2. Ocean Currents:Ocean Currents:
the motions of oceansthe motions of oceans
(sorry, couldnât resist the bad rhyme!)(sorry, couldnât resist the bad rhyme!)
⢠Causes:Causes:
â Tides â gravitational pull from moon and sunTides â gravitational pull from moon and sun
causes predictable tidal currentscauses predictable tidal currents
â Wind â Surface CurrentsWind â Surface Currents
â 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 âcircles of moving waterCreate Gyres âcircles of moving water
within the oceanswithin the oceans
â Clockwise â Northern HemisphereClockwise â Northern Hemisphere
â Counterclockwise â Southern HemisphereCounterclockwise â Southern Hemisphere
7. What is upwelling?What is upwelling?
⢠Subsurface water rises to surfaceSubsurface water rises to surface
⢠Characteristics:Characteristics:
â ColderColder
â Rich in nutrientsRich in nutrients
â Biologically productive = Good fishingBiologically productive = Good fishing
12. Ocean WavesOcean Waves
⢠What makes big waves?What makes big waves?
â Wind â speed and durationWind â speed and duration
â Fetch â distance that a wave has to growFetch â 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
â 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 âprotectiveâ structuresBuilding âprotectiveâ structures
⢠River modification and dredgingRiver modification and dredging
27. Which direction is the longshore drift?Which direction is the longshore drift?
28. SummerSummer ââ
The lower waves of summer build sandThe lower waves of summer build sand
onshore and widen the beach.onshore and widen the beach.
29. WinterWinter -- Higher winter waves moveHigher winter waves move
sand offshore and narrow the beach.sand offshore and narrow the beach.