2. Ocean Currents:Ocean Currents:
the motions of oceansthe motions of oceans
(sorry, couldn’t resist the bad rhyme!)(sorry, couldn’t resist the bad rhyme!)
• Causes:Causes:
– Tides – gravitational pull from moon and sunTides – gravitational pull from moon and sun
causes predictable tidal currentscauses predictable tidal currents
– Wind – Surface CurrentsWind – Surface Currents
– Thermohaline Circulation (density differences)Thermohaline Circulation (density differences)
= Deep Currents= Deep Currents
3. Surface CurrentsSurface Currents
• Rotate due to CoriolisRotate due to Coriolis
• Create Gyres –circles of moving waterCreate Gyres –circles of moving water
within the oceanswithin the oceans
– Clockwise – Northern HemisphereClockwise – Northern Hemisphere
– Counterclockwise – Southern HemisphereCounterclockwise – Southern Hemisphere
7. What is upwelling?What is upwelling?
• Subsurface water rises to surfaceSubsurface water rises to surface
• Characteristics:Characteristics:
– ColderColder
– Rich in nutrientsRich in nutrients
– Biologically productive = Good fishingBiologically productive = Good fishing
12. Ocean WavesOcean Waves
• What makes big waves?What makes big waves?
– Wind – speed and durationWind – speed and duration
– Fetch – distance that a wave has to growFetch – distance that a wave has to grow
13. Breaking WavesBreaking Waves
• Friction between sea floor and waterFriction between sea floor and water
• Waves become too steepWaves become too steep
• Breakers formBreakers form
14. The basic parts andThe basic parts and
movement of a non-movement of a non-
breaking wavebreaking wave
15. Changes that occur whenChanges that occur when
a wave moves onto shorea wave moves onto shore
19. Example of Longshore DriftExample of Longshore Drift
Shoreline ErosionShoreline Erosion
– Tucker Island Lighthouse, NJ, 1927Tucker Island Lighthouse, NJ, 1927
22. Human-Induced CoastalHuman-Induced Coastal
ErosionErosion
• Removing vegetation and protectiveRemoving vegetation and protective
dunesdunes
• Building “protective” structuresBuilding “protective” structures
• River modification and dredgingRiver modification and dredging