Name: Answer Key ____________________________________________ Date: _______________________________ Block: ___________
Chapter 13 – Exploring the Oceans
All Sections
S6E3.c: Describe the composition, location, and subsurface topography of the world’s oceans.
I. Earth’s Oceans
A. Divisions of the Global Ocean
1. What are the five main oceans? Pacific, Atlantic, Indian, Arctic, Southern Ocean
B. How did the Oceans Form?
1. How did water form on Earth? Just before 4 billion years ago, the Earth cooled enough for
water vapor to condense.
C. Characteristics of Ocean Water
1. Ocean Water is Salty
a. What is another name for salt? Sodium Chloride
2. Chock-Full of Solids
a. What is salinity? A measure of the amount of dissolved solids in a given amount of
liquid.
b. How is salinity measured? Measured as grams of dissolved solids per kilogram of
liquid.
3. Climate Affects Salinity
a. Hot, Dry Climate = high salinity
b. Cool, Humid Climate = lower salinity
4. Water Movement Affects Salinity
a. Slower-moving water has higher salinity.
5. Temperature Zones
a. As the depth increases, what happens to the temperature? decreases.
6. Surface Temperature Changes
a. Does the temperature of the ocean vary with latitude and time of year? yes
D. The Ocean and the Water Cycle
1. Why is the ocean an important part of the Water Cycle? The ocean is what feeds the
Water Cycle.
E. A Global Thermostat
1. A Thermal Exchange
a. Why is it important for the ocean to absorb and release thermal energy slowly?
If the ocean did not regulate temperatures, there would be a great difference in
Temperatures between day and night.
2. Have Heat, Will Travel
a. What does the ocean help to regulate? Regulate temperatures at different locations
of the Earth.
II. The Ocean Floor
A. What is Bathymetry? Ocean topography. It is the study of the geological features of the floor of
the ocean.
B. Why do you think that geological features in the ocean are bigger than the ones on land? _________
The features on the ocean floor are larger than the ones on land because the rate of erosion is slower
on the ocean floor than it is on land.
C. Earth’s Crust
Continental Crust
Ocean Crust
Granite
Thicker
Less dense
Average elevation 838m (2,750ft)
Basaltic
Thinner
Denser
Average depth 3800m (12,500ft)
D. Studying the Ocean Floor
1. What does sonar stand for? Sound navigation and ranging
2. How does sonar work? Scientists send sound pulses from a ship down into the ocean. The
Sound moves through the water, bounces off the ocean floor, and returns to the ship.
3. What is the most widely used topographic maps for the ocean floor? Heezen-Tharpe maps.
They use thousands of sonar tracks.
E. Revealing the Ocean Floor
1. Continental Shelf: begins at the shoreline and slopes gently toward the open ocean. Depth
Can reach 200 meters.
2. Continental Slope: begins at the edge of the continental shelf. Continues down to the
Flattest part of the ocean. Depth from about 200 meters to 4,000 meters.
3. Continental Rise: base of the continental slope, is made of large piles of sediment. This is
the boundary between the continental margin and deep-ocean basin.
4. Abyssal Plain: the broad, flat part of the of the deep-ocean basin. Average depth is
4,000 meters.
5. Mid-Ocean Ridges: mountain chains that form where tectonic plates pull apart.
6. Rift Valley: as mountains builds up, a valley forms between them.
7. Ocean Trenches: huge cracks in the deep-ocean basin. Form when an oceanic plate is
Pushed beneath another oceanic plate or continental plate.
8. Seamounts: individual mountains of volcanic material. If a seamount builds up above
Sea level it becomes a volcanic island
III. Life in the Ocean
A. Ocean Zones
1. Intertidal Zone: the shallowest zone. It is located between the low- and high tide limits.
2. Sublittoral Zone: begins where the low-tide limit is and ends at the edge of the continental
shelf. It is about 200 meters below sea level.
3. Bathyal Zone: extends from the edge of the continental shelf to the abyssal plain. The depth
of this zone ranges from 200 meters to 4,000 meters below sea level.
4. Abyssal Zone: the largest ecological zone of the ocean and can reach a depth of
4,000 meters
5. Hadal Zone: the deepest zone. It consists of the ocean floor and ocean trenches. It has
depths of 6,000 meters to 7,000 meters.
6. Neritic Zone: covers the continental shelf. This warm, shallow zone contains the largest
concentration of marine life.
7. Oceanic Zone: includes the volume of water that covers the entire sea floor except for the
Continental shelf.
A. Intertidal Zone
B. Bathyal Zone
C. Hadal Zone
D. Sublittoral Zone
E. Abyssal Zone