The Ocean
Chapters 18 & 19
Importance of the ocean
H.W. pg 517 ques. 1-4
The oceans are important sources of food,
energy and minerals for many living
organisms.
Energy sources like coal and oil can be
found underneath the ocean floor.
1/3 of the worlds table salt is taken from
the oceans salt water.
They also make the transportation of
goods, by ship, possible.
Origin
When the Earth first formed, its surface
was mostly volcanoes and cooled volcanic
rock.
When all of these volcanoes erupted, they
released a lot of water vapor into the
atmosphere.
Over millions of years this water vapor
gathered in the atmosphere and
condensed to form torrential rains which
formed our oceans today.
Composition
The oceans contain dissolved gasses like
oxygen, carbon dioxide, and nitrogen.
Waters salinity is the measure of dissolved
salt in seawater. Today's average is 3.5%
of the oceans water is salt.
The oceans also contains many dissolved
salts along with other elements like
calcium, magnesium, and sodium.
Desalination
Because the demand for freshwater is so high,
scientists are trying to come up with technology
to take the salt out of water.
They are doing so by using a desalination plant.
This is a large peaked roof building that is filled
with saltwater from oceans.
The room is heated so the water evaporates and
condenses on the ceiling, once it condenses, it
then drips down the ceiling as freshwater into
drums.
Ocean currents
An ocean current is a mass movement, or
flow of ocean water. They are like rivers
within oceans.
Surface currents move water horizontally
and are powered by winds. These winds
force the currents to move in a circular
motion.
These currents only move the upper few
hundred meters of ocean water.
Ocean currents
Warm currents are shown with red lines
and cold ones with blue lines.
West coast currents of the U.S. originate
at the poles and move down past Cal.
Surface currents that flow along the East
coast of the U.S. originate near the
equator and are warmer.
Upwelling and Density currents
Upwelling is the vertical circulation of ocean
water. This brings deep, colder water from the
bottom of the ocean, closer to the surface.
This water brings with it many nutrients from the
ocean floor and promotes a healthy ecosystem
for marine organisms.
A density current is when a mass of seawater
becomes more dense than the surrounding
water and sinks beneath less dense seawater.
H.W. pg 523 ques. 1-4
Waves and Tides
A wave is a rhythmic movement that
carries energy through matter or space
caused by the varying speeds of winds.
The crest is the highest point of a wave
and a trough is the waves lowest point.
The distance between to adjacent crests
equals a wavelength.
The height of a wave is the difference
between the crest and the trough.
The amplitude of a wave is half of the
waves height.
Wave movement
Waves makes water appear to move
forward, but unless the wave breaks onto
a shore, all water returns close to its
original spot after the wave passes.
Only the energy in the wave is moving
forward not the water.
When a wave does crash onto a shore
that wave is called a breaker. This is the
collapse of a wave is what propels a surfer
back toward the shore.
Tides
Tides are the rise and fall of sea level.
They are created by giant waves that are
produced by the gravitational pull of the
sun and moon.
Water levels moves out at low tide and
rise again at high tide. Tidal range is the
difference between high and low tide
ocean levels.
Oceans react to the pull b/w the earth and
moon. 2 budges of water are always
forming when the moon rotates the earth
Tides and the moon
Oceans react to the pull b/w the earth and
moon. 2 bulges of water are always
forming when the moon rotates the earth.
One is going to be where the moon is
closest to the earth and the other on the
opposite side.
These bulges cause high tides where the
moon is closest to the earth, and the areas
of the earth that the moon is not over at
that time experience low tides.
Spring and Neap tides
When the sun, moon and earth are all
lined up it causes more gravitational pull
and creates spring tides, which make high
tides higher and low tides lower than
normal.
When the sun, earth, and moon are at
right angles to each other they cause neap
tides, which give lower high tides and
higher low tides than normal.
H.W. pg 538 1-15 on loose leaf.
The Sea Floor
Ocean basins are low area of Earth filled
with water, that have many different
features.
The continental shelf is a feature, which is
the gradually sloping end of a continent
that extends under the ocean.
The continental slope is where the ocean
floor drops steeply and extends from the
outer edge of the continental shelf down to
the ocean floor.
Ridges and Trenches
Mid-ocean ridges are found at the bottom of all
ocean basins, and is an area where new ocean
floor is formed.
New ocean floor is created by plates separating,
and hot magma from the earth’s core forming
new ocean crust through a process called sea
floor spreading.
This new floor forms along new ocean ridges.
A trench is a long narrow steep sided
depression where one crustal plate sinks below
another.
Life in the Ocean
The ocean is home to life forms of all Kingdoms,
that go through many different life processes.
Photosynthesis is the process in which
organisms can make their own food with the use
of a green pigment called chlorophyll.
This process uses carbon dioxide, water,
sunlight to produce food for the organism and
energy in the form of ATP and oxygen which
other organisms like fish and other animals use.
Life in the Ocean
Chemosynthesis involves using sulfur or
nitrogen as an energy source instead of
the sun to produce food.
Bacteria use sulfur compounds and live
near hot sulfur vents that spew extremely
hot water.
These bacteria serve as food for many
organisms like clams, crabs and shrimp.
Ocean Life Forms
Plankton from the Kingdom Protista are very
important to the food chain of the ocean. They
are producers that are one celled and drift with
the ocean currents. Ex: Diatom.
Animals that swim with the current instead of
drifting with it are called nekton.
Plants or animals that live on the seafloor are
called benthos. Snails, sea urchins and crabs.
H.W. pg. 568 1-15 on loose leaf.