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