EARTH SCIENCEDirections: Read each slide use the RED underlined words to complete the organizer.

Tarbuck Lutgens

Directions: READ each slide then

decide what is important to record (Use the RED & or underlined words). Some slides are just FACTS (Read them) others you will need to use for the organizer.

Chapter

13Ocean Water

S6E3. Obtain, evaluate, and communicate information to recognize

the significant role of water in Earth processes.

c. Ask questions to identify and communicate, using graphs and maps,

the composition, location, and subsurface topography of the world’s

oceans.

Learning Target: I can tell about underneath the ocean, the Earth has plains, mountains, and valleys, what the ocean is made up of, and where the oceans are located.

Guiding Question

• Is the ocean the same everywhere?

• How many oceans are there?

•What is the composition of ocean

water?

Salinity

13.1 The Ocean’s Composition

Salinity is the total amount of solid

material dissolved in water. Because the proportion of dissolved

substances in seawater is such a small

number, oceanographers typically express

salinity in parts per thousands. Most of the salt in seawater is sodium chloride,

common table salt.

Salinity

Where does the Salt come from?

Sources of Sea Salt

a. Chemical weathering of rocks on the

continents is one source of elements found in

seawater.

b. The second major source of elementsfound in seawater is from Earth’s interior.

Graph: Dissolved Salts in

Ocean water

Natural Processes Affecting Salinity

Salinity

Processes Affecting Salinity

Processes Affecting Salinity

• Processes that decrease salinity:

• Processes that increase salinity:

- Precipitation

- Runoff from land

- Icebergs melting

- Ice melting

- Evaporation

- Formation of sea ice

Ocean Temperature Variation The ocean’s surface water temperature

varies with the amount of solar radiation

received, which is primarily a function of

latitude.

13.1 Seawater

• 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.

Temperature Variation with Depth

• The thermocline is a very important structure

because it creates a barrier to marine life.

Variations in Ocean

Surface Temperature

Variations in Ocean

Water 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.

13.1 Factors Affecting Seawater Density

• Seawater density is influenced by two main factors:

salinity and temperature.

Factors Affecting Seawater Density

Salinity map showing areas of high salinity (36 o/oo) in green,

medium salinity in blue (35 o/oo), and low salinity (34 o/oo) in

purple. Salinity is rather stable but areas in the North Atlantic,

South Atlantic, South Pacific, Indian Ocean, Arabian Sea, Red Sea,

and Mediterranean Sea tend to be a little high (green). Areas near

Antarctica, the Arctic Ocean, Southeast Asia, and the West Coast

of North and Central America tend to be a little low (purple).

http://www.biosbcc.net/ocean/marinesci/02ocean/swcomposition.htm

Chemical Composition of Ocean Water

(Use this to label the diagram)

Making connections

Read the next sides when you are finished go

to Classzone and explore salinity and the

ocean

Aunt

Patty

Seldom

Ate

Inchworms

What?

The 5 Oceans on Earth

Atlantic

Southern

Artic

Indian

Pacific

Back page

The 5 Oceans on Earth

• The continents divide the 5 major oceans

and the equator subdivides these oceans

into the North Atlantic Ocean and South

Pacific Ocean

On average, the Atlantic is the saltiest of

the world's major oceans; but the Pacific is the

largest ocean

Ocean Topography:

*Oceanographers studying the oceans and ocean floor have delineated three (3) major units:

1. Continental margin

2. Ocean basin floor

3. Mid-oceanic ridges

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

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

1. The continental margin includes:

a. Continental shelf -- very gentle slope (submerged land)

b. Continental slope -- steep slope on edge of continental shelf.

c. Continental rise -- gentle slope where trenches do not exist

Deep sea fans exist where sediment is accumulated and falls off of the continental slope. Mixture of sediment-laden heavy water forms submarine turbidity currents.

Continental Margin

2. The Deep Sea includes:

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

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

The Deep Sea includes:b. Abyssal plains are the flat portions of the deep 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. Isolated volcanic peaks (mantle hot spots) are referred to as

"seamounts". Likewise volcanic cones near mid-oceanic ridges are called seamounts as well. Harry Hess called these “guyots”.

Examples of mid-ocean ridges

Slow spreading ridges like

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

ridges like the East Pacific Rise are

narrow, sharp incisions surrounded by generally flat topography that slopes away from the ridge over many hundreds of miles.

Technology: Exploring the

Ocean Floor1. How can scientists study the ocean floor?

2. What did they find?

3. With state of the art technology, scientists

have discovered a wide variety of landforms

and sea life on the ocean floor.

Underwater Explorer

• Some parts of the ocean are too deep for humans and so they must use special underwater equipment.

• One piece is a minisub called Alvin.

• Alvin has been used to search for sunken ships, recover lost hydrogen bombs, and explore landforms on the ocean floor.

Viewing the ocean floor with sonar• SONAR (sound navigation and ranging) is a technology

based on the echo-ranging behavior of bats.

• We can measure the ocean’s depth with SONAR by sending high frequency sound waves to the ocean floor.

• The sound bounces off the ocean floor and back to the boat.

• The time it takes to get back to the boat can be use to

find the depth. Depth = t/2x1500m/s

Draw and label the Topography of

the Ocean Floor And circle the

deepest feature

Go back to ikeepbookmarks

Classzone. How Do

Temperature and Salinity

Affect Mixing in the Oceans?

or the BLOG

or USATESTPREP

Review any concept

• Congratulation Oceanographer

– Job well done!