The Oceans, Atmosphere, and Climatic Effects

Chapter 24: The Oceans, Atmosphere, and Climatic Effects

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Chapter 24 Lecture

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This lecture will help you understand:

Earth’s Atmosphere and Oceans

Components of Earth’s Oceans

Ocean Waves, Tides, and Shorelines

Components of Earth’s Atmosphere

Solar Energy

Driving Forces of Air Motion

Global Circulation Patterns

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Earth’s Atmosphere and Oceans

Seventy-one percent of Earth’s surface is covered by water.

Water’s high specific heat capacity accounts for moderate temperatures in coastal lands.

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Earth’s Atmosphere and Oceans

Earth’s early atmosphere appeared before the Sun was fully formed.

Hydrogen

Helium

The Sun’s formation swept away Earth’s original atmosphere and a new atmosphere formed.

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Earth’s Atmosphere and Oceans

Earth’s atmosphere developed in stages:

Hot gases escaped through volcanoes and fissures.

Free oxygen occurred as a result of photosynthesis by cyanobacteria.

Ozone began to accumulate in the upper atmosphere.

Water vapor condensed to form oceans.

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Components of Earth’s Oceans: The Ocean Floor

The ocean floor encompasses continental margins and deep ocean basins.

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Components of Earth’s Oceans: The Ocean Floor

Continental margins are between shorelines and deep ocean basins.

Continental shelf—shallow, underwater extension of the continent.

Continental slope—marks boundary between continental and oceanic crust.

Continental rise—wedge of accumulated sediment at base of continental slope.

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Components of Earth’s Oceans: The Ocean Floor

The ocean bottom is etched with deep canyons, trenches, and crevasses.

Underwater mountains rise upward from the seafloor.

The deep-ocean basin:

Basalt from seafloor spreading plus thick accumulations of sediment

Abyssal plains, ocean trenches, and seamounts

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Components of Earth’s Oceans: The Ocean Floor

The deep-ocean basin:

Abyssal plains—flattest part of the ocean floor due to accumulated sediment

Ocean trenches—long, deep, steep troughs at subduction zones

Seamounts—elevated seafloor from volcanism

Mid-ocean ridges:

Sites of seafloor spreading (volcanic and tectonic activity)

A global mid-ocean ridge system winds all around the Earth

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Components of Earth’s Oceans: The Ocean Floor

The deepest parts of the ocean are at the ocean trenches near some of the continents.

The shallowest waters are in the middle of the oceans around underwater mountains (mid-ocean ridge system).

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Ocean trenches are the deepest parts of the ocean floor because

that is where oceanic crust meets continental crust.

that is where subduction occurs.

no sediment accumulates in trenches.

all accumulated sediment settles in the abyssal plain.

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Components of Earth’s Oceans CHECK YOUR NEIGHBOR

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B. that is where subduction occurs.

Ocean trenches are the deepest parts of the ocean floor because

that is where oceanic crust meets continental crust.

that is where subduction occurs.

no sediment accumulates in trenches.

all accumulated sediment settles in the abyssal plain.

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Components of Earth’s Oceans CHECK YOUR ANSWER

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B. that is where subduction occurs.

Oceanic crust does meet continental crust at deep ocean trenches, but these plate boundaries do not all have deep trenches.

C. and D. sediment does accumulate in the trenches.

Ocean Waves, Tides, and Shorelines

Characteristics of waves—waves get their energy from the wind.

The crest is the peak of the wave.

The trough is the low area between waves.