this camera's going to be able
389
00:30:04,840 --> 00:30:06,120
to see.
390
00:30:06,120 --> 00:30:09,360
Because, in those early days,
I didn't know what I was seeing.
391
00:30:09,360 --> 00:30:12,000
And over time, I've gotten
so I can identify a lot
392
00:30:12,000 --> 00:30:15,320
of the animals by the types
of flashes they produce, but I think
393
00:30:15,320 --> 00:30:18,680
that's going to be even easier to do
now with this camera system.
394
00:30:20,840 --> 00:30:25,160
Widder will work from the second
submersible, the Deep Rover.
395
00:30:26,680 --> 00:30:31,120
And Robison gets ready to head
down in the Nadir again.
396
00:30:33,200 --> 00:30:37,040
On this dive, they're planning
to descend right to the ocean floor.
397
00:30:47,280 --> 00:30:48,520
Control, Rover.
398
00:30:48,520 --> 00:30:53,760
My depth - 770 metres on bottom,
over.
399
00:30:55,800 --> 00:30:58,600
After an hour, they have made it.
400
00:31:03,400 --> 00:31:06,120
The sea floor is thronged with fish.
401
00:31:15,280 --> 00:31:20,120
Nutrients falling to the bottom
and accumulating there attract
402
00:31:20,120 --> 00:31:22,240
a great variety of animals.
403
00:31:22,240 --> 00:31:24,480
Isn't this a small little
sea pen just there?
404
00:31:24,480 --> 00:31:26,840
Yeah, that's what we wanted.
405
00:31:30,160 --> 00:31:34,000
Sea pens are coral-like creatures
that anchor themselves
406
00:31:34,000 --> 00:31:35,840
to the sea floor.
407
00:31:35,840 --> 00:31:38,400
They prefer deep waters,
where they're less likely
408
00:31:38,400 --> 00:31:40,360
to be uprooted by ocean currents.
409
00:31:43,960 --> 00:31:46,600
But they're not safe
from the robotic arm
410
00:31:46,600 --> 00:31:47,960
of the submersible.
411
00:31:51,480 --> 00:31:53,880
And, when touched, they glow.
412
00:32:04,800 --> 00:32:07,800
This is a different kind of sea pen.
413
00:32:07,800 --> 00:32:11,400
It produces a blue, pulsating light.
414
00:32:19,360 --> 00:32:23,200
Widder is keen to try out
the new splat screen to see
415
00:32:23,200 --> 00:32:27,280
if that will stimulate animals to
glow that they might otherwise miss.
416
00:32:28,560 --> 00:32:30,720
Are you ready for the screen up?
417
00:32:30,720 --> 00:32:32,160
Yeah. OK.
418
00:32:41,040 --> 00:32:42,560
OK, all lights off.
419
00:32:42,560 --> 00:32:43,640
All lights off.
420
00:32:50,520 --> 00:32:54,320
As their eyes adjust
to the darkness, they see
421
00:32:54,320 --> 00:32:56,520
the first faint glow.
422
00:32:58,720 --> 00:33:01,360
It's a jellyfish, and as it comes
closer,
423
00:33:01,360 --> 00:33:04,280
Widder is able to identify it.
424
00:33:04,280 --> 00:33:06,440
A nice little jelly.
425
00:33:06,440 --> 00:33:08,040
I think that's atolla.
426
00:33:08,040 --> 00:33:09,640
Yeah, it is. It's atolla.
427
00:33:11,560 --> 00:33:14,960
And the ultrasensitive
camera is able to record
428
00:33:14,960 --> 00:33:16,880
its complex light display.
429
00:33:22,320 --> 00:33:26,920
As it touches the screen,
it produces a spectacular strobing
430
00:33:26,920 --> 00:33:28,640
of blue light.
431
00:33:31,280 --> 00:33:35,040
Widder suspects that the function
of this display isn't to scare
432
00:33:35,040 --> 00:33:36,600
off the enemy.
433
00:33:36,600 --> 00:33:38,200
It may convey another message.
434
00:33:39,280 --> 00:33:42,720
Now, she brings her electric
jellyfish into action.
435
00:33:50,640 --> 00:33:54,760
It's programmed to emit the same
pattern of light as atolla.
436
00:34:03,400 --> 00:34:07,080
A low-light camera reveals
that the blue flashes quickly
437
00:34:07,080 --> 00:34:08,640
attract large fish...
438
00:34:13,640 --> 00:34:18,160
And a gigantic deep-sea predator.
439
00:34:21,440 --> 00:34:25,640
A Pacific sleeper shark, nearly
three metres long.
440
00:34:26,960 --> 00:34:28,880
It's not a threat to the jelly.
441
00:34:28,880 --> 00:34:32,480
It seems to be preying
on the smaller fish that are in fact
442
00:34:32,480 --> 00:34:34,560
the jelly's real enemies.
443
00:34:34,560 --> 00:34:38,640
So, the jelly's flashing lights
may be acting as a call for help -
444
00:34:38,640 --> 00:34:41,080
a kind of living burglar alarm.
445
00:34:49,720 --> 00:34:53,440
It has this remarkable
ability to produce this pinwheel
446
00:34:53,440 --> 00:34:54,880
of light.
447
00:34:54,880 --> 00:34:58,360
And so, clearly, if it was a scream
for help, then
448
00:34:58,360 --> 00:35:00,920
you would think that that pattern
should be very attractive
449
00:35:00,920 --> 00:35:02,360
to a large predator.
450
00:35:03,960 --> 00:35:06,160
It's an intriguing idea.
451
00:35:08,080 --> 00:35:12,120
In the meantime, Bruce Robison
is in the Nadir, and making
452
00:35:12,120 --> 00:35:13,560
his own discoveries.
453
00:35:16,800 --> 00:35:18,280
Rover Nadir, over?
454
00:35:18,280 --> 00:35:19,320
Ooh!
455
00:35:19,320 --> 00:35:20,520
Stop bending. Over.
456
00:35:20,520 --> 00:35:21,600
See that fish?
457
00:35:25,200 --> 00:35:28,880
This is a viperfish -
a fearsome predator.
458
00:35:28,880 --> 00:35:31,000
And it, too, creates light.
459
00:35:36,560 --> 00:35:38,920
You see those spots along his belly?
Oh, yeah.
460
00:35:38,920 --> 00:35:40,600
Those are bioluminescent organs.
461
00:35:40,600 --> 00:35:42,520
Ah!
462
00:35:42,520 --> 00:35:47,000
Rows of small photophores run
along the length of its underbelly
463
00:35:47,000 --> 00:35:48,640
and produce blue light.
464
00:35:51,440 --> 00:35:55,160
From below, the fish lights up
like an airport runway.
465
00:35:56,520 --> 00:35:59,960
Interestingly, many deep-sea
creatures generate light
466
00:35:59,960 --> 00:36:01,320
on their undersides.
467
00:36:01,320 --> 00:36:03,400
Why should this be so?
468
00:36:06,280 --> 00:36:09,800
It seems that the lights
may actually help to camouflage
469
00:36:09,800 --> 00:36:12,680
the animals from predators
lurking beneath them.
470
00:36:17,240 --> 00:36:22,880
One creature that uses its lights
to this effect is the firefly squid.
471
00:36:32,400 --> 00:36:36,680
Hundreds of tiny photophores
illuminate their bodies.
472
00:36:36,680 --> 00:36:39,640
Why don't these bright
lights attract predators?
473
00:36:42,800 --> 00:36:45,680
A small amount of light
from the surface filters
474
00:36:45,680 --> 00:36:47,840
down into the twilight zone.
475
00:36:47,840 --> 00:36:51,800
So, from below, a black silhouette
would be clearly visible,
476
00:36:51,800 --> 00:36:54,760
and make an easy target for deep-sea
hunters.
477
00:36:56,560 --> 00:37:01,640
A predator from down below looking
for a meal might see the body
478
00:37:01,640 --> 00:37:06,480
of an animal silhouetted against the
lighted waters above,
479
00:37:06,480 --> 00:37:11,080
and it would use that silhouette as
a guide to strike and feed on it.
480
00:37:12,600 --> 00:37:17,120
But the squid's lights prevent
that by breaking up its silhouette.
481
00:37:17,120 --> 00:37:21,960
Through a thick layer of water,
this effect is even more pronounced.
482
00:37:21,960 --> 00:37:25,760
And, by controlling the intensity
of its own light to match
483
00:37:25,760 --> 00:37:29,280
the background, the animal blends
into its surroundings.
484
00:37:30,320 --> 00:37:33,480
So, contradictory
though it may sound,
485
00:37:33,480 --> 00:37:35,760
light in fact conceals.
486
00:37:37,200 --> 00:37:41,320
Many animals who live
in this part of the ocean
487
00:37:41,320 --> 00:37:46,320
eliminate that threat by producing
light along their bellies
488
00:37:46,320 --> 00:37:49,360
and erasing their shadows
so that they cannot be seen.
489
00:37:52,120 --> 00:37:56,040
But there is one predator that's not
deceived by this trick -
490
00:37:56,040 --> 00:37:57,240
the barreleye.
491
00:37:58,520 --> 00:38:02,080
It has evolved its own
special hunting technique.
492
00:38:05,400 --> 00:38:09,560
It hangs almost motionless
in the water with its large eyes
493
00:38:09,560 --> 00:38:13,040
directed upwards, searching
for the faint silhouettes
494
00:38:13,040 --> 00:38:14,520
of prey overhead.
495
00:38:17,760 --> 00:38:24,840
The eyes are green because they
contain a pigment that screens out
496
00:38:24,840 --> 00:38:30,360
bioluminescence that other animals
use to hide with,
497
00:38:30,360 --> 00:38:35,200
so it's not fooled
by the counter-illumination
498
00:38:35,200 --> 00:38:36,560
of that bioluminescence.
499
00:38:39,200 --> 00:38:42,680
Although no-one has ever seen
how the barreleye hunts,
500
00:38:42,680 --> 00:38:47,240
Robison has studied the animal
closely and come up with a theory.
501
00:38:48,760 --> 00:38:52,360
It feeds on small krill
and other plankton.
502
00:38:52,360 --> 00:38:55,840
Some prey try to hide
by using bioluminescence.
503
00:38:59,080 --> 00:39:03,760
But, seen through the eyes
of the barreleye, the deception
504
00:39:03,760 --> 00:39:06,000
has not worked.
505
00:39:06,000 --> 00:39:08,400
The hunter can clearly see its prey.
506
00:39:13,960 --> 00:39:17,360
The barreleye approaches
stealthily from below and,
507
00:39:17,360 --> 00:39:21,880
as it rises to the level
of its prey, it rotates its eyes.
508
00:39:31,120 --> 00:39:35,640
Eternal darkness has caused
creatures that live here to evolve
509
00:39:35,640 --> 00:39:39,440
all kinds of shapes and strategies
that are utterly different
510
00:39:39,440 --> 00:39:42,040
from those we use ourselves.
511
00:39:42,040 --> 00:39:46,200
And one of the key elements
is the ability to create light.
512
00:39:57,240 --> 00:40:01,960
They just seem strange to us
because we are so accustomed
513
00:40:01,960 --> 00:40:04,160
to living in a very different world.
514
00:40:05,640 --> 00:40:09,280
Some are virtually blind
and rely on other senses
515
00:40:09,280 --> 00:40:11,400
to catch their food.
516
00:40:11,400 --> 00:40:15,360
While others have particularly
large eyes that enable them to see
517
00:40:15,360 --> 00:40:17,600
in the dimmest of light.
518
00:40:19,000 --> 00:40:23,440
They've all evolved their own ways
of dealing with the darkness,
519
00:40:23,440 --> 00:40:27,800
but most of them use bioluminescence
in some way or other.
520
00:40:29,000 --> 00:40:33,920
So, perhaps it's not surprising that
nature's greatest light show happens
521
00:40:33,920 --> 00:40:36,920
in the one place where
there is continuous darkness.
522
00:40:48,360 --> 00:40:50,320
Control, control, rover.
523
00:40:50,320 --> 00:40:53,440
Passing 300 metres. Descending...
524
00:40:57,160 --> 00:41:01,040
Deep Rover is slowly heading
upwards, with the splat screen
525
00:41:01,040 --> 00:41:02,520
still extended.
526
00:41:06,040 --> 00:41:09,480
It lights up with the glow
of small creatures that come
527
00:41:09,480 --> 00:41:11,280
into contact with the net.
528
00:41:15,600 --> 00:41:18,840
By freezing the image
from the camera, it's possible
529
00:41:18,840 --> 00:41:22,400
to identify some of the animals
that are creating the light.
530
00:41:24,920 --> 00:41:28,480
These are copepods -
small crustaceans just
531
00:41:28,480 --> 00:41:30,440
a few millimetres long.
532
00:41:30,440 --> 00:41:34,400
When threatened, they can discharge
a bioluminescent liquid.
533
00:41:36,440 --> 00:41:39,040
They're one of the most abundant
creatures in the ocean,
534
00:41:39,040 --> 00:41:41,400
and the main source of food for many
fish.
535
00:41:50,080 --> 00:41:54,440
These small creatures may provide
a clue to understanding why
536
00:41:54,440 --> 00:41:57,720
bioluminescence is so widespread
in the deep ocean.
537
00:42:06,000 --> 00:42:11,240
It's long been a mystery as to how
deep-sea animals produce light.
538
00:42:11,240 --> 00:42:14,200
But science is now beginning to find
some of the answers.
539
00:42:18,440 --> 00:42:22,360
Most deep-sea animals produce
bioluminescence with a molecule
540
00:42:22,360 --> 00:42:25,680
called coelenterazine.
541
00:42:25,680 --> 00:42:28,600
When this reacts with certain
enzymes in their bodies,
542
00:42:28,600 --> 00:42:31,440
it produces light.
543
00:42:31,440 --> 00:42:35,320
So, bioluminescence may seem like
magic, but in fact,
544
00:42:35,320 --> 00:42:38,400
it's the result of a straightforward
chemical reaction.
545
00:42:40,960 --> 00:42:44,440
But there is nonetheless
one mystery.
546
00:42:44,440 --> 00:42:47,960
Most deep-sea animals
themselves cannot produce
547
00:42:47,960 --> 00:42:50,440
this light-imaging substance.
548
00:42:50,440 --> 00:42:52,040
So, where does it come from?
549
00:42:53,440 --> 00:42:59,560
A Japanese researcher, Yuichi Oba,
may have found the answer.
550
00:42:59,560 --> 00:43:03,000
Oba has been studying
deep-sea copepods,
551
00:43:03,000 --> 00:43:07,120
and he's discovered that one
particular species is able to make
552
00:43:07,120 --> 00:43:09,880
coelanterazine within its body.
553
00:43:09,880 --> 00:43:12,280
It's called Metridia pacifica.
554
00:43:13,320 --> 00:43:17,760
We still don't know how many others
can do the same, but it's a clue
555
00:43:17,760 --> 00:43:20,560
as to where the luminous molecule
could have come from.
556
00:43:23,600 --> 00:43:27,640
But how is it that the same molecule
is also found in many other
557
00:43:27,640 --> 00:43:29,560
deep-sea creatures?
558
00:43:29,560 --> 00:43:33,640
Well, it appears that it's spread
through the food chain.
559
00:43:36,200 --> 00:43:40,600
Copepods are the main source of food
for many shrimps and small fish,
560
00:43:40,600 --> 00:43:44,200
so the coelanterazine molecule will
be transferred
561
00:43:44,200 --> 00:43:46,240
into the bodies of their predators.
562
00:43:50,360 --> 00:43:54,720
The shrimp in turn may pass
on the molecule to their predators -
563
00:43:54,720 --> 00:43:57,960
squid and larger fish -
which, in turn, are eaten
564
00:43:57,960 --> 00:43:59,640
by even larger hunters.
565
00:44:03,960 --> 00:44:07,800
So, the light-emitting molecule
could have spread from prey
566
00:44:07,800 --> 00:44:13,240
to predator and so through the whole
community of deep-sea animals.
567
00:44:13,240 --> 00:44:16,440
It's an extraordinary thought
that the living light
568
00:44:16,440 --> 00:44:19,440
produced by some of the smallest
creatures in the sea
569
00:44:19,440 --> 00:44:20,800
could be the basis for some
570
00:44:20,800 --> 00:44:23,600
of the incredible light
shows in the ocean.
571
00:44:28,600 --> 00:44:31,560
The precise function
of bioluminescence may vary.
572
00:44:33,280 --> 00:44:37,720
Some use it to intimidate
their enemies,
573
00:44:37,720 --> 00:44:41,560
others to hide from predators or to
call for help.
574
00:44:41,560 --> 00:44:45,440
But the meaning of many of their
messages still remains a mystery.
575
00:44:57,480 --> 00:45:03,640
As the expedition draws to a close,
the team prepare for one last dive,
576
00:45:03,640 --> 00:45:06,560
to watch a particularly
spectacular event.
577
00:45:10,520 --> 00:45:15,040
It happens every night as the sun
drops below the horizon.
578
00:45:22,640 --> 00:45:26,560
It's a time when vast numbers
of deep-sea creatures rise
579
00:45:26,560 --> 00:45:28,120
towards the surface.
580
00:45:32,200 --> 00:45:36,080
The team are hoping to film
this spectacle and the light show
581
00:45:36,080 --> 00:45:37,760
that goes with it.
582
00:45:37,760 --> 00:45:41,800
And to do that properly,
they will deploy both submersibles.
583
00:45:44,480 --> 00:45:49,240
When we get up to 200 metres -
or maybe 100 - we should coordinate
584
00:45:49,240 --> 00:45:53,720
and, if there is a thick
layer of luminescence,
585
00:45:53,720 --> 00:45:56,680
we should try to shoot each other
as we drive through it. Yeah.
586
00:45:59,040 --> 00:46:02,000
The submersibles are launched
while there's still light.
587
00:46:10,920 --> 00:46:13,920
As they descend deeper, and night
falls,
588
00:46:13,920 --> 00:46:16,880
they once more enter the world of
darkness.
589
00:46:20,080 --> 00:46:23,040
And it's not long before they're
travelling through
590
00:46:23,040 --> 00:46:24,840
a large swarm of krill.
591
00:46:27,000 --> 00:46:28,640
Not bad.
592
00:46:28,640 --> 00:46:29,680
Just going up.
593
00:46:31,480 --> 00:46:34,520
The small crustaceans
are on their daily migration
594
00:46:34,520 --> 00:46:37,480
up to the surface, where
they will feed on plankton.
595
00:46:41,280 --> 00:46:44,320
Others have also been
hiding in deep waters,
596
00:46:44,320 --> 00:46:45,720
to avoid predators.
597
00:46:48,360 --> 00:46:52,160
Now there's a mass migration
of animals up towards the surface,
598
00:46:52,160 --> 00:46:53,800
where food is more abundant.
599
00:46:55,040 --> 00:46:58,800
But this vast migration attracts
some bigger hunters.
600
00:47:00,920 --> 00:47:03,920
It's an electric torpedo ray.
601
00:47:03,920 --> 00:47:06,440
They usually live down near the
bottom, but at night,
602
00:47:06,440 --> 00:47:08,200
it comes up to feed.
603
00:47:16,680 --> 00:47:21,320
It's 5:30pm and the sun has set.
604
00:47:21,320 --> 00:47:23,920
The submersibles are in position.
605
00:47:23,920 --> 00:47:25,080
Control, control.
606
00:47:25,080 --> 00:47:27,600
At 200 and metres, with rover.
607
00:47:27,600 --> 00:47:28,640
Over.
608
00:47:30,320 --> 00:47:35,720
The submersibles are hanging
motionless at a depth of 200 metres.
609
00:47:35,720 --> 00:47:38,000
But, to really see
what they've come for,
610
00:47:38,000 --> 00:47:41,360
they need to turn
off all the lights.
611
00:47:41,360 --> 00:47:42,920
Just give it a try. Mm-hm.
612
00:47:56,000 --> 00:47:58,760
The first glowing lights appear.
613
00:48:04,480 --> 00:48:06,560
And the show begins.
614
00:48:11,080 --> 00:48:15,040
With every passing minute,
the firework display gets bigger.
615
00:48:17,120 --> 00:48:20,440
The subs are now surrounded
by light on all sides.
616
00:48:24,760 --> 00:48:26,640
Ooh! Oh!
617
00:48:26,640 --> 00:48:28,040
Ooh!
618
00:48:28,040 --> 00:48:29,520
Yeah!
619
00:48:29,520 --> 00:48:32,360
Pretty good. Pretty good. Yeah.
620
00:48:38,560 --> 00:48:42,520
Wave after wave of living lights
well up from the deep.
621
00:48:46,800 --> 00:48:50,680
So, copepods and krill.
622
00:48:51,960 --> 00:48:53,360
There's an anemone.
623
00:48:59,240 --> 00:49:03,680
Millions of glowing marine
creatures continue to appear.
624
00:49:03,680 --> 00:49:07,400
And amongst them could well
be other strange life forms
625
00:49:07,400 --> 00:49:09,200
that we've not yet encountered.
626
00:49:23,600 --> 00:49:27,800
The underwater night sky is now
illuminated by hundreds
627
00:49:27,800 --> 00:49:29,520
of shooting stars.
628
00:49:46,200 --> 00:49:49,800
The show continues
for over two hours.
629
00:49:51,320 --> 00:49:54,400
And when they come back
up to the surface,
630
00:49:54,400 --> 00:49:57,440
the scientists are ecstatic.
631
00:49:57,440 --> 00:49:58,880
Look at that! Yeah.
632
00:49:58,880 --> 00:50:00,680
It is the Milky Way.
633
00:50:00,680 --> 00:50:03,760
But it's also scientifically
very interesting that you can
634
00:50:03,760 --> 00:50:05,640
actually see the different colours.
635
00:50:07,680 --> 00:50:11,720
But scientists have yet to discover
the meaning of many of these living
636
00:50:11,720 --> 00:50:14,680
lights, and how and why
they are produced.
637
00:50:17,760 --> 00:50:22,680
Most of the animals in this vast,
vast volume make light,
638
00:50:22,680 --> 00:50:27,280
And much of it, we still don't
understand what it's used for.
639
00:50:27,280 --> 00:50:30,040
That's a huge mystery.
640
00:50:30,040 --> 00:50:32,600
We have only begun to explore.
641
00:50:33,960 --> 00:50:38,400
And we continue to find new
discoveries
642
00:50:38,400 --> 00:50:41,200
every time we go into the ocean.
643
00:50:41,200 --> 00:50:46,920
So, yes, we've only begun to find
out what's down there,
644
00:50:46,920 --> 00:50:53,080
to learn how these pieces
of a gigantic puzzle fit together
645
00:50:53,080 --> 00:50:55,000
and work as an ecosystem.
646
00:50:56,120 --> 00:50:58,600
Yes, we're just getting started.
647
00:51:05,160 --> 00:51:08,000
The deep oceans and their
mysterious,
648
00:51:08,000 --> 00:51:11,720
light-producing creatures have long
been out of our reach.
649
00:51:11,720 --> 00:51:14,760
Now, with the help
of new technology
650
00:51:14,760 --> 00:51:17,880
and the latest research,
we are beginning to unravel
651
00:51:17,880 --> 00:51:19,480
some of their secrets.
652
00:51:21,800 --> 00:51:25,480
But many mysteries remain,
and we're still a long way off
653
00:51:25,480 --> 00:51:29,440
from understanding
just what makes these marvellous,
654
00:51:29,440 --> 00:51:32,680
living lights glow in the abyss.