1. Cycles in Earth Systems

2. Cycles in Earth Systems
Cycle – a group of processes that happen over and over and eventually lead back to the starting point.
Matter and energy are moved through reservoirs
(temporary storage place).

3. Cycles in Earth Systems
Many elements on Earth cycle between reservoirs.
Nitrogen
Phosphorus
Carbon

4. Carbon Cycle Carbon (C) is the basis of all life.
Carbon moves through all 4 spheres on Earth.
It is found in the atmosphere, rocks and the ocean.

5. Carbon Cycle Short term cycle: Photosynthesis!
Plants convert CO2 (from air) to food (sugar)
Organisms eat plants and release carbon back into the air and ground (wastes)

6. Carbon Cycle Long term cycle – Fossil Fuels
Over millions of years carbon is buried and becomes fossil fuels (coal, oil, natural gas).
Humans burn fossil fuels returning the carbon back into the environment.

7. Carbon Returned to Atmosphere by…
Carbon can be returned to the atmosphere through…
DECOMPOSERS
Bacteria and fungi that break down dead organisms
RESPIRATION
Humans breathe in oxygen and release carbon dioxide (CO2) and water (H2O)
COMBUSTION
Burning of fossil fuels (oil, natural gas, coal)

8. Carbon Cycle

9. Carbon Cycle

10. Nitrogen Cycle
Organisms use Nitrogen (N) to build proteins, which build cells.
Organisms cannot use the atmospheric form of Nitrogen (N2)!
It needs to be altered or “fixed”. This process is called nitrogen fixation.

11. Nitrogen Fixation
Nitrogen is removed from the air by nitrogen-fixing bacteria which live in the soil and roots.
These bacteria chemically change Nitrogen from air into nitrogen compounds.
Ammonia is an example

12. Nitrogen Cycle

13. Nitrogen Cycle