the ocean's composition

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 others you will need to use for the organizer.

Chapter

13Ocean Water

S6E3. Students will recognize the significant role of water in earth processes.

c. Describe 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, which are often larger than those on dry land

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 elements found in seawater is from Earth’s interior.

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

Natural Processes Affecting Salinity

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 (Read ONLY)

Variations in Ocean Water Temperature (Read ONLY)

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

Chemical Composition of Ocean Water(Use this to label the diagram)

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The 5 Oceans on Earth

AtlanticSouthernArticIndian

Pacific

The 5 Oceans on Earth

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;

Ocean Topography:*Oceanographers studying the oceans and ocean floor have delineated three (3)

major units: 1. Continental margin2. Ocean basin floor3. 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-sounding devices, 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 ridgesSlow spreading ridges like the Mid-Atlantic Ridge generally 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 Floor

1. 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 ikeepbookmarksor the BLOGor USATESTPREPReview any concept

• Congratulation Oceanographer– Job well done!