1. The Water Cycle
11.2 Ocean Currents

2. A large amount of ocean water that moves (like a river) in a particular and unchanging pattern
More than 20 major currents in the world that transport huge quantities of dissolved minerals, solar energy, oxygen and carbon dioxide as well as fish and plankton

4. Surface Currents
Direction and speed of surface currents is directly connected to the direction and speed of the wind blowing over the water and hot and cold air rising and falling
Spinning of the Earth on its axis affects both winds and ocean current
Spins west to east so the winds and currents get deflected right (east) in the northern hemisphere
Called the Coriolis effect
Continent shape and placement affects how and where surface currents will move

5. Deep Currents
Dense, cold water tends to sink beneath warmer water and then move along the ocean floor
Called a density current
Three different layers to ocean water: the surface (Sun’s energy heats the water), the thermocline (water temperature drops rapidly here), and deep water

6. Deep Currents Cont.
The amount of salt in ocean water also contributes to the movement of density currents
High salinity is denser than water with low salinity
Areas near melting ice or near huge rivers are less saline
Increased salinity results from evaporation and freezing
The saltiest, coldest and densest waters are found at the North and South Poles

7. Eventually the dense, cold water will be warmed enough to rise or pushed up by colder, denser water from below
Called upwelling which brings nutrient-rich waters to the surface

8. Ocean Waves and How they Shape the Land
Large, rolling waves that form in open oceans are called swells and as they reach shallow water, they become “breakers”
Huge waves called tsunamis are created by underwater earthquakes

9. Waves can erode even the rockiest cost and deposit huge amounts of sediment on shores
Softer rock erodes more readily from waves and the sediment carried in them
Headlands are sections of the coastline that extend out into the ocean (harder rock)
Can create interesting features like sea stacks
Bays are indented areas where more deposition occurs

11. Tides
The daily cycle of rising and falling ocean water is called the tide and they are caused by the gravitational attraction between the Earth and the Moon

12. the difference between high tide and low tide is called the tidal range
if the Sun and Moon are both lined up then you get an extra high tide called a spring tide (occurs twice a month)
if the Sun and Moon are not lined up then you get less extreme tides called neap tides