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By: Gene Pearl R. Divinagracia

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What is Current?

A current is a large stream of water that flows through the

ocean Or mass of water moving from one place to another

importance:

moves drifting organisms from place to placeplankton,

disperse young

carries eggs and larvae of organisms that have external

fertilization

brings food, oxygen carries away waste,

pollutants

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Two types of currents

Surface Currents

Deep Currents

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Surface Currents Driven mainly by the wind

They follow Earths major wind patterns which move in a

circular pattern

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Surface Currents

About 10% of the water in the world ocean is involved in

surface currents, which are water flowing horizontally in

the uppermost 400 meters (1,300 feet) of the oceansurface

Due to the Coriolis effect, currents in the Northern

Hemisphere curve to the right and to the left in the

Southern Hemisphere.

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Surface CurrentsIn physics, the Coriolis effect is a deflection of moving

objects when they are viewed in a rotating reference

frame. In a reference frame with clockwise rotation, thedeflection is to the left of the motion of the object; in one

with counter-clockwise rotation, the deflection is to the

right.

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The Coriolis effect

Is a result of Earths rotation

curves or deflects the path of global winds

Example: rolling a ball over a spinning disk will curve the line of

travel

-> N. Hemisphere- turn clockwise and in the S. Hemisphere- turn --

counterclockwise

Coriolis Effect Caused by the rotation of Earth

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Deep Currents Deep currents occur within our oceans and are not controlled by global winds but by

density or density cause them to move.

Higher temperatures and Lower salinity= decreased density

Lower temperatures and higher salinity= increased density

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Deep currents flow slowly. They may take as long as

1,000 years to flow from pole to equator and back

again.

Make up about 90% of oceans water

Deep Currents

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Density Impact on Water Movement

A. Decreasing Temperature

Cold, arctic air decrease heat energy and

therefore temperatures at the surfacedecrease. Water becomes more dense and

sinks and travels towards the equator.

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Increasing Salinity via Freezing

Ice floats as it is less dense than the liquidwater and the dissolved solids are not frozen

and add salinity to the liquid water beneath

the ice. Higher salinity = higher density and

the water sinks.

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Increasing salinity via evaporation

In warm climates, water molecules at the

surface evaporate leaving behind dissolved

solids which increases salinity. Denser water

sinks.

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