Lesson 2: Water, Nitrogen and Phosphorous Cycle

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

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

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

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

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

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

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

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

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

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

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

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)