Transcript Document 7225131

The Blue Planet
Oceans
• 71% of the Earth’s
surface is covered by
oceans.
• The ocean’s contain
97% of the Earth’s
water.
• Less than 1% of the
water on Earth is fresh
water.
Exploring the Oceans
• Since ancient times,
people have used the
oceans for food,
travel, and adventure.
• The ancient Egyptians
were the first to build
seafaring ships,
around 4000 B.C.
Exploring the Oceans
• Early Polynesians and
Phoenicians were
accomplished
fisherman and sailors
who discovered new
lands and sea routes
for commerce.
Exploring the Oceans
• Between the 9th and
12th centuries, Viking
seafarers discovered
Iceland, Greenland,
and parts of North
America.
• In 1492, Columbus
rediscovered America
and helped launch the
great European age of
exploration.
HMS Challenger
• This ship left England
December 21, 1872.
• And sailed around the
world in 3 years.
• Explored ocean
currents, water
temperature and
chemical composition,
and marine life.
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Pacific Ocean
Atlantic Ocean
Indian Ocean
Antarctic Ocean
Arctic Ocean
• The total salt content of
seawater averages 3.5%
Phytoplankton
• Microscopic plants
that live in the ocean.
• Phytoplankton are the
basis of the marine
food chain.
• Responsible for nearly
half of Earth’s
photosynthesis.
• A soda can of seawater
can contain 100
million phytoplankton.
Why is the ocean blue?
• The ocean looks blue because seawater
absorbs all the colors of the light
sprectrum…
• except blue.
• Blue light is reflected back off of the water
and…
• The ocean appears blue.
• The Red Sea is red because of red algae.
What would life be like without
the oceans?
• Without oceans, the temperature would
fluctuate dramatically, making our planet
inhospitable to life.
• The ocean water is always on the move.
Waves, tides, and currents influence climate
and living conditions, both in the water and
on land.
• Ocean currents regulate temperatures
around the globe.
Waves
• Caused by wind.
• Do not move
horizontally.
• They only move up
and down.
• Tsunamis (a.k.a. tidal
waves) are caused by
earthquakes, volcanic
eruptions, or
landslides.
Tides
• Tides are periodic
rises and falls of large
bodies of water.
• The are caused by the
Sun and the Moon.
• The Moon is the
biggest factor.
• Because the Earth is
rotating...
• 2 tides occur each day.
Resources from the ocean
• 60% of the people in
the world live in a
coastal area.
• Over 1 billion people
rely on fish as their
primary source of
protein.
• 90% of the world’s
biomass is contained
in the oceans.
Humans have not always taken
care of these resources
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Chemical and petroleum spills
Sewage and waste dumping
Overfishing
Destruction of sea-life habitats
Nature interacts with the ocean…
which affects human life
• Storms grow bigger and more dangerous as
the ocean supplies them with warm, watersaturated air.
• Coastal towns have milder winters and
cooler summers.
• El Niño and La Niña, periodic shifts of
warm waters in the Pacific Ocean, can
affect the climate worldwide.