Land and Sea Breezes

Land and Sea Breezes

Deep Ocean Current!Cold water or salty water at the bottom

of the ocean can also travel in a current.

Deep Ocean Currents!These currents are caused by differences in

density rather than surface winds. !Usually “cold” in temperature (compared to

surface currents) !They are found near the bottom of the ocean !These currents flow much more slowly than

surface currents. They can take as long as 1,000 years to make a round trip from the pole to the equator and back.

Upwelling

! Surface and deep currents can mix when winds cause UPWELLING.

!Upwelling is the upward movement of cold water from the deep ocean.

!Winds blow away the warm surface water, and cold deep water replaces it

Upwelling! Upwelling brings tiny organisms, minerals, and

nutrients from the deeper layers of the water . ! The extra nutrients provide food to enormous

schools of fish!

Upwelling

Upwelling and Fishing! The most important fishing spots in the

world are found where upwelling occurs. Why?

El Niño! El Niño prevents upwelling because warm winds

are blown TOWARD the coast of South America ! This pushes the deep, cold, nutrient-rich water

downward and many fish lose their food source

Normal—Upwelling El Niño—Downwelling

The End