1. Lesson 2: Water, Nitrogen and Phosphorous Cycle

2. Water Cycle
What are the 4 processes that allow water to continually cycle?
Evaporation
Transpiration
Condensation
Precipitation

3. Water Cycle
Why is water conservation important? Even in areas with high amounts of rainfall.
Limited resource
Use varies throughout the year
Not always in usable form for humans
Once we reach low levels it’s hard to replenish

4. Nitrogen Cycle
Nitrogen is important to living organisms because it is needed for:
DNA
Proteins
Chlorophyll in plants
Watch this video

5. Nitrogen Cycle Nitrogen makes up 78% of the Earth’s atmosphere
The nitrogen in the Earth’s atmosphere is not usable for plants and animals
Usable forms:
NH4, NO3, NO2

6. Nitrogen Cycle
Using the diagram on the last page, explain two ways that nitrogen moves from the atmosphere to the biosphere
Nitrogen fixation by bacteria in root nodules, by bacteria in soil, by decomposers
Lightning, acid rain, leaching and runoff

7. Nitrogen Cycle
Using the diagram on the last page, explain two ways nitrogen transfers from biosphere or geosphere to the atmosphere.
Denitrification by bacteria, nitrogen oxides from pollution

8. Nitrogen Cycle How do producers obtain nitrogen?
Absorb usable forms from the soil
How is this different from how consumers obtain nitrogen?
Consumers eat the plants to obtain nitrogen

9. Phosphorus Cycle
Phosphorus is important to living organisms because it is needed for:
DNA
Energy transfer
Growth of body tissues

10. Phosphorus Cycle
Most phosphorus on Earth is trapped inside the Earth’s crust (geosphere).
Phosphorus moves from the geosphere to the biosphere by:
Weathering of rocks
Dissolving of Earth’s crust
Fertilizers
Plant and animal waste

11. Phosphorus Cycle How do producers obtain phosphorus? From the soil
How do consumers obtain phosphorus?
Eat plants

12. What happens when there is too much nitrogen or phosphorus?
Eutrophication
Excessive nutrients in lakes or bodies of water, usually caused by runoffs
Algae blooms
Prevent light
Decrease oxygen
Cause other organisms to die

13. What human activities contribute to excess nitrogen and phosphorus?
Overuse of fertilizers
Combustion of fossil fuels
Clearing of forests and grasslands
Dishwasher detergents (phosphorus only)