Transcript The Carbon Cycle

Topic Two
Biogeochemical Cycles
2-3 Carbon-Oxygen Cycle
The Carbon Cycle
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Circulation of CO2
Biotic Component
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Carbon is the key element in living compounds
Carbon is trapped and stored in organic compounds by
photosynthesis
CO2 is released to the atmosphere by respiration
Abiotic Component
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CO2 – found in atmosphere (0.03%) and in oceans
Can be trapped in fossil fuels
In oceans, it is incorporated into rocks, shells, corals
CO2 released into the atmosphere by combustion
Oxygen Cycle
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Movement of oxygen between the
atmosphere and the biota
21% of atmosphere
Released by photosynthesis\
Consumed by respiration
Carbon Oxygen Cycle
Carbon Oxygen Cycle
1 Atmospheric pool of carbon dioxide
2
Plants take up carbon dioxide for
photosynthesis
3 Animals eat plants
4
Carbon didxide released by respiration
5
Fossil fuels
6
Carbon dioxide released by combustion
7
Death of organisms and decay by bacteria
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Human impact:
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burn excess fossil fuels
Use up forests
Result is more CO2 added to atmosphere
Leads to the greenhouse effect
Greenhouse effect:
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Heat blocking action of gasses in the
atmosphere
Short waves converted to long – unable to
escape atmosphere
Greenhouse Gasses
Name of Gas
Chemical
Formula
Source
Carbon Dioxide
CO2
Fossil fuels
Methane
CH4
Bacteria decay,
farts
Nitrous Oxide
N2O
Fertilizers,
animal wastes
CFC’s
Styrofoam,
accelerants
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Humans continue adding excess amounts of
CO2
Since 19th century, levels have increased 25%
Possible increase in global temperature
Human Population
Human Population and
Technology
Carbon Dioxide Levels
Emission Levels
Past and Present C02 Levels
Greenhouse Gases
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Effects:
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Melting ice caps
Sea levels to increase – flooding
Change in climate patterns
More/less rainfall
Large impact on agriculture
Natural vegetation could change
Some say that oceans are a large sink for CO2
Image of a Dust Bowl
Ozone Layer
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Protects earth from UV radiation
~ 99% of UV radiation is screened and never
reaches surface
Ozone holes:
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Above the poles (N & S)
Increase in skin cancer and eye problems
Major cause?
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CFC’s
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CFC’s released in sprays and as a waste
product
When in upper atmosphere, Chlorine reacts
with ozone and breaks it down
CFC’s stay in atmosphere for a very long
time
May continue to break down ozone layer
Solution?