Download Ocean Zones - Earth Science With Mrs. Locke

The
Ocean
and its
Zones
Oceans
• There are 5
• Pacific is the biggest
• We get many resources from them:
–Food
–Minerals
–Fuel (oil)
–Freshwater (through evaporation)
• contain water and salts
The main
salt is
Sodium
Chloride
Salinity is a measurement of the
total amount of dissolve salts in
water.
The ocean is
35 parts per
thousand or
3.5% salt.
•The ocean is
divided into
zones
horizontally (like
layers of a cake)
and vertically.
These are the horizontal zones
Surface  0- 600ft
Transition 600 – 2600ft
Deep  2600ft- sea floor
As you go from the surface
to the transition and into
the deep zone:
Light decreases
Temperature decreases
Pressure increases
Oxygen and nutrients levels
fluctuate but are lowest in
the transition zone
Surface, Sunlit, Photic Zone
• On top (0 to 200m or 0 – 600
ft.)
• Gets sunlight
• Warmest layer but temps.
drop quickly
• Plenty of food and plankton
growth
• Lots of oxygen and gases
• Color and light fades quickly in the
order of the rainbow. By 60 ft. there are only
blacks, browns, grays, and whites. The deeper
you dive the more water is over the top of you.
• Pressure is increasing
• Contains familiar plants and animals.
• Once you get down to about a depth of 100 feet you will feel the
pressure against every square inch of your body. It really becomes
noticeable as you breathe. At a depth of 100 feet, the size and
volume of your lungs has been reduced to 1/3rd their capacity at
sea level. You will also notice that it is much darker at 100 feet and
COLD. The lack of sunlight at that depth also means the ocean is not
getting warmed by sunlight, either. At a depth of about 180 feet
you’ve pretty much reached the
limit of safe diving for a human
breathing compressed air.
Transition, Thermocline, or Twilight Zone
•
•
•
•
•
•
•
200m- 1 km down
Rapid temperature drop to 4OC
less food and plankton b/c less light
Little oxygen
more pressure (over 100 atms at the bottom)
lowest in nutrients
Few things live here
Deep, Midnight, bathypelagic Zone
• 1km to ocean floor
• Deepest
• Darkest (absolutely no light not even, a realm of perpetual
darkness, where even the faintest blue tendrils of sunlight cannot
penetrate)
• tremendous pressure
• near freezing temperatures
• Little food (most falls from the surface zone)
• Most dense water
Life that in the midnight zone is very difficult. It relies indirectly on
the benefits of sunlight; organisms thriving in the sunny upper
layers of the sea die their eventual deaths and rain down upon the
sea floor a steady flow of organic nutrients to feed the masses
living at or near the bottom. The organic “rainfall” includes dead
microscopic organisms, such as phytoplankton and dinoflagellates,
sinking downward, fecal pellets of fish and mammals, and carcasses
of larger organisms sinking down to the sea bed. Those creatures
that do not feed directly on the “leftovers” raining down from
above, usually prey upon those that do. Many of the creatures
thriving in the deep sea have taken on fascinating, gruesome and
horrifying visages and proportions, developing special adaptations
to surviving in this harsh environment
Vertical zones include the open
ocean, the neritic, & intertidal zones
The ocean and its zones are constantly
in motion and are impacted by:
• plate tectonics,
• weather,
• climate,
• river systems, and
• human activities.