THE CARBON CYCLE
What Is Carbon?An element
The basis of life of earth
Found in rocks, oceans, atmosphere, and all living organisms.
Carbon CycleThe same carbon atoms are used repeatedly on
earth. They cycle between the earth and the atmosphere.
Plants Use Carbon DioxidePlants pull carbon dioxide (CO2) from the
atmosphere.Using sunlight with the CO2 they make glucose.This process is photosynthesis.The carbon can be used by the plant (food) and
used to build the plant (cellulose).Also gives off CO2 from cellular respiration.
Animals Eat PlantsWhen organisms eat plants, they take in the
carbon and some of it becomes part of their own bodies.
They generate CO2 from cellular respiration(break down of glucose) and exhale this CO2 into the atmosphere.
Animals Eat AnimalsWhen organisms eat animals, they take in the
carbon and some of it becomes part of their own bodies.
They generate CO2 from cellular respiration (break down of glucose) and exhale this CO2 into the atmosphere.
Plants and Animal DieWhen plants and animals die, most of their
bodies are decomposed and carbon atoms are returned to the atmosphere.(CO2)
Some are not decomposed fully and end up as deposits underground (oil, coal, etc.= fossil fuels=Carbon)
Carbon Slowly Returns to Atmosphere
Carbon in rocks and underground deposits is released very slowly into the atmosphere.
This process takes many years.
Carbon in OceansAdditional carbon is stored in the ocean.CO2 passes into the water from the atmosphere.Plants & phytoplankton use for photosynthesis.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.
Burning wood and Fossil Fuels
Releases carbon compounds in air, water, and soil
* one gallon of gas burned in a car=19lbs of CO2 (Who Killed the Electric Car, 2004)
Cycle – Repeats Over and Over and Over
and Over …
Human ImpactFossil fuels release carbon stores very slowlyBurning anything releases more carbon into
atmosphere — especially fossil fuelsIncreased 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