Ocean Systems

I. Oceans are connected Cover most of Earth (3/4) 7 continents divide ocean into sections

Contain salts and gases from rain & rivers and from elements underground/undersea

Salinity and Density Salinity is the measurement of dissolved saltDensity is the measurement of matter in a given

spaceWater that contains salt is heavier therefore has

a greater density than fresh waterThe more dense water is, the easier it is to float

(Dead Sea near Israel p. 429)When water evaporates from ocean, salt is left

behind increasing the salinity of remaining waterSalinity is also high in cold areas (glaciers)

GasesOcean water has same gases as air (oxygen, nitrogen and carbon dioxide) which is essential to ocean life

Oxygen increases with plants and algae that live near the surface of the ocean where the sun shines

Temperature Varies Layer 1-Surface- heated by sun so is the

warmest and less dense Layer 2-Thermocline-below surface with

temp dropping as depth drops (graph p. 431)Layer 3-Deep Water-cold all year all over the

globe (near freezing temps)

Location and season does change the temp (pic p. 431)

Ocean Floor Continental shelf-sloping land going into ocean on the Continental slope –steep slope into ocean Trenches-narrow steep cliffs in ocean floor Mariana Trench is deepest place in world (11,000+

meters below sea level)

Abyssal plane-wide flat area of ocean floor Mid ocean ridge-chain of mountains under ocean Molten rock rises up within Earth to form ridges (p.

432-33)

Ocean Exploration Water pressure makes it difficult to explore

depthsOther obstacles: Dark, lack or air, cold

watersScuba, submarines and robots help explore

the ocean floorSonar is a system that uses sound waves to

measure distances, give detailed pics and locate objects. A fast echo return means shallow and a slow echo return means deep.

Review p. 434What substances are contained in ocean water? Draw and label/describe 5 features of the ocean

floor. Describe 3 kinds of technology or equipment used

to explore the ocean.Where in the ocean do you think water pressure is

greatest and why?What are 2 problems in ocean exploration?Where does oxygen in the ocean come from? Why doesn’t warm surface water sink to the

bottom?

II. Oceans move in currents Ocean current is a large amount of moving water. Surface currents are caused by strong winds

blowing across globe due to uneven heating of Earth. They are curled into giant clockwise whirlpools in Northern hemisphere-spreading heat. They move warm water away from equator and cool water away from poles. (pic p. 437)

Gulf Stream-surface current that moves warm water NE towards Europe

Deep currents are caused by differences in density.

Downwelling/Upwelling Deep currents involve both down and up

wellingDownwelling-from surface to depths carrying

oxygen down allowing animals to live in depths

Upwelling-from depths to surface carrying nutrients from floor for sea life near surface

Cycle and a symbiotic relationship – goes on continuous and one depends on the other

Climate and Weather Weather is daily conditions and climate is

patterns of weather in an area over a long period of time.

Ocean and atmosphere interact in unpredictable ways

Change in one current can result in huge changes

El Nino is when global weather changes for 12-18 months (more/less snow, warmer/cooler)

Review p. 440What are 2 causes of currents in the ocean?How do currents distribute heat around the globe?How are climate & weather related to currents?Describe how upwelled water differs from the

water around it. How do surface currents occur? What is the Gulf Stream and how does it affect

Europe?What would happen if all ocean currents halted?

III.Waves Wave is an up & down motion along surface

of water due to winds, earthquakes, landslides, any movement

Shape of wave includes: crest/high point, trough/low point, height/vertical distance between crest and trough, wavelength/distance between one crest to the next crest (pic p. 443)

Waves move energy-not water.

Waves cause currents near shoreLongshore current- moves water parallel to

the shore where waves meet land and angle – zigzag motion moves and piles sand along beach-can produce sand bars out in ocean

Rip current- narrow streams of water that break through sandbars and drain rapidly back to deep sea-occur when high winds or waves cause large amount of water to wash back from shore/beach-very dangerous-swimmers should swim parallel to shore to escape it

Review p. 445What can cause waves in the ocean?What happens to waves near the shore?Name and describe 2 kinds of currents that

waves cause.Describe the shape of all waves. Why are rip currents formed near sandbars?How should swimmers respond if caught in a rip

current?

IV. Tides Tide is the periodic rising and falling of the

water level of the ocean High tide is when the water level along a

beach is high-exposing little beach/sand. Low tide is when the water level along a

beach is low-exposing more beach/sand. There are 2 high and 2 low tide per day

(totaling 4)

Gravity causes tides Gravity of sun and moon pull on Earth

causing oceans to bulge on the side facing the moon and the opposite side-high tide

Between the two bulges are dips-low tide (pic p. 449)

As Earth rotates, different parts of Earth pass through the bulges and dips

Tidal range is difference in height of high and low tide and it depends on the shape of land above and below ocean

Monthly Tides Spring tide – an extra high tide and an extra

low tide – occurs when both gravity of sun and moon pull at the same time

Neap tide- a smaller high tide and a smaller low tide (less extreme between) – occurs when sun and moon are not lined up with Earth so gravity pulls in different directions (pic p. 451)

Generate Electricity Energy of tides generates electricityDam built near path of water, water flows

and is trapped in dam during high tide, when tide is low dam gates open and water rushes out. Water spins turbines that power electric generators.

Benefit of hydroelectricity – less pollution and water is a renewable resource

Review p. 452Describe the appearance of tidal changes at

the beach.Explain the difference between sun and moon

and creating tides. How are tides used to generate electricity?Compare & contrast neap and spring tides. How would tides differ if the moon revolved

around the Earth twice a month?What are the benefits of hydroelectricity?

Test Time Review the power point and complete

Chapter review on page 455 (#1-14). Complete graph for # 1-3Use testing strategies and notes to answer

#4-10. Use ALL CAPSAnswer in thorough complete sentences for

#11-14. On any drawings, be sure to label and

describe.