The Dynamic Ocean

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Surface CirculationSurface Currents

movements of water that flow horizontally near the surface

develop from friction between the ocean and the wind

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Surface CirculationGyres

huge circular-moving current systems that dominate the surfaces of the oceans.

Coriolis effectdeflection of currents away

from their original course as a result of Earth’s rotation

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Ocean Currents and ClimateCurrents from low-latitude

regions moving into higher latitudes transfer heat from warmer to cooler areas

Upwellingrise of cold water from deeper

layers to replace warmer surface water

brings greater concentrations of dissolved nutrients to the surface

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Deep Ocean CirculationDensity currents

Vertical currents of ocean water that result from density differences among water masses

Increases in seawater density can be caused by a decrease in temperature or an increase in salinity

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Conveyor Belt ModelOcean circulation is similar to a conveyor belt that

travels from the Atlantic Ocean, through the Indian and Pacific Oceans, and back again.

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WavesMost ocean waves obtain their energy and motion from

the wind.wave height - vertical distance between the trough and crest.Wavelength - horizontal distance between two successive crests

or two successive troughs.wave period - time it takes one full wave to pass a fixed position.Fetch - distance that the wind has traveled across open water.

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TidesDaily changes in the elevation of the ocean

surfaceResult from the gravitational attraction exerted

upon Earth by the moon

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TidesTidal range - difference in height between

successive high and low tidesSpring tides - have the greatest tidal range due to

the alignment of the Earth–moon–sun systemNeap tides - have the lowest tidal range, occurring

near the times of the first-quarter and third-quarter phases of the moon.

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Forces Acting On The ShorelineWaves along the shoreline are constantly

eroding, transporting, and depositing sediment.

Wave ImpactAbrasion - the sawing and grinding action of rock

fragments in the waterWave Refraction - the bending of waves

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Forces Acting On the ShorelineWave Refraction

Because of refraction, wave energy is concentrated against the sides and ends of headlands that project into the water, whereas wave action is weakened in bays.

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Forces Acting On The ShorelineLongshore Current - a near-shore current that

flows parallel to the shoreTurbulence allows longshore currents to easily move fine

suspended sand and to roll larger sand and gravel particles along the bottom.

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