Scientists explore the ocean’s eerie twilight zone


This is the ocean twilight zone,
a swath of deep sea that starts 200 meters
below the surface where
sunlight barely reaches.
It’s the least explored part of the ocean.
– A lot of us are familiar with the
idea that there’s lots of things
living in the upper ocean,
but we have maybe forgotten
about the deep ocean and don’t
realize how interesting it is
and how important it is to our planet.
The creatures here live in the dark
at pressures that would kill us.
And far from the ocean floor,
they’re constantly moving,
making them harder to track.
– You go down in the deep water and
that is just paradise for those animals.
There’s so many different kinds down
there that nobody has ever seen before.
Scientists from the Woods
Hole Oceanographic Institution
are embarking on an unprecedented six
year project to explore the twilight zone
and what they’re finding could be key
to feeding and protecting life on Earth.
I’m Kayle Hope and this is Quartz.
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This is the second expedition for
the ocean twilight zone project.
By 2025, they expect to make dozens of trips
to study the deep sea all over the world.
The twilight zone is home to more
fish than any other part of the ocean.
– Pretty exciting actually
to be able to go down
in a submarine and look
out the window or the port
and you see some animal
that you know probably
nobody in the history of
humanity has ever seen before
and especially even
better if you can catch it
and bring it back and describe
it and give it a name.
There are only 15 or 20 submersibles
in the world that can go this deep.
– The twilight zone is kind of
this important piece of the puzzle
that’s connecting the surface ocean
and the deep ocean in intricate ways.
Heidi Sosik is the lead
scientist on the project
and the sub is just a small part of their research.
They’re towing a system of nets behind the ship
that can be open and closed with a
click of a mouse at different depths.
They’re also collecting DNA from the water
to better understand what organisms
live there that we can’t see.
– We can identify possibly
new organisms that don’t exist
in any reference database yet.
And they want to understand more
about where all these creatures
are going and what they do.
We’re 300 meters down in the twilight
zone, looking to see what we can find.
– Most of the animals that live in
the twilight zone are quite small,
but they’re able to make these
incredible movements through the ocean.
This is called the diel
vertical migration.
It’s the largest migration of animals
on earth and it happens every day.
The animals in the twilight
zone don’t just stay there.
A lot of them move through the
ocean hundreds of meters every day
up into surface waters.
When it’s dark at night,
they come up and they
can be kind of stealthy
and feed on plankton that had been
growing in the sunlit surface ocean.
So there’s this like sweeping
wave of animals moving
up and down through the ocean every day,
all across the globe.
They’re part of what’s called
the global carbon pump.
Tiny plants and bacteria at the surface,
pull carbon dioxide out of
the air using photosynthesis.
During the diel migration,
deep sea animals come up to eat them.
Then they descend,
pulling carbon down with them
and adding to what’s called marine snow.
– Each of those particles is carbon
and it’s heading down to the sea floor
and if it makes it all the way down there,
it can be stored away
for thousands of years.
Joel Llopiz is a fish and
zooplankton ecologist.
He’s also a co-chief
scientist on this project.
He says understanding the carbon pump
could be key to fighting climate change.
And it’s one more thing
scientists are just starting
to understand about the twilight zone.
– The truth about the twilight zone is
that we don’t know what
we don’t know about it.
There could be a whole
lot of species down there
that we have not discovered yet
And he says, scientists are
in a race against time.
The animals here could become a
big food source for aquaculture.
– The world’s population
is growing so fast
and humans are struggling
to feed themselves.
The twilight zone is a
rich source of protein
that could not feed humans directly,
but it’s likely to be fishmeal
for food that we do eat.
The scientists from
Woods Hole want to gather
as much information about
the twilight zone as they can
before humans change it irreversibly.
– I think the challenge
for us as humans who care
about the health of our planet is that
we know so little about the
life in the ocean twilight zone
that we don’t have the
information that we need.
We don’t even know how long many
of the fish that live there live,
we don’t know how long it
takes them to reproduce
and without that kind of information,
you’re flying blind.

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