1. Cycling of Materials  The Carbon Cycle – the process by which carbon is cycled between the atmosphere, land, water and organisms.  Carbon is necessary for life. Proteins, fats, and carbohydrates all contain carbon.

2. Carbon Cycle  Short Term – when consumers eat producers, the consumers obtain carbon from the carbohydrates.

3. Carbon Cycle  Long Term – carbon is converted into carbonates, the hard parts of bones and shells. These do not break down easily.  Some carbohydrates are converted into fats, oils, and other molecules that store energy. These deposits are known as fossil fuels.

4. The Carbon Cycle

5. Nitrogen Cycle  Nitrogen is used to build proteins, which build new cells.  Nitrogen makes up about 78% of the gases in the atmosphere.  Nitrogen must be fixed by nitrogen-fixing bacteria in order for living organisms to obtain nitrogen.

6. The Nitrogen Cycle

7. Phosphorus Cycle  Phosphorus is contained in many molecules that make up the cells of living organisms.  The cycling of phosphorus occurs mostly in the environment and does not usually occur in the atmosphere.

8. The Phosphorus Cycle

9. Human Impact  Carbon – burning of fossil fuels. Global warming Acid Rain Nitrogen and Phosphorus – used in fertilizers Runoff causes algal blooms which destroys aquatic ecosystems by depleting oxygen. Nitrogen- Acid Rain