Download 4 Resources from the Ocean Critical Thinking

Name
Class
CHAPTER 13
Date
Exploring the Oceans
SECTION
4 Resources from the Ocean
BEFORE YOU READ
After you read this section, you should be able to answer
these questions:
• What are the living resources from the ocean?
• What are the nonliving resources from the ocean?
What Are the Living Resources of the Ocean?
People have been harvesting plants and animals from
the ocean for thousands of years. Today, harvesting food
from the ocean is a multi-billion-dollar industry. As the
population of humans on Earth has grown, the demand
for these resources has increased. However, the availability of these resources has not increased as much.
Harvesting fish from the ocean can harm the environment. Usually, fish can reproduce faster than people
can catch them. However, new technology, such as drift
nets, has allowed people to catch more fish in less time.
This may allow people to take fish faster than they can
reproduce. This could cause the population of fish in the
oceans to decrease. Also, other animals, such as dolphins
and turtles, can be caught in fishing nets.
Recently, laws have been passed that control fishing
more strictly. These laws are supposed to help reduce
the damage fishing can cause to the environment. As a
result of these laws, people have begun to raise fish and
other types of seafood, such as shellfish and seaweed, in
farms near the shore. By growing seafood in these farms,
people can conserve and protect wild organisms.
STUDY TIP
Summarize As you read,
make a chart describing the
resources that people use
from the ocean.
Critical Thinking
1. Explain When can fish
be considered a renewable
resource? When would fish not
be considered a renewable
resource?
New technology, such as these drift nets, allows people to
catch more fish in less time. However, other animals, such as
dolphins and turtles, can sometimes get caught in the nets.
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Exploring the Oceans
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SECTION 4
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Resources from the Ocean continued
What Are the Nonliving Resources of
the Ocean?
Fish and other seafood are important resources that
people take from the oceans. However, people also take
many nonliving resources from the oceans. These resources
include energy resources and material resources.
FRESH WATER
READING CHECK
2. Define What is
desalination?
Fresh water is often considered a renewable resource.
However, in parts of the world where the climate is dry,
fresh water is limited. In these parts of the world, ocean
water is desalinated to provide fresh drinking water.
Desalination is the process of removing salt from sea
water.
Most desalination plants heat ocean water to cause the
water to evaporate. The water vapor, which is not salty, is
collected and condensed into liquid fresh water. Another
method of desalination involves passing the ocean water
through a membrane to leave the salts behind. However,
no matter what process is used, desalination is expensive
and can be slow.
TIDAL ENERGY
Critical Thinking
3. Infer Why can’t tidal
energy be used everywhere?
The ocean is constantly moving as tides come in and
go out. People can use the motion of the water to generate electricity. Energy that is generated from the movement of tides is called tidal energy. Tidal energy is clean,
inexpensive, and renewable. However, it can only be used
in certain parts of the world.
High tide
Low tide
Gate closed
Gate closes
TAKE A LOOK
4. Explain Why is tidal
energy considered to be
renewable?
1 As the tide rises,
water enters a bay
behind a dam. At
high tide, the gate
closes to keep the
water in the bay.
2 The gate stays
closed as the tide
goes out.
Gate opens
3 At low tide, the gate
opens and the water
rushes out of the bay.
As it moves through
the dam, the water
turns wheels called
turbines that generate
electricity.
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Resources from the Ocean continued
OIL AND NATURAL GAS
Oil and natural gas are considered the most valuable
resources in the ocean. Oil and natural gas form from
the remains of tiny plants and animals. These remains
take millions of years to turn into oil and natural gas.
Therefore, oil and gas are nonrenewable resources.
Many deposits of oil and natural gas are found in rock
near the continental margins. In order to obtain these
resources, engineers must drill wells through the rock.
About one-fourth of the world’s oil is now obtained from
wells in rock beneath the oceans.
Oil is refined by manufacturers to make gasoline. Gasoline
powers vehicles and generators that make electricity. Oil is
also used to make plastic and other products.
Say It
Discuss In a small group,
talk about different ways that
you use resources from the
ocean every day.
READING CHECK
5. List Give two ways that
people use oil or natural gas.
MINERALS
Many different kinds of minerals can be found on the
ocean floor. These minerals are commonly in the form of
nodules. Nodules are potato-shaped lumps of minerals
that form from chemicals dissolved in ocean water.
Nodules can be made of many different kinds of minerals. Most nodules contain the element manganese.
Manganese can be used to make certain kinds of steel.
Some nodules contain the valuable metals iron, copper,
nickel, or cobalt. Some contain phosphorus, which can
be used in fertilizer.
Nodules can be very large. They may contain a large
amount of valuable minerals. However, they form in the
very deep parts of the ocean. For this reason, they are
difficult to mine.
READING CHECK
6. Explain Why are nodules
hard to mine?
Minerals can be found on the
ocean floor in the form of
nodules. These nodules are
difficult to mine because they
are found in very deep water.
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Exploring the Oceans
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Section 4 Review
SECTION VOCABULARY
desalination a process of removing salt from
ocean water
1. List Name two living resources from the ocean.
2. Define Write your own definition for desalination.
3. Describe How can the tides be used to generate electricity?
4. Identify Give five minerals that may be found in nodules.
5. List Give four nonliving ocean resources.
6. Infer Why are people starting to farm the oceans instead of harvesting
wild organisms?
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Earth Science Answer Key continued
8. It would be flat and uniform, without any
Review
1. Plankton are organisms that float and drift
mountains or valleys in it.
9. a volcanic mountain on the sea floor
10. where tectonic plates are moving apart
11. An ocean trench is a deep depression in the
ocean floor where a tectonic plate subducts.
12. Feature
What it is
Where it is found
Seamount
an underwater
volcano
at plate boundaries
or in the middle of
a plate
Abyssal plain
flat part of the
ocean basin,
covered in
sediment
in the deep-ocean
basins
Mid-ocean
ridge
long,
underwater
mountain chain
where plates move
apart
Rift valley
crack in the
crust at a midocean ridge
where plates move
apart
2.
3.
4.
5.
6.
Review
1. Scientists use underwater vessels, sonar, and
SECTION 4 RESOURCES FROM THE OCEAN
satellite information to study the ocean floor.
2. When plates move together, one plate sinks
beneath another. This produces a large, deep
trench in the ocean floor.
3. Some comes from the land. Some is made
of the remains of sea creatures that settle to
the bottom when the creatures die.
4. Tectonic plates move apart, creating tension.
Cracks form in the crust. Melted rock rises
through the cracks, cools, and hardens. The
hardened rock forms the ridge.
1. Fish are a renewable resource because they
2.
3.
4.
5.
6.
can usually reproduce faster than we hunt
them. If we hunt them too quickly, they are a
nonrenewable resource.
removing salt from sea water
Most places are not close enough to the
ocean to use tidal power.
the tides cannot be used up
for energy and to make plastics
They form deep underwater.
Review
1. fish, seaweed
2. Desalination is a method people use to make
SECTION 3 LIFE IN THE OCEAN
1. plankton, nekton, benthos
2. the ocean floor, the area near it, and the
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
freely near the ocean surface. Nekton are
organisms that actively swim in the open ocean.
The benthic environment is found at the
bottom of the ocean. It includes the animals
living near, on, or in the ocean floor. The
pelagic environment is found near the ocean
surface and in the open and deep-ocean water.
It gets more sunlight than any other zone,
so many phytoplankton can grow. These
phytoplankton act as food for other marine
organisms in this zone.
No sunlight reaches these zones.
Sometimes the zone is underwater, and
sometimes it is not. The organisms in this
zone must be able to survive dry and wet
conditions, as well as crashing waves.
neritic zone, oceanic zone
organisms that live there
between the low-tide and high-tide limits
They attach themselves to rocks.
about 645 ft
The sublittoral zone is always underwater.
The animals eat other animals for food.
the abyssal plain
a hot-water vent in the ocean floor
in ocean trenches
the water above the benthic environment
above the continental shelf
oceanic zone
3.
4.
5.
6.
fresh water from ocean water.
Water enters a bay behind a dam as the tide
rises. When high tide reaches its peak, the
gate closes. The gate remains closed as the
tide falls. The gate opens at low tide, and
water rushes through the dam. This moves
the turbines to generate electricity.
iron, copper, manganese, phosphorus, nickel
water, minerals, oil, tides
People consume more fish than can be
harvested from the oceans without causing
fish to become too scarce. By farming the
fish, people ensure a supply of fish without
reducing wild populations too much.
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Earth Science