WARMUP

*Have your Vocab Sheets laying out so I can check them*

What percentage of earth do you think is covered by water?

EXPLORING THE OCEANSEarth Science: Book H, Chapter 2

SECTION 1: EARTH’S OCEANS

By the end of this section, you should be able to:

List the major divisions of the global ocean.

Describe the history of Earth’s oceans. Identify the properties of ocean water. Describe the interactions between the

ocean and the atmosphere.

DIVISIONS OF THE GLOBAL OCEAN

The largest ocean is the Pacific Ocean.

The other oceans, listed from largest to smallest, are: the Atlantic Oceanthe Indian Oceanthe Arctic Ocean the Southern Ocean

HOW DID THE OCEANS FORM? About 4.5 billion years ago, there were no

oceans.

Sometime before 4 billion years ago, water vapor in the atmosphere condensed and fell as rain.

The rain filled the deeper levels of Earth’s surface and the first oceans began to form.

The shape of the oceans has changed over time.

Need Pangaea image here

CHARACTERISTICS OF OCEAN WATER Nitrogen, oxygen, and carbon dioxide are

the main gases dissolved in ocean water.

Sodium chloride, or table salt, is the most abundant dissolved solid in the ocean. Other solids are also found in ocean water.

CHARACTERISTICS OF OCEAN WATER Salinity is a measure of the amount of

dissolved salts in a given amount of liquid.

If you evaporated 1 kg of ocean water, 965 g of fresh water would be removed and 35 g of salts would remain.

CHARACTERISTICS OF OCEAN WATER

Climate and water movement affect salinity.

Coastal water in cool, humid places has a low salinity.

Slow-moving bodies of water, such as bays, gulfs, and seas, have higher salinity than other parts of the ocean do.

CHARACTERISTICS OF OCEAN WATER The temperature of ocean water

decreases as depth increases.

CHARACTERISTICS OF OCEAN WATER Surface-zone temperatures vary with

latitude and the time of year.

Surface temperatures range from 1ºC near the poles to about 24 ºC near the equator.

The surface zone is heated more in the summer.

THE OCEAN & THE WATER CYCLE

The water cycle is the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean.

The ocean is an important part of the water cycle because nearly all of Earth’s water is in the ocean.

A GLOBAL THERMOSTAT The ocean regulates atmospheric

temperatures.

The ocean absorbs and releases thermal energy much more slowly than dry land does.

The circulation of warm water causes some coastal lands to have warmer climates than they would have without the currents.

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If you walked off the edge of North America into the depths of the Atlantic Ocean what

would you see?

SECTION 2: THE OCEAN FLOOR

By the end of this section, you should be able to:

Describe technologies for studying the ocean floor.

Identify the two major regions of the ocean floor.

Classify subdivisions and features of the two major regions of the ocean floor.

STUDYING THE OCEAN FLOOR Scientists use sonar to determine the

ocean’s depth.

STUDYING THE OCEAN FLOOR Scientists use images from the satellite

Seasat to study ocean currents.

Scientists use the Geosat satellite to measure slight changes in the height of the ocean’s surface.

REVEALING THE OCEAN FLOOR

The two regions of the ocean floor are the continental margin and the deep-ocean basin.

The continental margin is made of continental crust and the deep-ocean basin is made of oceanic crust.

REGIONS OF THE OCEAN FLOOR

Continental margin is subdivided into the continental shelf, continental slope, and continental rise.

These divisions are based on depth and changes in slope.

REGIONS OF THE OCEAN FLOOR

The deep-ocean basin consists of the abyssal plain, mid-ocean ridges, rift valleys, and ocean trenches.

All of these form near the boundaries of Earth’s tectonic plates.

REGIONS OF THE OCEAN FLOOR

On parts of the deep-ocean basin not near plate boundaries, there are thousands of seamounts.

Seamounts are submerged volcanic mountains on the ocean floor.

EXPLORING THE OCEAN Alvin and Deep Flight are two research

vessels that can reach some of the deepest parts of the ocean.

JASON II and Medea are a robotic team. JASON II explores the ocean floor. Medea is attached to JASON II with a tether and explores above the sea floor.

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Imagine you are a marine biologist who must classify marine life into 3 groups.

What criteria would you use for your classification system?

SECTION 3: LIFE IN THE OCEAN

By the end of this section, you should be able to:

Identify the three groups of marine life. Describe the two main ocean

environments. Identify the ecological zones of the

benthic and pelagic environments.

THREE GROUPS OF MARINE LIFE

Organisms that float or drift freely near the ocean’s surface are called plankton.

Organisms that swim actively in the open ocean are called nekton.

Organisms that live on or in the ocean floor are called benthos.

THE BENTHIC ENVIRONMENT

The benthic environment is the region near the bottom of a pond, lake, or ocean.

The benthic environment is divided into ecological zones based on where different types of benthos live.

THE BENTHIC ENVIRONMENT The intertidal zone is where the ocean

meets the land.

The intertidal zone is exposed to air for part of the day. Organisms found in this zone include starfish, sea anemones, barnacles, crabs, and seaweed.

THE BENTHIC ENVIRONMENT The sublittoral zone begins at the low-tide

limit and extends to the continental shelf, which is about 200 m below sea level.

The temperature, water pressure, and amount of sunlight remain fairly constant in this zone. Coral is found in this zone.

THE BENTHIC ENVIRONMENT The bathyal zone extends from the

continental shelf to the abyssal zone. The depth of this zone ranges from 200 m to 4,000 m below sea level.

Because of the lack of sunlight, few plants are found in this zone. Animals such as sea stars, sponges, and octopuses are found here.

THE BENTHIC ENVIRONMENT The abyssal zone is the largest ecological

zone of the ocean and can reach 4,000 m in depth.

No plants live in this zone. The few animals that can be found include crabs, sponges, sea cucumbers, and worms.

THE BENTHIC ENVIRONMENT The hadal zone consists of the floor of the

ocean trenches and any organisms found there. The depth can reach from 6,000 m to 7,000 m below sea level.

The only organisms that have been found in this zone include a type of sponge, a few species of worms, and a type of clam.

THE PELAGIC ENVIRONMENT The zone near the ocean’s surface and at

the middle depths is called the pelagic environment.

The pelagic environment is above the abyssal zone and beyond the littoral zone.

The two major zones of the pelagic environment are the neritic zone and the oceanic zone.

THE PELAGIC ENVIRONMENT

The neritic zone is a warm, shallow zone that covers the continental shelf.

The neritic zone contains the largest concentration of marine life.

THE PELAGIC ENVIRONMENT

The neritic zone receives more sunlight than other ocean zones, allowing plankton to grow and serve as a food supply.

THE PELAGIC ENVIRONMENT

The oceanic zone includes the volume of water that covers the entire sea floor except for the continental shelf.

The deeper parts of the oceanic zone have colder water temperatures and much greater pressure than the neritic zone.

THE PELAGIC ENVIRONMENT

Organisms are more spread out in the oceanic zone.

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Samantha drove her car to the market to buy a tuna steak for dinner. When she got home she poured herself a glass of water, and then fired up her gas grill to cook the

tuna.

What are 3 items or activities mentioned above that involve ocean resources?

SECTION 4: RESOURCES FROM THE OCEAN

By the end of this section, you should be able to:

List two ways of harvesting the ocean’s living resources.

Identify three nonliving resources in the ocean.

Describe the ocean’s energy resources.

LIVING RESOURCES Fish are the largest group of organisms

taken from the ocean.

People have begun to raise ocean fish and other organisms in fish farms to help meet the demand for seafood.

LIVING RESOURCES

Many types of seaweed are harvested from the ocean for use as food.

NONLIVING RESOURCES

Oil and natural gas are used for energy and are found under layers of impermeable rock.

Scientists use seismic equipment to find oil and natural gas under the ocean floor.

NONLIVING RESOURCES

Fresh water can be collected for human use by desalination, the process of removing the salt from ocean water.

NONLIVING RESOURCES

Scientists estimate that 15% of the ocean floor is covered with mineral-rich nodules. However, mining them is costly and difficult.

Nodules form from dissolved substances in sea water that stick to solid objects, such as pebbles.

NONLIVING RESOURCES Tidal energy is energy generated from

the movement of the tides.

NONLIVING RESOURCES

The constant motion of waves is a clean, renewable energy resource.

Researchers have found certain areas of the world where wave energy can generate enough electrical energy to make building power plants worthwhile.

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How do you contribute to ocean pollution in your daily lives?

SECTION 5: OCEAN POLLUTION

By the end of this section, you should be able to:

Explain the difference between point-source and nonpoint-source pollution

Identify three different types of point-source pollution.

Describe what is being done to control ocean pollution.

NONPOINT-SOURCE POLLUTION Pollution that comes from many sources

rather than from a single site is called nonpoint-source pollution.

Most ocean pollution is nonpoint-source pollution and can be difficult to regulate and control.

POINT-SOURCE POLLUTION Dumping trash in the deeper parts of the

ocean is a common practice in many countries.

Trash thrown in the ocean can be harmful to ocean organisms.

POINT-SOURCE POLLUTION Sludge is the solid waste removed from

raw sewage. Sludge can pollute beaches and kill marine life.

POINT-SOURCE POLLUTION If not handled properly, oil transports can

cause oil spills.

POINT-SOURCE POLLUTION

Oil spills can harm or kill many plants and animals.

POINT-SOURCE POLLUTION

New technology is being used to safeguard against oil spills. Oil tankers are now being built with two hulls instead of one.

SAVING OUR OCEAN RESOURCES Many international agreements and laws

restrict ocean pollution.

People have demanded that their governments work to solve ocean pollution and have begun organizing beach cleanups.

SAVING OUR OCEAN RESOURCES

The U.S. has passed laws to control local pollution.

Some of these laws include the Clean Water Act and the U.S. Marine Protection, Research, and Sanctuaries Act.

SECTION REVIEW

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