Welcome Back Scientists! Ch. 14: The Movement of Ocean Water

Learning Target: I will be able to explain how currents affect our lives.

- “Rivers” of circulating water Currents What are currents? - “Rivers” of circulating water Causes? - Wind - Coriolis effect - Continental deflection

2 types of OCEAN currents 1. SURFACE currents 2. DEEP currents

Surface Ocean Currents Wind generated creates circular gyres

Surface Currents (Notice deflection/changes direction when hits land)

Surface Currents are caused by Global winds (and deflected by Earth’s rotation) Affect climates and transports sea plants and animals

What are Deep Currents? Caused by density differences Currents below the surface Water density depends on: 1. temperature (cold sinks) 2. salinity (saltier water sinks)

Example of cold water sinking

Deep Ocean Currents Moves from North to South Flows beneath the surface Crosses the equator Moves from North to South

The Cause of Deep Currents Deep currents are separated from surface currents by boundary called a “Thermohaline” (difference in densities). A difference in density is the main cause of deep currents.

Importance Of Deep Currents Upwelling/ Importance of deep currents Brings deep water to surface Circulates nutrients up Moves plankton & larvae

Coriolis Effect The apparent curving of the path of a moving object from an otherwise straight path Caused by Earth’s rotation

Click the links below for the Coriolis effect demonstration: http://www.montereyinstitute.org/noaa/lesson08/l8ex1.htm

Direction currents flow due to the Coriolis Effect Northern Hemisphere – clockwise (Right) Southern Hemisphere – counterclockwise (Left)

Gulf Stream - In the North Atlantic - Brings warm water from equator north along east coast of N. A. Sometimes form eddies – circulating water that pinches off from the current

IMPORTANCE OF SURFACE CURRENTS 2. NAVIGATION 1. MIGRATION 3. WEATHER

Questions 1. What are surface currents caused by? 2. Deep currents are caused by differences in _____________. 3. What is the importance of deep currents (what does it help do)? 4. Explain the Coriolis effect 5. What is the importance of surface currents?