The water column is incredibly huge. It's definitely the
largest habitat on earth encompassing 95% or more of all
the livable space on the planet. It's always moving and
in float. If you go to a bottom habitat, you could go back to
the same coral mound but in the water column, if you go back to
the exact same place but at a different time, the water
column is going to be different. It is the least
explored habitat on planet Earth.
Water column is important because it's home to trillions
of organisms in more than a million species or so. The lack
of light has led to all sorts of incredible adaptations in
mid-water animals. Red and black are really great colors
to be if you don't want to be seen in the depths. Many will
make light so by bioluminescence and of course some organisms
prey on them. A lot of those organisms have a dark red
pigmented gut in order to block out the light that might
accumulate in their stomachs. A lot of the deep sea fishes have
hese long thin teeth and those are good for grabbing on to
prey and holding on to them.
In the early 1800s, people with nets would find that if they
collected in the shallows during the day and at night
that they would collect different types of organisms.
Now we can use more sophisticated tools with
acoustics for instance to understand where organisms are
concentrating in the water column. What we call the deep
scattering layer. Dial vertical migration is been dubbed the
greatest migration on planet Earth. That's because billions
and billions of organisms primarily zoo plankton which
are small fishes, crustaceans, and jellies, they will move up into
shallow waters at night and then when the sun starts to
come up, they move back down into the dark, deep waters and
they do this all over the planet even in lakes on this
daily basis. These water column animals are important for lots
of reasons. They are playing different roles in the
environment as predators but then also as prey to large
animals such as whales. They're also very important in
planetary processes. They tie up a lot of carbon through
their feeding and then when they move down to deeper
waters, that carbon is then locked in those deeper waters
or even transferred all the way to the ocean floor so they're
really critical part of the carbon cycle on planet Earth.
The future of water column research is going to be
characterizing the water column in new ways. One of the new
ways is with environmental DNA where we'll basically be able
to take collections of water and that water contains bits of
cells that have come off of different organisms and then
we'll be able to sequence all the DNA that's in that water to
understand better the organisms that are living around that
place. This is a really efficient technology so it can
be deployed many times over and over in many different parts of
the world. Because the water column is so connected and
always moving, it's all one big giant system and so we need to
characterize it in multiple places to really understand it
better.