Waves, Tides, and Currents MOTION IN THE OCEAN

Write the following under your WAVES Column  Write everything that is in Red

Waves  A disturbance which moves through or over the surface of a fluid  Mostly caused by winds (Also earthquakes, volcanoes, gravitational pull) (Also earthquakes, volcanoes, gravitational pull)  Form of great energy

Wave Characteristics  Parts of a Wave Crest = high point Crest = high point Trough = low point Trough = low point Height = vertical distance from crest to trough Height = vertical distance from crest to trough Wavelength = Horizontal distance between crest to crest or trough to trough Wavelength = Horizontal distance between crest to crest or trough to trough

Wave frequency : the number of crests that pass a certain point in an amount of time.

Size of Wind Generated Waves  Depends on 2 things : Wind Speed Wind Speed Wind Duration (length of time wind blows) Wind Duration (length of time wind blows)

Importance of Waves  Shaping Coastlines Erode cliffs Erode cliffs Grind rock into sand Grind rock into sand  Ecology Returns O 2 to water Returns O 2 to water Stir up food for filter feeders Stir up food for filter feeders

Types of Waves CHOP – Short period (back bays) SWELL – Long period (boat rolls; seasickness) SWASH – water up beach BACKWASH – back down

Caused by undersea quake or volcano Wavelength = ~150 mi. Wave height = 6ft – 1mile Can NOT perceive in boat Speed > 500 mph Slows down to ~25 mph at shore; water builds up to ~65+ ft TSUNAMI “TIDAL WAVE”

Tsunami Waves

Creation of a Tsunami

Write the following under your TIDES Column  Write everything that is in Red

Tides  The rhythmic rise and fall of the ocean’s water High tide = rising, incoming tide, flow Low tide = lowering, outgoing tide, ebb Slack tide = vertical movement stops

 Tides are very long, slow waves They have a wave period of 12 hours 25 min They have a wave period of 12 hours 25 min Tidal day is 24 hours 50 min Tidal day is 24 hours 50 min NJ has 2 high and 2 low tides daily NJ has 2 high and 2 low tides daily

1. Gravitational pull of sun & moon on Earth What Causes Tides? Moon closer, therefore greater effect Like magnet, pulls water away from surface = TIDAL BULGE

Types of Tides 2x’s/month 2x’s/month Spring Tide - Moon and sun are in direct line with one another - Results in unusually high tidal range -Tidal Range = vertical distance between high & low tides

 Neap Tide sun and moon are at right angles sun and moon are at right angles Pulls cancel each other out – causes a weak pull Pulls cancel each other out – causes a weak pull unusually low tidal range unusually low tidal range 2 x’s / month 2 x’s / month

Spring vs. Neap Tides

Importance of Tides Expose & submerge orgs Circulate water in bays & estuaries Trigger spawning (grunion, horseshoe crab) Circulates food, wastes, etc

Write the following under your CURRENTS Column  Write everything that is in Red

Currents What are currents? - “Rivers” of circulating water Causes - Wind - Rotating Earth - Density Changes

Surface Ocean Currents Created by wind

Coriolis Effect - Northern Hemisphere – clockwise; Right - Southern Hemisphere – counterclockwise; Left

Gulf Stream - Brings warm water from equator north along east coast of North America -Located in the North Atlantic Ocean

MIGRATION NAVIGATION WEATHER

RIP CURRENT - Caused by converging longshore currents - Very dangerous ; Red Flag - DO NOT fight rip current; swim parallel to shore to get out of channel

Deep Ocean Currents  Separated from surface currents by the density of the water  Density = mass volume volume  Flow beneath surface; cross equator  Move North to South

Importance Of Deep Currents Upwelling Upwelling Brings deep water to surf.Brings deep water to surf. Circulates nutrients upCirculates nutrients up Moves plankton & larvaeMoves plankton & larvae