Chapter 20 Section 1Chapter 20 Section 1

Properties of Ocean WaterProperties of Ocean Water

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• Water in the oceanWater in the ocean– contains many dissolved solids and contains many dissolved solids and

gases.gases.

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• Scientists do NOT describe ocean Scientists do NOT describe ocean water by using properties such aswater by using properties such as– presence of dissolved vitamins and presence of dissolved vitamins and

dissolved minerals.dissolved minerals.

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• Why do scientists study the Why do scientists study the properties of ocean water?properties of ocean water?– To understand the interactions between To understand the interactions between

the:the:•oceanocean

•atmosphereatmosphere

• landland

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• The two principal gases in the The two principal gases in the atmosphere areatmosphere are– nitrogen and oxygen.nitrogen and oxygen.

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• Ocean water contains a large amount Ocean water contains a large amount of dissolvedof dissolved– carbon dioxide.carbon dioxide.

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• Most oxygen in the oceanMost oxygen in the ocean– enters at the surface of the ocean from enters at the surface of the ocean from

the atmosphere.the atmosphere.

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• The dissolved solids that give the The dissolved solids that give the ocean its salty taste are commonly ocean its salty taste are commonly calledcalled– sea salts.sea salts.

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• Solids dissolved in ocean water are Solids dissolved in ocean water are composed of about how many composed of about how many chemical elements?chemical elements?– 7575

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• The most common salt, halite, which The most common salt, halite, which makes up more than 85% of the makes up more than 85% of the ocean solids, is made ofocean solids, is made of– sodium and chloride ions.sodium and chloride ions.

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• Elements that exist in very small Elements that exist in very small amounts are called _______ _________.amounts are called _______ _________.– trace elementstrace elements

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• What are three examples of trace What are three examples of trace elements found in the ocean?elements found in the ocean?– goldgold– zinczinc– phosphorousphosphorous

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• What are the three main sources of What are the three main sources of the elements that form sea salts?the elements that form sea salts?– volcanic eruptionsvolcanic eruptions– chemical weathering of rock and landchemical weathering of rock and land– chemical reactions between sea water chemical reactions between sea water

and newly formed sea-floor rocksand newly formed sea-floor rocks

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• How do dissolved salts and other How do dissolved salts and other dissolved solids enter the ocean?dissolved solids enter the ocean?– RiversRivers

•Carry about 400 billion kg of dissolved solidsCarry about 400 billion kg of dissolved solids

– EvaporationEvaporation•Salts and other minerals remainSalts and other minerals remain

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• Why does the temperature of the Why does the temperature of the zone of surface water decrease only zone of surface water decrease only slightly as the depth increases?slightly as the depth increases?– The mixing of the ocean’s surface water The mixing of the ocean’s surface water

distributes heat downwards keeping the distributes heat downwards keeping the temperature of surface water constant.temperature of surface water constant.

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• What happens to the temperature of What happens to the temperature of surface water as latitude increases?surface water as latitude increases?– Temperature decreasesTemperature decreases

• it gets colder dudeit gets colder dude

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• Where does the greatest amount of Where does the greatest amount of solar energy reach the surface of the solar energy reach the surface of the ocean?ocean?– The EquatorThe Equator

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• What is the common temperature at What is the common temperature at the surface in tropical areas?the surface in tropical areas?– 3030ooCC

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• Why do vast amount of sea ice exist Why do vast amount of sea ice exist in polar oceans? Explain your in polar oceans? Explain your answer.answer.– The temperature of ocean water is -2The temperature of ocean water is -2ooCC– It freezes at about -2It freezes at about -2ooCC

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• A floating layer of sea ice that A floating layer of sea ice that completely covers an area of the completely covers an area of the ocean surface is called ________.ocean surface is called ________.– pack ice.pack ice.

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• Why is pack ice rarely more than 5m Why is pack ice rarely more than 5m thick?thick?– Ice insulates water below and keeps it Ice insulates water below and keeps it

from freezing.from freezing.

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• What determines changes in ocean What determines changes in ocean surface temperature in the middle surface temperature in the middle latitudes?latitudes?– SeasonsSeasons

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• Why does the temperature of the Why does the temperature of the water decrease sharply below the water decrease sharply below the surface layer of the ocean?surface layer of the ocean?– The sun can’t directly heat ocean water The sun can’t directly heat ocean water

below the surface layer.below the surface layer.

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• The layer in a body of water in which The layer in a body of water in which water temperature drops with water temperature drops with increased depth faster than it does in increased depth faster than it does in other layers is called aother layers is called a– thermocline.thermocline.