15.2 Seawater 15.2 Seawater Pages 392 - 398 Pages 392 - 398
15.2 Seawater15.2 Seawater
Pages 392 - 398Pages 392 - 398
Goal 1Goal 1
Discuss the chemical and Discuss the chemical and physical properties of physical properties of
seawaterseawater
GasesGases OxygenOxygen NitrogenNitrogen Carbon dioxideCarbon dioxide
NutrientsNutrients NitratesNitrates PhosphatesPhosphates SilicatesSilicates
Salts (see table 15-1 page 392)Salts (see table 15-1 page 392) Salinity 35 ppt = 3.5% Salinity 35 ppt = 3.5% Salt ionsSalt ions
ChlorideChlorideSodiumSodiumSulfateSulfateMagnesiumMagnesiumCalciumCalcium
Salinity Variation (figure 15-10 page Salinity Variation (figure 15-10 page 393)393) High salinity (up to 37 ppt)High salinity (up to 37 ppt)
EvaporationEvaporationHotHotLow precipitationLow precipitation
Low salinity (down to 32 ppt)Low salinity (down to 32 ppt)Low EvaporationLow EvaporationHigh precipitationHigh precipitationFreshwater influxFreshwater influx
Glacier meltGlacier meltRiver mouthRiver mouth
Sources of SaltsSources of Salts Volcanic gasesVolcanic gases Weathered Rocks & MineralsWeathered Rocks & Minerals
Removal of saltsRemoval of salts Precipitate (become solid) in dry Precipitate (become solid) in dry
areasareas Sea Spray deposited inlandSea Spray deposited inland Marine organismsMarine organisms
Physical PropertiesPhysical Properties More dense than freshwaterMore dense than freshwater Freshwater = 1.00 g /mLFreshwater = 1.00 g /mL Seawater = 1.02 g/mL to 1.03 Seawater = 1.02 g/mL to 1.03
g/mLg/mL Freezing point = -2° CFreezing point = -2° C
Light absorption (see figure 15-14 Light absorption (see figure 15-14 page 396)page 396) Seawater absorbs lightSeawater absorbs light RYO (Long wavelengths) 50 mRYO (Long wavelengths) 50 m Green to 100 mGreen to 100 m Photosynthesis ??Photosynthesis ??
Goal 2Goal 2
Explain ocean layeringExplain ocean layering
See page 397See page 397
Warm water = less dense = floatsWarm water = less dense = floats
Cold water = more dense = sinksCold water = more dense = sinks
Temperature decrease with depthTemperature decrease with depth Surface layer (top layer)Surface layer (top layer)
~ 100 m depth~ 100 m depth Nonexistent at polesNonexistent at poles Warm Warm Temperature varies Temperature varies EquatorEquator
Thermocline (middle layer)Thermocline (middle layer) Depth location variesDepth location varies Nonexistent at polesNonexistent at poles Temperature rapidly decreasesTemperature rapidly decreases
Bottom layer (bottom layer)Bottom layer (bottom layer) Depth variesDepth varies Very cold <4° C Very cold <4° C Near freezing tempsNear freezing temps
Goal 3Goal 3
Explain deep water Explain deep water massesmasses
Deep water mass formationDeep water mass formation Polar areasPolar areas
Cold Salty water = very dense Cold Salty water = very dense Salts do not freeze out of waterSalts do not freeze out of waterSinks Sinks Migrates toward equatorMigrates toward equator
Movement of salty water to polesMovement of salty water to polesCoolsCoolsMore salty = more denseMore salty = more denseSinksSinks
Three major water massesThree major water masses
1.1. Antarctic Bottom WaterAntarctic Bottom Water Antarctic winterAntarctic winter Freezing, salt concentrationFreezing, salt concentration ColdestColdest densestdensest
Three major water massesThree major water masses
2.2. North Atlantic DeepwaterNorth Atlantic Deepwater GreenlandGreenland Freezing, salt concentrationFreezing, salt concentration 22ndnd Coldest Coldest 22ndnd Densest Densest
Three major water massesThree major water masses
3.3. Antarctic Intermediate WaterAntarctic Intermediate Water Antarctic winterAntarctic winter Temperature decreaseTemperature decrease 33rdrd Coldest Coldest 33rdrd Densest Densest
Atlantic oceanAtlantic ocean Affected by all 3 deep water Affected by all 3 deep water
massesmasses
Pacific OceanPacific Ocean Affected by only 2 Affected by only 2 Which one does not ???Which one does not ???
THETHE
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