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What Is Carbon?
An element
The basis of life of earth
Found in rocks, oceans, atmosphere
Carbon Cycle
The same carbon atoms are used repeatedly on earth. They cycle between the earth and the atmosphere.
Plants Use Carbon Dioxide
Plants pull carbon dioxide from the atmosphere and use it to make food –— photosynthesis.
The carbon becomes part of the plant (stored food).
Animals Eat Plants
When organisms eat plants, they take in the carbon and some of it becomes part of their own bodies.
Plants and Animal Die
When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere.
Some are not decomposed fully and end up in deposits underground (oil, coal, etc.).
Carbon Slowly Returns to Atmosphere
Carbon in rocks and underground deposits is released very slowly into the atmosphere.
This process takes many years.
Cycle – Repeats Over and Over and Over and Over …
Carbon Cycle Diagram
Carbon in Atmosphere
Plants use carbon to make food
Animals eat plants and
take in carbon
Plants and animals die
Decomposers break down dead things,
releasing carbon to
atmosphere andsoil
Bodies not decomposed —
after many years, become part of oil or coal deposits
Fossil fuels are burned; carbon is
returned to atmosphere
Carbon slowly released from
these substances returns to
atmosphere
Carbon in Oceans
Additional carbon is stored in the ocean.
Many animals pull carbon from water to use in shells, etc.
Animals die and carbon substances are deposited at the bottom of the ocean.
Oceans contain earth’s largest store of carbon.
The Carbon Cycle
Human Impact
Fossil fuels release carbon stores very slowly
Burning anything releases more carbon into atmosphere — especially fossil fuels
Increased carbon dioxide in atmosphere increases global warming
Fewer plants mean less CO2 removed from atmosphere
What We Need to Do
Burn less, especially fossil fuels
Promote plant life, especially trees
Carbon reservoirs
Carbon Cycle
Carbon is released into the atmosphere in several ways
Respiration by plants and animals.
Decay of animal and plant matter.
Combustion of organic material
Production of cement.
The ocean releases CO2 into the atmosphere. Volcanic eruptions and metamorphism
Carbon is taken from the atmosphere in several ways
Photosynthesis. The oceans when the seawater becomes
cooler, more CO2 dissolve and become carbonic acid.
In the upper ocean areas organisms convert reduced carbon to tissues, or carbonates.
Photosynthesis
CO2 + H2O + sunlight CH2O + O2
Respiration
CH2O + O2 CO2 + H2O + energy
Combustion or Oxidization of hydrocarbon
CH4 + 2 O2 CO2 + 2 H2O + energy
Human Impacts on the Carbon Cycle
Burning fossil fuels have serious impact on the carbon cycle.
Fossil Fuel
86% of global primary energy consumption is fossil fuels.
Fossil Fuels
• Petroleum• Natural Gas
• Coal
CO2
Concentration
Pre-Industrial value: 280 ppm (600 billion tons)Current value: 380 ppm (800 billion tons)Critical value: 560 ppm (1200 billion tons)
Organic Carbon
Hydrocarbons: CH4
Carbohydrate: CH2O
Inorganic carbon
Carbon Dioxide: CO2
Calcium Carbonate: CaCO3
Mandale Limestone Quarry
Carbon reservoirs
•The atmosphere.
•The biosphere (include fresh water systems and non-living organic material, such as soil carbon).
•The oceans ( including dissolved inorganic carbon and living and non-living marine biota).
•The lithosphere (sediments, Earth core including fossil fuels).
Carbon
Carbon exists in the nonliving environment as:
Carbon dioxide (CO2) Carbonic acid ( HCO3
−)
Carbonate rocks (limestone and coral = CaCO3)
Deposits of Fossil fuels Dead organic matter