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No prizes for guessing the smallest of the
world's oceans. It's the Arctic Ocean, which is almost completely
surrounded by Eurasia, North America and Greenland. It
extends south
from the North Pole to the shores of Europe, Asia, and North
America. The total surface area of the Arctic Ocean is 14.1 million
square kilometers.
The waters of the
Arctic Ocean join two other great oceans, namely the Pacific and the
Atlantic. The surface waters of the
Arctic Ocean mix with that of the Pacific through the Bering Strait.
It (the waters of the Arctic) mixes with the Atlantic Ocean across a
system of submarine shallow ridges that cover the distance between
Scotland and Greenland and Greenland and Baffin Island. The
Norwegian, Barents, Kara, Laptev, and Beaufort seas are some of the
major subdivisions of the Arctic Ocean. Some of the rivers that
empty their waters into the Arctic include the Mackenzie River in
North America and the Ob, Yenisey, and Lena rivers in Asia.
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Ice forms
There are
three forms of ice to be found in the Arctic Ocean, which is
practically a full covering of ice. These include - land ice,
river ice, and sea ice. It is in the form of icebergs that
land ice enters the ocean. Icebergs, as you probably know,
are created when pieces of glaciers break off. Icebergs in the
Arctic Ocean are primarily created along the Greenland coast.
Small areas of continental shelves, near the shore, in
the regions of Siberia and North America are where river
ice is formed in the Arctic Ocean. River ice is formed
with the freezing of fresh water and its subsequent transport
into the ocean by rivers. |
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The
most extensive form of ice to be found in the Arctic Ocean is sea
ice. Sea ice is formed when seawater freezes.
Sea ice is seasonal
between about 60° N and 75° N, while it is relatively permanent
above 75° N.
Ice cap
Except in the
region northeast of Iceland and north of Scandinavia, there is a
permanent covering of sea ice in the Arctic Ocean during the winter
months. Known as ice caps, they are composed of pieces of ice that pile
up and are pressed in ridges or hummocks. The ice thus piled and
pressed is also known as packed ice. The depth of the packed ice may
measure around thirty feet or more.
During the summer months, the size of the area covered by the cap
reduces and narrow strips of coastal areas along Siberia, Alaska and
Canada become visible.
Salt free ice
As sea ice forms, salt is expelled
from it as brine. When it is about a year old, the ice is
practically salt-free and may be melted for use as drinking water.
The salt-free ice is known as polar pack. It is smooth and pale blue
in color. Younger ice is jagged and gray. It measures about six
feet in thickness, whereas the salt-free older ice is almost twice
as thick.
Effect of ice pack
Among the several factors that have rendered the Arctic's
physical, chemical, and biological processes significantly different
from the North Atlantic and Pacific oceans is the ice pack. The ice
pack reduces the exchange of energy between the ocean and atmosphere
by a factor of about 100 and reduces the penetration of sunlight
necessary for the photosynthetic processes of marine life.
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