Physical OceanographyPhysical Oceanography

Chapter 15Chapter 15

Major Major OceansOceans

• The three major oceans are : The three major oceans are : 1._______-largest, deepest, 1._______-largest, deepest, coldest, least salty. 2.__________- second coldest, least salty. 2.__________- second largest, shallow, warm, salty. largest, shallow, warm, salty. 3. _________- intermediate 3. _________- intermediate in depth, temperature, and salinity.in depth, temperature, and salinity.

• The _______Ocean near the north pole, and the The _______Ocean near the north pole, and the ____________ Ocean near the south pole contain ____________ Ocean near the south pole contain vast expanses of sea ice.vast expanses of sea ice.

PacificAtlantic

Indian

ArcticAntarctic

Methods of Studying the Ocean

The Topex/Poseidon _____________ orbits 1331 km above the Earth, gathering information about the oceans.

_____________ maps ocean floor topography by timing how long it takes sound waves to bounce off the ocean floor.

Underwater vessels called _________________ investigate the deepest ocean trenches.

satellite

Sonar

submersibles

Sonar (also called echo-Sonar (also called echo-sounding)sounding)

• Sound waves travel Sound waves travel how fast in seawater?how fast in seawater?

• How deep is the How deep is the water if it takes ten water if it takes ten seconds for the sound seconds for the sound wave to go from ship wave to go from ship to ocean floor and to ocean floor and back to ship?back to ship?

1,454 m/s

7,270 m

Calculation: (10 s times 1,454 m/s divided by 2 )

• The picture below is of a _____________.The picture below is of a _____________.submersible

SalinityThe amount of salt per unit water is known as

salinity.

The average salinity of seawater is _____ ppt. Therefore, for every 1,000 ml water, there are ___ grams of dissolved salts.

The most abundant salt in seawater is ________, but there are many other salts present in the form of ions.

Near the equator salinity is __________ than average due to ___________________.

Near the poles salinity is __________ than average due to _______________.

In the Mediterranean the salinity is __________than average due to __________.

NaCl

3535

lowergreater precipitation lowermelting sea ice higher

evaporation

Natural Processes Affecting Natural Processes Affecting SalinitySalinity

The salinity here would likely be:

A. 35 ppt

B. 34 ppt

C. 36 ppt

Colorful SeawaterColorful Seawater• What makes the ocean What makes the ocean water in the picture to water in the picture to the left different the left different colors?colors?

• Why would a shrimp Why would a shrimp that appears bright red that appears bright red at the surface appear at the surface appear black at greater black at greater depths, and why might depths, and why might this be beneficial?this be beneficial?

differences in depth

Longer (red) wavelengths are absorbed before reaching deep water. Shrimp can hide and not become a meal.

Ocean Temperature Variation The ocean’s surface water temperature

varies with the amount of solar radiation received, which is primarily a function of latitude.

15.1 15.1 The Composition of The Composition of SeawaterSeawater

• The thermocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of temperature with depth.

• The thermocline is a very important structure because it creates a barrier to marine life.

Variations in Ocean Variations in Ocean Surface TemperatureSurface Temperature

Variations in Ocean Variations in Ocean Water TemperatureWater Temperature

Ocean Density Variation Density is defined as mass per unit volume.

It can be thought of as a measure of how heavy something is for its size.

15.115.1 The Composition of The Composition of SeawaterSeawater

• Seawater density is influenced by two main factors: salinity and temperature.

Factors Affecting Seawater Density

Ocean Density Variation Density Variation with Depth

15.1 15.1 The Composition of The Composition of SeawaterSeawater

• The pycnocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of density with depth.

Variations in Ocean Variations in Ocean Water DensityWater Density

Ocean Layering Oceanographers generally recognize a

three-layered structure in most parts of the open ocean: a shallow surface mixed zone, a transition zone, and a deep zone.

15.1 15.1 The Composition of The Composition of SeawaterSeawater

Surface Zone

• Sun-warmed zone

• Zone of mixing

• Shallow (300 to 450 meters)

Ocean Layering Transition Zone

15.115.1 The Composition of The Composition of SeawaterSeawater

Deep Zone

• Constant high-density water

• Temperatures are just a few degrees above freezing.

• Sunlight never reaches this zone.

• Thermocline and pycnocline

• Between surface layer and deep zone

Ocean Layers

Surface layer

Thermocline

Bottom layer

Label the wave diagram below with the following terms: wavelength, waveheight, trough, crest

Ocean Movements

trough

crest

wavelength

waveheight

0

5

10

15

20

25

30

0 4 8 12 16 20 24

SemidiurnalMixedDiurnal

Tides

Label the key with the correct tide cycle names:

semidiurnalmixed

diurnal

Match the following terms to their correct letter in the diagram:

A

B

C

D

E

D

F

G

H

Island

Continental shelf

Continental slope

Abyssal plain

Seamount

Continental rise

Trench

Guyot

Seafloor Topography

A.

B.

C.

D.

E.

F.

G.

H.

Listed below are some of the major surface currents. The force which generates these currents is ____________.wind

Chapter Review1. What is the average salinity of seawater?

2. What is the deepest area of the seafloor?

3. What is the largest ocean?

4. Why is the ocean “blue”?

5. What is the force responsible for surface currents?

6. What causes density currents?

7. What causes tides?

8. List the 3 tidal patterns.

9. What is the highest part of a wave called?

10.Name the ocean that borders Virginia.

35 ppttrench

Pacific

shorter wavelengths not absorbed

wind

differences in temperature and salinity

gravity of the sun and moon

diurnal, semidiurnal, mixed

crest

Atlantic