1. Chapter 3: The Biosphere

2. Warm Up 1. On average, what percentage of the energy in an ecosystem is transferred from one trophic level to the next? 2. Where does the rest of the energy go? 3. How does energy flow through an ecosystem?

3. 3.4 Cycles of Matter Matter is recycled within and between ecosystems. Biogeochemical cycles Matter is transformed – never created or destroyed destroyed!

4. Biogeochemical Cycles Matter is passed from one organism to another and to one part of the biosphere to another. Water, Carbon, Nitrogen, and Phosphorous

5. The Water Cycle

6. Nutrient Cycles Nutrients pass through organisms and the environment through biogeochemical cycles! 1. Carbon cycle 2. Nitrogen Cycle 3. Phosphorus cycle

7. The Carbon Cycle Carbon = large component of all organic compounds! Forms carbon dioxide (important in atmosphere and oceans) Oil, natural gas, coal (fossil fuels)

8. The Carbon Cycle

9. The Nitrogen Cycle Nitrogen gas makes up 78% of earth’s atmosphere Organisms need nitrogen to make amino acids and nucleic acids Nitrogen fixation: Bacteria convert nitrogen gas into ammonia Denitrification: Bacteria obtain energy by converting nitrates into nitrogen gas (released to atmosphere)

11. Phosphorus Cycle Phosphorus forms a part of DNA and RNA Not abundant in atmosphere Mostly on land in the form of rock and soil, or as dissolved phosphate in oceans Phosphate released as rocks and sediments wear down

12. The Phosphorus Cycle

13. Nutrient Limitation Nutrients whose supply limits productivity is called the limiting nutrient Growth of crop plants limited by nutrients—so farmers use fertilizers Nitrogen is the limiting nutrient in the ocean, phosphorus is the limiting nutrient in lakes and freshwater streams All nutrient cycles work together! If any nutrient is in short supply, the wheel “sticks”