
Ocean Currents


Movement of ocean
water in a regular
pattern
Influenced by
weather, Earth’s
rotation, position of
continents

Surface Currents


Horizontal
movement of ocean
water near the
surface
Controlled by global
winds, the Coriolis
effect, continental
deflections

Global Winds



Blow across Earth’s
surface
Near Equator blow
east to west
Near Poles blow west
to east

The Coriolis Effect



The apparent
curving of the path
of a moving object
due to Earth’s
rotation
N. Hemisphere
curves clockwise
S. Hemisphere curves
counterclockwise

Continental
Deflection

Currents change
direction when they
hit a continent

Affected by
Temperature

Currents carry the
temp. of its point of
origin to its
destination
Ex: The Gulf Stream
carries warm water
to southern England


Deep Current
Streamline movement
deep below the
surface
 NOT controlled by
wind
 Forms where density
increases because of
changing temp. &
salinity
 Less dense water rises
to top
 Dense water sinks
 See p. 420

Describe how global winds, the Coriolis
Effect and continental deflection form a
pattern of ocean surface currents.
 Explain how salinity controls deep
currents.


Surface Currents



Warmer than deep
currents
Ex: Gulf Stream—
warm water
Ex: California
Current—cold water

Upwelling




Occurs when local
warm winds blow
across surface currents
& leaves the cold
deep currents
exposed or uncovered
Cold, nutrient rich
deep water rises to the
surface
Small fish rise with the
cold water
Big fish come in for
“dinner”—Example of
the food chain

El Nino






Occurs every 2 to 12 years
S. Pacific Trade Winds
move less warm water to
the W. Pacific
Causes high temp. &
decreased trade winds in
tropical ocean
Has global impact by
changing the interaction
between the ocean &
atmosphere
Causes extreme weather—
drought & floods
Prevents upwelling