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OCEANS
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The majority of water that is present on the surface of the earth is
present in the oceans.
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The extensive body of water is present in the form Oceans and seas.
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These bodies are interconnected and are called the World Ocean or Global Ocean.
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There are 5 major oceans in the World.
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Pacific Ocean
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Atlantic Ocean
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Indian Ocean
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Arctic Ocean (North)
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Southern Ocean (South)
(Note: Please look at the World Map. You will remember for a
long period. Remember you need to be successful in the examination.)
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Shall we learn more about each ocean?
PACIFIC
OCEAN:
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| PACIFIC OCEAN |
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This is the largest Ocean in the World.
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This is the deepest ocean in the World.
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The Pacific Ocean occupies major part of the Hydrosphere.
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This covers the 1/3rd are of the earth.
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The Pacific Ocean contains more than 25,000 Islands.
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The Atlantic Ocean extends in both Northern and Southern Hemispheres.
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This is divided by the equator into the North Pacific Ocean and the
South Pacific Ocean.
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Pacific extends between Bering Sea (Arctic) in the North and Southern
Ocean in the South.
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Mariana Trench is present in the Western North pacific Ocean.
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| MARIANA TRENCH |
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The depth of Mariana Trench is 11 Km (10, 911 met).
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Mariana trench is the deepest point in the Pacific Ocean.
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Mariana trench is also the deepest point in the World.
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The Strait of Malacca joins the Pacific Ocean with the Indian Ocean. (Look at the map between
Malaysia and Sumatra Island, Indonesia).
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| STRAIT OF MALACCA |
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What is a Strait?
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Strait
is a narrow strip of water connecting two larger bodies of water.
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| STRAIT |
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The Strait of Magellan joins the Pacific Ocean with Atlantic Ocean. (Look at the South of
South America. Also look at the North of separates Tierra del Fuego
(Southernmost tip of South America).
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The Atlantic and Pacific Oceans are also joined by Drake Passage. (Look at the map South of South America at
Cape Horn (The Southernmost tip of South America) and South Shetland Islands of
Antarctica.
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| DRAKE PASSAGE |
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The Bering Strait connects the Pacific Ocean with the Arctic Ocean.
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| BERING STRAIT |
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The places around the edge of the Pacific Ocean are called Pacific Rim.
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| PACIFIC RIM |
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The lands around the Pacific Rim are full of volcanoes.
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The Pacific Rim is very often attacked by Tsunamis and Earthquakes.
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The movement of Pacific waters is clockwise in the Northern Hemisphere.
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The movement of Pacific waters is anti clock wise in the Southern
Hemisphere.
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The largest Island of Pacific Ocean is New Guinea. (North of Australia).
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The Australia and New Guinea are separated by Torres Strait.
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THE LARGEST ISLAND IN THE WORLD IS GREENLAND.
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NEW GUINEA IS THE SECOND LARGEST ISLAND IN THE WORLD.
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ATLANTIC
OCEAN
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This is the second largest Ocean in the World.
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This covers up 20 to percent of Earth’s surface.
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The Atlantic Ocean has the shape of “S” (English Alphabet).
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The Atlantic Ocean has the longest coastline in the World.
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Mediterranean Sea that separates Europe and Africa is the large marginal Sea of Atlantic Ocean.
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This is connected to Arctic Ocean in the North.
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The Atlantic Ocean is connected to Southern Ocean in the South.
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The Atlantic Ocean is connected to Indian Ocean in the Southeast.
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The Atlantic Ocean is connected to Pacific Ocean in the Southwest.
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The Atlantic Ocean extends in both Northern and Southern Hemispheres.
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The Atlantic Ocean is divided into North Atlantic and South Atlantic by
the equator.
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The Panama Canal connects the Pacific and Atlantic Oceans.
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| PANAMA CANAL |
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The strait of Gibraltar connects the Atlantic Ocean to Mediterranean
Sea. (Please at South of Spain (Europe) and North of Morocco (Africa).
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Largest Oceans (In the sequence)
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Pacific Ocean
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Atlantic Ocean
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Indian Ocean
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Southern Ocean
v Arctic Ocean
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INDIAN OCEAN:
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This is the third largest Ocean after Pacific and Atlantic Oceans.
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The Indian Ocean has two major extensions, Arabian Sea (West of India)
and Indian Ocean (East of India).
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Indian Ocean is also called half an Ocean as it extends mainly in the
Southern hemisphere.
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The Ocean is named after “India”.
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The Indian Ocean is bounded by Indian Subcontinent in the North.
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The Western boundary is East Africa.
ARCTIC OCEAN:
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This is the smallest of all the oceans in the World.
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This is located in the Northern Hemisphere.
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The North Pole of the earth is situated in Arctic Ocean.
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This Ocean has the lowest salinity of all the Oceans. This is because of
heavy fresh water inflow.
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The large part of the Arctic Ocean is frozen most of the year.
SOUTHERN
OCEAN
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This is the fourth largest Ocean in the World.
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This Ocean is located only in the Southern hemisphere.
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The Antarctica continent is surrounded by the Southern Ocean.
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This is also called Antarctic Ocean.
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Pacific Ocean and Arctic Ocean are connected by Bering
Strait.
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Mediterranean Sea and the Red Sea are connected by Suez
Canal.
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Pacific Ocean and the Caribbean Sea are connected by
the Panama Canal.
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Atlantic Ocean and the Mediterranean Sea are connected
by the Strait of Gibraltar.
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Now, let us try to know more about Oceans. These
are the common phenomenon with all the Oceans in the World. We also make an
attempt to know continental shelf, Continental Slope etc.
Oceans occupy the deepest areas on the earth.
Just like the continents the floor of the
ocean is also not uniform.
The base of the Ocean is called Ocean Floor.
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Depending on the
surface configuration the Ocean floor is divided into
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The Continental Shelf
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The Continental Slope
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The Continental Rise
And
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The Deep Sea Plain (The Abyssal Plain)
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THE
CONTINENTAL SHELF
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The Continental Shelf is the extended area of the Continent.
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This is associated with the coastal plain.
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This is the lower lying part of the Continent that is submerged by the
Ocean.
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The Coastal part of the Ocean slope of the bottom is very gentle.
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The Costal part of the Ocean is not very deep.
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The Coral reefs are formed in the Continental shelves.
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The continental shelves occupy seven percent of the total ocean.
THE
CONTINENTAL SLOPE:
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This is the extension into the deeper sea.
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The continental slope is very steep.
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The boundary between the Continental Shelf and the Continental slope is
called the Andesite line. (Andesite Rock is an volcanic rock that is present
only in seas and not present on the continents).
THE
CONTINENTAL RISE:
- This is present between the Continental slope and deep Sea Plain.
- The area at the foot of the Continental slope is slightly rising because of the accumulation of the debris.
- This is like an underwater hill.
- This is composed of accumulated sediments.
- This area is rich in minerals.
THE DEEP SEA
PLAIN
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This is the largest portion of the Ocean.
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This is the deepest part of the earth.
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This is like plains (without many ups and downs) on the continents.
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A large number of volcanic mountains are also present here.
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Ridges and trenches in the Oceans are present in the Deep Sea Plain.
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Ridges are the raised areas.
Trenches are the
deeper parts.
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The trenches are excavations or depressions on the deep sea plain.
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They are narrow and very deep.
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The depth may be more. (Mariana Trench is about 11 km deep)
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Mariana Trench
This is present
in the Pacific Ocean.
This is located
near Japan.
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The ridges that reach the surface of the Ocean would form islands.
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The mountains that do not reach the surface and remain under water are
called Sea Mounts.
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Salinity in the ocean is because of the presence of an element called
Chlorine.
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One kg of sea water contains 34.5 gm of salt.
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Salinity in the Ocean is more where there is less addition of the fresh
water through rain.
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Salinity in the Ocean is less where there is more addition of fresh
water through rain.
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Dead sea has the highest salinity.
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| DEAD SEA |
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Dead Sea is also called salt sea.
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This is the hyper saline lake in the World.
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Dead is located in the Jordan rift valley.
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This is the lowest elevation on the earth’s surface.
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More addition of fresh water – Less Salinity
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Less addition of fresh water – More Salinity.
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