The atmosphere
Earth Science II
(Session 1)
Atmosphere
• It is a covering of gases that protects the
Earth from radiation and cosmic objects.
• It makes possible the maintenance of life
because of the role it plays within
biochemical cycles of our planet.
• It is divded into layers, each with special
characteristics
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Air
• Air as we know it, is a mixture of gases
that only constitute a small part of the
atmosphere.
• What are the primary gasses we find in
air?
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Composition of the Air
Percentage
Nitrogen (N2)
78%
Oxygen (O2)
21%
Argon (Ar)
0.9%
Carbon Dioxide (CO2)
0.03%
Other gases
0.07%
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DiSpezio, Michael , et al. (1999)
Element or compound
Composition of air
0.03%
0.90%
21%
O2
N2
78%
Dióxido de Carbono
Otros Gases
Argón
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Oxígeno
Nitrógeno
DiSpezio, Michael , et al. (1999)
0.07%
Cycle of oxygen and
carbon dioxide
DiSpezio, Michael , et al. (1999)
Carbon Dioxide
Oxygen
Carbon Dioxide
The combustible fossil
fuels come from organisms
that died millions of years
ago. When these
combustibles burn, carbon
returns to air as carbon
dioxide.
Carbon dioxide is converted
into oxygen and sugars
through photosynthesis
completed by plants.
Carbon Dioxide
When an animal or plant
dies, the carbon that was
Is in its organism returns
to the Earth as tissue
disintegrates.
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Nitrogen Compounds
After carbon and gas burn
nitrogen is liberated in form
of niotrogen oxides.
Soil bacteria produce nitrogen
Compounds from decaying
Organisms and animal wastes.
Denitrifying bacteria in the soil
Can break down the nitrogen
Compounds to form nitrogen gas.
Nitrógen
Decomposers
During the fixation of
atmospheric nitrogen, the
bacteria that lives in the
nodules of the roots, fixate
the pure nitrogen of the air
in the ground and
transform it into nitrates
and nitrites.
Nitrogen Compounds
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Cycle of nitrogen
Nitrogen Compounds
DiSpezio, Michael , et al. (1999)
After nitrogen is converted into nitrate by the
rays, it accumulates in the atmosphere and
is eliminated from the air by means of rain
and depositied on the ground.
Bibliografía
• DiSpezio, M. et al. (1999). Science
Insights: Exploring Earth and Space. first
ed. USA: Prentice Hall.
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