Water in Earth’s Processes 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.

1. Lesson
The World’s Oceans
• EQ: How does the
composition and topography
of earth’s oceans vary by
location?

2. 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.

3. Ocean Water Chemistry- Questions
you will be able to answer
How salty is ocean
water?
How do the conditions
in the ocean change
with depth?
How did the ocean
form and how is it
currently divided?
Describe one factor
that increases the
salinity of seawater &
one factor that
decreases salinity.

4. Read ONLY: World Oceans Largest to Smallest

5. Divisions of the Global Oceans
Largest to smallest
Start Here:
1. Pacific- 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. Atlantic- 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

6. Continue largest to smallest
3. Indian- Area of 26,469,900 square miles
A
(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. Southern- Extends from the coast of Antarctica
E
to 60 degrees south latitude. It has a total area of
7,848,300 square miles (20,327,000 sq km)

7. Continue smallest
5. 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 oceanographers
consider it as an extension of the
Pacific, Atlantic, and Indian

8. What divides the global
oceans?
• The global ocean is divided by the
continents into five main oceans.

9. How Did the Oceans Form?
Use key words underlined
• About 4 billion years ago, the Earth
cooled enough for water vapor to
condense.
• The water began to fall as rain .
• The rain filled the deeper levels of
Earth’s surface and the first
oceans began to form.

10. Locate the Oceans
• label these on your map: See next slide
–
–
–
–
–
Pacific Ocean
Atlantic Ocean
Indian Ocean
Arctic Ocean
Southern Ocean aka Antarctic Ocean

12. Arctic Ocean
Arctic Ocean
Arctic Ocean
North
Atlantic
Ocean
Pacific
Ocean
Southern
Ocean
Pacific
Ocean
South
Atlantic
Ocean
Southern
Ocean
Indian Ocean
Southern Ocean

13. Characteristics of Ocean Water
Read ONLY:
• Ocean water is salty full of dissolved
•
•
•
•
solids
Climate affects salinity
Water movement affects salinity
Temperate zones
Surface temperature Changes

14. Why is the Ocean Salty?
Dissolved solids
• Most of the salt found in oceans is
sodium chloride (table salt).

15. Where does the salt come
from? Read only
• solid materials
come from volcanic
eruptions
• hot springs
• ocean waves
crashing against
rocks/minerals

16. Where does the salt come
from? Read Only
• Also, during the
water cycle, fresh
water from the
ocean is
evaporated leaving
only the salts
behind.

17. Where does the salt come
from? Read ONLY
• Salts have been added to the oceans
for billions of years by running waters
(rivers, streams) which dissolve
various minerals, and then dump the
water into the oceans.

18. How Salty is the Ocean?
READ ONLY
• Salinity- the measure of the amount of
dissolved salts in a given amount of water
• 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

19. Solids substances dissolved in
ocean. Read ONLY
• Main substance dissolved in ocean water:
sodium chloride aka table salt
• Other solid substances dissolved in ocean:
sulfate, magnesium, calcium, and potassium.
• Where do these dissolved solid substances
come from?
– rivers, streams, rocks from the shore, volcanoes
and underwater hot springs.
• The concentration of all the dissolved
substances in sea water is about 3.5%.

20. This compound consists of the elements
sodium, Na, and chlorine, Cl. Figure 3
shows the relative amounts of the dissolved solids in ocean water.

22. Factors Effecting Salinity
Chock-Full of Solids
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)
•
•
•
•
•
•
•
Evaporation
Precipitation
Freezing
Rivers dumping water into oceans
Climate
Location
water movement

23. Natural Processes Affecting
Salinity

24. Climate Affects Salinity
• Some parts of the ocean are saltier than other
parts of the ocean.
– Coastal waters in places with hotter, drier
climates have a higher salinity . ( More
evaporation because it is hotter, so less
water, more salt).
– Coastal waters in places with cooler, more
humid climates have a lower salinity (Less
heat, so less evaporation, more water is left

25. Climate Affects Salinity
Along which coast would salinity be
higher? Lower?

26. Increasing and Decreasing
Salinity
– 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

27. Increasing and Decreasing
Salinity
• 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.

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

29. Water Movement Affects
Salinity
• Some parts of the ocean (bays, seas,
gulfs) move less than other parts.
• Also, some parts of the open ocean that
do not have currents run through them
can be slow moving.
• Slower-moving areas of water develop
high salinity.

30. Water Movement Affects
Salinity

31. Water Movement Affects
Salinity
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.

32. If you were to go scuba diving…
you would experience….
• The Temperature decreases as you go
deeper.
• Pressure increases with as you go deeper
Interesting Fact:
• You could only dive to a depth of 40 m.
Any further depth will cause the lungs to
collapse!

33. 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-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 .

34. Continental Margin

35. 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 .

36. 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”.

37. The Deep Sea includes:
d. Mid-oceanic ridges : A series of
mountain ranges on the ocean floor,
more than 84,000 kilometers (52,000 miles) in
length, extending through the North and South
Atlantic, the Indian Ocean, and the South
Pacific. According to the plate tectonics
theory, volcanic rock is added to the sea floor
as the mid-ocean ridge spreads apart.
Occur at divergent plate boundaries
(Mid-Atlantic) and the narrow region at the
ridge crest is called the rift zone .
e. Coral reefs and atolls develop usually in relatively shallow water where 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 crust

38. Examples of mid-ocean
ridges
Slow 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.

39. The Deep

40. Diagram of the Ocean Floor: pick
ONE to draw and LABEL

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