1. Notes: Biogeochemical Cycles Pg. 8-9
Ecology Packet
Notes: Biogeochemical Cycles
Pg. 8-9

2. Notes: Biogeochemical Cycles
Earth’s organisms need many elements, including carbon, oxygen and nitrogen, to carry out their life’s processes.
Nutrients: all the chemicals that an organism needs to sustain life.

3. Unlike the one-way flow of energy, these elements are passed from one organism to another through biogeochemical cycles.
Bio= life Geo= Earth Chem= chemicals
So literally… connecting chemicals needed for life through the Earth
These elements move between the biotic (living) and abiotic (non-living) parts of the biosphere.

4. Carbon-Oxygen Cycle
Both carbon and oxygen exist in Earth’s atmosphere as carbon dioxide (CO2) and oxygen gas (O2).
Carbon is the key ingredient of living tissue and essential for organic compounds which are the building blocks of life. (Carbohydrates, Lipids, Proteins, Nucleic Acids)

5. Carbon-Oxygen Cycle
Photosynthesis: Plants remove carbon dioxide (CO2) from the atmosphere and store carbon in a carbohydrate such as glucose.
Cellular Respiration: Organisms use glucose (C6H12O6) and oxygen (O2) and release carbon dioxide (CO2) and water (H2O)

6. Carbon-Oxygen Cycle
Decomposition: carbon dioxide (CO2) is released as decomposers (fungi, bacteria) break down dead organisms and organic compounds.
Combustion: burning of fossil fuels (wood, coal, natural gas, oil) which release CO2

7. Carbon-Oxygen Cycle
Volcanic Eruptions: release carbon dioxide (CO2) and carbon monoxide (CO) into the atmosphere.
Deforestation: forest fires and cutting down forests for firewood releases the carbon dioxide (CO2) stored in trees.

8. Nitrogen Cycle
Continuous movement of nitrogen among Earth’s organisms, water, rocks, minerals and the atmosphere.
Nitrogen is needed for amino acids which build proteins.
Amino Acid
Protein

9. Nitrogen Cycle
78% of nitrogen in the atmosphere is nitrogen gas (N2) but organisms cannot use it in this form.
Nitrogen Fixation: process in which certain bacteria break down nitrogen gas (N2) into a form that is usable by plants.

10. Nitrogen Cycle
Denitrification: nitrogen compounds released from dead organisms get converted back into nitrogen gas to re-enter the atmosphere.

11. Water Cycle
Water Cycle: The continuous circulation of water among Earth’s organisms, atmosphere and surface.

12. Water Cycle
Evaporation: the sun changes liquid water at Earth’s surface into water vapor which goes back into the atmosphere.
Transpiration: release of water vapor through the stomata, or openings, in a plant’s leaves.

13. Water Cycle
Condensation: process in which a gas changes to a liquid when it loses thermal energy. (Water vapor in clouds condense to form precipitation)
Precipitation: water that falls from the atmosphere to Earth as rain, snow, sleet or hail.

14. Water Cycle
Water is stored in oceans, lakes, glaciers and plants. It can also travel deep into Earth to be stored as groundwater.