1. Biogeochemical Cycles

2. Water Cycle Defined: Movement of water through the atmosphere
75% of the earth is water
99% of water undrinkable (salty & frozen)
Water recycles over and over

3. How Does Water Go Up? Water rises into the atmosphere in two ways:
Evaporation: Heat changes water from a liquid to a gas
Transpiration: Water evaporates from the leaves of plants through openings called stomata

4. How Does Water Come Down?
Warm, moist air rises and eventually cools
Condensation: process where water vapor turns into a liquid
Rain, snow, sleet, or hail falls when water drops become heavy (Precipitation)

12. Water on the Ground
Infiltration: Water soaks into the soil and collects as groundwater
Process repeats
Runoff: Water runs down hill into rivers, lakes, streams, oceans…

13. 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

14. Carbon Cycle
CO2
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

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

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

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

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

19. Nitrogen Cycle
Nitrates
Plants
Absorb nitrates through their roots

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

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

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

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

24. Phosphorus (P) Cycle
Plants
Absorb P into their roots P

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

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

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