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Ocean Motions Ocean Motions Text references are given but remember I always give you Text references are given but remember I always give you more!more!
A.A. Ocean water contains horizontal, Ocean water contains horizontal, stream-like movements of water stream-like movements of water called called ocean currentsocean currents..
B.B. Affected by weather, Earth’s Affected by weather, Earth’s rotation, and the position of the rotation, and the position of the continents.continents.
C.C. Importance:Importance:
1.1. moves drifting organisms moves drifting organisms from place to place – from place to place – plankton, disperse youngplankton, disperse young
2.2. carries eggs and larvae of carries eggs and larvae of organisms that have external organisms that have external fertilizationfertilization
3.3. brings food, oxygenbrings food, oxygen
4.4. carries away waste, pollutantscarries away waste, pollutants
I. Currents (pgs. 84-88)I. Currents (pgs. 84-88)
1. 1. Surface CurrentsSurface Currentsa.a. Horizontal movements of ocean water Horizontal movements of ocean water
caused by wind and occurring at or near the caused by wind and occurring at or near the ocean’s surface are called ocean’s surface are called surface currentssurface currents..
b.b. Can reach depths of several hundred meters Can reach depths of several hundred meters and lengths of several thousand kilometers.and lengths of several thousand kilometers.
c.c. The The Gulf Stream Gulf Stream is one of the longest is one of the longest surface currents, transporting 25 times surface currents, transporting 25 times more water than all the rivers in the world more water than all the rivers in the world combined.combined.
d.d. Controlled by 3 factors:Controlled by 3 factors: Global windsGlobal winds
Continental barriersContinental barriers
Coriolis EffectCoriolis Effect
D. Three Main TypesD. Three Main Types
• Different winds Different winds cause currents to cause currents to flow in different flow in different directions.directions.– The The trade windstrade winds
are located just are located just north and south of north and south of the equator.the equator.• In both In both
hemispheres, they hemispheres, they push currents push currents westward across westward across the tropical the tropical latitudes.latitudes.
– The The westerlieswesterlies are are located in the located in the middle latitudes.middle latitudes.
d1. Global Windsd1. Global Winds
• The continents are another major influence on The continents are another major influence on surface currents.surface currents.– They act as barriers to these currents.They act as barriers to these currents.– When a surface current flows against a continent, When a surface current flows against a continent,
the current is deflected and divided.the current is deflected and divided.
d2. Continental Barriersd2. Continental Barriers
• As Earth rotates, As Earth rotates, ocean currents and ocean currents and wind belts curve.wind belts curve.– The curving of the The curving of the
paths of ocean paths of ocean currents and winds currents and winds due to Earth’s due to Earth’s rotation is called rotation is called the the Coriolis EffectCoriolis Effect..
– The wind belts and The wind belts and the Coriolis Effect the Coriolis Effect create huge circles create huge circles of moving water, of moving water, called called gyresgyres..
d3. Coriolis Effectd3. Coriolis Effect
a.a. Stream-like movements of ocean water located Stream-like movements of ocean water located far below the surface are called far below the surface are called deep deep currentscurrents..
b.b. Move much Move much slowerslower than surface currents.than surface currents.
c.c. Form as cold, dense water of the polar regions Form as cold, dense water of the polar regions sinks and flows beneath warmer ocean water.sinks and flows beneath warmer ocean water.
•The density of ocean water if affected by The density of ocean water if affected by temperature and salinity.temperature and salinity.
– Decreasing temperature and increasing Decreasing temperature and increasing salinity will increase the water’s salinity will increase the water’s density.density.
ColdCold water is more dense than water is more dense than warmwarm water!water!
2. Deep Currents2. Deep Currents
d. when combined with d. when combined with surface currents, results in surface currents, results in conveyor belt movement of conveyor belt movement of waterwater around globearound globe
3. upwelling3. upwelling
a.a.wind blows, moves water away, wind blows, moves water away, causes new water to rise up to replace itcauses new water to rise up to replace it
b.b.brings up tiny ocean organisms, brings up tiny ocean organisms, minerals, and other nutrients from the minerals, and other nutrients from the deeper layers of the water.deeper layers of the water.
1. Currents can greatly 1. Currents can greatly affect the climate in affect the climate in many parts of the world.many parts of the world.– Warm-water Warm-water currents:currents:
• The Gulf Stream carries The Gulf Stream carries warm water from the warm water from the Tropics to the North Tropics to the North Atlantic Ocean.Atlantic Ocean.
– Cold-waterCold-water currents: currents:For example: The California For example: The California
current carries cold water current carries cold water from the North Pacific from the North Pacific Ocean toward Mexico Ocean toward Mexico along the western coast of along the western coast of the USA the USA therefore, therefore, cooler climate year-round cooler climate year-round than inland states.than inland states.
E. Currents and ClimateE. Currents and Climate
2. Every 2 to 12 years, the South Pacific 2. Every 2 to 12 years, the South Pacific trade winds move less warm water to trade winds move less warm water to the western Pacific than they usually the western Pacific than they usually do.do.
a.a. El Niño-El Niño-Pacific Ocean trade winds slow Pacific Ocean trade winds slow and almost stop which brings warmer and almost stop which brings warmer conditions and weak upwelling currents conditions and weak upwelling currents to the eastern Pacific which hurts fishing to the eastern Pacific which hurts fishing in Peruin Peru
b.b. La NiñaLa Niña-winds blow stronger than normal -winds blow stronger than normal pushing warm water out and allowing cold pushing warm water out and allowing cold water in. A stronger upwelling occurs.water in. A stronger upwelling occurs.
Normal ConditionsNormal Conditions
El Niño ConditionsEl Niño Conditions
La Niña ConditionsLa Niña Conditions
II. Waves (pgs. 89-93)II. Waves (pgs. 89-93)1.1. A A WaveWave is a is a rhythmicrhythmic movementmovement that carries that carries energyenergy
through matter or space.through matter or space.
2.2. When a wave passes through the ocean, individual water When a wave passes through the ocean, individual water molecules move molecules move up and down up and down in a circular motionin a circular motion but but they do not move forward or backwardthey do not move forward or backward
3.3. As waves approach shore, the wave length As waves approach shore, the wave length decreasesdecreases and and wave height wave height increasesincreases
4.4. When a wave breaks against the shore, the crest outruns When a wave breaks against the shore, the crest outruns the trough and the crest collapses-this is called a the trough and the crest collapses-this is called a breakerbreaker (water moves forward and backward at this point).(water moves forward and backward at this point).
5. Parts of a Wave5. Parts of a Wave
a.a. CrestCrest – highest point of a wave – highest point of a wave
b.b. Trough Trough – lowest point of a wave– lowest point of a wave
c.c. Wave HeightWave Height – vertical distance – vertical distance between the crest and the between the crest and the troughtrough
d.d. WavelengthWavelength – horizontal – horizontal distance between two crests or distance between two crests or two troughstwo troughs
Wavelength
Wave Height
Crest
Trough
Still Water
Wave Parts
PLEASE DRAW AND LABELPLEASE DRAW AND LABEL
5. Effects of Waves on 5. Effects of Waves on ShoreShore
a. Longshore current- a. Longshore current- As waves come into shore, water As waves come into shore, water washes up the beach at an angle, carrying sand grains. The washes up the beach at an angle, carrying sand grains. The water and sand then run straight back down the beach. water and sand then run straight back down the beach.
5b5b. Rip Current-. Rip Current-long ridges or piles of sand long ridges or piles of sand create sand bars. A break in a sand bar create sand bars. A break in a sand bar allows a fast-moving narrow stream of allows a fast-moving narrow stream of water through water through
6. Cause of Waves6. Cause of Wavesa.a. WindWind
– When wind blows across a body of water, When wind blows across a body of water, frictionfriction causes the water to move along causes the water to move along with the wind.with the wind.
– Wave Height depends on – Wave Height depends on – •Wind speedWind speed•Distance over which the wind blowsDistance over which the wind blows•Length of time the wind blowsLength of time the wind blows
6b. 6b. Earthquakes-Earthquakes- Waves caused Waves caused by earthquakes are called by earthquakes are called TsunamisTsunamis
i.i. Tsunamis were once called Tsunamis were once called Tidal waves, but they have Tidal waves, but they have nothing to do with the nothing to do with the tides.tides.
ii.ii. They are produced by They are produced by earthquakes and other earthquakes and other seismic disturbances. seismic disturbances. That’s why they’re also That’s why they’re also called called seismic sea waves.seismic sea waves.
iii.iii. Sudden outflow of water Sudden outflow of water then it returns much higherthen it returns much higher
iii. Tsunamis are very long, fast iii. Tsunamis are very long, fast moving waves!moving waves!
•They can have wavelengths of They can have wavelengths of 150150 milesmiles, wave heights of , wave heights of 100 ft100 ft and and move as fast as move as fast as 450 mph450 mph (jet (jet speed!).speed!).
6c. 6c. Gravitational force of Gravitational force of the Moon and Sun the Moon and Sun creates creates Tides (pgs 96-Tides (pgs 96-100)100)..
. .
i.i. The rise and fall in sea level is The rise and fall in sea level is called a called a tidetide..
ii.ii. One low-tide/high-tide cycle One low-tide/high-tide cycle takes about 12 hrs and 25 min.takes about 12 hrs and 25 min.
iii.iii. Tidal range Tidal range is the is the difference difference in ocean levelin ocean level between high- between high-tide and low-tidetide and low-tide
What is the Tidal Range?What is the Tidal Range?
•HT = 30 ft, LT = 20 ftHT = 30 ft, LT = 20 ft
•HT = 20 ft, LT = 12 ftHT = 20 ft, LT = 12 ft
•HT = 50 ft, LT = 20 ftHT = 50 ft, LT = 20 ft
10 ft
8 ft
30 ft
iv. Gravitational Effect of iv. Gravitational Effect of the Moonthe Moon
•Two big bulges of water form on Two big bulges of water form on the Earth:the Earth:– one directly under the moon one directly under the moon – another on the exact opposite another on the exact opposite
sideside
•As the Earth spins, the bulges As the Earth spins, the bulges follow the moon.follow the moon.
•These are normal daily tidesThese are normal daily tides
v. Gravitational Effect of the v. Gravitational Effect of the SunSun
a. a. Spring TidesSpring Tides– Earth, Moon, and Sun are lined Earth, Moon, and Sun are lined
up and work togetherup and work together– High Tides are higher and Low High Tides are higher and Low
Tides are lower than normalTides are lower than normal
b. b. Neap TidesNeap Tides– Earth, Moon, and Sun form right Earth, Moon, and Sun form right
angles and work against each angles and work against each otherother
– High Tides are lower and Low High Tides are lower and Low Tides are higher than normalTides are higher than normal
