1. Biogeochemical Cycles

2. Cycles
rapid cycling: substances cycle between nutrient rersevoirs (holding areas) quickly
slow cycling: substances accumulate and are unavailable to organisms

3. The Water Cycle

4. Evaporation from the land (water to the atmosphere)
As it cools, water vapor condenses and eventually falls as precipitation

5. Ground water transports the water in the soil
Plants pull water from the ground and lose it to the air through transpiration

6. Carbon and Oxygen Cycles

7. Photosynthesis and Cellular Respiration
C6H12O6 + 6O2
Energy released
6CO2 + 6H2O
Energy from sun
Although the processes are very different, the overall equations are very complimentary to one another. Both contribute to the RAPID cycling of carbon and oxygen

8. Slow cycle
Living organisms play an important role in the slow cycling of carbon
Trees act as carbon reservoirs (carbon sinks) until they die
Deforestation accounts for the return of 2 gigatonnes of carbon into the atmosphere per year

9. in the ocean, phytoplankton and algae reproduce creating biomass
a small % drifts to the ocean floor and is converted to fossil fuel deposits (over millions of years)

10. Boreal forest is recognized as a significant carbon sink due to the accumulation of peat (muskeg)

11. Human Impact on Carbon
Burning fossil fuels release stored carbon into the atmosphere (as carbon oxides)
Wildfires also return carbon from trees into the atmosphere (as carbon oxides)

12. Nitrogen Cycle

13. Nitrogen
makes up 78.1% of the Earth’s atmosphere
N2 is nitrogen gas

14. Nitrogen Fixation
Some bacteria convert atmospheric nitrogen into ammonium
these bacteria live in the lumpy roots of legumes and share their ammonium with the plants
Plants share their glucose with the bacteria…

15. Ammonium
also produced when decomposers break down organic matter (called ammonification)
NH4  NO2-  NO3-
Ammonium to nitrite to nitrate to be used by plants

16. Denitrification
denitrifying bacteria convert nitrite or nitrate back to nitrogen gas
occurs in environment with very little oxygen

17. Human Impact on Nitrogen
Fertilizers contain nitrogen that may run off into water and create harmful algal blooms
Burning fossil fuels contain nitrogen that leads to photochemical smog and acid rain

18. Wildfires convert N2 into usable nitrates, ammonia and ammonium.
Wildfires also warm the soil making it less acidic allowing for greater growth of plants

19. Phosphorous Cycle

20. Phosphorous essential nutrient available in limited quantities
concentrated in living organisms
part of DNA and ATP

21. phosphorus does not cycle through the atmosphere
found in soil and water and gradually released out of rocks

22. animals eat milk, grain, meat to get phosphorus
plants can only use phosphorus if it’s a phosphate (PO4 3-) which dissolves in water

23. phosphorus keeps the growth of producers in balance, but it also limits the growth of crops
how might the increased availability of phosphorus affect the aquatic ecosystem?

24. Algal Bloom overgrowth of algae caused by excess phosphorus
as decomposers break down the organic matter, they use up the oxygen resulting in the death of fish