Download The Ocean

The Ocean
The Continental Shelf
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1st region of the ocean floor
Can be as short as 19 meters
Made up of the continental crust
Ends at the continental slope
Continental Slope
• Average depth=3720 meters
• Found at border of continental crust and
oceanic crust
• Sometimes slope is more like a steep cliff
Abyssal Plain
• Flat floor of the deep
ocean
• Mid-ocean ridges
– Earth’s tectonic plates
being split apart
– Earth is pushed up
• Deep ocean trenches
– Earth’s crust pushed down
and creates trench
– Some plunge +10,000
meters below surface
• This plain covers ½ of the
surface of Earth
The Ocean Floor
Ocean Currents
• Currents are caused by:
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Gravity
Wind
Heat from the surface
Earth’s rotation
• Effects on Earth’s climate:
– Keep land cooler in summer (water takes time to cool
off
– Keep land warmer in winter (water takes time to cool
down)
Surface Currents
• Currents near the surface of the ocean
produces by global winds
– Warm water currents: Gulf Stream begins in the
tropical region. ..flows NE from Caribbean Sea to
Europe
– Cool water currents: California current that forms
near the poles and flow toward the equator down
the West Coast of the U.S. (keeps water cooler in
California than on the East Coast)
Ocean Currents
Ocean Zones
• Each zone=unique types of plants and
animals.
• Zones are determined by depth of the water
communities
• As the depth increases, there is less light.
Intertidal Zone
• Area of the ocean between
the levels of high tide and low
tide
• Most shallow and brightest
ocean zone
• Environment always changing
– Low tide: organisms have to
hide from hot sun
(crabs buy themselves in mud)
– High tide: have to protect
against rough water
(mussels open up to feed on
plankton)
Near Shore Zone
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Includes most of the ocean over continental shelf
No deeper than 200 meters (relatively shallow)
Receives a great deal of sunlight
LOTS OF LIFE IN THIS ZONE!
Open-Ocean Zone
• Most of the water over the
continental slope and abyssal
plain
• Most animals live near the
surface, because that’s where
the food is.
• 1000 meters below surface
and beyond
– Little food
– Little or no light
– Life:difficult due to pressure of
water (most lungs would crush
– COLD, deep, dark
– Makes up 90% of all oceans
Coral Reefs
• Some of the largest structures on Earth built by living
organisms
• Coral=animals
• Live in shallow, sun-lit, near shore waters
• Very delicate and easily damaged
• Corals use minerals dissolved in ocean water to form hard
outer skeleton
– Living coral attaches to dead coral’s skeleton
Coral Reefs Continued…
• They provide:
– Surfaces under water that sunlight reaches easily
– Shelter for animals: sea urchins, sponges, surgeon
fish, parrot fish
– Living space for algae and some plants (seaweed
and plankton are the main food source)
– Most corals are polyps: mouth at end of body with
stinging tentacles
– Take up less than 1% of ocean floor (25% of
marine species live on , in, or around this area!)
Deep Ocean Vents
• Ecosystem below 1,000 meters
• Gets energy from chemical
reactions NOT sunlight
• Ecosystem uses bacteria from
volcanic vents
– Water spews out at around 662
degrees F. (a mix of sulfer and
iron-based chemicals
– Bacteria uses chemical NOT the
sun for energy
• Other organisms depend on
the energy of bacteria. Some
have no stomach or
mouth…tubeworms!