CHAPTER 5 Water and Seawater

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Earth ’ s Water • 97.2% in the world ocean • 2.15% frozen in glaciers and ice caps • 0.62% in groundwater and soil moisture • 0.02% in streams and lakes • 0.001% as water vapor in the atmosphere © 2011 Pearson Education, Inc.

Seawater Components • Water • Dissolved material • Suspended (sediment) material © 2011 Pearson Education, Inc.

The Water Molecule • Polar material • Hydrogen Bonds © 2011 Pearson Education, Inc.

• Loves other polar molecules.

Polar Material • What happens when all + and – are taken????

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Hydrogen Bonding • Hydrogen bonds (between water) and polarity result in unique properties • See Coursenotes…… © 2011 Pearson Education, Inc.

pH – Fresh water is 7 (Neutral) – Seawater is around 8 (Slightly Basic) – Buffered……it changes little © 2011 Pearson Education, Inc.

Freezing and Boiling Points • Freezing point = melting point: 32 ° F • Boiling point = condensation point: 212 ° F © 2011 Pearson Education, Inc.

Water

’

s Three States of Matter

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Latent Heat • High latent heats: energy released from – Condensation – Freezing © 2011 Pearson Education, Inc.

Water ’ s Heat Capacity • High heat capacity • Can take in or lose much heat without changing temperature © 2011 Pearson Education, Inc.

Sea and Land Breezes • Differential heat capacities of land and water.

• Summer day – From ocean to land • Winter Day – From land to ocean © 2011 Pearson Education, Inc.

Water In The Ocean • Moderates temperatures on Earth • Moderates temperatures in the Ocean © 2011 Pearson Education, Inc.

Salinity • Dissolved solids/Water • Expressed in parts per thousand (ppt) • Typical ocean salinity is 35 ppt ( o / oo ) (33-37 o / oo ) © 2011 Pearson Education, Inc.

Earth ’ s Hydrologic Cycle © 2011 Pearson Education, Inc.

Processes Affecting Salinity All Occur on Surface!!!

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Surface Salinity Variation by Latitude © 2011 Pearson Education, Inc.

Global Salinity © 2011 Pearson Education, Inc.

Salinity Variation with Depth • Low latitudes – salinity decreases with depth • High latitudes – salinity increases with depth • Deep ocean salinity fairly consistent globally • Halocline – change in salinity © 2011 Pearson Education, Inc.

Seawater Density

• Freshwater density = 1.000 g/cm 3 • Ocean surface water =1.022 to 1.030 g/cm 3 • Ocean layered according to density © 2011 Pearson Education, Inc.

Seawater Density • Density increases with decreasing temperature • Density increases with increasing salinity © 2011 Pearson Education, Inc.

Temperature/Density Variation With Depth • Pycnocline – abrupt change of density with depth • Thermocline – abrupt change of temperature with depth © 2011 Pearson Education, Inc.

Layered Ocean

Three distinct water masses based on density: • Mixed surface layer – above thermocline • Upper water – thermocline and pycnocline • Deep water – below thermocline to ocean floor • High latitude oceans – thermocline and pycnocline rarely develop © 2011 Pearson Education, Inc.

Thermocline Curves

Deepwater

is Always Cold

Surfacewater

is

Polar

: Cold

Tropical:

Warm

Temperate

: Both!!!!

Warm Summer, Cold Winter © 2011 Pearson Education, Inc.