Ch. 16 SG - Chapter 16: Oceans and Coastlines 16.1...

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Chapter 16: Oceans and Coastlines 16.1 Geography of Oceans 5 ocean basins: Pacific (largest and deepest), Atlantic, Arctic, Antarctic, Indian 16.2 Seawater Salinity — is the total quantity of dissolved salts, expressed as a percentage Almost every element on land is found dissolved in seawater. Seawater also contains dissolved carbon dioxide and oxygen If the atmospheric pressure of carbon dioxide or oxygen rises, much of the gas quickly dissolves into seawater; thus, the seas buffer atmospheric concentrations of gases. High rainfall dilutes salinity and high evaporation increases salinity Temperature Oceans develop a temperature layering, but because sea waves and currents stir the surface water, the warm layer in the ocean extends from the surface to 450 meters. Below this layer is the thermocline— a zone in which the temperature drops rapidly with depth Three temperature zones in the ocean 16.3 Tides Tides—the cyclic rise and fall of ocean water caused by the gravitational force of the Moon and, to a lesser extent, of the Sun Most coastlines experience two high and two low tides during an interval of 24 hours and 53 minutes. Moon’s influence predominates because it is closer to the Sun High tide: one region of Earth lies directly under the moon; gravity is greater for objects that are closer together, and part of the ocean nearest to the Moon is attracted with the strongest forces. The water rises, resulting in high tide. Spring tides— a relatively large tide that forms when the Sun, Moon, and Earth are aligned Neap Tides—a relatively small tide that forms when the Moon is about (0 degrees out of alignment with the Sun and Earth 16.4 Sea Waves Most waves develop when wind blows across water In deep water the size of the wave depends on: (1) the wind speed, (2) the length of time that the wind has blown, (3) the distance that the wind has traveled (fetch). Crest— highest part of a wave Trough— lowest part of a wave Wavelength—the distance between successive crests Wave height—the vertical distance from the crest to the trough While a wave moves across the sea surface, the water itself moves only in small circles 16.5 Storm Surge Storm Surge— responsible for 90% of all human fatalities during hurricanes and tropical cyclones; on onshore flood of water created by a low-pressure water system such as a hurricane or tropical cyclone Galveston, Texas: September 8, 1900 = deadliest storm surge Caused by strong winds blowing over the sea surface and causing seawater to pile up above sea level Highest and most damaging at high tides 16.6 Ocean Currents Current— a continuous flow of water in a particular direction
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This note was uploaded on 02/13/2011 for the course ESC 1000 taught by Professor Staff during the Fall '08 term at University of Florida.

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Ch. 16 SG - Chapter 16: Oceans and Coastlines 16.1...

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