June 4, 2015 • 38 mins
It's easy to overlook the importance of ocean currents - they move along out at sea, while we stay mostly on land. But we are globally affected by them every day. Currents form the base of the food chain, drive weather and keep life as we know it going.
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Episode Transcript
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Speaker 1 (00:00):
Welcome to Stuff You Should Know from House Stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh
Clark with Charles W. Chuck Bryant, and Jerry and this
is Stuff you Should Know, the one about ocean currents.
(00:21):
We should start titling our episodes like Friends did. Yeah,
the one where Ross talks about ocean currents. Yeah, the
one where Chuck's eyes glazed over. I love this stuff, man,
Like Earth science really gets me jazz. That's good, it
really does. Like it's so like, it's very detailed. There's
(00:43):
a lot to it. It's often oversimplified, but it's also
very understandable. And when you really like learn about it,
you realize what an elegant system the whole thing is. Sure,
maybe not necessarily a living organism, but I could see
how someone would characterize it as such. I like that.
(01:03):
It's good intro. Yeah, that's what I got. Uh so, Yes,
tidal ocean currents, well, not tidal, that's part of the
ocean currents. It's a type of current. It's under the
current umbrella. I've misspoken the first ten seconds. I think
it's funny that in this article the word current refers
to the motion of water when speaking of water? Is
(01:26):
that what it says when speaking of water, the word
current refers to the motion of the water. Yeah, it
was a little clumsy Miriam's defines. Yeah, uh, well, this
is about ocean currents. Are all kinds of currents, river currents, Yeah,
you know, there's currents in marshes and swamps and currents
(01:46):
all over the place. But this is about ocean currents. Yeah,
as long as water is not stagnant, there's currents present.
And if it's stagnant, it's bad news Jack mosquitoes disease. Sure,
But then again, you can make the case that if
it's not stagnant, if if there's a current, it'll carry
your car away in the blink of an eye. I
don't even think about it. Boy, did you see the
(02:08):
photos of the Downtown Connector the other day in Atlanta
when it flooded. Apparently the storm drains backed up in
the downtown Connector of Atlanta was a lake. Wow, Like
it literally stopped traffic. I can believe that. Yeah, people
in Atlanta don't know how to drive in the rain
to begin with. Oh, I don't know about that really. Yeah,
(02:31):
that's all we do was driving the rain man. People
in l A don't have to driving the rain. Seems
to me like everybody's brain just drops a couple of
years when rain starts, and everyone starts like bumping into
everybody else and like driving it two miles an hour,
and you just like pedal to the metal. What's different
all the time. I got good tires. Yeah, Look, because
(02:52):
you liked our stores, right, I don't like tip stores,
but I'm willing to spend time there to get good
tires that move water away from my car so I
can if I have really fast no matter what the weather,
you should start your I want to point out. Jerry
just sighed heavily at this tangent. I think your retirement
(03:15):
business should be Josh's tire house. Yeah, and then have
a really sweet setup. Would be like fine tires. Just
here's like no place else on earth. Oh yeah, you
got WiFi. You got a coffee machine? Well there's well no,
I mean a baristah, like a you know, a little
mini Starbucks right there in your tire shop. Games have
icebreakers meet and greets. Yeah, I could serve icebreakers come
(03:38):
to you get have tinder Tinder day. Okay, Well, I
don't know a Roman therapy would be good to be
a big one massage. Yeah, alright, let's my's my plan
b all right, Josh's tire warehouse and pourium, I think
is what we came up with. Josh's big house of
tires or house with big tires. Okay, so ocean currents
(04:01):
we're back to it. So um. One of the things
that I did not realize, Chuck, when researching this is
that ocean currents they're they're old, but they aren't permanent.
They haven't always been around. Currents change, you know. Some
currents have been at it for thousands and thousands of years.
Other currents change months a month, very fickle in some cases.
(04:26):
But there are some really ancient currents, some ancient ocean
currents out there that are um very old and have
been this way since say, like um, like the Gulf
Stream has been around for about five million years, ever
since the Isthmus of Panama. Pretty cool stuff, huh. Yeah.
I think what I found the most interesting was that
(04:49):
ocean currents they have a purpose. You know, it's not
just like water moving around willy nilly. You know. If
it wasn't for ocean currents, there would be no life
in Antarctica. Right, well, maybe not all of Antarctica, but
no ocean marine life. But that's that's an important point. Like,
if there's no ocean marine life, then there's no like
(05:11):
to say, there's no phytoplankton, there's no phytoplankton, there's no
fishies eating the phytoplankton. There's no fishies around to eat
the phytoplankton. There's no seals to eat the fishies. If
there's no seals, Like, everything finds its support, its basis
in the ocean. Life that's all supported by the currents.
(05:32):
That's right. So the fact that has purpose, it's very
teleological of you, chuck. So let's not put this off anymonger.
Let's talk about different types of currents. You can't talk
about tire stores anymore. Okay, we're done with the tire stores.
Like I started to get nauseated just talking that much
about tire stores. Alright, I don't feel good. Well, uh,
let's start with surface currents then, but I'll bring you
(05:54):
back to the to the ocean earth science, your home
earth sciences that you love. Uh. Surface currents occur about
three to fo um deep and above. Yeah, they're called
surface currents, right, and they're driven by the wind. Yeah,
they make up for about ten percent of the ocean.
And um, if you've ever gone to the beach, you've
(06:17):
seen coastal currents. UM surface currents. There's a couple of types.
Coastal is one of them. You see them in action, right,
like playing in the sand as a little kid or
as an adult. You're you're seeing coastal surface currents at work.
So let's step back one more degree. So service currents
are created by wave action, that's right. Especially coastal currents
(06:42):
are created by wave action, which is created by wind.
Waves are created by wind. And you know Buckminster Fuller,
the inventor of the geodesic dome, among other great things,
he was the person who pointed out that the wind
doesn't blow, the wind sucks. It's a good point, right, So,
and so if coastal currents begin with waves, waves begin
(07:04):
with wind. Wind begins with heat because at the equator
you have a lot of sunshine all year round and
it's very warm, as anyone who's been near the equator
can attest. Um, And that heat heats up air, and
as the air heats up, it moves away from the equator.
It's like, I gotta go cool off. It moves towards
(07:27):
the poles north and south, and as it moves toward
the poles, it cools down and turns back around. It's
like I need to heat back up at the equator, right.
And as a result of this, you have wind. And
this wind pushes on the surface of the water, transfer
some of its energy in the form of friction to
the water surface and creates waves and those waves transfer
(07:48):
the energy to shoreline and when they come in at
an angle, that's when you get that coastal current. Right. Yeah,
Like with you've again, if you ever been to the
beach and you see the tide or the waves coming
in at that angle, and you see it moving with
the beach, Like if you've ever been out playing on
like a raft is a little kid, you look up
(08:09):
an hour later and your parents are like half a
mile down the beach from where you start, right. It's
a bit of a panicky situation, it is. And also
you're like, what kind of parents do I have that
they just let me drift half a mile? Yea, you
know they're passed out in the sand at that point.
Uh So that is called when when uh, a wave
breaks on the beach at that angle, it's gonna pull
sediment and sand and water down in what's known as
(08:32):
a long shore current. That is, uh it's directed off parallel,
also perpendicular, but the parallel movement is the long shore
uh current. Yeah. It's like when a wave comes into
an angle to the shore, it distributes its energy. Part
of it directly on to the shore. Part of it
parallels is short and um, that's that long shore current,
like you said. And one of the things that it does,
(08:52):
you also said, is it takes sand and other stuff
and deposits it elsewhere further down and along the way.
It creates things like barrier islands and sandbars and all
that stuff. And that's ever shifting, ever moving, um, eroding
and depositing of sand and sediment and those little underwater
(09:14):
and sometimes above water deposits create other types of current,
specifically a riptide current. Yeah. Um, that's the longshore drift
and um, like if you've ever seen like the beach
curve back in pretty hard. The water can't make that
turn really, so it's just gonna deposit stuff and sort
of drop it off there at the end of that
(09:35):
point and it'll build up and what's known as a spit, right,
and so all of those, all those obstructions, um, all
those deposits form obstructions for waves. When they're going back
out once they transfer their energy, they're like, oh, I'm
pretty far inland. I need to get back out of
the ocean. Yeah, And so it backs up right, and
(09:59):
as it does encounters these underwater barriers that it itself
have deposited. It's kind of a big ironic moment. And
so it can't get back out to see as fast
as it wants because it's running into these obstructions. And
when there's like a break in the obstruction, like a
sandbar or something like that had a break in the sandbar,
(10:19):
it provides a natural funnel and that creates a rip
tide current. Yeah, like, hey, look at that little narrow channel.
I'm gonna take all this water that would normally just
flow out nice and easy. I'm gonna send it through there,
and I'm gonna grab your little kid and take it
taken with me. Right. If this, it creates basically suction.
Just like when you open a drain in a bathtub
(10:40):
and it starts to drain, it drains pretty quick. Yeah,
it's dangerous, Like that's how you drown when you're swimming
in the ocean. You hear about strong rip currents and
inclement weather and um, it's no joke. Even really good
swimmers can get caught in a ripping. Yeah, and it's
bad news riptide, very bad news. Um. And then there's
(11:00):
some other currents that are created that um don't just
occur at the at the shore, but they do. They
occur in the ocean and at the shore there's this
thing called upwelling. This stuff and upwelling can happen in
a few different ways, but as far as the coast
is concerned. When wind comes in and it basically blows
(11:22):
water away from an area, like from the shore, right,
water likes to try to even itself out. So as
some water is blown away from the surface, this stuff
that's below it, the deeper water will come up and
basically replace it, and that's upwelling. Yeah. It's another like
what strikes me when you look at wind and all
these currents. Everything is circular almost right, so a lot
(11:45):
of spinning going on. Yeah, there's a really um distinct
relationship between wind and water. It's inseparable, especially when you're
talking about global winds and currents together, right, But both
of them are broken down to fluid dynamic X and
they do form these circles and cycles and clockwise motions
and counterclockwise motions depending on where you are in the world. Yeah.
(12:07):
And in the case of upwelling and downwelling, it's not
a horizontal spin, but it is a vertical um from
top to bottom and then from bottom back up to
the top. Yeah. And you want to talk about um
that was which one. Well, both it's the same pattern
from top to bottom and bottom to top with upwelling
and down welling. Right. And the whole thing about upwelling
(12:29):
and downwelling, whether it's at the shore or in the ocean, um,
is that the ocean is kind of It's not like
if you take a slice of ocean at the top,
you take a slice of ocean at the bottom, very
different and you look at them. Yeah, under a microscope
or test um for whatever, you know, using some sort
of uh, spectroscope, maybe some sort of oscillator, glavin or
(12:53):
something like that, or just look at it. Yeah, you're
going to find that there's it's like two different types
of water. Even though it's from the same part of
it's from the same section of ocean, right, And the
stuff at the top is going to be very oxygen rich.
There's gonna be a lot of life phytoplankton, that kind
of stuff, um, but not too many nutrients. The stuff
(13:14):
at the bottom is gonna be lousy with C O two. Yeah,
very cold and a lot of nutrients. Right. And when
both of these things are needed at different spots, So
the upwelling and the downwelling creates this kind of gas
exchange and nutrient exchange throughout the ocean. And the oxygen
at the top when it's deposited down lower thanks to
(13:37):
down welling, all of that oxygen circulates downward through the
ocean and all the fishies that need oxygen in their
gills get to breathe it in, right. Yeah. And with upwelling,
like I mentioned earlier in Antarctica, where it's super cold
and you would not expect marine life to do so well,
it is because of the upwelling that brings the nutrients
(13:57):
from the bottom up to the top. And that's iCal
and that's called life. And one other really neat thing
about upwelling and down welling is um that oxygen that's
at the top of the ocean. Were it to just
sit there for very long and dissolve, we would have
a very big problem because all of that life, once
it dies, would decay very quickly up tops. No, it wouldn't,
(14:21):
because anaerobic bacteria would begin to thrive and we'd have
a over abundance of hydrogen sulfide, which would lead to
ocean acidification, which would mean the end of the world. Basically,
So that nutrient swap is very important for everybody on
the planet. Yeah, and there's this elegant solution to the
oceans that happens every day everywhere in the ocean thanks
(14:42):
to upwelling and downwelling. All right, well that's a good start,
my friend. Um my eyes are not glazed over, actually good,
they're sharp, full of life. Um. We will talk after
this break about some more surface currents. All right, Josh,
(15:17):
there's more than one kind of surface current. We covered
the I kind of like that first part, but there's
also surface ocean currents. And uh, again, the wind is
the big contributor to how these babies form um and specifically,
I guess we should talk about the Coriolis effect. Yeah,
this is a this is a game changer, as people
(15:39):
who read self help books on airplanes would call it. Right, yeah,
so um. Again, it all starts with heat, and all
that heat is found in its thickest part at the equator.
And my brain is broken. So at the equator it's
the hottest, right, that's right. And it's also also a
spinning fast or the equator than at the poles, right,
(16:02):
it is okay, so um, it's the Earth that is yeah,
so um. At the equator it's hot, it's spinning faster
because of the spin. Because of the heat. The ocean
is actually about eight centimeters high higher here than at
the rest of the ocean. That's so much higher, So
there's a right, it's just enough to make water flow
(16:24):
away from the equator. Plus you've got wind that's whipped
up because hot air at the equator starts moving northward
and cools down and that creates wind. Right, So if
the Earth didn't rotate, you would still have these things.
But wind would travel in a straight line away from
the equator towards the poles, cool down and turn around
(16:46):
and come back in a straight line. That's right. But
that's not the case. No, it isn't because the Earth
does rotate and it produces the Coriolis effect. Yeah, it's
like a curve. Basically, it uh curves to the right
in the northern hemisphere and to the left in the
southern hemisp here. Right, so it makes wind curve and
since wind drives surface currents, it makes surface currents curve
(17:07):
as well. Right, that's right. So what's really cool is
the ocean has its own topography. It's it's definitely not fight.
Anybody who's looked at ocean could be like, oh, it's
pretty choppy. But if you if you could step back
even further and you had the right kind of topographical
glasses on, maybe you would see that there's like valleys
(17:28):
and ocean and mountains and maybe not mountains, but little
tiny hills and valleys in the ocean. So, like I said,
it has its own topography. And this is created by
those winds that push on the water. And as they're
pushing the water up and the Coriolis effect is turning
at some water starts to kind of mound. So in
(17:48):
some parts of the ocean you have water that forms
a mountain that's about like three to six ft tall. Yeah,
it doesn't sound intuitive, no water mounding up on itself.
You think if it as ye, But there is actually
water that's mounded up into little hills, okay. And so
that means that gravity wants to push this water downward, right,
(18:12):
But it doesn't just go back down the hill, because
the Coriolis effect pushes it upward. And the net outcome
is that instead the water just says, how about it
just go around instead? Yeah, you stay up here on
the mound, you stay down here, but I AM going
to just go around. And what it does is, since
(18:32):
a mound is roughly circular, it creates a current that
goes around these things, around these mounds. And there's five
major ones in the entire world where you're headed, and
they form what are called gyres, that's right, g y R, E, S,
and um. They are the North Atlantic, South Atlantic, North Pacific,
South Pacific, and then the Indian Ocean has its very
(18:53):
own gyre. There are smaller ones around Antarctica, but those
are the five major gyres. We about the Gulf Stream earlier.
That is a part of the North Atlantic gyre, and
it carries times the water of the entire Mississippi River.
The Gulf Stream does. Yeah, the Gulf Stream is the
(19:14):
hero of all gyres. It is it moves um. Let
me see, I've got to find this one because this
is so amazing. So the the Gulf Stream, at any
given point, it moves water at a rate of fifteen
superdomes worth per second. So you remember the superdome in Louisiana. Yes,
(19:38):
say you've filled it with water, and then you took
copied fourteen more times, so you have fifteen superdomes full
of water. That's how much water passes through any given
point per second. Okay in the Gulf Stream. All right,
that's a lot of water. How many big max is
at It's trillions of big max billions and billions served.
(20:01):
But the the Gulf Stream itself is actually um. It's
technically the western boundary current of the North Atlantic gyre. Yeah,
and it's gonna carry warm water. It's it has a
big impact in the world. It's gonna carry warm water
up north from the Gulf of Mexico. And that's why
if you're living on the east coast of Florida, you're
(20:23):
gonna have cooler summers and warmer winters. Um. Western Europe
is gonna be a lot warmer than other places on
its exact same latitude. And this is all because of
the Gulf Stream. You can deposit bodies in it if
you're dexter, and those things are gonna yep, see a
later body. Yeah, it will probably get carried to England
and they'll be like blind, me was this? Uh So
(20:46):
that's just the Gulf Stream. There's actually at least four
major currents that form the boundary currents of the North
Atlantic Gyre, and the North Atlantic Gire is just one.
We've also talked about jarres before with the Great Pacific
Garbage Patch. Yeah we covered did we do waves or
did we just do We did rogue waves too, but
we covered waves and surfing. Okay, ye remember that. Um
(21:08):
But these these boundary currents are created again in part
by the the winds flowing away from the um equator,
the Coriolis effect, turning the waves and the mounds of
water circulating the waves in around them. So you've got
these like just clockwise or counterclockwise depending on which hemisphere
(21:29):
you are, currents that are just massive that move water
around and again they cycle nutrients. Like you said, they
affect the weather because they deposit warm water from the
south up to all the way up to England apparently.
Um so you know, England is on the same latitude
(21:52):
as like, um, some glacial parts of Canada. Yeah, that
makes sense. But they're they're winners, are like nothing into that,
you know, Thank you ocean. Same thing as a Bermuda
is very temperate, has very nice climate, and it's on
the same latitude as North Carolina, which is you know,
it can get kind of cold there. That's all thanks
(22:14):
to the Gulf Stream. Thank you Gulf Stream. And if
you want to thank the Gulf Stream, Chuck, you can
thank Ben Franklin because he's the one who named it. Yeah.
As the first Postmaster General of the United States, he
wanted to figure out why Mayo took so many more
weeks longer to get from England to the US than
it did from the US to England, because they're they're
(22:36):
going against traffic exactly. But he didn't know that, and
he found out and he took some measurements and roughly
charted the Gulf Stream back in the eighteenth century. He
was a smart dude, he really was. That was pretty amazing.
I didn't know he dabbled in oceanography. But again, the
Gulf stream amazing, and it's just one boundary current of
(22:56):
one major gyre. Yeah, it's kind of a hypnotic. If
you look at these motion maps of global motion maps
of like trade winds and ocean currents. Yeah, I could
watch those videos all day. It's just stuff spinning around
and like traveling around, and it's really it's soothing, and
especially when they do like heat gradients or topographical gradients,
(23:17):
so it's really colorful too, and it's ever shifting. You
can just get a little jewel out of the corner
of my mouth when I watched though, it's about as
good as watching Phantasia. Um. There's one other thing we
should say about those surface currents is they drag on
the water below them, right, So the wind is transferring
its energy to the surface of the water. Yeah, and
(23:38):
it drags a little bit less is the deeper you go. Right.
Apparently though, the current that the motion of water, um
usually goes in opposition to the motion of wind. So
what you end up having if you could take a
column slice from top to bottom of the ocean, you
would find that the water ultimately is making a very
(23:59):
long down words spiral. Yeah. So, and that's called the
ekmun spiral. Yeah, that there's a graphic of that that
looks pretty neat as well, pretty neat again, mesmerizing stuff,
so chuck um. After this, we will talk about the
global conveyor belt. It's my favorite part, I think, all right,
(24:36):
my favorite part of ocean currency. Ocean currents, the deep
ocean current a k a. The Global conveyor belt is
fascinating to me. Um. If you're talking about this is
about if the surface currents are about ten about of
the ocean's water, uh is part of the deep ocean current,
(24:57):
and we can't see it, um because we're up here
on Earth and we are not deep under the water.
It's invisible to us. But um, it circles the globe
at a four sixteen times is strong as all of
the world's rivers combined, which is again still not as
much as the the the Gulf Stream. Still pretty impressive.
(25:20):
It's pretty impressive, um, but slow so like water. It
moves super water a few centimeters a second, whereas the
Gulf stream moves waters at like a couple dred centimeters
a second. Yeah, I think the conveyor belt, they said,
like one patch will take a thousand years to completely Yeah,
around yeah, the circuit. Yeah, and it takes ten years
(25:42):
for water to make a full circuit on the North
Atlantic gyre. Yeah, so ten years and then a thousand years. Yeah. Um.
So the global conveyor belt, it is uh driven by density,
which I think is pretty interesting. Um. Yeah, because up
to this point it's all been driven by wind, which
is ultimately driven by heat. This is also driven by
(26:03):
heat in a way, but in a completely different way. Yeah,
heat and salt um thermohaline circulation thermo being heat and
haling being salt. Uh. Warm water holds less salt. So
what happens is like let's say you're in the Antarctic
and water freezes to form an iceberg or water evaporates.
(26:26):
Either way, salt is not going to be a part
of that equation. Now the salt is left behind as
the water freezes, and you know, icebergs on salt salty
their fresh water. Yeah, so the salt is left behind.
It's got to go somewhere. Um, it is going to
be very dense at that point. So it is going
to be cold and dense and sink to the ocean floor.
(26:46):
So remember back on talking about right, and we were
talking about um, coastal um coastal currents and upwelling and
down welling. Yeah, this plays apart. When water sinks, other
water moves in to replace it. And so what starts
off here? And this actually I think starts around the
North Pole definitely in the North Atlantic. Um, as that
(27:07):
water sinks and moves downward, it creates it starts this
current that goes all the way around the world and
again takes a thousand years to complete. Yeah, it just
kick starts at basically. And um it's called the conveyor belt,
I think because it never stops moving and it's super slow. Yeah,
I kept getting that remember that, um whatever that Bugs
(27:27):
Bunny assembly line song? Like it was always the same,
Like do you remember that? I can't remember it either.
Now I have our theme song in my head. I'm
trying to think about it. But there's like anytime Bugs
Bunny messed around on a conveyor belt or something, they
use the same like composition. I'll try to find it. So, uh,
once this water hits Antarctica, basically the same thing happens
(27:49):
all over again. The cold water is gonna split. Some
of it heads to the Indian Ocean, some heads to
the Pacific, and this upwelling and downwelling, the cycle just
start all over again, yeah, is it? As it moves
closer to like the Indian Ocean and the Pacific, it
gets closer to the equator, the water starts to warm up,
it loses some of its salinity, it starts to thin
(28:11):
out a little bit, and so it rises. And when
it does, it takes all those nutrients and all that
CEO two up with it. And it's very much like
the gas exchange that occurs in the human cardio pulmonary system. Right. Yeah,
it's not homeostasis, but it almost feels like that if
you took the whole system overall. Yeah, it's homeostatic for sure,
(28:32):
but it's like that by this exchange, this transfer from
one part to another, from the deep ocean to the surface. UM.
And and this this as it reaches the surface and
it depletes its nutrients, it's carried back around UM. It
basically tries to go up hits Um Alaska, Russia, Asia,
(28:53):
North Asia, Northeast Asia, and UM turns back around and
goes ends up finally back in the North Atlantic, up
near the North Pole and gets cold and starts all
over right, And by the time it gets there, it's
basically nutrient depleted and it sinks and it starts to
recharge again. That's right. And that just like blood in
(29:14):
your in your cardio pulmonary system, it gets depleted, it
ends up going past the lungs, it transfers out CEO two,
it gets in oxygen. This is just the opposite. This
is transferring out oxygen and gaining CEO two and nutrients.
That's a good way to feel connected to the Earth.
When you start looking at things like that, you know,
it's not so different. It's I mean, we're all connected, man. Uh.
(29:40):
And again there's a big nutrients swap meat happening as
well with the conveyor belt like we're talking about, and
basically kind of has the same effect as those surface
uh currents do ye as far as exchanging the the
oxygen and the CEO two and nutrients and just moving
everything where needs to be. UM. I thought this was
(30:02):
pretty cool in this article, UM, the it talks about
there's also a density driven a thermohalen current in the
Mediterranean because the Mediterranean is apparently saltier than the Atlantic,
and as a result, this gradient. Anytime you have a
difference in something, whether it's height, temperature, um, salinity, density.
(30:24):
Homeostasis is the ultimate goal, so it's going to try
to go towards the middle, from higher to lower. And
this is the same thing. So it creates that oceanic current.
And apparently in World War two, subs would um run
silent by going in and out of the Mediterranean without
their engines on, just using that currently, so they would
(30:48):
run deep, run silent, run deep exactly. That's frightening. Alright,
are we a title currents? You don't have to be frightened.
It was years ago. Yeah, we're a title current that
they still do that. Now there's no submarines anymore. We
haven't been at war for years. They retired all the submarines. UM. Alright.
(31:09):
Tidal currents are generated by the tides. UM. We did
talk about UM, like we said, I think in the
rogue waves and surfing about tides and waves and UM.
The gravitational pull of the moon and the Sun, but
more of the Moon because the Moon is closer, is
what's gonna cause that bulge on the sides, and it's
(31:30):
gonna drive the water level UM at that bulge. Basically,
it's going to decrease, it's going to increase where it's
a line with the moon and decrease at the halfway
point between those two places. And so and it's always
changing because the moon, the position of the Moon and
the Sun and the Earth are always changing, but they
(31:51):
change in a very predictable manner, so we can predict
when the tides happen. But if you just took a
snapshot at any given point of the title effect, right,
and if you imagine that the Moon is on one side,
the Sun is on one side, and the Earth is
on the middle. The world's oceans around the Earth stretch
(32:13):
out on the sides and um because of that gravitational pull,
and just imagine that it's always like that. It's always
just this elliptical oval shape the world's oceans are and
then the Earth, the dry Earth, is spinning within that
and so the land masses on the Earth are always
coming in and out of that bulge, and so they're
(32:36):
going from higher to lower tide. It's kind of it
just makes it easier for me, rather than to think
of the oceans moving around the Earth, to think of
the Earth spinning within the ocean, and that causes the
change and tides that does something for you, does it
all the way? Uh? And these are different than the
other currents we talked about because they're not it's not
(32:56):
a continuous stream and they switch directs. That's the high
tide and low tide and um, it doesn't impact like
the ocean current that much. It's shoreline stuff. Yeah, but
it's pretty important. I mean, like fish, fishes lay eggs,
and uh, low tide will pull those eggs out into
(33:17):
the open ocean and those fish will they'll hatch. It
also brings food in from the ocean into like marshland
and that kind of stuff, or washes up jellyfish and
to delight the children on the beach, yes, but don't
touch them, you can just look. Uh. And when the
tide is rising, um, that flow is directed towards the store.
(33:40):
That's called the flood current. I've heard about that flood
and the EBB. And the EBB is when it's directed
back out to sea. And that makes it all very predictable.
Like you said, we can go to the beach and
listen to the tide report. It's also a very relaxing
thing to do. Oh yeah, oh yeah, I listen to that.
Like the a m like fishing and sharks and title reports. Yeah,
(34:02):
it's very relaxing for me. I like it. I remember
growing up listening to like grain future reports and hog
reports or stuff like that. Pork futures, um chuck, just
a couple more things. So, like, there are plenty of
other currents, and there's also plenty of other wind patterns
that drive these currents. They do things like create the
l Nino, which basically takes weather, thunderstorms and stuff around
(34:26):
the equator and moves them in different places that were
not used to, which can lead to droughts and floods
depending on where you are. And then also there's a
lot of concern among scientists who are who know about
this kind of stuff that um changes. Climate change is
going to is going to ultimately and negatively affect the
(34:49):
global conveyor belt because as um as the earth warms
up uh more and more icebergs are gonna melt, creating
much less salinity. And since the water will be less
saline um and warmer, it's gonna sink less. And so
that global conveyor belt that relies on cold, dense salty
(35:12):
water to sink to get it started, is going to slow,
and that could be bad because remember it's all that's
the global nutrient exchange. Would no, because then the phytoplankton dies.
And again when the phytoplankton dies, the fishes die, the
seals die, polar bears are upset. Well, the poor seals die.
Either way, it is very sad. Yeah, do you got
(35:37):
anything else? No, that's it. That's ocean currents. Uh. If
you want to know more about ocean currents, you can
type those words into the search bart how stuff works
dot com. And since I said search bars, time for
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(35:59):
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(36:22):
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(37:05):
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(37:28):
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(38:16):
and thousands of other topics, is it how stuff Works
dot com
Welcome to Stuff You Should Know from House Stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh
Clark with Charles W. Chuck Bryant, and Jerry and this
is Stuff you Should Know, the one about ocean currents.
(00:21):
We should start titling our episodes like Friends did. Yeah,
the one where Ross talks about ocean currents. Yeah, the
one where Chuck's eyes glazed over. I love this stuff, man,
Like Earth science really gets me jazz. That's good, it
really does. Like it's so like, it's very detailed. There's
(00:43):
a lot to it. It's often oversimplified, but it's also
very understandable. And when you really like learn about it,
you realize what an elegant system the whole thing is. Sure,
maybe not necessarily a living organism, but I could see
how someone would characterize it as such. I like that.
(01:03):
It's good intro. Yeah, that's what I got. Uh so, Yes,
tidal ocean currents, well, not tidal, that's part of the
ocean currents. It's a type of current. It's under the
current umbrella. I've misspoken the first ten seconds. I think
it's funny that in this article the word current refers
to the motion of water when speaking of water? Is
(01:26):
that what it says when speaking of water, the word
current refers to the motion of the water. Yeah, it
was a little clumsy Miriam's defines. Yeah, uh, well, this
is about ocean currents. Are all kinds of currents, river currents, Yeah,
you know, there's currents in marshes and swamps and currents
(01:46):
all over the place. But this is about ocean currents. Yeah,
as long as water is not stagnant, there's currents present.
And if it's stagnant, it's bad news Jack mosquitoes disease. Sure,
But then again, you can make the case that if
it's not stagnant, if if there's a current, it'll carry
your car away in the blink of an eye. I
don't even think about it. Boy, did you see the
(02:08):
photos of the Downtown Connector the other day in Atlanta
when it flooded. Apparently the storm drains backed up in
the downtown Connector of Atlanta was a lake. Wow, Like
it literally stopped traffic. I can believe that. Yeah, people
in Atlanta don't know how to drive in the rain
to begin with. Oh, I don't know about that really. Yeah,
(02:31):
that's all we do was driving the rain man. People
in l A don't have to driving the rain. Seems
to me like everybody's brain just drops a couple of
years when rain starts, and everyone starts like bumping into
everybody else and like driving it two miles an hour,
and you just like pedal to the metal. What's different
all the time. I got good tires. Yeah, Look, because
(02:52):
you liked our stores, right, I don't like tip stores,
but I'm willing to spend time there to get good
tires that move water away from my car so I
can if I have really fast no matter what the weather,
you should start your I want to point out. Jerry
just sighed heavily at this tangent. I think your retirement
(03:15):
business should be Josh's tire house. Yeah, and then have
a really sweet setup. Would be like fine tires. Just
here's like no place else on earth. Oh yeah, you
got WiFi. You got a coffee machine? Well there's well no,
I mean a baristah, like a you know, a little
mini Starbucks right there in your tire shop. Games have
icebreakers meet and greets. Yeah, I could serve icebreakers come
(03:38):
to you get have tinder Tinder day. Okay, Well, I
don't know a Roman therapy would be good to be
a big one massage. Yeah, alright, let's my's my plan
b all right, Josh's tire warehouse and pourium, I think
is what we came up with. Josh's big house of
tires or house with big tires. Okay, so ocean currents
(04:01):
we're back to it. So um. One of the things
that I did not realize, Chuck, when researching this is
that ocean currents they're they're old, but they aren't permanent.
They haven't always been around. Currents change, you know. Some
currents have been at it for thousands and thousands of years.
Other currents change months a month, very fickle in some cases.
(04:26):
But there are some really ancient currents, some ancient ocean
currents out there that are um very old and have
been this way since say, like um, like the Gulf
Stream has been around for about five million years, ever
since the Isthmus of Panama. Pretty cool stuff, huh. Yeah.
I think what I found the most interesting was that
(04:49):
ocean currents they have a purpose. You know, it's not
just like water moving around willy nilly. You know. If
it wasn't for ocean currents, there would be no life
in Antarctica. Right, well, maybe not all of Antarctica, but
no ocean marine life. But that's that's an important point. Like,
if there's no ocean marine life, then there's no like
(05:11):
to say, there's no phytoplankton, there's no phytoplankton, there's no
fishies eating the phytoplankton. There's no fishies around to eat
the phytoplankton. There's no seals to eat the fishies. If
there's no seals, Like, everything finds its support, its basis
in the ocean. Life that's all supported by the currents.
(05:32):
That's right. So the fact that has purpose, it's very
teleological of you, chuck. So let's not put this off anymonger.
Let's talk about different types of currents. You can't talk
about tire stores anymore. Okay, we're done with the tire stores.
Like I started to get nauseated just talking that much
about tire stores. Alright, I don't feel good. Well, uh,
let's start with surface currents then, but I'll bring you
(05:54):
back to the to the ocean earth science, your home
earth sciences that you love. Uh. Surface currents occur about
three to fo um deep and above. Yeah, they're called
surface currents, right, and they're driven by the wind. Yeah,
they make up for about ten percent of the ocean.
And um, if you've ever gone to the beach, you've
(06:17):
seen coastal currents. UM surface currents. There's a couple of types.
Coastal is one of them. You see them in action, right,
like playing in the sand as a little kid or
as an adult. You're you're seeing coastal surface currents at work.
So let's step back one more degree. So service currents
are created by wave action, that's right. Especially coastal currents
(06:42):
are created by wave action, which is created by wind.
Waves are created by wind. And you know Buckminster Fuller,
the inventor of the geodesic dome, among other great things,
he was the person who pointed out that the wind
doesn't blow, the wind sucks. It's a good point, right, So,
and so if coastal currents begin with waves, waves begin
(07:04):
with wind. Wind begins with heat because at the equator
you have a lot of sunshine all year round and
it's very warm, as anyone who's been near the equator
can attest. Um, And that heat heats up air, and
as the air heats up, it moves away from the equator.
It's like, I gotta go cool off. It moves towards
(07:27):
the poles north and south, and as it moves toward
the poles, it cools down and turns back around. It's
like I need to heat back up at the equator, right.
And as a result of this, you have wind. And
this wind pushes on the surface of the water, transfer
some of its energy in the form of friction to
the water surface and creates waves and those waves transfer
(07:48):
the energy to shoreline and when they come in at
an angle, that's when you get that coastal current. Right. Yeah,
Like with you've again, if you ever been to the
beach and you see the tide or the waves coming
in at that angle, and you see it moving with
the beach, Like if you've ever been out playing on
like a raft is a little kid, you look up
(08:09):
an hour later and your parents are like half a
mile down the beach from where you start, right. It's
a bit of a panicky situation, it is. And also
you're like, what kind of parents do I have that
they just let me drift half a mile? Yea, you
know they're passed out in the sand at that point.
Uh So that is called when when uh, a wave
breaks on the beach at that angle, it's gonna pull
sediment and sand and water down in what's known as
(08:32):
a long shore current. That is, uh it's directed off parallel,
also perpendicular, but the parallel movement is the long shore
uh current. Yeah. It's like when a wave comes into
an angle to the shore, it distributes its energy. Part
of it directly on to the shore. Part of it
parallels is short and um, that's that long shore current,
like you said. And one of the things that it does,
(08:52):
you also said, is it takes sand and other stuff
and deposits it elsewhere further down and along the way.
It creates things like barrier islands and sandbars and all
that stuff. And that's ever shifting, ever moving, um, eroding
and depositing of sand and sediment and those little underwater
(09:14):
and sometimes above water deposits create other types of current,
specifically a riptide current. Yeah. Um, that's the longshore drift
and um, like if you've ever seen like the beach
curve back in pretty hard. The water can't make that
turn really, so it's just gonna deposit stuff and sort
of drop it off there at the end of that
(09:35):
point and it'll build up and what's known as a spit, right,
and so all of those, all those obstructions, um, all
those deposits form obstructions for waves. When they're going back
out once they transfer their energy, they're like, oh, I'm
pretty far inland. I need to get back out of
the ocean. Yeah, And so it backs up right, and
(09:59):
as it does encounters these underwater barriers that it itself
have deposited. It's kind of a big ironic moment. And
so it can't get back out to see as fast
as it wants because it's running into these obstructions. And
when there's like a break in the obstruction, like a
sandbar or something like that had a break in the sandbar,
(10:19):
it provides a natural funnel and that creates a rip
tide current. Yeah, like, hey, look at that little narrow channel.
I'm gonna take all this water that would normally just
flow out nice and easy. I'm gonna send it through there,
and I'm gonna grab your little kid and take it
taken with me. Right. If this, it creates basically suction.
Just like when you open a drain in a bathtub
(10:40):
and it starts to drain, it drains pretty quick. Yeah,
it's dangerous, Like that's how you drown when you're swimming
in the ocean. You hear about strong rip currents and
inclement weather and um, it's no joke. Even really good
swimmers can get caught in a ripping. Yeah, and it's
bad news riptide, very bad news. Um. And then there's
(11:00):
some other currents that are created that um don't just
occur at the at the shore, but they do. They
occur in the ocean and at the shore there's this
thing called upwelling. This stuff and upwelling can happen in
a few different ways, but as far as the coast
is concerned. When wind comes in and it basically blows
(11:22):
water away from an area, like from the shore, right,
water likes to try to even itself out. So as
some water is blown away from the surface, this stuff
that's below it, the deeper water will come up and
basically replace it, and that's upwelling. Yeah. It's another like
what strikes me when you look at wind and all
these currents. Everything is circular almost right, so a lot
(11:45):
of spinning going on. Yeah, there's a really um distinct
relationship between wind and water. It's inseparable, especially when you're
talking about global winds and currents together, right, But both
of them are broken down to fluid dynamic X and
they do form these circles and cycles and clockwise motions
and counterclockwise motions depending on where you are in the world. Yeah.
(12:07):
And in the case of upwelling and downwelling, it's not
a horizontal spin, but it is a vertical um from
top to bottom and then from bottom back up to
the top. Yeah. And you want to talk about um
that was which one. Well, both it's the same pattern
from top to bottom and bottom to top with upwelling
and down welling. Right. And the whole thing about upwelling
(12:29):
and downwelling, whether it's at the shore or in the ocean, um,
is that the ocean is kind of It's not like
if you take a slice of ocean at the top,
you take a slice of ocean at the bottom, very
different and you look at them. Yeah, under a microscope
or test um for whatever, you know, using some sort
of uh, spectroscope, maybe some sort of oscillator, glavin or
(12:53):
something like that, or just look at it. Yeah, you're
going to find that there's it's like two different types
of water. Even though it's from the same part of
it's from the same section of ocean, right, And the
stuff at the top is going to be very oxygen rich.
There's gonna be a lot of life phytoplankton, that kind
of stuff, um, but not too many nutrients. The stuff
(13:14):
at the bottom is gonna be lousy with C O two. Yeah,
very cold and a lot of nutrients. Right. And when
both of these things are needed at different spots, So
the upwelling and the downwelling creates this kind of gas
exchange and nutrient exchange throughout the ocean. And the oxygen
at the top when it's deposited down lower thanks to
(13:37):
down welling, all of that oxygen circulates downward through the
ocean and all the fishies that need oxygen in their
gills get to breathe it in, right. Yeah. And with upwelling,
like I mentioned earlier in Antarctica, where it's super cold
and you would not expect marine life to do so well,
it is because of the upwelling that brings the nutrients
(13:57):
from the bottom up to the top. And that's iCal
and that's called life. And one other really neat thing
about upwelling and down welling is um that oxygen that's
at the top of the ocean. Were it to just
sit there for very long and dissolve, we would have
a very big problem because all of that life, once
it dies, would decay very quickly up tops. No, it wouldn't,
(14:21):
because anaerobic bacteria would begin to thrive and we'd have
a over abundance of hydrogen sulfide, which would lead to
ocean acidification, which would mean the end of the world. Basically,
So that nutrient swap is very important for everybody on
the planet. Yeah, and there's this elegant solution to the
oceans that happens every day everywhere in the ocean thanks
(14:42):
to upwelling and downwelling. All right, well that's a good start,
my friend. Um my eyes are not glazed over, actually good,
they're sharp, full of life. Um. We will talk after
this break about some more surface currents. All right, Josh,
(15:17):
there's more than one kind of surface current. We covered
the I kind of like that first part, but there's
also surface ocean currents. And uh, again, the wind is
the big contributor to how these babies form um and specifically,
I guess we should talk about the Coriolis effect. Yeah,
this is a this is a game changer, as people
(15:39):
who read self help books on airplanes would call it. Right, yeah,
so um. Again, it all starts with heat, and all
that heat is found in its thickest part at the equator.
And my brain is broken. So at the equator it's
the hottest, right, that's right. And it's also also a
spinning fast or the equator than at the poles, right,
(16:02):
it is okay, so um, it's the Earth that is yeah,
so um. At the equator it's hot, it's spinning faster
because of the spin. Because of the heat. The ocean
is actually about eight centimeters high higher here than at
the rest of the ocean. That's so much higher, So
there's a right, it's just enough to make water flow
(16:24):
away from the equator. Plus you've got wind that's whipped
up because hot air at the equator starts moving northward
and cools down and that creates wind. Right, So if
the Earth didn't rotate, you would still have these things.
But wind would travel in a straight line away from
the equator towards the poles, cool down and turn around
(16:46):
and come back in a straight line. That's right. But
that's not the case. No, it isn't because the Earth
does rotate and it produces the Coriolis effect. Yeah, it's
like a curve. Basically, it uh curves to the right
in the northern hemisphere and to the left in the
southern hemisp here. Right, so it makes wind curve and
since wind drives surface currents, it makes surface currents curve
(17:07):
as well. Right, that's right. So what's really cool is
the ocean has its own topography. It's it's definitely not fight.
Anybody who's looked at ocean could be like, oh, it's
pretty choppy. But if you if you could step back
even further and you had the right kind of topographical
glasses on, maybe you would see that there's like valleys
(17:28):
and ocean and mountains and maybe not mountains, but little
tiny hills and valleys in the ocean. So, like I said,
it has its own topography. And this is created by
those winds that push on the water. And as they're
pushing the water up and the Coriolis effect is turning
at some water starts to kind of mound. So in
(17:48):
some parts of the ocean you have water that forms
a mountain that's about like three to six ft tall. Yeah,
it doesn't sound intuitive, no water mounding up on itself.
You think if it as ye, But there is actually
water that's mounded up into little hills, okay. And so
that means that gravity wants to push this water downward, right,
(18:12):
But it doesn't just go back down the hill, because
the Coriolis effect pushes it upward. And the net outcome
is that instead the water just says, how about it
just go around instead? Yeah, you stay up here on
the mound, you stay down here, but I AM going
to just go around. And what it does is, since
(18:32):
a mound is roughly circular, it creates a current that
goes around these things, around these mounds. And there's five
major ones in the entire world where you're headed, and
they form what are called gyres, that's right, g y R, E, S,
and um. They are the North Atlantic, South Atlantic, North Pacific,
South Pacific, and then the Indian Ocean has its very
(18:53):
own gyre. There are smaller ones around Antarctica, but those
are the five major gyres. We about the Gulf Stream earlier.
That is a part of the North Atlantic gyre, and
it carries times the water of the entire Mississippi River.
The Gulf Stream does. Yeah, the Gulf Stream is the
(19:14):
hero of all gyres. It is it moves um. Let
me see, I've got to find this one because this
is so amazing. So the the Gulf Stream, at any
given point, it moves water at a rate of fifteen
superdomes worth per second. So you remember the superdome in Louisiana. Yes,
(19:38):
say you've filled it with water, and then you took
copied fourteen more times, so you have fifteen superdomes full
of water. That's how much water passes through any given
point per second. Okay in the Gulf Stream. All right,
that's a lot of water. How many big max is
at It's trillions of big max billions and billions served.
(20:01):
But the the Gulf Stream itself is actually um. It's
technically the western boundary current of the North Atlantic gyre. Yeah,
and it's gonna carry warm water. It's it has a
big impact in the world. It's gonna carry warm water
up north from the Gulf of Mexico. And that's why
if you're living on the east coast of Florida, you're
(20:23):
gonna have cooler summers and warmer winters. Um. Western Europe
is gonna be a lot warmer than other places on
its exact same latitude. And this is all because of
the Gulf Stream. You can deposit bodies in it if
you're dexter, and those things are gonna yep, see a
later body. Yeah, it will probably get carried to England
and they'll be like blind, me was this? Uh So
(20:46):
that's just the Gulf Stream. There's actually at least four
major currents that form the boundary currents of the North
Atlantic Gyre, and the North Atlantic Gire is just one.
We've also talked about jarres before with the Great Pacific
Garbage Patch. Yeah we covered did we do waves or
did we just do We did rogue waves too, but
we covered waves and surfing. Okay, ye remember that. Um
(21:08):
But these these boundary currents are created again in part
by the the winds flowing away from the um equator,
the Coriolis effect, turning the waves and the mounds of
water circulating the waves in around them. So you've got
these like just clockwise or counterclockwise depending on which hemisphere
(21:29):
you are, currents that are just massive that move water
around and again they cycle nutrients. Like you said, they
affect the weather because they deposit warm water from the
south up to all the way up to England apparently.
Um so you know, England is on the same latitude
(21:52):
as like, um, some glacial parts of Canada. Yeah, that
makes sense. But they're they're winners, are like nothing into that,
you know, Thank you ocean. Same thing as a Bermuda
is very temperate, has very nice climate, and it's on
the same latitude as North Carolina, which is you know,
it can get kind of cold there. That's all thanks
(22:14):
to the Gulf Stream. Thank you Gulf Stream. And if
you want to thank the Gulf Stream, Chuck, you can
thank Ben Franklin because he's the one who named it. Yeah.
As the first Postmaster General of the United States, he
wanted to figure out why Mayo took so many more
weeks longer to get from England to the US than
it did from the US to England, because they're they're
(22:36):
going against traffic exactly. But he didn't know that, and
he found out and he took some measurements and roughly
charted the Gulf Stream back in the eighteenth century. He
was a smart dude, he really was. That was pretty amazing.
I didn't know he dabbled in oceanography. But again, the
Gulf stream amazing, and it's just one boundary current of
(22:56):
one major gyre. Yeah, it's kind of a hypnotic. If
you look at these motion maps of global motion maps
of like trade winds and ocean currents. Yeah, I could
watch those videos all day. It's just stuff spinning around
and like traveling around, and it's really it's soothing, and
especially when they do like heat gradients or topographical gradients,
(23:17):
so it's really colorful too, and it's ever shifting. You
can just get a little jewel out of the corner
of my mouth when I watched though, it's about as
good as watching Phantasia. Um. There's one other thing we
should say about those surface currents is they drag on
the water below them, right, So the wind is transferring
its energy to the surface of the water. Yeah, and
(23:38):
it drags a little bit less is the deeper you go. Right.
Apparently though, the current that the motion of water, um
usually goes in opposition to the motion of wind. So
what you end up having if you could take a
column slice from top to bottom of the ocean, you
would find that the water ultimately is making a very
(23:59):
long down words spiral. Yeah. So, and that's called the
ekmun spiral. Yeah, that there's a graphic of that that
looks pretty neat as well, pretty neat again, mesmerizing stuff,
so chuck um. After this, we will talk about the
global conveyor belt. It's my favorite part, I think, all right,
(24:36):
my favorite part of ocean currency. Ocean currents, the deep
ocean current a k a. The Global conveyor belt is
fascinating to me. Um. If you're talking about this is
about if the surface currents are about ten about of
the ocean's water, uh is part of the deep ocean current,
(24:57):
and we can't see it, um because we're up here
on Earth and we are not deep under the water.
It's invisible to us. But um, it circles the globe
at a four sixteen times is strong as all of
the world's rivers combined, which is again still not as
much as the the the Gulf Stream. Still pretty impressive.
(25:20):
It's pretty impressive, um, but slow so like water. It
moves super water a few centimeters a second, whereas the
Gulf stream moves waters at like a couple dred centimeters
a second. Yeah, I think the conveyor belt, they said,
like one patch will take a thousand years to completely Yeah,
around yeah, the circuit. Yeah, and it takes ten years
(25:42):
for water to make a full circuit on the North
Atlantic gyre. Yeah, so ten years and then a thousand years. Yeah. Um.
So the global conveyor belt, it is uh driven by density,
which I think is pretty interesting. Um. Yeah, because up
to this point it's all been driven by wind, which
is ultimately driven by heat. This is also driven by
(26:03):
heat in a way, but in a completely different way. Yeah,
heat and salt um thermohaline circulation thermo being heat and
haling being salt. Uh. Warm water holds less salt. So
what happens is like let's say you're in the Antarctic
and water freezes to form an iceberg or water evaporates.
(26:26):
Either way, salt is not going to be a part
of that equation. Now the salt is left behind as
the water freezes, and you know, icebergs on salt salty
their fresh water. Yeah, so the salt is left behind.
It's got to go somewhere. Um, it is going to
be very dense at that point. So it is going
to be cold and dense and sink to the ocean floor.
(26:46):
So remember back on talking about right, and we were
talking about um, coastal um coastal currents and upwelling and
down welling. Yeah, this plays apart. When water sinks, other
water moves in to replace it. And so what starts
off here? And this actually I think starts around the
North Pole definitely in the North Atlantic. Um, as that
(27:07):
water sinks and moves downward, it creates it starts this
current that goes all the way around the world and
again takes a thousand years to complete. Yeah, it just
kick starts at basically. And um it's called the conveyor belt,
I think because it never stops moving and it's super slow. Yeah,
I kept getting that remember that, um whatever that Bugs
(27:27):
Bunny assembly line song? Like it was always the same,
Like do you remember that? I can't remember it either.
Now I have our theme song in my head. I'm
trying to think about it. But there's like anytime Bugs
Bunny messed around on a conveyor belt or something, they
use the same like composition. I'll try to find it. So, uh,
once this water hits Antarctica, basically the same thing happens
(27:49):
all over again. The cold water is gonna split. Some
of it heads to the Indian Ocean, some heads to
the Pacific, and this upwelling and downwelling, the cycle just
start all over again, yeah, is it? As it moves
closer to like the Indian Ocean and the Pacific, it
gets closer to the equator, the water starts to warm up,
it loses some of its salinity, it starts to thin
(28:11):
out a little bit, and so it rises. And when
it does, it takes all those nutrients and all that
CEO two up with it. And it's very much like
the gas exchange that occurs in the human cardio pulmonary system. Right. Yeah,
it's not homeostasis, but it almost feels like that if
you took the whole system overall. Yeah, it's homeostatic for sure,
(28:32):
but it's like that by this exchange, this transfer from
one part to another, from the deep ocean to the surface. UM.
And and this this as it reaches the surface and
it depletes its nutrients, it's carried back around UM. It
basically tries to go up hits Um Alaska, Russia, Asia,
(28:53):
North Asia, Northeast Asia, and UM turns back around and
goes ends up finally back in the North Atlantic, up
near the North Pole and gets cold and starts all
over right, And by the time it gets there, it's
basically nutrient depleted and it sinks and it starts to
recharge again. That's right. And that just like blood in
(29:14):
your in your cardio pulmonary system, it gets depleted, it
ends up going past the lungs, it transfers out CEO two,
it gets in oxygen. This is just the opposite. This
is transferring out oxygen and gaining CEO two and nutrients.
That's a good way to feel connected to the Earth.
When you start looking at things like that, you know,
it's not so different. It's I mean, we're all connected, man. Uh.
(29:40):
And again there's a big nutrients swap meat happening as
well with the conveyor belt like we're talking about, and
basically kind of has the same effect as those surface
uh currents do ye as far as exchanging the the
oxygen and the CEO two and nutrients and just moving
everything where needs to be. UM. I thought this was
(30:02):
pretty cool in this article, UM, the it talks about
there's also a density driven a thermohalen current in the
Mediterranean because the Mediterranean is apparently saltier than the Atlantic,
and as a result, this gradient. Anytime you have a
difference in something, whether it's height, temperature, um, salinity, density.
(30:24):
Homeostasis is the ultimate goal, so it's going to try
to go towards the middle, from higher to lower. And
this is the same thing. So it creates that oceanic current.
And apparently in World War two, subs would um run
silent by going in and out of the Mediterranean without
their engines on, just using that currently, so they would
(30:48):
run deep, run silent, run deep exactly. That's frightening. Alright,
are we a title currents? You don't have to be frightened.
It was years ago. Yeah, we're a title current that
they still do that. Now there's no submarines anymore. We
haven't been at war for years. They retired all the submarines. UM. Alright.
(31:09):
Tidal currents are generated by the tides. UM. We did
talk about UM, like we said, I think in the
rogue waves and surfing about tides and waves and UM.
The gravitational pull of the moon and the Sun, but
more of the Moon because the Moon is closer, is
what's gonna cause that bulge on the sides, and it's
(31:30):
gonna drive the water level UM at that bulge. Basically,
it's going to decrease, it's going to increase where it's
a line with the moon and decrease at the halfway
point between those two places. And so and it's always
changing because the moon, the position of the Moon and
the Sun and the Earth are always changing, but they
(31:51):
change in a very predictable manner, so we can predict
when the tides happen. But if you just took a
snapshot at any given point of the title effect, right,
and if you imagine that the Moon is on one side,
the Sun is on one side, and the Earth is
on the middle. The world's oceans around the Earth stretch
(32:13):
out on the sides and um because of that gravitational pull,
and just imagine that it's always like that. It's always
just this elliptical oval shape the world's oceans are and
then the Earth, the dry Earth, is spinning within that
and so the land masses on the Earth are always
coming in and out of that bulge, and so they're
(32:36):
going from higher to lower tide. It's kind of it
just makes it easier for me, rather than to think
of the oceans moving around the Earth, to think of
the Earth spinning within the ocean, and that causes the
change and tides that does something for you, does it
all the way? Uh? And these are different than the
other currents we talked about because they're not it's not
(32:56):
a continuous stream and they switch directs. That's the high
tide and low tide and um, it doesn't impact like
the ocean current that much. It's shoreline stuff. Yeah, but
it's pretty important. I mean, like fish, fishes lay eggs,
and uh, low tide will pull those eggs out into
(33:17):
the open ocean and those fish will they'll hatch. It
also brings food in from the ocean into like marshland
and that kind of stuff, or washes up jellyfish and
to delight the children on the beach, yes, but don't
touch them, you can just look. Uh. And when the
tide is rising, um, that flow is directed towards the store.
(33:40):
That's called the flood current. I've heard about that flood
and the EBB. And the EBB is when it's directed
back out to sea. And that makes it all very predictable.
Like you said, we can go to the beach and
listen to the tide report. It's also a very relaxing
thing to do. Oh yeah, oh yeah, I listen to that.
Like the a m like fishing and sharks and title reports. Yeah,
(34:02):
it's very relaxing for me. I like it. I remember
growing up listening to like grain future reports and hog
reports or stuff like that. Pork futures, um chuck, just
a couple more things. So, like, there are plenty of
other currents, and there's also plenty of other wind patterns
that drive these currents. They do things like create the
l Nino, which basically takes weather, thunderstorms and stuff around
(34:26):
the equator and moves them in different places that were
not used to, which can lead to droughts and floods
depending on where you are. And then also there's a
lot of concern among scientists who are who know about
this kind of stuff that um changes. Climate change is
going to is going to ultimately and negatively affect the
(34:49):
global conveyor belt because as um as the earth warms
up uh more and more icebergs are gonna melt, creating
much less salinity. And since the water will be less
saline um and warmer, it's gonna sink less. And so
that global conveyor belt that relies on cold, dense salty
(35:12):
water to sink to get it started, is going to slow,
and that could be bad because remember it's all that's
the global nutrient exchange. Would no, because then the phytoplankton dies.
And again when the phytoplankton dies, the fishes die, the
seals die, polar bears are upset. Well, the poor seals die.
Either way, it is very sad. Yeah, do you got
(35:37):
anything else? No, that's it. That's ocean currents. Uh. If
you want to know more about ocean currents, you can
type those words into the search bart how stuff works
dot com. And since I said search bars, time for
a listener mail. I'm gonna call this French speaker. Um
doesn't like our heavy metal music interludes. There's a few
(35:59):
people out there who don't. So here we go. I'm
gonna read this just as it came. I like you
very much. Sorry for my bad English, but I speak
French so it compensates. I have a little problem. I
feel like I need to tell you. Please don't take
it the wrong way. I have had problems to sleep
for a while now, and I found that listening to
podcasts helped me a lot. I put my iPod under
(36:22):
my pillow while it plays, where I put only one head.
Sound thing in one ear. I love your podcast because
it's very interesting, intelligent, and also your voices are nice
and you're never yelling. So I do fall asleep every
single time. This is a good thing, I swear. Of course,
it takes me three or four times to listen to
(36:43):
all of it. Usually I really listened to it in
the car. Now my problem, why do you have to
put loud heavy metal music for a break? I always
wake up in panic when it starts. I do want
to continue to listen to you at night, I really do.
So you have two choices. Either don't change your music
and think of me every time and laugh, or you
(37:05):
change it for something, let's say it nicer. Maybe in exchange.
I'm sorry, exchange, I could give you pickup lines in
French voir or what? Or what Danielle? I have to say,
hats off, Danielle, because I could not. I couldn't write
that in French. Oh well you'll speak French, do you? Um?
(37:28):
Picquito perfect? Thanks to lat Danielle. We will consider removing
the heavy metal music, which we did before and then
we brought back because other people are like, bring back
the heavy metal music. So we're kind of caught between
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and a hard place. Yeah, yes uh. If you want
(37:51):
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