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11/22/2016

ES Ch 15 Oceanography 1

11/22/2016 ES Ch 15 Oceanography

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Chap 15 Oceanography Objectives 1. Identify methods used by scientists to study Earth’s oceans. This means I can

explain how sonar works and is used to calculate the depth of the oceans.

2. Discuss the origin and composition of the oceans according to scientific theory. This means I can:

A. Contrast the two main theories on where water on the earth may have come from.

3. Describe the distribution of oceans and major seas. This means I can:

A. List the 3 largest oceans in order by size.

B. Contrast and compare oceans and seas.

C. Explain how warm (interglacial, global warming) and cool (ice ages) affect sea level.

4. Compare and contrast the physical and chemical properties of seawater. This means I can:

A. List the percentage salt water and fresh water on earth, and where most of the fresh water is located.

B. Explain how evaporation, precipitation, freezing, melting and river discharge affect the salinity and density of water.

C. Describe how temperature and salinity affect density.

D. Explain how salinity affects the freezing point of water.

E. Describe means that remove and add salt from the ocean (See Figure 15-13 p.395)

5. Explain ocean layering (surface, bottom, thermocline). This means I can:

A. List the layers of the ocean in order from top to bottom.

B. Describe which layers are present at the equator, 30oN & S, and the poles.

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Objectives 6. Describe the formation of the 3-main deep-water masses: Antarctic Bottom Water,

Antarctic Intermediate Water, North Atlantic Deep Water. (Fig 15-17 p. 398) I can:

A. List their order from bottom to top at the equator.

B. Contrast their density and temperature.

C. Explain causes the density differences in the 3 deep-water masses. 7. Describe the physical properties of waves. This means I can:

A. Define/label the following terms: crest trough, wave length, wave height, wave.

B. Describe what causes breakers to form.

8. Explain how tides form. This means I can differentiate between spring & neap tides (Figure 15-22 p.403) including:

A. Alignment of sun, earth and moon, moon phase.

B. Size of low and high tides.

9. Compare and contrast various ocean currents. This means I can:

A. Differentiate cold vs. warm currents based on where they originate.

B. Define gyre. (Figure 15-23 p.404)

C. Understand the effect of global wind systems on currents and how the currents would change if the wind blew in the opposite direction.

10. Compare and contrast the effects of ocean currents during normal and El Nino winters on climate. This means I can:

A. Describe the climate changes of NW South America, the United States and

Australia during an El Nino season.

B. I can explain how changes in wind and ocean currents causes the climate changes

11. Additional miscellaneous vocabulary terms I can define and use properly: tidal

range, breakers, upwelling, oceanography, surface current, density current, fetch.


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Chapter 15 - Oceanography


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Intro – Are Oceans Distributed Equally Throughout Earth?


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Water Distribution 1. 97% of Earth’s water is saltwater in oceans and seas

2. 3% freshwater, but ¾ of the freshwater is unavailable since it is in

glaciers & icebergs (Greenland & Antarctica)

3. Sea level varies due to

A. Warming & cooling periods with ice varying from 0-10% of the

hydrosphere

B. Currently rising 1-2mm/year as glaciers melt

i. Melting of GLACIERS DOES affect sea level

ii. Melting of ice bergs does NOT influence as much.

C. Tectonic forces also lift or lower portions of the sea floor

D. NOTE: All seas and oceans are interconnected, so sea level rises

or falls in ALL oceans at the same time


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What might happen if sea levels continue to rise?

http://www.planetsave.com/files/2007/12/two-meter-sea-level-rise.gif

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The Blue Planet-Ocean Size & Fig 15-5 p.389

1. 71% of Earth is covered by oceans, but they are not distributed evenly

A. There is more ocean in the Southern hemisphere

B. There is more land in the Northern hemisphere

2. 3 major oceans: Pacific (largest), Atlantic (2nd), and Indian (3rd)


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Fig 15-6 Northern vs. Southern Hemisphere Water


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Sea Ice: The Arctic and Antarctic are covered with sea ice

NOTE: Frozen water is UNUSUAL. Solid water (ice) is LESS dense so it floats.

Otherwise bodies of water would freeze from bottom up until ALL frozen.

Since it floats it acts as an insulator and organisms live in cold water

beneath it.

Native American discusses sea ice melting & effect on way of life – 2 minutes

https://www.youtube.com/watch?v=u5DiHp76gjs

OR watch downloaded video saved as “Video “Sea Ice Native American”


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Seas: Seas: are smaller then oceans and are partly or mostly

landlocked

NOTE: All seas & oceans are connected, so they have similar types of dissolved salts AND the same sea level.


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Salinity • Prior Knowledge: What is “saline”?

Salinity: Measure of amount of dissolved salts in seawater

1. Seawater is 95% water & 3.5% salts

2. NaCl is the most common salt. Other salts contain

Mg, K, Ca.

3. Units: parts per thousand, ppt, which is the number

of grams of salt per kilogram (1000grams) of water

A. Sea water salt content is 35 ppt or 3.5%

4. Seawater also contains dissolved gases & nutrients

https://www.youtube.com/watch?v=u5DiHp76gjs

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Variations in Salinity 5. Salinity varies due to

A. Evaporation exceeds precipitation. Leads to increased salinity. (Subtropical areas 30oN&S – hot and not much rain)

B. Abundant precipitation decreases salinity. (Tropical areas near equator – even though hot, have LOTS of rain which dilutes & lowers salinity)

C. Decreased salinity where rivers empty into oceans


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Sources of Salt 6. Sea Salt Sources (Addition)

A. Volcanic gases contain chlorine & sulfur dioxide which

dissolve in water to form ions

B. Weathering of crustal rock carries sodium, calcium,

potassium into rivers and on to oceans

This diagram in

notes after

addition,

removal &

desalinization


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Removal of Sea Salts 7. Sea Salt Removal

A. Sea salts precipitate out (become solid) in arid, coastal regions leaving salt deposits

B. Spray droplets from waves are carried by wind inland

C. Marine organisms use salts to build shells, bones, etc.

8. NOTE: Salinity remains relatively constant as addition (sources of salt) are balanced by these removal processes


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Fig 15-13 p. 395 & TT # 44

Processes that Add & Remove Salts


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Desalinization

8. Desalinization: Human removal of salt to obtain

fresh water for drinking

A. Methods: distillation, reverse osmosis


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Physical Properties of Seawater Physical Properties of Seawater

1. Higher density than freshwater, because of salt content.

2. Temperature also affects density

3. Why do we salt roads in the winter?

• The freezing point of seawater is lower (-2oC) compared to freshwater which freezes at is (0oC )

• Note: -2C = 28F

4. Water absorbs light, so water is darker with depth

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Ocean Layering 1. Surface temps vary from –2oC (28F) in polar water to 30oC

(86F) near the equator

A. Temp decreases with depth

2. Temperature profile; 3 layers

3. Surface Layer: Relatively warm and sunlit

A. Thermocline: Rapid temperature change

B. Bottom Layer: Cold & dark

C. NOTE: The surface and thermocline layers are absent

in polar waters.

WHY??_____________


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Fig 15-15 & 15-16 Ocean Layers & Temps


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Fig 15-18 p. 399 Waves

NOTE: Energy, not water

molecules, are

moved/pushed.

Example: Make a

“wave” like at a game.


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Wave Diagram-compared to still water level


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Tides:

Tides are periodic rise and fall of sea level

1.Caused by the gravitational attraction between Earth,

moon & sun

2.Moon’s gravity causes Earth to bulge

Lunar Bulge follows moon http://oceanservice.noaa.gov/education/kits/tides/media/supp_tide04.html

http://oceanservice.noaa.gov/education/kits/tides/media/supp_tide04.html

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Spring vs. Neap Diagram



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Drawing comparing water levels of spring, neap &

average tide levels


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Animation – Spring & Neap Tides

Other animations: http://ww2.valdosta.edu/~cbarnbau/astro_demos/tides/neap_sp.html

http://ww2.valdosta.edu/~cbarnbau/astro_demos/tides/neap_sp.html



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Fig 15-17 p. 398 Water Masses/Density Currents

From Weather Unit define: Air Mass, Source Region

Before notes, use the diagram above and determine:

Which deep-water mass has temps below 0C?

1. Which deep-water mass is the least dense? How can you tell?

2. Which deep-water mass forms off the shore of Greenland?

How do you know?


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Water Masses 1. Cold (almost freezing), bottom layer in the tropics comes from polar

regions.

A. Freezing water at the poles, leaves salt behind

B. Salt builds up below the ice

C. Cold, salty water is more dense and sinks

D. Concentrated salt water diffuses (moves) as the water mass

moves along the ocean floor towards the equator

2. 3 major water masses account for most of the deep water in the

Atlantic:

A. Antarctic Bottom

(coldest)

B. North Atlantic Deep

C. Antarctic Intermediate

Water (Warmest)

1. Cold (almost freezing), bottom layer in the tropics comes from polar

regions.

A. Freezing water at the poles, leaves salt behind

B. Salt builds up below the ice

C. Cold, salty water is more dense and sinks

D. Concentrated salt water diffuses (moves) as the water mass

moves along the ocean floor towards the equator

2. 3 major water masses account for most of the deep water in the

Atlantic:

A. Antarctic Bottom

(coldest)

B. North Atlantic Deep

C. Antarctic Intermediate

Water (Warmest)



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Density Currents

Density Current: Current caused by a difference in temp &

salinity

1. Current moves slowly in deep waters

2. The 3 deep water masses are density currents

because they move from their source region in the

poles toward the equator.


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Gyres

1. Landmasses deflect ocean currents to north or south

A. Prevent global belts of easterly or westerly ocean

currents

2. Gyre = Closed, circular currents


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Gyres cont’d & Upwelling

3. 5 main gyres: North Pacific, North Atlantic, South Pacific,

South Atlantic, & Indian Ocean

4. Coriolis effect

A. Gyres in the Northern hemisphere rotate clockwise

B. Gyres in the Southern hemisphere rotate counter-

clockwise


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Fig 15-24 p. 405 Upwelling

Upwelling: Upward motion of ocean water

1. Cold because it originates at the bottom of the

ocean

2. Usually occurs on the west coast of continents in the

area of trade winds

3. Rich in nutrients, supports abundant marine life

A. Good fishing off of Peru & California


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Fig 15-23 p. 404 Major Ocean Currents

Message in a Bottle: If a bottle was dropped in the Atlantic

by Florida, list 3 locations it might end up. Test it out at:

http://serc.carleton.edu/details/images/19052.html

Currents: Warm vs. Cold


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http://www.sailingissues.com/currents1.png Ocean Current Temp Review: Use the diagram above, or on page 404, to complete the table:

Current Circle which direction the current COMES FROM

Circle whether the current is relatively warm or cold

Kuroshio Current Comes from: Poles vs. Equator Warm vs. Cold

E. Australian Current Comes from: Poles vs. Equator Warm vs. Cold

Gulf Stream Comes from: Poles vs. Equator Warm vs. Cold

Brazil Current Comes from: Poles vs. Equator Warm vs. Cold

California Current Comes from: Poles vs. Equator Warm vs. Cold

Peru Current Comes from: Poles vs. Equator Warm vs. Cold

Canary Current Comes from: Poles vs. Equator Warm vs. Cold

Benguela Current Comes from: Poles vs. Equator Warm vs. Cold

http://serc.carleton.edu/details/images/19052.html

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Bellwork #1: Earth’s Water

1. What percent of Earth’s water is salt water?

2. Where is most of Earth’s freshwater located?

3. What region of Earth contains the most water?

Northern Hemisphere or Southern Hemisphere?


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Bellwork #2 Adding & Removing Salt, Thermocline

1. What are two natural processes that remove sea salt and

decrease ocean salinity?

2. What are two methods responsible for adding salt back into

the ocean?

3. Draw the temperature profile found in the ocean and label

each of the three layers with the appropriate name.


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Bellwork #3 Wave height, Melting, Cold Water Mass

1. What is a factor that causes wave height to increase

(List as many as you can think of)?

2. If water melts at the poles, how is ocean salinity

affected?

3. Name the coldest water mass at 0o latitude.


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Bellwork #4 Parts of Waves

1. Explain what happens to water when waves move

through it?

2. Label the parts of the wave labeled A, B, C, D.


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Bellwork #5 Tides

1. What needs to happen for high tides to occur? Low

tides?

2. How often do you see high tides? Low tides?

3. Draw the alignment of the Sun, Earth, and Moon

needed to produce a spring tide and a neap tide.

4. What makes a spring tide different from other tides?


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Bellwork #6 Currents

3. Use the Major Ocean

Currents Diagram: If the

trade winds blew from

the west to the east

instead, what effect

would that have on the S.

Equatorial Current?

1. What is the name of circular currents between the

continents?

2. What has high salinity and moves slowly in deep water?

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Lab Ocean Tides & Tidal Ranges KEY

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