2. Plants & The Carbon Cycle
Plants take in carbon dioxide and convert it to sugar which can be stored until used for energy.
This process is called photosynthesis.

3. Photosynthesis:
CO2 + H2O + sunlight yields O2 + C6H12O6

4. Animals & The Carbon Cycle
Animals eat carbon contained in animal and plant tissues and release carbon dioxide as a waste product.
This process is respiration.

5. Respiration:
C6H12O6 + O2 yields CO2 + H2O + energy

6. Atmospheric CO2 Concentration-1
Accurate measurements of the concentration of CO2 in the atmosphere began in 1957 at the South Pole and in 1958 at Mauna Loa, Hawaii.
4/12

7. What level is safe? Current CO2 levels- 395 ppm
The upper safety limit for atmospheric CO2 is 350 parts per million (ppm). Atmospheric CO2 levels have stayed higher than 350 ppm since early 1988.

8. Decay & The Carbon Cycle:
Decomposers can release the carbon from dead plant and animal tissues back into the atmosphere.
The majority is put in the atmosphere by burning.

9. Fossil Fuels & The Carbon Cycle:
Over millions of years fossil fuels may form from the buried remains of plants and animals.

10. Fossil Fuels & The Carbon Cycle:
This carbon reenters the atmosphere during combustion.

11. The Oceans & The Carbon Cycle:
Dissolved carbon dioxide in sea water becomes deposited as calcium carbonate shells.

12. The Oceans & The Carbon Cycle:
Over millions of years, these shells form sedimentary rock.

14. Sedimentary Rock is the biggest reservoir of carbon on the planet.
The Rock Cycle ultimately releases carbon stored in sedimentary rock.

17. water
carbon
nitrogen
Question
What are the three cycles (rings) that we have discussed in class? We will discuss the nitrogen cycle tomorrow.