Introduction to Oceanography

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Introduction to Oceanography

• The Water Planet

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The Water Planet

• Over 97 of all the water on or near Earths
  surface is contained in the ocean basins.
• Approximately 70.78 of the surface of the Earth
  is covered with water.
• Historically we have divided the ocean into
  artificial compartments called oceans and seas.

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The Water Planet

• There are few great natural divisions to separate
  the on great mass of water on planet Earth.
• The Mediterranean and Baltic seas are only
  temporary features of a single
• World Ocean

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The Water Planet

• The ocean is massive from a human perspective
• It covers 361 million square kilometers of the
  Earths surface
• The average depth of the ocean is about 3, 7896
  (rounded to 4,000) meters
• The average temperature is 3.9-degrees C
  (39-degrees F)

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The Water Planet
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The Water Planet

• The deepest spot in the world ocean is known as
  the Mariana Trench. It is 11,022 meters (36,163
  feet) from the surface
• The Northern Hemisphere is 60.7 sea and 39.3
  land
• The Southern Hemisphere is 80.9 sea and 19.1
  land

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The Water Planet

• The theory which explains the origin of the
  universe is called the big bang theory.
• The big bang probably occurred about 15 billion
  years ago.
• The very early universe was unimaginably hot, but
  as it expanded it cooled.

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The Water Planet

• About a million years after the big bang,
  temperatures fell enough to permit the formation
  of atoms from the energy and particles that had
  predominated up to that time.
• About a billion years after the big bang, this
  matter began to congeal into the first galaxies
  and stars.

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A Spiral Galaxy
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The Water Planet

• Our sun is a typical middle aged star
• The sun and its family of planets, called the
  solar system, are located about three quarters of
  the way out from the center of the galaxy.

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The Water Planet

• Accretion of cold particles created the young
  earth.
• In the midst of the accretion phase, the earths
  surface was heated by the impact of meteors and
  other falling debris.
• This heat, gravitational compression and
  radioactive decay caused the Earth to partially
  melt.

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The Water Planet

• Gravity pulled most of the iron inward to form
  the planets core.
• The sinking iron released huge amounts of
  gravitational energy, which, through friction
  heated the Earth even more.
• A slush of lighter minerals like silicone,
  magnesium, aluminum and oxygen-bonded compounds
  migrated to the surface.

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The Water Planet

• This process of density stratification lasted
  about 100 million years.
• The earth began to cool and its first surface is
  thought to have formed about 4.6 billion years
  ago.
• Erupting volcanoes vented volatile gasses
  (outgassing) which condensed into clouds in the
  cooler upper atmosphere.

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The Water Planet

• After millions of years the upper clouds began
  to cool enough for some of the outgassed water to
  form droplets.
• These heavy rains may have lasted about 10
  million years.
• Some recent studies suggest that the Earths
  entire surface may have been covered with water
  for 200 million years

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The Water Planet

• The primitive atmosphere was much different from
  our atmosphere today.
• The primitive atmosphere was rich in carbon
  dioxide, water vapor, carbon monoxide, nitrogen,
  hydrogen chloride, with traces of ammonia and
  methane.

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The Water Planet

• It was from this primitive atmosphere that life
  arose in the primitive seas.
• The first life forms were simple single celled
  bacteria.
• These organisms lived in an environment devoid of
  free oxygen.
• They are said to be anaerobic.

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The Water Planet

• Later some of these single celled organisms
  incorporated chlorophyll into their cells and
  produced atmospheric oxygen by photosynthesis.
• The oxygen in the atmosphere was poisonous to the
  earlier single celled organisms and many died off.

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The Water Planet

• The new life forms. Living in the presence of
  oxygen, diversified and evolved into the
  multitude of variety of life present on the
  planet today and many that have become extinct.

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The Water Planet

• The End