- Though all life on Earth likely began in the oceans,
we as human things know that our domain
is not underneath the waves.
Only a humanoid hero like Aquaman can survive everything
that the seas have to throw at us, or can he?
Can Aquaman drown?
Let's get technical.
(sucks in air) (grunts)
Being happy Atlantean, Arthur Curry or Aquaman
has the physiology, canonically speaking,
to thrive both inside and outside of water.
So asking a question like, can he drown?
Will depend entirely on our definitions of drowning
and his physiology.
And I know that this question
sounds like it has an obvious answer to it,
but this analysis turns out to be surprisingly complicated.
so let's start with the basics.
How does Aquaman breathe underwater?
I'm a shark.
Whether in water or in air,
breathing fundamentally comes down to one process
All particles in the universe like atoms and molecules,
if they have any temperature at all,
they are necessarily bouncing around
and wiggling all over the place.
And as they do this in some volume, for instance,
they bump into each other and against the volume
and they tend, over time, to move into spaces
with less particles in them.
This tendency is called molecular diffusion
and it makes breathing possible.
In breathing things, such as we,
biology has evolved to take advantage
of this passive movement of particles
from one place to another, it requires no energy.
For example, when we breathe in, (breathing deeply)
in that air there is more oxygen in the air
than in our bodies tissues, in our lungs.
And so some of that oxygen goes across
and through those tissues and into our bloodstream,
and the opposite happens with carbon dioxide.
And if you looked inside our lungs
the basic structure would be like this,
it wouldn't be just a flat interface,
it would be a lot of small pockets
that would increase surface area available to the air
to enhance molecular diffusion.
And in gills, like in fish,
you would see just the opposite.
With those structures and that increased surface area,
in direct contact with the water for the same reason.
But breathing with water changes a lot more
than just this basic shape.
(water splashing) (bird squawks)
I landed on a bird.
When his superpowers aren't just glossed over,
it sometimes mentioned that Aquaman
breathes underwater using gills.
Hello fish friend, aid us on our learning quest.
If we looked inside our fish friends mouth and head here,
we would find rows and rows on the outside edges
of what are called gill filaments,
and these are just sections of very, very thin tissue
with a lot of blood running through them,
positioned such that, as the fish moves through the water
or opens its mouth,
water comes into direct contact with them.
And if we looked even more closer at these gill filaments
we would see that yes,
they are in direct contact with water,
but the blood flowing through these filaments
is actually flowing in the opposite direction
that the water is flowing.
At least in Chad the shad here.
This counter current flow evolved
because of efficiency.
Let's say we had some concentration of oxygen
dissolved into the water.
Let's say it starts at 100 and it ends in five,
after it passes the gill filaments.
As long as these two flows are counter to each other,
there will always be a gradient
that helps molecular diffusion.
If the deoxygenated blood comes into contact
with the more deoxygenated water,
rather than the other way around,
because that would not have as good of a gradient
and you wouldn't be able to breathe underwater as well.
And that is important because relatively speaking
getting oxygen out of water is kinda hard.
(water bubbling) (water splashing)
Woo, my man.
Here I have two, one liter cubes
filled with both water and air.
In the probably regular air,
that you're probably regularly breathing right now,
there is around 210 milliliters per liter of oxygen in it.
In one liter of fresh water though,
there are only eight milliliters
of dissolved oxygen available to a fish.
This is in part why gills evolved to be so dang efficient.
Not only is there less oxygen available to a fish in water
compared to air.
Water is obviously a lot more dense
and a lot more viscous than air,
making it harder to move physically
past structures like gills.
We breathe via molecular diffusion too,
but our lungs didn't have to evolve to be so efficient
because there's so much more oxygen
in the air that we breath.
If fish and their gills are so good
at getting oxygen out of water though,
you might be asking,
what's stopping them from breathing on land?
Geez, I'm sorry Garry.
I didn't look look where I was jumping.
What will determine this DC drowning
all comes down to Aquaman's form and function. (laughs)
Water isn't just important for fish either.
Every single breath you take (breathing deeply)
is first warmed and humidified,
more water is added to it before any oxygen
makes it into your bloodstream.
And we have a consistent, thin, liquid layer
covering all of our lung tissue, at all times.
All of this is to say that dry breathy bits
are bad for living,
and this is a big reason why fish out of water
have a hard time staying alive.
But what the simple demonstration
I can show you the biggest reason.
The biggest reason why fish suffocate out of water
is because of what happens to their gills
when you take gills out of water.
So to demonstrate this we have a science tube here
filled with fresh water
and here is our representation of gills.
It has just torn up tissue paper
because gill tissue is very thin,
there's a lot of gill filaments and as you can see,
they present a lot of surface area to the water.
And if we submerge this tissue paper in our water here,
just like a fish's gills,
you can see that everything spreads out,
exposing all that critical surface area to the water.
The waters density and viscosity helps keep everything apart
and the fish is breathing just fine here.
But now watch what happens when I take our paper out
of the water just like taking a fish's gills,
and the fish itself, out of the water.
You can see that instead of staying spread out,
everything clumps together.
Weighed down by the water and without any buoyancy
our gills stick together
and look at the difference in the surface area here.
Instead of having many, many different channels available
for molecular diffusion,
you have basically just two sides a huge decrease.
This is what happens to a fish
when you pull it out of water,
all of its gills stick together which dramatically reduces
its ability to take oxygen out of the environment.
This is biggest reason why your typical fish
will not survive very long when on land.
In terms of gas transfer,
this is like asking someone to breathe
after putting a hand over their mouth.
And this is such a simple and understandable demonstration
of this fact, that I wish I would have gotten
my feet wet more often with these kinds of questions
when I was kid.
It's an idiom.
(sighs) Of course not all aquatic organisms
have such a hard time with living on land
or with dry gills.
The mudskipper, for example,
can absorb up to a half the oxygen it needs
directly through its skin.
And many species of catfish can just straight-up gulp air
and absorb oxygen in their guts,
and then they just fart out the rest.
Given the diversity of respiratory solutions
in the animal kingdom,
and who knows how Aquaman breathes from comic to comic,
whether or not Aquaman can drown is now gonna to depend on
our definition of drowning. (Aquaman grunting)
Not not that kind
of definition dude. - My man.
- Merriam Webster's dictionary defines two drown as
suffocation via submersion especially in water.
Suffocation of course meaning a deadly lack of oxygen.
Given this specific definition
is there a way to drown Aquaman? (chuckles)
If Aquaman used gills like your typical fish,
there is a way for him to suffocate
via submersion in water, and that way
has everything to do with what's called dissolved oxygen.
We've already talked about how oxygen can dissolve
into water in specific concentrations as a gas,
but that concentration can change.
For example, if you wanted to populate a fish tank
with a lot of fish,
you would need to increase the amount of dissolved oxygen
in the water with something like your standard bubbler.
But you can also decrease the amount of dissolved oxygen,
in the water, by adding more fish
or by adding more things that require oxygen
to break them down, stuff like organic pollution.
When a lot of new organic material
or chemical pollution enters an aquatic ecosystem,
microbes like algae rush to eat it,
using oxygen as they do so.
And if the pollution is bad enough
there is enough algae that the dissolved oxygen goes down
so much there can be literally no oxygen in the water left
for anything to breathe.
Depleting the world's oceans of oxygen
sounds like a super villain plot you'd find in a comic book,
except we're doing it right now.
Thanks to organic pollution and chemical runoff,
from agriculture, into the sea,
for years now there has been a massive dead zone,
in the United States, the size of New Jersey,
in the Gulf of Mexico.
The dissolved oxygen, here, in this water is so low
that almost nothing can live there,
aside from the algae
that created this situation, thanks to us.
It could be incredibly impactful to the environment
and it is and dead zones happen
like this all over the world,
and if Aquaman really existed,
he would be really angry about this.
But appalling ocean pollution aside for a second,
if you threw a fish into dead zone like water
it would suffocate via submersion in water,
it would drown.
(metal clanks) (waves crashing)
The last variable here is of course
how Aquaman actually breathes.
But whether he is absorbing o2 through his skin
or using gills or he needs to occasionally
return to the surface to gulp some air,
there should be a way he can drown.
If Aquaman used gills like your typical fish,
a super villain could simply create a dead zone
in all of the oceans or in his Atlantean home,
that would lead to lethal levels of dissolved oxygen.
Or if he gulped air from the surface,
you could simply deny Aquaman access to the surface
and he would eventually drown in the water.
This actually happens to fish that we know about,
like the betta fish or Siamese fighting fish.
And if he absorbed o2 through his skin
you could just do a combination of both.
Aquaman can drown.
Hey, get up, you can't be dead,
you have to save the DC EU with money.
So can Aquaman drown?
Well sounds like a silly question at first,
but once you know how fish actually breath
and how they depend on oxygen,
just as much as we do,
you can think of situations where,
if nothing magical is going on, yes,
Aquaman could drown.
He may be the king of the seven seas,
but he's still subject to almighty o2.
Just like you, just like me and just like Gary.
Don't you have like a parking lot to be annoying in?
As a child I do not think you have
a fundamental understanding of what dissolved oxygen is,
why would you have one?
And so that's why your goldfish died.
That's why my goldfish died.
You assume that the water is what allows the fish to live,
but you don't realize that there's dissolved oxygen
as a resource, a finite resource in that water.
And so if you just keep a fish in just a small bag
or just a small bowl,
where oxygen is entering the water from the atmosphere
but not enough, there won't be enough oxygen in the water
and the fish will suffocate or drown, by our definition,
in that water.
So that's why your goldfish died
and that's why you need a bubbler.
That's why I was a sad boy at the county fair.
Thank you so much for watching Aaron.
If you like this video you might like some of our other
sciencey Aquamany videos that we've done.
Like how he swims supersonically through water
and how his body, ripped though it may be,
survives the sea.
And if you wanna give us suggestions for future episodes,
one of you suggested this episode,
you can follow us here at these social media handles.
And hey, (laughs) all right.
'Kay, my man.
Can dig it.
Like a bet. (laughs)
Shave my beard.
(upbeat electronic music)