OCEAN CURRENTS
HOW DOES WATER MOVE IN THE OCEAN?
Ms. May
WHAT ARE OCEAN CURRENTS?
“STREAM LIKE” MOVEMENTS OF WATER
SURFACE CURRENTS: occur near the surface and are caused
by wind. Surface currents usually reach depths of 100 meters, but
some can be as deep as 1000 km. Example: The Gulf Stream.
WHAT AFFECTS SURFACE
CURRENTS?
1. CONTINENTAL DEFLECTIONS: Currents change
direction when they meet continents.
WHAT AFFECTS SURFACE
CURRENTS?
2. Coriolis Effect: Deflection of moving objects from a straight
path due to Earth’s rotation. Deflection means to “turn away” or
“turning aside”. Example: wind and water traveling south from the
North Pole actually go towards the southwest instead of straight
south because of the rotation of earth.
In the Northern Hemisphere currents are deflected to the right,
and in the Southern Hemisphere to the left.
WHAT AFFECTS SURFACE
CURRENTS?
WHAT AFFECTS SURFACE
CURRENTS?
Global Winds: winds that blow across the surface of Earth’s
oceans push water across Earth’s surface.
WHAT POWERS SURFACE
CURRENTS?
The Sun: heats up the water in the equator and causes pressure
changes. Warm water goes up (less dense), cool water goes down
(more dense).
HOW DO DEEP CURRENTS FORM?
Deep Currents occur far below the surface and they are caused by differences in water
density and temperature.
Salinity affects the density of water (more salt more density) and Cold water is denser
than warm water.
When water gets cold it goes to the bottom and when it gets warm it goes to the surface.
CONVECTION CURRENTS
Movement of water that results from density differences.
WHAT IS UPWELLING?
During Upwelling, cold nutrient-rich (Iron, Nitrate) water from
the deep ocean rises to the surface. This process is EXTREMELY
important for life because the nutrients that are brought to the
surface support the growth of phytoplankton and zooplankton.
PLANKTON
WHAT DO CURRENTS
TRANSPORT?
Ocean water circulates through all of Earth’s ocean basins.
Global circulation transports energy in the form of heat, matter like salt (NaCl), nutrients
(N, P) and gases like O2 ,N, CO2,
OCEAN CURRENTS VIDEO
https://www.youtube.com/watch?v=UuGrBhK2c7U