Oceanography Ocean Currents Chapter 24.1 and 24.2

There are 2 types of ocean currents 1.Surface Currents 2.Density Currents ( currents under the surface)

Surface Currents Wind is the driving force behind surface currents **This should look REALLY familiar! Click here to see how wind and surface currents are related!

Layers of the Ocean Deep waters Mixed Layer (2%) SURFACE CURRENTS Temp Change Density Currents

Surface Currents In the Northern Hemisphere, travel clockwise In the Southern Hemisphere, travel counterclockwise Like winds, this is due to the Coriolis Effect

Turn to page 533!

Global Surface Currents p.532

Warm Ocean Currents Travel __________ the equator. This transfers ______ from the _________to the _______ Example: Creates the Sargasso SeaSargasso Sea AWAY FROM GULF STREAM ENERGY EQUATOR POLES

Cold Ocean Currents CANARY CURRENT (AFRICA) CALIFORNIA CURRENT

Cold Ocean Currents Travel __________ the equator. Example: TOWARDS California Current: travels down the WEST side of the U.S. Canary Current: travels down the WEST side of AFRICA

El Nino vs. Normal Conditions ~ Normal Conditions:

El Nino vs. Normal Conditions ~ El Nino:

What Makes Surface Currents? 1.Wind 2.Density Differences of water (salinity and temperature) 3.Earthquakes

The Mixed Layer Is Driven By ____, While the Deeper Layers Are Driven By ____. 1.Density Differences, Wind 2.Salinity Differences, Temperature Differences 3.Wind, Density Differences

In the Northern Hemisphere, currents travel _________. In the Southern Hemisphere, currents travel ___________. 1.Counterclockwise, Clockwise 2.Clockwise, Counterclockwise 3.The Coriolis Effect Does Not Effect Currents

What Do Warm Currents Do? 1.Bring cold water to the equator 2.Bring warm water to the poles 3.Bring cold water to the poles 4.Bring warm water to the equator

What Do Cold Currents Do? 1.Bring cold water to the equator 2.Bring warm water to the poles 3.Bring cold water to the poles 4.Bring warm water to the equator

Subsurface Currents The driving force behind a subsurface current is _________________. They are also known as ____________________________. –If water becomes denser it will ___________. –If it becomes less dense it will ___________. density density currents sink rise

Global Conveyor Belt

What are the ways (liquid)water becomes denser? Freezing – leaves salt behind Evaporation – leaves salt behind Cooling – molecules closer together

Antarctic Bottom Water is created at the poles where freezing and cooling increase the salinity and the density of the water.

Mediterranean Sea (p538) This density current is caused by evaporation instead of freezing and cooling. Close to 30° latitude = Dry Air

Upwelling As wind drives water away from the coast, deep cold waters replace it This brings CO 2 to the surface for phytoplankton to feed on Click the picture to see the animation!

Global Conveyor Belt

Ocean Temperature Mixed Layer -Wind and waves mix heat evenly -Absorbs almost all of the sun’s light -Maximum depth usually 100 meters Thermocline -Area where temperature drops rapidly -Maximum depth usually 1000 meters Deep Water -Very cold water moving from poles to equator -Most dense water -Found beneath other ocean water in almost all ocean locations

What Drives Density Currents? 1.Wind 2.Coriolis Effect 3.The Sun Only 4.Density Differences, duh!

How Can Ocean Water Become More Dense? 1.Get Colder (molecules get closer together) 2.Evaporation (leaving salt behind) 3.Freeze (leaving salt behind) 4.All of the above

What Is The Most Dense Ocean Water? 1.Antarctic Bottom Water 2.North Atlantic Deep Water 3.Intermediate Water 4.Surface Water

The Mediterranean Sea Is… 1.More Dense Than The Atlantic Ocean 2.Less Dense Than The Atlantic Ocean

What Does Upwelling Do? 1.Brings Oxygen To The Surface 2.Brings CO2 To The Surface 3.Drives Down Minerals To The Deep Water