1 10 ocean composition-location Water in Earth’s Processes

LessonLesson

The World’s The World’s OceansOceans

•EQ: How does the EQ: How does the composition and composition and topography of earth’s topography of earth’s oceans vary by location?oceans vary by location?

Directions: Directions: READREAD each slide each slide then decide what is important to then decide what is important to

record record (Use the (Use the REDRED & & or or underlinedunderlined words). words). Some slides are just FACTS Some slides are just FACTS others you will need to use others you will need to use for the organizer.for the organizer.

Ocean Water Chemistry- Ocean Water Chemistry- QuestionsQuestions you will be able to you will be able to

answeranswerHow did the ocean How did the ocean form and how is it form and how is it currently divided?currently divided?

Describe one factor Describe one factor that increases the that increases the salinity of seawater salinity of seawater & one factor that & one factor that decreases salinity.decreases salinity.

How salty is How salty is ocean water? ocean water?

How do the How do the conditions in the conditions in the ocean change with ocean change with depthdepth? ?

Read ONLYRead ONLY: World Oceans Largest to : World Oceans Largest to SmallestSmallest

Divisions of the Global Divisions of the Global OceansOceans

Largest to smallestLargest to smallestStart Here:Start Here:1. 1. PacificPacific- the largest ocean; - the largest ocean; it covers 28% of the Earth and is

equal in size to nearly all of the land area on the Earth.2. 2. AtlanticAtlantic- - An area of 29,637,900 square miles (76,762,000 sq km). The Atlantic Ocean is important to the world's weather (as are all oceans) because strong Atlantic hurricanes are known to develop off the coast of Cape Verde, Africa and move toward the Caribbean Sea from August to November.

•Indian- third largest; Indian- third largest; the deepest area is the Java Trench at 7,725 m; The Indian Ocean is known for causing the monsoonal weather patterns that dominate much of southeast Asia and for having waters that have been historical chokepoints.

•Southern- located along the border of AntarcticaSouthern- located along the border of Antarctica•Arctic- smallest ocean; most oceanographers consider it as an Arctic- smallest ocean; most oceanographers consider it as an extension of the Pacific, Atlantic, and Indian Oceansextension of the Pacific, Atlantic, and Indian Oceans

Continue largest to smallestContinue largest to smallest3. 3. IndianIndian- A- Area of 26,469,900 square miles (68,566,000 sq km). ; ; the deepest area is the Java Trench at 7,725 m; The Indian Ocean is known for causing the monsoonal weather patterns that dominate much of southeast Asia and for having waters that have been historical chokepoints.4. 4. Southern-Southern- E Extends from the coast of Antarctica to 60 degrees south latitude. It has a total area of 7,848,300 square miles (20,327,000 sq km)

Continue smallestContinue smallest

5. 5. Arctic-Arctic- World's smallest with an area of 5,427,000 square miles (14,056,000 sq km); covered by a drifting polar icepack; most most oceanographers consider it as an oceanographers consider it as an extension of the Pacific, Atlantic, extension of the Pacific, Atlantic, and Indian Oceansand Indian Oceans

What divides the global What divides the global oceans?oceans?

•The global ocean is divided by the

continents into five main oceans.

How Did the How Did the Oceans FormOceans Form? ? Use key words underlinedUse key words underlined

•About 4 billion years ago, the About 4 billion years ago, the Earth Earth cooledcooled enough for enough for water water vapor to condense.vapor to condense.

•The water began to fall as The water began to fall as rainrain..

•The rain The rain filled the filled the deeper levels deeper levels of of Earth’s surface Earth’s surface and the first and the first oceans began to form.oceans began to form.

Locate the OceansLocate the Oceans

• label these on your map: See label these on your map: See nextnext slideslide– Pacific OceanPacific Ocean– Atlantic OceanAtlantic Ocean– Indian OceanIndian Ocean– Arctic OceanArctic Ocean– Southern Ocean aka Antarctic OceanSouthern Ocean aka Antarctic Ocean

Arctic Ocean Arctic Ocean Arctic Ocean

North Atlantic Ocean

South Atlantic Ocean

Pacific Ocean

Pacific Ocean

Indian Ocean

Southern Ocean

Southern Ocean

Southern Ocean

Characteristics of Ocean Characteristics of Ocean WaterWaterRead ONLY:Read ONLY:• Ocean water is salty full of dissolved Ocean water is salty full of dissolved

solidssolids

• Climate affects salinityClimate affects salinity

• Water movement affects salinityWater movement affects salinity

• Temperate zonesTemperate zones

• Surface temperature ChangesSurface temperature Changes

Why is the Ocean Salty? Why is the Ocean Salty? Dissolved solids Dissolved solids

•Most of the salt found in oceans Most of the salt found in oceans is is sodiumsodium chloridechloride (table (table salt).salt).

Where does the salt Where does the salt come from? Read onlycome from? Read only•solid materials solid materials

come from come from volcanic volcanic eruptionseruptions

•hot springshot springs•ocean waves ocean waves

crashing against crashing against rocks/mineralsrocks/minerals

Where does the salt Where does the salt come from? Read Onlycome from? Read Only

•Also, during the Also, during the water cyclewater cycle, , fresh water from fresh water from the ocean is the ocean is evaporatedevaporated leaving only the leaving only the salts behind.salts behind.

Where does the salt Where does the salt come from? Read ONLYcome from? Read ONLY

•Salts have been added to the Salts have been added to the oceans for billions of years by oceans for billions of years by running waters (rivers, streams) running waters (rivers, streams) which dissolve various minerals, which dissolve various minerals, and then dump the water into and then dump the water into the oceans.the oceans.

How Salty is the Ocean? How Salty is the Ocean? READ ONLY READ ONLY

• SalinitySalinity- the measure of the amount of - the measure of the amount of dissolved saltsdissolved salts in a in a given amount of given amount of waterwater

•The average amount of salt in ocean water is about 3.5% or 35 grams of salt per one kilogram (1000 g) of water

•Ocean water carries many different dissolved salts

Solids substances dissolved Solids substances dissolved in ocean. Read ONLYin ocean. Read ONLY

• Main substance dissolved in ocean water: Main substance dissolved in ocean water: sodium chloridesodium chloride aka table salt aka table salt

• Other solid substances dissolved in Other solid substances dissolved in ocean: ocean: sulfate, magnesium, calcium, and sulfate, magnesium, calcium, and potassium.potassium.

• Where do these dissolved solid Where do these dissolved solid substances come from?substances come from?– rivers, streams, rocks from the shore, rivers, streams, rocks from the shore,

volcanoes and underwater hot springs.volcanoes and underwater hot springs.

• The concentration of all the dissolved The concentration of all the dissolved substances in sea water is about 3.5%.substances in sea water is about 3.5%.

This compound consists of the elements

sodium, Na, and chlorine, Cl. Figure 3 shows the relative amounts of the dissolved solids in ocean water.

Factors Effecting SalinityFactors Effecting SalinityChock-Full of Solids

• EvaporationEvaporation• PrecipitationPrecipitation• FreezingFreezing• Rivers dumping water into oceansRivers dumping water into oceans• ClimateClimate• LocationLocation• water movementwater movement

Salinity- The measure of the amount of dissolved salts in a given amount of water. Measured: As grams of dissolved solids per kilogram of water. (Think of it this way: 1 kg (1,000 g) of ocean water can be evaporated to 35 g of dissolved solids)

Natural Processes Affecting Natural Processes Affecting SalinitySalinity

Climate Affects SalinityClimate Affects Salinity

• Some parts of the ocean are saltier than other Some parts of the ocean are saltier than other parts of the ocean.parts of the ocean.

– Coastal waters in places Coastal waters in places with with hotter, drier hotter, drier climatesclimates have a have a higher salinityhigher salinity. (. (More More evaporation because it is hotter, so less water, evaporation because it is hotter, so less water, more salt).more salt).

– Coastal waters in places with Coastal waters in places with cooler, more humid cooler, more humid climatesclimates have a have a lowerlower salinitysalinity (Less heat, so less (Less heat, so less evaporation, more water is left in ocean).evaporation, more water is left in ocean).

– Main reason: evaporationMain reason: evaporation

Climate Affects SalinityClimate Affects Salinity

Along which coast would salinity be Along which coast would salinity be higher? Lower?higher? Lower?

Increasing and Decreasing Increasing and Decreasing SalinitySalinity

–evaporation-

•increases salinity because only freshwater is evaporated. Therefore, salt is left behind.

– freezing-

•only freshwater freezes, so salt is left behind, causing an increase in salinity

Increasing and Decreasing Increasing and Decreasing SalinitySalinity

•precipitation- – decreases salinity because all forms of

precipitation are freshwater.

•rivers dumping water into oceans- – causes decreasing salinity, because rivers are

freshwater, and the amount of salt stays the same as freshwater is added.

Location Affects SalinityLocation Affects Salinity

• Also: Coastal waters in general have less Also: Coastal waters in general have less salinity salinity because more fresh water from because more fresh water from rivers run into the oceans in these areas.rivers run into the oceans in these areas.

Water Movement Affects Water Movement Affects SalinitySalinity

• Some parts of the ocean (bays, seas, Some parts of the ocean (bays, seas, gulfs) move less than other parts.gulfs) move less than other parts.

• Also, some parts of the open ocean Also, some parts of the open ocean that do not have currents run that do not have currents run through them can be slow moving.through them can be slow moving.

• Slower-moving areas of water Slower-moving areas of water develop high salinity.develop high salinity.

Water Movement Affects Water Movement Affects SalinitySalinity

Water Movement Affects Water Movement Affects SalinitySalinity

For the following chart on the next 2 slides (on the last page of your notes), fill in the chart using your notes from this Power Point.

If you were to go scuba If you were to go scuba diving… you would diving… you would experience….experience….• The TemperatureThe Temperature decreasesdecreases as you as you

go deeper.go deeper.

• Pressure increases Pressure increases with as you go with as you go deeperdeeper

Interesting Fact:Interesting Fact:

• You could only dive to a depth of 40 You could only dive to a depth of 40 m. Any further depth will cause the m. Any further depth will cause the lungs to collapse!lungs to collapse!

Ocean TopographyOcean Topography::*Oceanographers studying the oceans and ocean floor have delineated *Oceanographers studying the oceans and ocean floor have delineated

threethree (3) major units: (3) major units: 1. Continental margin1. Continental margin2. Ocean basin floor2. Ocean basin floor3. Mid-oceanic ridges3. Mid-oceanic ridges

Surprisingly, we know very little about the mapping of our ocean floor. We Surprisingly, we know very little about the mapping of our ocean floor. We probably have accurately mapped probably have accurately mapped only 5%only 5% of the ocean floor. It is time- of the ocean floor. It is time-consuming, expensive, and our current technology only allows us to map a consuming, expensive, and our current technology only allows us to map a few miles at a stretch. few miles at a stretch.

As technology develops, mapping will improve. Currently, we use As technology develops, mapping will improve. Currently, we use echo-echo-soundingsounding devices, which are slow and tedious. devices, which are slow and tedious.

1.1.  The continental margin includes: The continental margin includes: a.a.          Continental shelf -- very gentle slope (submerged land)Continental shelf -- very gentle slope (submerged land)b.b.          Continental slope -- steep slope on edge of continental Continental slope -- steep slope on edge of continental

shelf.shelf.c.c.          Continental rise -- gentle slope where trenches do not existContinental rise -- gentle slope where trenches do not exist  Deep sea fansDeep sea fans exist where sediment is accumulated and falls off of the exist where sediment is accumulated and falls off of the

continental slope. Mixture of sediment-laden heavy water forms submarine continental slope. Mixture of sediment-laden heavy water forms submarine turbidity currentsturbidity currents. .

Continental MarginContinental Margin

2.2.       The Deep Sea includes:The Deep Sea includes:a.a.        Deep ocean trenchesDeep ocean trenches (deepest part of ocean) some (deepest part of ocean) some

as deep as 36,000 feet; as deep as 36,000 feet; The The Marianas Trench Marianas Trench is 7 km is 7 km below the adjacent Pacific Ocean floor. Typically, below the adjacent Pacific Ocean floor. Typically, the deepest part of a trench is given a separate the deepest part of a trench is given a separate name. Ex. the name. Ex. the Challenger Deep is the deepest Challenger Deep is the deepest part of the Marianas Trench with part of the Marianas Trench with a maximum-known depth of about 11.03 kilometres (6.85 mi)

Ocean trenches are also associated with Ocean trenches are also associated with earthquakes, earthquakes, high heat flow, and volcanic activityhigh heat flow, and volcanic activity. .

The Deep Sea includes:The Deep Sea includes:b.b.        Abyssal plainsAbyssal plains are the flat portions of the deep are the flat portions of the deep ocean, likely to be the flattest portions of the earth. ocean, likely to be the flattest portions of the earth. •((gradient  (grd-nt) 1. The degree to which something inclines; a slope. A mountain road with a gradient of ten percent rises one foot for every ten feet of horizontal length.

•2. The rate at which a physical quantity, such as temperature or pressure changes over a distance.

•3. A operator on scalar fields yielding a vector function, where the value of the vector evaluated at any point indicates the direction and degree of change of the field at that point.)

c.c.          Isolated volcanic peaks (mantle hot spots) are referred to as Isolated volcanic peaks (mantle hot spots) are referred to as ""seamountsseamounts". Likewise volcanic cones near mid-oceanic ridges are ". Likewise volcanic cones near mid-oceanic ridges are called seamounts as well. Harry Hess called these “guyots”.called seamounts as well. Harry Hess called these “guyots”.

The Deep Sea includes:The Deep Sea includes:d. Mid-oceanic ridgesd. Mid-oceanic ridges : : A series of A series of

mountain ranges on the ocean floor,mountain ranges on the ocean floor, more than 84,000 kilometers (52,000 miles) more than 84,000 kilometers (52,000 miles) in length, extending through the North and in length, extending through the North and South Atlantic, the Indian Ocean, and the South Atlantic, the Indian Ocean, and the South Pacific. According to the plate tectonics South Pacific. According to the plate tectonics theory, volcanic rock is added to the sea floor theory, volcanic rock is added to the sea floor as the mid-ocean ridge spreads apart. as the mid-ocean ridge spreads apart.

Occur at divergent plate boundaries Occur at divergent plate boundaries (Mid-(Mid-Atlantic) and the narrow region at the ridge Atlantic) and the narrow region at the ridge crest is called the crest is called the rift zonerift zone. .

e.e.        Coral reefsCoral reefs and and atollsatolls develop usually in relatively develop usually in relatively shallowshallow water where water where light is present and organisms can thrive on nutrients and food sources in a light is present and organisms can thrive on nutrients and food sources in a warm water setting. Atolls develop in response to a sinking of the oceanic crustwarm water setting. Atolls develop in response to a sinking of the oceanic crust

Examples of mid-Examples of mid-ocean ridgesocean ridgesSlow spreading ridges like Slow spreading ridges like the the Mid-Atlantic Ridge Mid-Atlantic Ridge generally have large, wide generally have large, wide rift valleys, sometimes as big rift valleys, sometimes as big as 10–20 km (6.2–12 mi) as 10–20 km (6.2–12 mi) wide and very rugged terrain wide and very rugged terrain at the ridge crest that can at the ridge crest that can have relief of up to a have relief of up to a 1,000 m (3,300 ft). By 1,000 m (3,300 ft). By contrast, fast spreading contrast, fast spreading

ridges like ridges like the East the East Pacific RisePacific Rise are are narrow, sharp incisions narrow, sharp incisions surrounded by generally flat surrounded by generally flat topography that slopes away topography that slopes away from the ridge over many from the ridge over many hundreds of miles.hundreds of miles.

The Deep The Deep

DiagramDiagram of the Ocean Floor: of the Ocean Floor: pick ONE to draw and LABELpick ONE to draw and LABEL

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