(horns blaring)
- [Narrator] On land, it's always rush hour somewhere.
Highways are jammed with vehicles spewing carbon dioxide
that plays a role in warming the planet.
The ocean also has a daily commute, but instead of cars,
this commute involves tiny aquatic plants
called phytoplankton that helps soak up carbon dioxide
produced by burning fossil fuels,
shielding us from the harmful impacts of climate change.
Phytoplankton are an important part
of the biological pump, a carbon superhighway
that takes carbon dioxide out of the atmosphere
and transports it down into the deep ocean.
The biological pump starts when phytoplankton
and surface waters use sunlight to grow by taking up carbon.
Tiny animals called zooplankton gobble up the phytoplankton
and poop out little carbon rich pellets.
Fragments of phytoplankton, bits of zooplankton poop,
and particles of other dead organisms
all sink through the water column.
As the particles fall, they are eaten up in the deep ocean
and transformed into carbon dioxide.
That carbon dioxide then gets trapped
in the deep water layers, staying out of contact
with the atmosphere for a few thousand years.
We've learned more about the biological pump
thanks to hundreds of robotic floats
traveling the world's oceans,
collecting data about ocean health
and transmitting it back to scientists on shore.
These floats are part of an international research program
called Biogeochemical Argo and one thing they do
is provide data to estimate carbon in the ocean.
These three globes show how much carbon there is
in the Southern Ocean at different depths.
Each little dot is a float and the dots color changes
depending on how much carbon the float detects.
Green means more and brown means less.
See all the green dots at the surface?
Those sun lit waters have the most carbon
because that's where the phytoplankton
can use sunlight to photosynthesize and grow.
Now let's take some of this data from this section
of the Southern Ocean and look at it
on a graph of carbon versus depth.
The carbon superhighway grows
and shrinks depending on the month.
During the Southern Ocean spring and summer months,
carbon at the surface spikes
as the waters warm and phytoplankton bloom.
As those phytoplankton are eaten or die,
the carbon they carry is further broken down
by other organisms as it sinks,
until whatever little remains reaches the sea floor.
Thanks to the data from these floats,
scientists can better estimate
just how much carbon is produced in the ocean
and how much carbon dioxide actually makes it
to the deep ocean to be locked away.
However, as oceans continue to warm,
these patterns that we see might change.
As the heart of Earth's climate system,
the ocean currently protects us by soaking up
about 25% of the total human carbon emissions per year
and the biological pump is a big reason why,
but these climate services come at a cost to ocean health.
The phytoplankton and zooplankton
that power the carbon superhighway
come in a whole variety of species.
Some species are better than others
at transporting carbon down the highway,
and each species reacts differently
to changes in temperature, salinity,
and even wind patterns at the ocean's surface.
As these conditions alter with climate change,
responding shifts in plankton populations
will influence just how effective
the biological pump continues to be.
The slower the carbon superhighway,
the less carbon the ocean can store
and the faster our planet warms.
That's why the realtime information collected
by Biogeochemical Argo floats is so important.
By giving us a window into the carbon superhighway
and other ocean processes,
these floats are helping scientists
to better understand and predict the impacts
of climate change to improve ocean health.
(gentle music)