Complete Transcript

Complete Transcript

Narration:

Transcript:

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The oceans, they are always on

the move. Together, the ocean

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basins are like a big

interconnected highway that

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transports nutrients, carbon and

heat around the world. This

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mesmerizing data visualization

of ocean currents was created

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using a model called estimating

the circulation and climate of

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the ocean, or ECCO, for short.

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It's built using real world data

from satellites, buoys

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and all kinds of other

measurements.

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All of this movement starts with

physics.

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Because the Earth is spinning,

the water feels something called

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the Coriolis effect. This pushes

some of the strongest currents,

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like the Gulf Stream and the

East Australian Current, against

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the east side of the continents.

Because these currents wind up

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on the west side of the ocean

basins they sit in, scientists

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call them western boundary

currents. In this visualization,

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the currents closer to the

surface are white and the deeper

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currents are blue, almost like

you're seeing those deep

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currents through the top layer

of water. But what's causing all

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this motion and what makes some

water rise and some water sink?

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Let's take a look. Here, we can

see the Pacific Ocean's

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strongest current, the Kuroshio.

It begins in the warm, tropical

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Philippine Sea, and then flows

north past Taiwan. After it

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reaches Japan, it turns east and

heads across the Pacific Ocean,

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spinning off huge eddies where

it turns right. The Kuroshio

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carries over 200 times more

water than the world's largest

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river, the Amazon. This

visualization makes it easy to

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see how the ocean moves water

across the planet, but what's

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hard to see are the places where

the water moves up or down. This

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is called upwelling, or

downwelling. When upwelling

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brings cold, deep nutrients into

the sunlight near the surface,

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it creates a feeding ground for

all sorts of ocean life.

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Nutrients carried, in part by

the Kuroshio Current, help feed

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the fisheries in Japan and

create an important economic

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zone for the country. Another

major western boundary current

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is the Agulhas Current, which

carries water down the east

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coast of Africa to its southern

tip, called Cape Agulhas. There,

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the current makes a sharp turn

to the east, but sometimes it

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pinches off giant eddies called

the Agulhas rings, which drift

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west into the Atlantic. These

circular currents carry salt and

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heat into the Atlantic and form

an important part of the

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overturning circulation, also

called the Global Ocean conveyor

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belt. This so called conveyor

belt is a system of currents

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that carries heat northward,

across the equator and into the

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North Atlantic. It plays a big

role in the climates of North

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America, Europe and Africa.

Without it, winters in Europe

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would be much colder, and

droughts in Africa more severe.

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But the oceans do more than just

move heat around. In some

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places, they absorb heat from

the sun, and in others, they

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release it back to the air. We

can see that in the Gulf Stream,

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yet another part of the ocean's

conveyor belt, the Gulf Stream

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starts in the tropics, where the

water is very warm, as it drags

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warm water up the east coast of

North America, it acts like a

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heater for the atmosphere. By

the time this water has wandered

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across the Atlantic and wrapped

around Europe, Iceland and

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Greenland, it's gotten so cold

that it sinks deep into the

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North Atlantic Ocean. But

temperature isn't the only thing

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that can make water sink, so can

salt.Salinity or the amount of

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salt in the water, can make it

heavy. The saltier and colder

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water is, the heavier it gets.

As it gets warm and fresh water

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gets lighter, changes in the

heaviness or density of ocean

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water are what keep the ocean's

conveyor belt turning. Streaks

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near the surface show how water

is moving from one place to

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another. If you look close, you

can see below the surface.

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Sometimes the water down deep is

moving in a different direction,

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even the opposite direction.

Sometimes this cold, deep water

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headed south beneath the Gulf

Stream is another part of that

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same ocean conveyor belt that

keeps Europe warm. Some of that

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warm Gulf stream water that

heads north at the surface

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eventually winds up there,

moving south again after losing

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so much heat to the atmosphere.

Eventually this cold, deep water

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will spread around the globe and

slowly rise toward the surface.

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There it will warm up in the sun

and get ready to start the trip

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all over again.