An Ocean World

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Chapter 1

• An Ocean World

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What is Oceanography?

• Oceanography is the study of the oceans, their
  origins, and their effects on the planet and
  society
  
• Oceanography is a relatively new science
• We know more about the far side of the moon than
  we know about the deep ocean floor

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• Oceanography is an inter-disciplinary science
• It incorporates Biology, Geology, Physics and
  Chemistry

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The Oceans of the World

• Even though we talk of 7 oceans, these oceans are
  all connected
  
• There is really only one ocean

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A Water Planet

• 71 of the Earths surface is covered in water
• 97 of this water is found in the oceans

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• There is more ocean in the Southern Hemisphere
• The Northern Hemisphere is 61 ocean
• The Southern Hemisphere is 81 ocean

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• Average Ocean depth 2.36 mi.
• Deepest depth Mariana Trench (6.85 mi.)

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Some more ocean facts

• Average temperature 39F (3.9 C)
• Average salinity 3.4
• Average age 4 billion years
• Most abundant elements
• Oxygen 86
• Hydrogen 11
• Chlorine 1.9
• Sodium 1.1
• The ocean contains 4.6 trillion tons of salts

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The Scientific Method
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• Nothing is ever proved to be absolutely true by
  the scientific method
  
• Theories change as our knowledge of science
  changes

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The Beginning of the Universe

• Our universe began with a big bang about 15
  billion years ago
  
• The universe has been expanding ever since

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• Our address San Diego, California, United
  States, Earth, Solar System, ¾ down the Orion
  arm, Milky Way galaxy

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The Nebular Theory
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• As the particles that currently make up Earth
  collected, they were heated up by meteor impact.
  
• The molten metals began layering themselves
• Dense elements like nickel and iron sank to the
  core and lighter elements remained at the
  surface
  
• This layering is called stratification

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Present
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Sun becomes a black dwarf
Beginning of the Universe
Suns stable phase ends Sun becomes Red Giant
Milky Way galaxy forms
Solar System Forms
Earths crust solidifies 4.5 b.y.a.
Ocean Forms 4 b.y.a.
First life 3.5 b.y.a.
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• Earths early atmosphere was formed from gasses
  being burped from volcanoes
  
• Water vapor Carbon Dioxide
• Carbon Monoxide Nitrogen
• Hydrogen Hydrochloric Acid
• The early Earth would have been shrouded in
  clouds, similar to Venus

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The Formation of the Ocean

• After millions of years, the atmosphere cooled
  enough for rain to fall
  
• These rains are thought to have lasted 10 million
  years
  
• During this time, the ocean formed and the crust
  cooled

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The Beginning of Life

• Life began in the oceans a few hundred million
  years after the formation of the ocean
  
• It is thought that a spark of lightning as well
  as the intense UV radiation allowed the first
  components of life to form
  
• Eventually those components formed primitive
  algae and microorganisms

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• Water is necessary for all life on Earth
• All animals carry a small ocean around in their
  bodies
  
• The salinity of most organisms is very close to
  the salinity of the ocean
  
• Water also moderates Earths climate to allow for
  life

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How Unique is Earth?

• Heavy metals are fairly sparse in the universe.
• Many of the stars in the galaxy are multiple star
  systems
  
• Of the stars with planets, very few have a
  circular orbit
  
• Earth is just the right distance from the sun to
  keep liquid water on its surface year round
  
• Earth is massive enough to contain an atmosphere
• If there is extraterrestrial life out there, it
  probably would be different than any type of life
  we would recognize

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Chapter 2

• The History of Oceanography

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• Oceanography is a relatively new science
• It began with sailors trying to navigate the
  oceans for trade
  
• Oceanography didnt really enter the realm of
  science until the late 1700s

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Early Seafarers

• Polynesians 3000 B.C.
• Phonecians 1200 B.C.
• Greeks and Romans (900 B.C. 400 A.D.)
• Discovered that earth was a sphere 600 BC
• Calculated the circumference of earth to within
  8 - 200 BC
  
• Created latitude and longitude
• Chinese invented compass in 325 B.C.

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Dark Ages

• During the dark ages, most of the discoveries of
  the Greeks and Romans were forgotten
  
• The Vikings were the only real seafarers in
  Europe
  
• By 1000 A.D., the Vikings had a colony in
  Vinland, the area we call Newfoundland
  
• The Chinese were building navies, and invented
  the central rudder and boats with multiple masts

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The Age of Discovery

• The age of discovery and the navigation of the
  ocean began again in the 1400s because the Turks
  conquered Constantinople
  
• Christopher Columbus discovered America
• Magellan attempted to circumnavigate the globe

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Scientific Oceanography

• Chronometer was invented, so the ocean could be
  accurately mapped with longitude and latitude
  
• Expeditions by Cook, Darwin, Maury, and Franklin
  studied the oceans currents, chemistry, biology
  and created accurate maps still used through WWII.

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Latitude

• Latitude was determined by measuring the angle
  from the north star to the horizon
  
• in the S. Hemisphere, the Southern Cross was
  used
  
• Usually a sextant was used to measure this angle
• During the day (or on hazy nights), the angles of
  the sun, moon, or planets could be used

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Longitude

• Longitude couldnt be determined until the
  chronometer was invented in 1760
  
• With a chronometer set for Greenwich time, you
  could compare the time difference between local
  noon (when there are no shadows) and Greenwich
  noon
• For each hour of difference, you are 15º from the
  Prime Meridian

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• These are some of the ways that cartographers
  turn a spherical earth into a flat map
  
• Most of these methods distort either the equator
  or the poles