1. Biogeochemical Cycles

2. Oxygen Cycle • Autotrophs: Release O2 into atmosphere via photosynthesis • All life: Absorbs O2 to be used during cellular respiration • Respiration: creates ATP energy for cells O2 O2

3. Carbon Cycle CO2 • Carbon = (organic molecules) carbohydrates, proteins, lipids, nucleic acids • Plants & autotrophs: • Intake: Absorb CO2 from atmosphere • Create glucose & sugar via photosynthesis • Output: Release CO2 during respiration CO2

4. Carbon Cycle • Consumers • Intake: Carbon moves up the food chain as 1 feeds on another • Output: Release CO2 during respiration CO2 CO2

5. Carbon Cycle • Decomposers • Input: Feed on dead organic matter • Output: Release CO2 during respiration • Output: Organic molecules returned to soil during decomposition C C C

6. Carbon Cycle • Human Industry • Output: Release CO2 into atmosphere when fossil fuels (coal, oil, natural gas) are burned CO2

7. Nitrogen Cycle N2 • N = 78% atmosphere (most unusable) • Soil Bacteria • Nitrogen fixation: convert atmospheric nitrogen into ammonia • Nitrification: ammonia converted into nitrates Ammonia Nitrates

8. Nitrogen Cycle • Plants • Absorb nitrates through their roots Nitrates

9. Nitrogen Cycle • Animals • Ingest nitrates through the food chain (plants eaten) Nitrates

10. Nitrogen Cycle • Decomposers • Return ammonia to soil by feeding on dead matter Ammonia Ammonia Ammonia

11. Nitrogen Cycle • Lightning • Energy breaks atmospheric nitrogen into Nitrogen oxide • Nitrogen oxide falls in rain to soil

12. Phosphorus (P) Cycle • No phosphorus in atmosphere • Rocks • Phosphorus released by weathering of rocks P

13. Phosphorus (P) Cycle • Plants • Absorb P into their roots P

14. Phosphorus (P) Cycle • Animals • Ingest P when plants eaten • P continues to move up food chain P

15. Phosphorus (P) Cycle • Decomposers • Breakdown dead matter and release P into soil P

16. Phosphorus (P) Cycle • Human Contribution • Adding excess P from fertilizers…. P washes into lakes, etc… • Excess P causes extreme algae growth