Physical Oceanography

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Physical Oceanography
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Why is the ocean important?

• The ocean covers most of Earths surface.
• It is an important source of food and mineral
  resources.
• We use it for transportation and recreation.
• The ocean stores heatwater has high specific
  heat, so it takes a lot of energy to heat it up.
  Water holds on to this heat energy and stays
  warmer longer than the air.
• The stored heat in the ocean drives much of
  Earths weather and causes climate near the ocean
  to be milder than climate in the interior of
  continents.
• Ocean currents distribute energy (heat) and
  resources.

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Major Oceans

• The five major oceans are
  1._______-largest,
  deepest, coldest, least salty. 2.__________-
  second largest, shallow, warm, salty.
  3.
  _________- intermediate in depth, temperature,
  and salinity.
• The _______Ocean near the north pole, and the
  ____________ Ocean near the south pole contain
  vast expanses of sea ice.
  

Pacific
Atlantic
Indian
Arctic
Southern
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What gases are dissolved in the ocean?

• Ocean water has many different gases dissolved in
  it, mostly nitrogen, oxygen, and carbon dioxide.
• The movement of wind over the ocean and waves
  agitates (mixes up) the water at the surface,
  speeding up the exchange of gases between the
  ocean and the atmosphere (like shaking a soda
  bottle!).
• Marine (ocean) plants need carbon dioxide
  dissolved in the water to go through
  photosynthesis?photosynthesis releases oxygen
  into the water, which is then used by ocean
  organisms (like fish) to go through respiration.
• As atmospheric levels of gases rise, so do levels
  of those gases dissolved in ocean water.

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Methods of Studying the Ocean
The Topex/Poseidon _____________ orbits 1331 km
above the Earth, gathering information about the
oceans.
satellite
Sonar
_____________ maps ocean floor topography by
timing how long it takes sound waves to bounce
off the ocean floor.
submersibles
Underwater vessels called _________________
investigate the deepest ocean trenches.
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Sonar (also called echo-sounding)

• Sound waves travel how fast in seawater?
• How deep is the water if it takes ten seconds for
  the sound wave to go from ship to ocean floor and
  back to ship?

1,454 m/s
7,270 m
Calculation (10 s times 1,454 m/s divided by 2 )
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submersible

• The picture below is of a _____________.

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Salinity
The amount of salt per unit water is known as
salinity.
NaCl
The most abundant salt in seawater is ________,
but there are many other salts present in the
form of ions.
The average salinity of seawater is _____ ppt.
Therefore, for every 1,000 ml water, there are
___ grams of dissolved salts.
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Near the equator salinity is __________ than
average due to ___________________.
lower
greater precipitation
lower
Near the poles salinity is __________ than
average due to _______________.
melting sea ice
higher
In the Mediterranean the salinity is
__________than average due to __________.
evaporation
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Where does the salt come from?

• The ocean is salty due to dissolved chemicals
  eroded form the earths crust and washed into the
  sea. Solid and gaseous ejections from volcanoes,
  suspended particles swept to the ocean from the
  land by onshore winds, and materials dissolved
  from sediments deposited on the ocean floor.
• Main reason surface water washes over rock
  containing salts such as sodium chloride (common
  table salt)
• Also Volcanoes

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• The salinity here would likely be
• 35 ppt
• 34 ppt
• 36 ppt

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Colorful Seawater

• What makes the ocean water in the picture to the
  left different colors?
• Why would a shrimp that appears bright red at the
  surface appear black at greater depths, and why
  might this be beneficial?

differences in depth
Longer (red) wavelengths are absorbed before
reaching deep water. Shrimp can hide and not
become a meal.
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Label the three ocean temperature layers in the
diagram below.
Surface layer
Thermocline
Deep layer
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How does wind affect the ocean?

• Wind causes waves
• A wave is an up-and-down motion along the surface
  of a body of water.
• Moving air drags across the waters surface and
  gives energy to the water, causing waves.
• Wind blows over the ocean, causing surface
  currents.
• carry warm water away from the equator cold
  water away from the poles
• Earths rotation makes them spin in circles
  (clockwise in N. Hemisphere, counterclockwise in
  S. Hemisphere)
• Ocean current mass of moving water many
  currents in the ocean distribute heat and
  nutrients
• Currents move water, waves move energy.

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What are deep ocean currents?

• Deep currents are caused by differences in
  density (due to temp, salinity, etc)
• Downwelling water moving from the surface DOWN
  to the bottom
• carries oxygen down
• allows animals to live in the deep ocean
• Upwelling water moving UP to the surface
• Occurs when warm surface water is blown offshore
  by wind. This allows the cold water at the bottom
  of the ocean to rise.
• carries nutrients up
• large numbers of animals gather in areas where
  upwelling occurs because of the availability of
  nutrients.

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Upwelling

• Water that rises to the surface as a result of
  upwelling is typically colder and is rich in
  nutrients. These nutrients fertilize surface
  waters, meaning that these surface waters often
  have high biological productivity.  Therefore,
  good fishing grounds typically are found where
  upwelling is common.

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Ocean Floor

• Continental shelf starts at the shore and
  slopes into the ocean
• Continental slope where the slope starts to get
  deeper
• Abyssal plain huge, dark flat region that
  encompasses most of the ocean floor / covered
  with mud and remains of marine life
• Mid-ocean ridge underwater mountain range
  separated by rift valley (where new oceanic crust
  is made, hydrothermal vents discovered here)
• Ocean trench large, V-shaped valley

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Seafloor Topography
C
B
Match the following terms to their correct letter
in the diagram
E
Island Continental shelf Continental
slope Abyssal plain Seamount Continental
rise Trench Guyot
C.
F
B.
E.
D
A.
G
F.
G.
A
H.
A
D.
H
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Chapter Review

1. What is the average salinity of seawater?
2. What is the deepest area of the seafloor?
3. What is the largest ocean?
4. Why is the ocean blue?
5. What is the force responsible for surface
   currents?
6. What causes density currents?
7. Name the ocean that borders North Carolina.

35 ppt
trench
Pacific
shorter wavelengths not absorbed
wind
differences in temperature and salinity
Atlantic
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Ocean Feeding Relationships

• What is a Food Chain?
• A food chain is a way to describe the feeding
  relationships between different organisms.

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What are animals that eat plants called
again?Primary Consumers
What is a feeding relationship?

• A feeding relationship describes who is eating
  what in a particular habitat.

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Carnivores, or animals that eat primary
consumers, are called secondary consumers.
So a food chain shows who eats what in a
particular habitat. For example, a piece of
willow (tree) is eaten by a moose, which is then
eaten by a wolf.
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The arrows between each item in the chain always
point in the direction of energy flow- in other
words, from the food to the feeder.
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A food web is a model that shows all the possible
feeding relationships between organisms living in
an ecosystem.
The arrows between each item in the chain always
point in the direction of energy flow- in other
words, from the food to the feeder.
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What is a keystone species?

• Keystone Species a species that has a
  greater-than-expected effect on an ecosystem if
  it is removed from the environment, the entire
  ecosystem is affected dramatically (sometimes, it
  completely collapses).
• Many keystone species are top predators (killer
  whales, starfish, wolves, bears)
• Example In the food web above, killer whales are
  the keystone species. If they are removed from
  the environment, there will be too many salmon,
  which will provide more food for the seals and
  sea lions whos population will increase, then
  seals and sea lions along with salmon will eat
  all of the herring, which will lead to too many
  zooplankton, which will eat all of the
  phytoplankton, which will lead to not enough food
  for the baleen whale (and less oxygen).

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Classwork

• Create a chart or list of who eats what in the
  food web on the previous slide