Welcome to a very special week, where we're joining The Swim to raise awareness around
ocean health.
Now climate change may call to mind: clouds of gases, smog blanketing cities, and rising
temperatures around the globe.
But it has also has many profound impacts on our oceans too--like the fact that climate
change is literally dissolving pieces of the ocean floor.
When we release excess gases like carbon dioxide, they linger in the air and insulate the world,
basically creating a thick gas blanket that traps heat and disregulates the world’s
natural temperature cycles--and our oceans come into play here in surprising ways.
For a lot of earth’s history, the ocean has acted as a carbon sink.
That means that it absorbs CO2 gas from the air.
That CO2 combines with the ocean’s H2O in a chemical reaction that produces carbonic
acid.
Which, as it sounds, is pretty acidic.
In a normal, healthy cycle, this CO2 absorption does lower the pH of the ocean, but luckily--the
seafloor is lined with a thick layer of calcium carbonate.
This is what seashells and the other bodies of some sea creatures are made out of, and
these form a layer on the bottom of the ocean just like leaves and other dead organisms
form the top layer of soil in a forest.
And luckily--calcium carbonate, also called calcite, is a basic compound.
Not as in---oh, calcite, she’s so basic--but like, the opposite of acidic.
In fact, we humans regularly consume calcium carbonate as an antacid for stuff like heartburn,
so we know firsthand how useful it is in combating acidic environments.
So, in a typical cycle, the seafloor basically acts like a big Tums tablet, reacting with
that carbonic acid to maintain the ocean’s normal pH and allowing ocean life cycles to
keep swimming along healthily.
But.
As we all know.
Global climate change is happening because we humans are putting WAY more carbon dioxide
and other greenhouse gases out there into the atmosphere.
And that means that the oceans are absorbing more and more of that CO2.
And they work so hard for us, guys -- absorbing up to a quarter of our total CO2 output every
year, so when global greenhouse gas emissions rise….so does the amount of CO2 absorbed
by the ocean.
This means that there’s not enough calcium carbonate to keep up with all the carbonic
acid that’s being produced, meaning our oceans are getting more acidic.
Not only that, but there’s SO much CO2 being absorbed that entire sections of the seafloor
are just straight up...dissolving.
Now, getting down to the very bottom of the seafloor is hard and expensive, so instead
scientists recreated deep sea conditions in laboratory microenvironments--down to the
currents, salinity, chemistry, temperature, alllll the deets.
Replicating these environmental variables--which were verified by physical sampling and computer
modeling--helped the research team pinpoint how fast the calcite dissolves in these environments,
both now and back in the day under different conditions.
And by comparing the dissolution rates pre- and post-industrialization, they calculated
how much is missing currently.
And it’s a lot.
In some hotspots, anywhere between 40-100% of the calcite seafloor is just gone.
Some specific areas, particularly in the northwest Atlantic, are faring worse than others because
ocean currents gather lots of dissolved CO2 there, making the calcite seafloor there have
to work a lot harder and thinning it out.
So...what’s underneath?
I mean there’s not just gaping holes in the ocean like big bathtub drains, there is
more stuff underneath it, it’s just not the calcium carbonate that used to be there,
that’s all dissolved away.
These gaping wounds in the ocean floor essentially mean we’re exhausting our stockpile of the
only material that keeps the ocean from becoming too acidic for life to thrive.
Think of it kinda like a deep sea version of the holes in the ozone layer.
As disheartening as this news is, maybe now that we know it’s a problem, we can start
to address it?
Maybe there’s a way to re-seed the ocean floor with calcium carbonate, maybe there
are human-made technological solutions to human-made problems.
More work is needed, like further mathematical modeling of the issue and more actual sampling
of the ocean floor in these areas, but we’ll be finding out soon enough whether there’s
anything we can do about it.
The health of our oceans is one of the most important issues facing humanity today, and
climate change poses a big threat.
Seeker is highlighting The Swim all this week, to bring awareness to the impact of specifically,
plastic pollution on our oceans.
We ask you to help us spread the message.
Tell us how you are reducing plastic pollution in the comments below.
Keep coming back to Seeker for all your environment updates, and thanks for watching.