1. Biogeochemical Cycles
By Stephen Monahan

2. Water Cycle
1. Draw (or present an image) and describe the steps of the water cycle.
Evaporation: Liquid-> gas (energy of sun)
Transpiration: Gaseous water released from leaves of plants
Condensation: When water particles condense to form rain droplets in clouds
Precipitation: When rain droplets fall to the earth from the clouds

3. Water Cycle (cont.) 2. Define: Evaporation and Transpiration
Evaporation: Liquid-> gas (energy of sun)
Transpiration: Gaseous water released from leaves of plants

4. Carbon Cycle
1. Draw (or present an image) and describe the steps of the carbon cycle.
Photosynthesis: The process of converting sunlight into food
Respiration: The process of converting food into carbon dioxide
Decomposition: The process of flesh decomposing.

5. Carbon Cycle (cont.) 2. Describe how fossil fuels form.
3. List human activities that increase the amount of atmospheric CO2.
Deforestation
4. What type of a gas is CO2?
Green House Gas
5. What problem is associated with elevated CO2 levels?
Global Warming

6. Nitrogen Cycle
1. Draw (or present an image) and describe the steps of the nitrogen cycle.
Nitrogen Fixation: Converting Nitrogen Gas into ammonia
Dentrification: Converting nitrates into nitrogen gas

7. Nitrogen Cycle (cont.)
2. What percent of the atmosphere is made of Nitrogen (N2) gas?
78%
3. Define and describe Nitrogen Fixation and Denitrification.
Nitrogen Fixation: bacteria takes nitrogen gas -> nitrogen compounds
Dentrification: Soil bacteria convert nitrates-> Nitrogen gas
4. Why do all organisms require nitrogen?
Nitrogen is required to make amino acids

8. Phosphorus Cycle
1. Draw (or present an image) and describe the steps of the phosphorus cycle.
Weathering: The process of wearing down rocks and sediments which releases phosphate
Some of the phosphate is washed into the ocean
Some Phosphate stays on land and is absorbed by plants
Plants bind phosphate into organic compounds

9. Phosphorus Cycle (cont.)
2. Why is phosphorus essential to living organisms?
Phosphorus is required to form part of DNA
3. How is the phosphorus cycle different than the other biogeochemical cycles?
Phosphorus doesn’t enter the atmosphere
4. Where is most of the phosphorus store In the biosphere?
Most phosphorus is stored in land, rock, soil and minerals
5. How does phosphorus become incorporated into organic compounds?
Plants bind phosphate for organic use through a food web

10. The End