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Bacteria.
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They're everywhere.
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They're invisible to the human eye
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and they're incredibly prolific.
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In just one millimeter of fresh water,
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there are a million of them.
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In a single gram of soil, over 40 million.
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Together, they weigh more
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than all the plants and
animals in the world.
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Humans may think they rule the world
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but in reality, they're
just lodgers on a planet
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whose first inhabitants were bacteria.
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All living beings are covered with them,
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on the inside as well as the outside.
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In a human body, there are
100 trillion of them.
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We're actually more bacterial than human
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by about 10 to 100 fold.
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We truly are less human than we think.
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Bacteria are generally very misunderstood.
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People think bacteria mean illness,
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but that's not true at all.
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In fact very few bacteria
are dangerous to humans.
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The fact is,
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the relationship that plants
and animals have to bacteria
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is often beneficial to both.
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These beneficial relationships
are called symbioses.
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I can't think of a single animal
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that's not symbiotic, especially us.
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We couldn't live without our bacteria.
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Symbiosis has played a fundamental role
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in the evolution of life.
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We found out during the
course of the 20th century
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that associations between symbiotic species
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were more common than we thought
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and are definitely one of the
greatest motors of evolution.
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Deep down at the bottom of the ocean
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lies the mysterious world of the abyss.
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Here in the greatest desert in the world,
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there's no plant life and very few animals.
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But when in the 1970s,
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oceanographers discovered
the first deep see vents,
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the phenomenal amount of
animal life they found there
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in an environment hitherto thought
hostile to all life forms
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raised a lot of questions.
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Could bacteria really survive
in such extreme conditions?
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Were they responsible for
this profusion of life?
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Could symbiosis explain
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these creatures' extraordinary success?
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To find answers to these questions,
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the BIOBAZ oceanographic expedition,
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founded and led by
professor François Lallier
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of the Roscoff Biological
Station in Brittany,
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took us in search of secrets
hidden since the dawn of time,
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many fathoms beneath the sea.
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We're on course for some volcanic sites
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out in the middle of the Atlantic.
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There are 32 scientists on board
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and they're all experts on
deep sea vents biology.
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The state of the art technology
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of their remote controlled
robot, Victor 6000,
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will enable them to minutely
explore the volcanoes
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of the mid-Atlantic ridge.
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Victor can dive to depths
of six kilometers.
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It's setting off into a
world of total darkness,
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heading for one of the most spectacular
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deep sea vents on the planet:
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Rainbow, which lies at a
depth of 2,300 meters.
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It's hard to get close to Rainbow.
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Powerful geysers constantly pump out
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gigantic swirls of scalding
liquids into the abyss.
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It's a boiling stew of
highly acidic fluids,
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their chemical composition
a long list of toxins,
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each more dangerous than the other.
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Yet, here at these geysers,
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there swarms an impressive
quantity of animal life.
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And right here among all
the chimney systems
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created by the geysers,
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hides the first creature the
scientists want to study,
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the Rimicaris shrimp.
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These chimneys, covered in cracks,
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are the only ones that release their fluids
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gently and regularly enough
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to provide the shrimps with
ideal living conditions.
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The Rimicaris huddle into the
channels of volcanic fluids,
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dancing together in an eternal ballet,
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as if in defiance of the
most extreme conditions
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to be found anywhere on the planet.
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Aboard the boat, under the leadership
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of Marie-Anne Cambon and Magali Zbinden,
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everyone's getting ready for the catch.
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They're hoping for a haul
of 100 Rimicaris shrimps.
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It's easy to catch them.
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You just Hoover them up.
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Coming up to the surface,
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the animals will suffer
the traumatizing effects
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of violent decompression.
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Down here at 2,300 meters,
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the pressure is 230 bars,
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that's 230 kilos per square centimeter.
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At the surface, the atmospheric pressure
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is just one kilo per square centimeter.
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We ourselves are organisms
that contain gas.
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If we are compressed at 300 bars,
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our thoracic cage is immediately squashed,
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which of course means instant death.
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Fortunately, these deep sea organisms
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contain no gases.
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It's more a question
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of the fluidity of cellular membranes.
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We know that if we vary pressure,
then fluidity varies, too.
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And membranes hold all an organism's
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channels of transmission:
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neural transmission, chemical
transmission, etcetera.
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From the moment you disturb
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any of an organism's membrane passages,
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if the variations in pressure are too much,
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the organism will die.
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At sea level pressure,
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the Rimicaris shrimps of the Rainbow vent
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cannot survive longer than a few days.
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But their anatomy still remains
intact enough to be studied.
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Dissection of their digestion tube
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reveals the first enigma
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of these creatures' strange way of life.
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Apart from a few morsels of rock
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that they've nibbled here and there,
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their intestines contain no food at all.
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The shrimps' digestive system
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doesn't appear to play a major
role in their feeding habits.
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So, what then do they live on?
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The researchers naturally
turn their attention
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to the strange crustaceans' enormous head.
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The head takes up half the creature's body.
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That's very big.
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Normally, it's not even a third.
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When they're very young, they
look like ordinary shrimps
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and at a certain point
in their development,
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they metamorphose,
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a bit like a caterpillar
turning into a butterfly.
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The head become so enormous,
and the shell too,
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that the shrimp can't graze
anymore and can't feed.
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No wonder the digestive
tube's almost empty.
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As for the huge head, that's
due to the terrific size
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of the chamber that hold the gills,
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the animal's respiratory organ.
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When they take a look inside that chamber,
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the biologists get a big surprise.
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There are billions of
bacteria living there.
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The bacteria have to get
into the gill cavity,
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so that creates really long filaments.
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And they also get into the scaphognathite,
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which is a kind of blade
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that pulsates in the cephalothoracic cavity
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to create a current of water,
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and has long bristles on it
that are covered in bacteria.
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Microbiological analysis
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shows that these resident bacteria
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are always the same species.
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In the absence of a true
functioning digestive system,
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the researchers wonder if,
when it comes to food,
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there isn't a relationship
between the shrimps
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and their vast colonies of bacteria.
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A kind of symbiosis, even.
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But to find out more about
this strange relationship,
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you have to work with
healthy shrimp specimens
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that haven't been through
the shock of decompression.
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And that's what Bruce
Shillito's team intend to do
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on a second trip to the Rainbow site,
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with the help of a revolutionary new
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high pressure aquarium system.
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To thrive with such success in
such different environments,
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bacteria must have an
amazing ability to adapt.
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The next step of the mission
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will be to verify this
hypothesis at another site.
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So the course is set for Lucky Strike,
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another volcano discovered in 1992
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down at a depth of 1,700 meters.
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The deep sea geysers at Lucky Strike
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aren't as powerful as the ones at Rainbow,
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so they haven't developed those spectacular
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tall black and gray chimneys.
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Over the decades, they have simply built up
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a succession of little hills.
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The whitish carpets that surround
the Lucky Strike geysers
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are actually vast colonies of bacteria
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visible to the naked eye.
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The first thing you notice
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are they big layers of microbes,
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like big yellowish-white carpets
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that cover the sediments of the seabed
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and the ends of the chimneys.
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And the extraordinary thing
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is that they're actually long filaments
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that float in the current.
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These carpets of bacteria
are flirting dangerously
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with the scalding emissions of fluid.
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Probes, placed by the team
right inside the chimneys,
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show temperatures of over 350 degrees.
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But as they mix with the sea water
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that's at only three or four degrees,
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within the space of less than a meter,
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the temperature of the fluids
drops to less than 30 degrees,
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thus creating conditions
that favor the development
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of most species of bacteria.
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The chemical composition
of the fluids, though,
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presents all the characteristics
of an environment
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hostile to most life forms.
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They are highly acidic and contain
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radioactive elements, heavy metals,
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and highly toxic molecules such as sulfurs.
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From our point of view, of course,
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what with the pressure, the
temperature, and the chemicals,
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because there are plenty of compounds there
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that would be toxic to animal life,
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the conditions look extreme.
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For these bacteria, it's
simply their habitat
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and they're fine there.
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Researchers have discovered
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that the bacteria feast
on the volcanic fluids
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as if they were nectar.
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All those toxic elements,
deadly poisons for us,
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are for them a source of nourishment.
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Obviously, we find our human enviroment
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a more welcoming place
than a volcanic abyss.
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But these bacteria have
no need of a human body.
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They're quite at home here.
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Not many scientists know more about
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00:18:12,340 --> 00:18:15,761
the role bacteria play in
our lives than Lora Hooper.
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In some ways we can consider the intestine,
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and maybe even the skin,
an extreme environment,
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in that these bacteria have to
cope with an immune system,
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00:18:25,012 --> 00:18:29,307
for example, that's lobbying
grenades at them all the time.
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They have to cope with shifts in pH
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00:18:32,508 --> 00:18:35,663
as they travel through the
stomach and to the intestine,
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00:18:35,664 --> 00:18:37,865
and vast changes in diet.
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00:18:45,829 --> 00:18:49,876
Bacteria's ability to
survive is remarkable.
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00:18:49,877 --> 00:18:52,716
For billions of years, they
were the only living creatures
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00:18:52,717 --> 00:18:56,285
to colonize the deep sea geysers.
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00:18:57,650 --> 00:19:00,051
But across millions of years of evolution,
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some enterprising creatures
from the surface
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have adapted to the conditions here
242
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and even managed to settle in permanently.
243
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So who are they, these pioneers,
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and how do they withstand
the extreme conditions?
245
00:19:30,740 --> 00:19:34,142
Jozée Sarrazin leads an animal ecology team
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that specializes in deep sea geysers.
247
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To gauge the capacity of animals
248
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to colonize new ground around the geysers,
249
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she has come with a system
of artificial habitats,
250
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made up of slate, wood,
muslin, and even beef bones.
251
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The whole range of them is
laid out close to the fluids
252
00:20:02,704 --> 00:20:05,447
and recuperated sometimes a few days later,
253
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but more often the following year
254
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during the next expedition.
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00:20:23,015 --> 00:20:25,097
In the space of just a few days,
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00:20:25,098 --> 00:20:27,409
bacteria from the surrounding
water have managed
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to settle on all the different habitats.
258
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In their turn, they have soon attracted
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00:20:41,192 --> 00:20:44,620
dozens of local species of a
particular kind of animal,
260
00:20:44,621 --> 00:20:46,728
the grazers.
261
00:20:47,641 --> 00:20:48,751
The first animals
262
00:20:48,752 --> 00:20:52,781
fed directly on the bacteria,
just like cows at pasture.
263
00:20:52,782 --> 00:20:56,272
They came to graze the fields of bacteria.
264
00:20:57,904 --> 00:20:59,507
Millions of years ago,
265
00:20:59,508 --> 00:21:02,632
thanks to the bacteria that
formed the basis of their diet,
266
00:21:02,633 --> 00:21:05,267
the very first animal
species from the surface
267
00:21:05,268 --> 00:21:07,535
were able to survive in the vicinity
268
00:21:07,536 --> 00:21:10,385
of the deep sea geysers.
269
00:21:13,602 --> 00:21:18,360
There are little gastropods,
little sea snails.
270
00:21:18,361 --> 00:21:21,266
There are also little
amphipods, little crustaceans
271
00:21:21,267 --> 00:21:24,631
that graze on the bacteria.
272
00:21:35,513 --> 00:21:37,966
Colonization of the geysers of the abyss
273
00:21:37,967 --> 00:21:40,223
could have ended there with the grazers,
274
00:21:40,224 --> 00:21:42,740
content just to eat the bacteria they found
275
00:21:42,741 --> 00:21:46,722
without establishing any
further relationship to them.
276
00:21:51,030 --> 00:21:52,991
But the grazers have had nothing like
277
00:21:52,992 --> 00:21:54,813
the success of other species
278
00:21:54,814 --> 00:21:57,688
that have gone on to
develop gigantic colonies.
279
00:21:57,689 --> 00:22:01,366
Species like the so called
Azorean deep mussels,
280
00:22:01,367 --> 00:22:04,542
which are particularly
numerous at Lucky Strike.
281
00:22:10,926 --> 00:22:13,318
One of the aims of the BIOBAZ program
282
00:22:13,319 --> 00:22:17,049
is to find out the reasons for
this exceptional success.
283
00:22:25,413 --> 00:22:27,901
The next dives of the robot Victor
284
00:22:27,902 --> 00:22:30,466
will be entirely dedicated
to the in depth study
285
00:22:30,467 --> 00:22:32,810
of the deep mussels' way of life.
286
00:22:44,640 --> 00:22:47,750
Whereas Rimicaris shrimp
are only to be found
287
00:22:47,751 --> 00:22:50,592
at depths of more than 2,000 meters,
288
00:22:50,593 --> 00:22:54,378
deep mussels are present
wherever there are hot geysers.
289
00:23:08,641 --> 00:23:10,625
The Lucky Strike deep mussels
290
00:23:10,626 --> 00:23:13,466
are harvested at depths
of less than 2,000 meters
291
00:23:13,467 --> 00:23:16,482
and stand up well to the decompression.
292
00:23:16,483 --> 00:23:20,628
The scientists can simply transport
them in Plexiglas boxes.
293
00:23:54,321 --> 00:23:55,661
What's most striking
294
00:23:55,662 --> 00:23:59,597
when you open a deep mussel, is
the sheer size of its gills.
295
00:24:01,424 --> 00:24:04,191
In this mussel, we found
bacteria in the gills
296
00:24:04,192 --> 00:24:06,559
and in great abundance, too.
297
00:24:08,984 --> 00:24:10,687
There are no bacterial filaments
298
00:24:10,688 --> 00:24:13,591
visible on the outside, though.
299
00:24:16,270 --> 00:24:18,311
Unlike with the Rimicaris shrimp,
300
00:24:18,312 --> 00:24:20,969
the deep mussel bacteria live right inside
301
00:24:20,970 --> 00:24:26,391
the cells of the gills,
a very rare phenomenon.
302
00:24:30,318 --> 00:24:31,508
The cells on the surface
303
00:24:31,509 --> 00:24:34,915
of the thousands of little
filaments that make up each gill
304
00:24:34,916 --> 00:24:38,712
have the specific task of
growing internal bacteria.
305
00:24:42,205 --> 00:24:45,356
It's quite clear when seen through
a fluorescent microscope,
306
00:24:45,357 --> 00:24:48,252
the nucleus of the cell is blue.
307
00:24:48,253 --> 00:24:52,071
The hundreds of little red and
green blobs are all bacteria,
308
00:24:52,072 --> 00:24:56,336
comfortably lodged right
inside each specialized cell.
309
00:25:01,754 --> 00:25:04,378
So the bacteria pull off the amazing feat
310
00:25:04,379 --> 00:25:07,776
of fooling the cells' immune
systems to get inside them,
311
00:25:07,777 --> 00:25:10,617
and once in, to stay there.
312
00:25:13,748 --> 00:25:15,481
The animal has to be able to regulate
313
00:25:15,482 --> 00:25:18,890
the rate of growth of the
bacteria within its own cells.
314
00:25:18,891 --> 00:25:21,473
In certain types of cells,
the bacteria are allowed,
315
00:25:21,474 --> 00:25:24,129
even encouraged to develop,
316
00:25:24,130 --> 00:25:25,547
whereas in all the other tissues,
317
00:25:25,548 --> 00:25:28,910
there are no symbiotic
bacteria to be found at all.
318
00:25:32,836 --> 00:25:34,576
But the mussels don't merely accept
319
00:25:34,577 --> 00:25:36,508
the presence of the bacteria,
320
00:25:36,509 --> 00:25:40,327
they make sure that their
guests can eat their fill.
321
00:25:41,269 --> 00:25:43,629
Mussels are in fact like filters.
322
00:25:43,630 --> 00:25:46,004
They circulate water through their gills.
323
00:25:46,005 --> 00:25:48,868
There's oxygen in this
water as well as sulfurs,
324
00:25:48,869 --> 00:25:51,872
a bit of methane, and a
bit of dissolved carbon.
325
00:25:51,873 --> 00:25:54,735
So everything the bacteria need is there,
326
00:25:54,736 --> 00:25:56,115
and since the water's circulating,
327
00:25:56,116 --> 00:25:59,362
their environment is
constantly being refreshed.
328
00:26:07,884 --> 00:26:09,945
This relationship between the bacteria
329
00:26:09,946 --> 00:26:12,657
and the mussels is most peculiar.
330
00:26:12,658 --> 00:26:14,803
It's as if, after millions of years
331
00:26:14,804 --> 00:26:16,496
of an intimate relationship,
332
00:26:16,497 --> 00:26:19,099
the bacteria were
progressively becoming part
333
00:26:19,100 --> 00:26:21,602
of the very cells of the mussel.
334
00:26:33,043 --> 00:26:35,384
To measure to what extent the deep mussels
335
00:26:35,385 --> 00:26:38,606
are dependent on the bacteria
in the cells of their gills,
336
00:26:38,607 --> 00:26:40,503
the scientists at BIOBAZ
337
00:26:40,504 --> 00:26:42,620
are going to try a little experiment
338
00:26:42,621 --> 00:26:46,254
1,700 meters under the sea.
339
00:26:48,758 --> 00:26:51,936
It consists of putting a
few dozen mussels in cages
340
00:26:51,937 --> 00:26:55,286
at a distance from the
source of the fluids.
341
00:27:02,619 --> 00:27:04,662
When we take them out of
their natural habitat
342
00:27:04,663 --> 00:27:07,123
the bacteria get no more
sulfurs, no more methane,
343
00:27:07,124 --> 00:27:09,620
so they have nothing to live on.
344
00:27:16,668 --> 00:27:18,130
Away from the fluids,
345
00:27:18,131 --> 00:27:22,247
the bacteria cease to multiply
and eventually disappear.
346
00:27:25,132 --> 00:27:27,389
And without their crop of bacteria,
347
00:27:27,390 --> 00:27:30,962
the mussels only survive
for two or three days.
348
00:27:35,069 --> 00:27:38,966
What is the reason for this
fundamental dependence?
349
00:27:40,008 --> 00:27:41,647
The gills are like their larder,
350
00:27:41,648 --> 00:27:44,141
where they grow their bacteria.
351
00:27:48,165 --> 00:27:50,203
Astonishing as it may seem,
352
00:27:50,204 --> 00:27:52,371
each of these specialized cells
353
00:27:52,372 --> 00:27:54,790
is constantly digesting within itself
354
00:27:54,791 --> 00:27:58,719
a small part of its
personal stock of bacteria.
355
00:28:00,638 --> 00:28:01,983
We also think the bacteria
356
00:28:01,984 --> 00:28:04,400
are capable of releasing compounds.
357
00:28:04,401 --> 00:28:06,320
For example, as a bacteria grows up,
358
00:28:06,321 --> 00:28:07,927
it will release sugars around it
359
00:28:07,928 --> 00:28:10,628
within the cell of the animal.
360
00:28:13,242 --> 00:28:15,121
By way of the blood circulation,
361
00:28:15,122 --> 00:28:18,766
molecules from the intracellular
bacteria in the gills
362
00:28:18,767 --> 00:28:22,283
actually feed all the mussels' cells.
363
00:28:44,495 --> 00:28:46,714
So it's an especially close symbiosis
364
00:28:46,715 --> 00:28:49,102
between animal and bacteria
365
00:28:49,103 --> 00:28:52,659
and it's the reason these deep
mussels have done so well
366
00:28:52,660 --> 00:28:55,654
in such extreme conditions.
367
00:28:58,090 --> 00:29:00,487
An intracellular symbiosis like this
368
00:29:00,488 --> 00:29:03,383
is a very rare phenomenon in biology.
369
00:29:03,384 --> 00:29:05,692
It's an extremely important discovery,
370
00:29:05,693 --> 00:29:07,776
since it demonstrates the fundamental role
371
00:29:07,777 --> 00:29:09,468
that bacteria have played
372
00:29:09,469 --> 00:29:12,811
in the most important phases of evolution.
373
00:29:15,436 --> 00:29:17,777
As long as two billion years ago,
374
00:29:17,778 --> 00:29:20,478
the symbiotic fusion of two bacteria,
375
00:29:20,479 --> 00:29:24,296
in a process resembling that
of intracellular symbiosis,
376
00:29:24,297 --> 00:29:28,582
was possibly at the origin of
the first cell with a nucleus.
377
00:29:30,589 --> 00:29:33,484
Soon after that, the
incorporation of a bacteria
378
00:29:33,485 --> 00:29:36,688
enabled cells with nuclei to breathe oxygen
379
00:29:36,689 --> 00:29:39,248
and evolve ever more complex organisms
380
00:29:39,249 --> 00:29:42,751
all the way up to mammals
and to the human species.
381
00:29:48,273 --> 00:29:50,412
A few hundred million years later,
382
00:29:50,413 --> 00:29:53,471
it was once again symbiosis with a bacteria
383
00:29:53,472 --> 00:29:56,301
that would allow cells to photosynthesize
384
00:29:56,302 --> 00:30:00,826
and enable algae and all the
earth's vegetation to evolve.
385
00:30:03,131 --> 00:30:05,134
So two of the most easily recognizable
386
00:30:05,135 --> 00:30:06,918
characteristics of plants and animals
387
00:30:06,919 --> 00:30:09,228
come from bacteria that they breathe,
388
00:30:09,229 --> 00:30:12,019
or in the case of plants, photosynthesize.
389
00:30:12,020 --> 00:30:15,552
These both originate from
symbiosis with bacteria.
390
00:30:32,032 --> 00:30:35,122
These huge populations of symbiotic mussels
391
00:30:35,123 --> 00:30:37,716
became an important food
source for other animals
392
00:30:37,717 --> 00:30:40,688
coming from the surface.
393
00:30:44,025 --> 00:30:45,623
This third type of animal
394
00:30:45,624 --> 00:30:48,483
was neither a grazer nor a symbiotic.
395
00:30:48,484 --> 00:30:52,331
They were predators, scavengers,
and bottom feeders.
396
00:30:56,379 --> 00:30:57,957
They may be the spitting image
397
00:30:57,958 --> 00:30:59,831
of their cousins at the surface,
398
00:30:59,832 --> 00:31:02,180
but these carnivores have adapted so well
399
00:31:02,181 --> 00:31:05,272
to the extreme physical and
chemical conditions here,
400
00:31:05,273 --> 00:31:06,974
that they have become species
401
00:31:06,975 --> 00:31:09,913
specific to the deep sea geysers.
402
00:31:12,506 --> 00:31:14,887
Take the Mirocaris shrimp, for instance,
403
00:31:14,888 --> 00:31:18,274
a distant cousin of the
Rimicaris with its huge head,
404
00:31:18,275 --> 00:31:20,898
or the Segonzacia crab,
405
00:31:20,899 --> 00:31:24,468
both of them scavengers and bottom feeders.
406
00:31:27,874 --> 00:31:30,425
These native species
spend their whole lives
407
00:31:30,426 --> 00:31:32,768
around the sources of volcanic fluids
408
00:31:32,769 --> 00:31:35,491
and are perfectly happy here.
409
00:31:46,728 --> 00:31:50,489
But at another nearby site 800 meters deep,
410
00:31:50,490 --> 00:31:54,679
there's another large species
of crab, the Chaceon.
411
00:31:56,057 --> 00:31:59,443
This big crustacean doesn't
live here at the geysers,
412
00:31:59,444 --> 00:32:02,066
it just drops by from time to time,
413
00:32:02,067 --> 00:32:04,638
drawn by all those mussels.
414
00:32:09,597 --> 00:32:11,616
Unlike the local crabs,
415
00:32:11,617 --> 00:32:14,654
the Chaceons can't withstand
the fluid emissions
416
00:32:14,655 --> 00:32:18,290
and often come away with painful burns.
417
00:32:31,987 --> 00:32:35,476
But their daring is rewarded
with copious meals.
418
00:33:13,239 --> 00:33:16,356
Those huge banquets have
their downside, though.
419
00:33:16,357 --> 00:33:18,668
All the creatures of the deep sea geysers
420
00:33:18,669 --> 00:33:21,053
have had to get used to
the presence everywhere,
421
00:33:21,054 --> 00:33:24,797
in the water and in their
food, of a lot of toxins.
422
00:33:26,582 --> 00:33:29,615
Top of the list, hydrogen sulfide.
423
00:33:29,616 --> 00:33:31,986
There's always plenty
of that in the fluids.
424
00:33:32,927 --> 00:33:35,742
It's what make rotten eggs smell so bad.
425
00:33:35,743 --> 00:33:37,869
It's a molecule, that in
contact with the air,
426
00:33:37,870 --> 00:33:40,362
gives off a very nasty smell.
427
00:33:41,899 --> 00:33:44,476
It's a molecule, that for
an animal, for example,
428
00:33:44,477 --> 00:33:46,102
is highly toxic
429
00:33:46,103 --> 00:33:49,324
because it replaces the
oxygen in the hemoglobin,
430
00:33:49,325 --> 00:33:52,808
so if you breathe in sulfur,
it can asphyxiate you.
431
00:33:55,571 --> 00:33:56,948
So the local inhabitants
432
00:33:56,949 --> 00:34:00,857
have adapted to the need to
detoxify these chemical elements
433
00:34:00,858 --> 00:34:02,874
but what is the strange hair
434
00:34:02,875 --> 00:34:06,691
that most of the crabs
seem to be covered with?
435
00:34:06,692 --> 00:34:08,189
Well, guess what?
436
00:34:08,190 --> 00:34:10,832
It's bacteria.
437
00:34:14,504 --> 00:34:15,845
Generally, if a bacteria
438
00:34:15,846 --> 00:34:17,778
can lodge itself on an animal,
439
00:34:17,779 --> 00:34:21,095
that means it's been accepted
and will benefit the animal.
440
00:34:21,096 --> 00:34:23,155
When the bacteria draw in heavy metals
441
00:34:23,156 --> 00:34:25,033
or elements like sulfurs,
442
00:34:25,034 --> 00:34:27,433
they transform them in order to grow,
443
00:34:27,434 --> 00:34:30,083
and so what they put back
into the environment
444
00:34:30,084 --> 00:34:32,721
is less toxic than what they took in.
445
00:34:32,722 --> 00:34:36,367
That's what we refer to as detoxification.
446
00:34:38,297 --> 00:34:40,112
The bacteria grow on the crabs
447
00:34:40,113 --> 00:34:42,019
because they like it there.
448
00:34:42,020 --> 00:34:44,775
It's like having their own
chauffeur-driven ride.
449
00:34:44,776 --> 00:34:47,888
One that keeps them neither
too near, nor too far,
450
00:34:47,889 --> 00:34:50,693
from those nourishing fluid streams.
451
00:34:50,694 --> 00:34:54,524
It is indeed a kind of
external bacterial symbiosis.
452
00:35:02,176 --> 00:35:05,656
We ourselves also wear
an overcoat of bacteria,
453
00:35:05,657 --> 00:35:08,621
but ours is totally invisible.
454
00:35:08,622 --> 00:35:12,805
Our bodies contain 10 times
more bacteria than cells.
455
00:35:12,806 --> 00:35:16,325
The mucous membranes of our
respiratory system and genitals,
456
00:35:16,326 --> 00:35:20,284
as well as the insides of our
digestive tube, are carpeted,
457
00:35:20,285 --> 00:35:23,509
and the surface of our
body covered with them.
458
00:35:23,510 --> 00:35:26,574
It's known that there are
approximately a million bacteria
459
00:35:26,575 --> 00:35:29,015
per square centimeter of skin,
460
00:35:29,016 --> 00:35:32,474
and interestingly, if you wash your hands,
461
00:35:32,475 --> 00:35:34,665
that will go down, but
only very temporarily.
462
00:35:34,666 --> 00:35:37,984
So 30 minutes later,
they're all back.
463
00:35:37,985 --> 00:35:40,023
They are making their home there
464
00:35:40,024 --> 00:35:42,534
so that other pathogenic bacteria
465
00:35:42,535 --> 00:35:47,140
are less likely to be able
to successfully colonize,
466
00:35:47,141 --> 00:35:50,576
but they also stimulate the
immune system of the skin
467
00:35:50,577 --> 00:35:54,497
and so that confers some
protection as well.
468
00:35:55,745 --> 00:35:58,941
Our best friends are the
bacteria on our skin.
469
00:35:58,942 --> 00:36:01,425
In exchange, we feed
them with the dead cells
470
00:36:01,426 --> 00:36:02,529
that are the product
471
00:36:02,530 --> 00:36:05,044
of the constant renewal of our epidermis.
472
00:36:05,045 --> 00:36:07,723
Just as with the crabs down in the abyss,
473
00:36:07,724 --> 00:36:11,133
it's a question of
symbiosis, of mutual aid.
474
00:36:21,119 --> 00:36:23,499
Let's return to the Rainbow cleft,
475
00:36:23,500 --> 00:36:27,726
where the Rimicaris shrimp has
carved out its little domain.
476
00:36:31,214 --> 00:36:33,480
To further their research
on the relationship
477
00:36:33,481 --> 00:36:35,856
between the shrimps and
the bacteria they carry
478
00:36:35,857 --> 00:36:37,495
in their outsized heads,
479
00:36:37,496 --> 00:36:40,476
the team needs to be able to
observe some healthy specimens
480
00:36:40,477 --> 00:36:42,321
that haven't suffered the effects
481
00:36:42,322 --> 00:36:44,853
of such brutal decompression.
482
00:36:48,769 --> 00:36:50,854
Bruce Shillito's team has come up with
483
00:36:50,855 --> 00:36:54,558
a little technological
jewel, made up of two parts:
484
00:36:54,559 --> 00:36:56,695
PERISCOP and BALIST
485
00:36:56,696 --> 00:36:58,713
that can bring shrimps up to the surface
486
00:36:58,714 --> 00:37:01,499
while maintaining the
pressure from down below.
487
00:37:07,625 --> 00:37:09,554
It's a totally unique invention.
488
00:37:09,555 --> 00:37:12,021
It's the only machine that
can connect with a cell
489
00:37:12,022 --> 00:37:15,904
that can itself harvest
quite sizable animals.
490
00:37:15,905 --> 00:37:18,301
Of course, we're not
talking about giant squid,
491
00:37:18,302 --> 00:37:21,542
but five centimeter shrimps
is still pretty good.
492
00:37:27,051 --> 00:37:30,061
With food preservation, we
talk about the cold chain,
493
00:37:30,062 --> 00:37:32,273
but here we're talking
about the pressure chain.
494
00:37:32,274 --> 00:37:33,736
From the place they were caught
495
00:37:33,737 --> 00:37:35,493
right up to where they're studied,
496
00:37:35,494 --> 00:37:37,370
we maintain the pressure of the seabed
497
00:37:37,371 --> 00:37:40,673
and maintain the most natural
conditions possible.
498
00:37:43,708 --> 00:37:46,532
BALIST, the more complex
part of the system,
499
00:37:46,533 --> 00:37:49,038
stays on board the boat.
500
00:37:49,039 --> 00:37:51,328
It's impressive stainless steel structure
501
00:37:51,329 --> 00:37:53,486
weighs nearly 400 kilos
502
00:37:53,487 --> 00:37:56,270
and means it can recreate the
extreme pressure conditions
503
00:37:56,271 --> 00:37:58,334
of the abyss.
504
00:38:05,453 --> 00:38:07,020
It works like an airlock,
505
00:38:07,021 --> 00:38:09,048
a bit like on a space shuttle.
506
00:38:09,049 --> 00:38:10,695
Like a craft that comes and connects
507
00:38:10,696 --> 00:38:12,993
to the space station to supply it.
508
00:38:12,994 --> 00:38:15,369
We pressurize the water
lock, the connection,
509
00:38:15,370 --> 00:38:17,945
then once everything's
at the same pressure,
510
00:38:17,946 --> 00:38:20,689
we open the main valves
just a quarter of a turn
511
00:38:20,690 --> 00:38:24,388
and we can transfer the animals
just by tipping it all in.
512
00:38:27,664 --> 00:38:29,286
The first into action, though,
513
00:38:29,287 --> 00:38:32,384
is PERISCOP, the movable part.
514
00:38:43,101 --> 00:38:45,247
It is placed on the elevator,
515
00:38:45,248 --> 00:38:47,937
a freestanding module
that shuttles up and down
516
00:38:47,938 --> 00:38:50,367
from the surface during Victor's dives,
517
00:38:50,368 --> 00:38:53,788
which can last up to 36 hours.
518
00:39:01,056 --> 00:39:02,939
The mission of the robot's pilots
519
00:39:02,940 --> 00:39:06,756
is to catch 20 Rimicaris
shrimps inside a sealed tube
520
00:39:06,757 --> 00:39:09,942
they call the "PERISCOPette."
521
00:39:30,533 --> 00:39:33,293
First stage accomplished.
522
00:39:44,930 --> 00:39:47,919
Victor straight away takes
control of PERISCOP,
523
00:39:47,920 --> 00:39:51,304
which is a few hundred
meters away on the elevator.
524
00:40:00,286 --> 00:40:02,480
Fitting the PERISCOPette full of shrimps
525
00:40:02,481 --> 00:40:04,764
into PERISCOP's steel cylinder
526
00:40:04,765 --> 00:40:07,727
is the most delicate maneuver
of the whole operation.
527
00:40:35,088 --> 00:40:38,331
Now it's just a case of
closing the powerful valve
528
00:40:38,332 --> 00:40:40,316
that will maintain the deep sea pressure
529
00:40:40,317 --> 00:40:42,928
all the way to the surface.
530
00:40:48,171 --> 00:40:51,808
After a few minutes, the
elevator casts off its ballast
531
00:40:51,809 --> 00:40:55,778
and its buoyancy carries
it back up to the surface.
532
00:41:23,929 --> 00:41:25,113
Back on board,
533
00:41:25,114 --> 00:41:28,764
Bruce Shillito is preparing
a cozy nest for his guests.
534
00:41:36,318 --> 00:41:39,576
Inside BALIST, the shrimps
will be quite at home.
535
00:41:39,577 --> 00:41:41,518
The water is at eight degrees
536
00:41:41,519 --> 00:41:45,603
and the pressure is around 230
kilos per square centimeter.
537
00:41:49,821 --> 00:41:52,934
Through the window of three
centimeter thick sapphire,
538
00:41:52,935 --> 00:41:54,951
the scientists can observe the animals
539
00:41:54,952 --> 00:41:57,529
throughout the experiments.
540
00:42:02,244 --> 00:42:04,051
That's it.
541
00:42:08,454 --> 00:42:10,246
Watch the handle.
542
00:42:15,951 --> 00:42:17,805
The last phase of the operation
543
00:42:17,806 --> 00:42:19,889
is to connect PERISCOP to BALIST
544
00:42:19,890 --> 00:42:21,758
without any loss of pressure.
545
00:42:21,759 --> 00:42:24,946
One, two, three.
546
00:42:24,947 --> 00:42:27,143
Is that good for you guys?
547
00:42:27,144 --> 00:42:29,984
On the trolley, there.
548
00:42:29,985 --> 00:42:32,505
Put it down gently.
549
00:42:33,736 --> 00:42:34,891
That's it.
550
00:42:35,871 --> 00:42:37,151
Okay.
551
00:42:38,190 --> 00:42:41,294
Put it where it usually
goes so it'll be clear.
552
00:42:41,295 --> 00:42:42,882
It's not quite in the joint yet.
553
00:42:42,883 --> 00:42:44,521
Almost, almost.
554
00:42:44,522 --> 00:42:46,676
A bit further onto the plate, keep sliding.
555
00:42:46,677 --> 00:42:48,086
More, more.
556
00:42:48,087 --> 00:42:49,409
Slide it.
557
00:42:49,410 --> 00:42:51,706
A bit more, okay that's good.
558
00:42:51,707 --> 00:42:54,051
Now we unscrew it.
559
00:42:54,052 --> 00:42:55,491
That's it.
560
00:42:58,115 --> 00:43:00,569
Before he opens the powerful water lock,
561
00:43:00,570 --> 00:43:02,810
Bruce has to balance to the nearest gram
562
00:43:02,811 --> 00:43:06,769
the pressure in both BALIST and PERISCOP.
563
00:43:07,765 --> 00:43:09,968
Now I balance it with BALIST
564
00:43:09,969 --> 00:43:12,472
so the water lock's okay.
565
00:43:12,473 --> 00:43:14,829
Now for this.
566
00:43:14,830 --> 00:43:16,625
Okay.
567
00:43:17,350 --> 00:43:20,582
Only now can they transfer the Rimicaris.
568
00:43:36,605 --> 00:43:39,248
But despite the sloping
angle of the system,
569
00:43:39,249 --> 00:43:42,042
the PERISCOPette refuses to go down.
570
00:43:42,043 --> 00:43:45,351
It looks like one of the valves
isn't perfectly aligned.
571
00:43:46,360 --> 00:43:47,607
I think I hit it.
572
00:43:53,734 --> 00:43:56,463
It felt like it was going in there.
573
00:43:56,464 --> 00:43:58,813
It's going through, it's fine.
574
00:44:05,582 --> 00:44:08,547
You got something going on your end?
575
00:44:08,548 --> 00:44:10,371
Right, wait. I'll close it.
576
00:44:12,322 --> 00:44:14,801
We messed it up once with Girard
577
00:44:14,802 --> 00:44:18,368
and all three of us were
banging on the tube there.
578
00:44:18,369 --> 00:44:20,461
Okay, wait.
579
00:44:22,655 --> 00:44:24,938
The shrimps can survive inside BALIST
580
00:44:24,939 --> 00:44:27,329
for up to four days.
581
00:44:33,772 --> 00:44:36,704
In the aquarium, we can
control the temperature,
582
00:44:36,705 --> 00:44:38,646
we can control the flow and pressure,
583
00:44:38,647 --> 00:44:40,045
and that allows us to carry out
584
00:44:40,046 --> 00:44:42,783
a lot of interesting experiments.
585
00:44:50,944 --> 00:44:52,865
The various experiments carried out
586
00:44:52,866 --> 00:44:54,986
using the PERISCOP BALIST system
587
00:44:54,987 --> 00:44:57,926
will lead to a surprising discovery.
588
00:45:02,084 --> 00:45:03,771
We'd always thought that the shrimps
589
00:45:03,772 --> 00:45:05,753
grazed on the inside of their gill cavity,
590
00:45:05,754 --> 00:45:07,321
that it was like a growing chamber
591
00:45:07,322 --> 00:45:10,081
and that they scratched at the
bacteria there to eat them.
592
00:45:10,082 --> 00:45:12,747
But then we found out that
the covering of bacteria
593
00:45:12,748 --> 00:45:15,858
was never actually scratched or damaged.
594
00:45:18,547 --> 00:45:20,103
Unlike the deep mussel,
595
00:45:20,104 --> 00:45:23,312
the shrimp does not eat the
bacteria in its gill cavity.
596
00:45:23,313 --> 00:45:24,865
On the contrary.
597
00:45:24,866 --> 00:45:27,810
The research shows that
the bacteria actually
598
00:45:27,811 --> 00:45:31,814
feed their host just by
transferring molecules.
599
00:45:33,681 --> 00:45:35,684
The bacteria produce organic molecules
600
00:45:35,685 --> 00:45:39,499
that are defused by passing
though the skin of the animal.
601
00:45:40,552 --> 00:45:42,515
This must mean that the internal surface
602
00:45:42,516 --> 00:45:45,473
of the gill chamber lets
food molecules through
603
00:45:45,474 --> 00:45:48,076
directly into the creature's blood supply.
604
00:45:48,077 --> 00:45:50,370
This is amazing news.
605
00:45:54,340 --> 00:45:56,683
Could it mean that there's
a direct comparison
606
00:45:56,684 --> 00:45:58,686
between the huge head of the shrimp
607
00:45:58,687 --> 00:46:00,758
and our own large intestine,
608
00:46:00,759 --> 00:46:03,751
which also contains billions of bacteria?
609
00:46:05,651 --> 00:46:09,183
Human intestinal bacteria
help us to digest.
610
00:46:09,184 --> 00:46:11,122
We have our gastric juices of course,
611
00:46:11,123 --> 00:46:13,438
but they can't digest everything we eat.
612
00:46:13,439 --> 00:46:16,964
We think it's more or less the
same thing for the Rimicaris.
613
00:46:16,965 --> 00:46:20,815
Basically it's a shrimp that has
its intestines in its head.
614
00:46:28,227 --> 00:46:29,620
However the exchange
615
00:46:29,621 --> 00:46:32,160
between the Rimicaris
shrimp and its bacteria,
616
00:46:32,161 --> 00:46:34,062
goes a lot further than that between
617
00:46:34,063 --> 00:46:36,971
our intestines and theirs.
618
00:46:38,683 --> 00:46:41,420
A human being has to
ingest a certain amount
619
00:46:41,421 --> 00:46:44,598
of vegetable or animal
sustenance every day,
620
00:46:44,599 --> 00:46:48,157
which helps to build up the
body's cell structure.
621
00:46:55,653 --> 00:46:58,555
The main purpose of our intestinal bacteria
622
00:46:58,556 --> 00:47:01,605
is to help us digest our food.
623
00:47:03,112 --> 00:47:05,755
They're producing metabolites
that we can utilize,
624
00:47:05,756 --> 00:47:08,260
they're also breaking
down dietary substances
625
00:47:08,261 --> 00:47:10,950
like complex polysaccharides
626
00:47:10,951 --> 00:47:14,313
that we don't have the enzymes to digest.
627
00:47:14,314 --> 00:47:18,946
So they're very beneficial to
our digestion in that way.
628
00:47:22,074 --> 00:47:25,290
But it's quite different
for the Rimicaris shrimps.
629
00:47:25,291 --> 00:47:27,979
They don't even need to eat.
630
00:47:27,980 --> 00:47:30,419
The molecules they need to survive
631
00:47:30,420 --> 00:47:33,567
are entirely provided by their bacteria.
632
00:47:35,109 --> 00:47:36,377
It's magic, really.
633
00:47:36,378 --> 00:47:38,505
Very well organized, anyway.
634
00:47:45,574 --> 00:47:47,984
For true symbiosis to occur,
635
00:47:47,985 --> 00:47:51,205
the relationship has to be
beneficial to both parties.
636
00:47:51,206 --> 00:47:54,884
So what's the advantage
here for the bacteria?
637
00:47:56,534 --> 00:47:58,320
The shrimp provides the bacteria
638
00:47:58,321 --> 00:47:59,809
with a closed cavity
639
00:47:59,810 --> 00:48:02,500
where nothing else can
get at them to eat them.
640
00:48:06,061 --> 00:48:07,562
Well, the shrimp provides them
641
00:48:07,563 --> 00:48:09,024
with a home, of course,
642
00:48:09,025 --> 00:48:11,314
but it also invites them to dinner.
643
00:48:11,315 --> 00:48:13,938
It provides constant access to the sulfurs
644
00:48:13,939 --> 00:48:17,490
and other energy sources present
in the volcanic streams.
645
00:48:21,295 --> 00:48:23,937
The shrimps going back
and forth into the heat
646
00:48:23,938 --> 00:48:25,238
but not for too long.
647
00:48:25,239 --> 00:48:29,032
Like, "Oh, ouch! That's enough,
better cool off a bit."
648
00:48:29,033 --> 00:48:31,583
But the bacteria get their
hydrothermal fluids
649
00:48:31,584 --> 00:48:34,286
that enable them to multiply and prosper
650
00:48:34,287 --> 00:48:38,637
and to provide the shrimp
with its organic matter.
651
00:48:41,490 --> 00:48:44,664
It's a risky business, though.
652
00:48:45,577 --> 00:48:47,245
Sometimes you come across shrimps
653
00:48:47,246 --> 00:48:51,081
whose shells are burnt and
have bits of them damaged
654
00:48:51,082 --> 00:48:52,627
and this is certainly because
655
00:48:52,628 --> 00:48:54,376
they got too close to the fluids
656
00:48:54,377 --> 00:48:56,991
and have been burnt by them.
657
00:49:05,410 --> 00:49:08,044
Our intestines, too, offer food and board
658
00:49:08,045 --> 00:49:11,437
to a vast community of bacteria.
659
00:49:11,438 --> 00:49:13,968
They enjoy a safe environment and,
660
00:49:13,969 --> 00:49:18,375
except in very hard times,
all the food they can eat.
661
00:49:22,182 --> 00:49:24,924
It turns out that it's actually
662
00:49:24,925 --> 00:49:27,281
a mutually beneficial relationship.
663
00:49:39,645 --> 00:49:41,841
Scientists have made enormous progess
664
00:49:41,842 --> 00:49:44,927
in understanding these
remarkable symbioses,
665
00:49:44,928 --> 00:49:47,797
but there's still a lot left to learn.
666
00:49:51,255 --> 00:49:53,228
How and when, for example,
667
00:49:53,229 --> 00:49:56,048
do the baby deep mussels
or Rimicaris shrimps
668
00:49:56,049 --> 00:49:59,803
first acquire their bacteria?
669
00:50:01,331 --> 00:50:02,959
The researchers have just found
670
00:50:02,960 --> 00:50:04,984
the first seed of an answer to this
671
00:50:04,985 --> 00:50:07,248
with the Rimicaris shrimps.
672
00:50:08,768 --> 00:50:11,192
This is definitely a
very mysterious creature
673
00:50:11,193 --> 00:50:13,128
and we don't know its life cycle.
674
00:50:13,129 --> 00:50:15,317
They carry a few eggs under their abdomen
675
00:50:15,318 --> 00:50:17,768
until they have a young
larva that can swim,
676
00:50:17,769 --> 00:50:21,652
and we find bacteria on
the outside of the eggs.
677
00:50:22,635 --> 00:50:24,613
It would appear that the bacteria
678
00:50:24,614 --> 00:50:27,272
are already there on their eggs.
679
00:50:33,562 --> 00:50:35,762
The human fetus, by contrast,
680
00:50:35,763 --> 00:50:37,867
protected in its mother's uterus,
681
00:50:37,868 --> 00:50:39,796
is completely sterile.
682
00:50:39,797 --> 00:50:41,184
The mother's immune system
683
00:50:41,185 --> 00:50:44,751
represents an impenetrable
barrier to any bacteria.
684
00:50:51,609 --> 00:50:54,851
So for us, the whole question of bacteria
685
00:50:54,852 --> 00:50:58,184
only starts at the moment of our birth.
686
00:51:04,213 --> 00:51:08,232
Early in life, the bacteria
that occupied the neonate
687
00:51:08,233 --> 00:51:12,094
are generally from the
mother's microbial flora.
688
00:51:12,095 --> 00:51:16,095
But the developing child,
in the case of humans,
689
00:51:16,096 --> 00:51:18,221
quickly acquires its own microbiota
690
00:51:18,222 --> 00:51:20,521
and this develops into an adult microbiota
691
00:51:20,522 --> 00:51:24,297
during the first years of life.
692
00:51:32,707 --> 00:51:34,452
Man is just one piece
693
00:51:34,453 --> 00:51:37,004
of earth's great biological puzzle,
694
00:51:37,005 --> 00:51:40,051
where it's the bacteria who reign supreme.
695
00:51:40,052 --> 00:51:41,314
That's the beauty of bacteria.
696
00:51:41,315 --> 00:51:42,942
They can adapt to anything.
697
00:51:42,943 --> 00:51:44,615
To them, from their perspective,
698
00:51:44,616 --> 00:51:47,168
probably nothing is an extreme environment.
699
00:51:54,227 --> 00:51:56,327
Bacteria may have been the very first
700
00:51:56,328 --> 00:51:58,127
living beings on earth,
701
00:51:58,128 --> 00:52:01,805
but they've never tried to wipe
out more complex life forms.
702
00:52:02,922 --> 00:52:05,719
On the contrary, they've constantly helped,
703
00:52:05,720 --> 00:52:09,646
stimulated, and accompanied
the evolution of live.
704
00:52:20,251 --> 00:52:23,440
The remarkable success of
the bacterial symbioses
705
00:52:23,441 --> 00:52:25,068
found down in the abyss
706
00:52:25,069 --> 00:52:27,714
has shed a lot of light on
the fundamental importance
707
00:52:27,715 --> 00:52:29,839
of mutual aid between creatures
708
00:52:29,840 --> 00:52:32,436
when it comes to maintaining life on earth,
709
00:52:32,437 --> 00:52:35,085
including our own.
710
00:52:37,256 --> 00:52:41,903
Here down in the deep, acidic,
burning geysers of the abyss,
711
00:52:41,904 --> 00:52:45,862
it's as if hell itself
opened its jaws to show us
712
00:52:45,863 --> 00:52:50,819
how symbiosis is the key to the
future of all life on earth.
56185
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