1. BIOGEOCHEMICAL CYCLES
Ecology UNIT

2. What is a Biogeochemical cycle?
ORGANISMS
matter matter
ENVIRONMENT

4. FOUR MAJOR CYCLES
CARBON
NITROGEN
PHOSPHORUS
WATER

5. Importance to Organisms
Carbon
Nitrogen
Organic compounds
Proteins & nucleic acids

6. Phosphorus
Water
A T P ,
Nucleic acids
Water !!

7. The Carbon Cycle In nature: CO2 gas in atmosphere
CO32- dissolved in oceans
HCO3- dissolved in oceans
limestone rocks
fossil fuels (coal, oil, CH4)
cellulose

8. In organisms:
plants/algae/cyanobacteria:
Photosynthesis (C-fixing)
animals:
consumption of plants and/or primary consumers

9. Return to Environment:
cellular respiration
combustion of fossil fuels
decomposition of organic
material

11. The Nitrogen Cycle
In nature:
N2 gas in atmosphere
NH4+ in soil
NH3 and N-containing waste
nitrite (NO2-), nitrate (NO3-)

12. In organisms:
plants:
absorption of NH4+ or nitrate in soil
animals:
consumption of plants and/or primary consumers

13. How do plants absorb Nitrogen?
Nitrogen Fixation
Nitrification
Assimilation

14. Nitrogen Fixation Bacteria in soil and plant nodules N2 gas
nitrogenase
or lightning
or UV radiation
N + H

16. Nitrification
Ammonium
Ammonia
Nitrite
soil bacteria
Nitrate

17. Assimilation
Plant roots absorb nitrate or ammonia formed by previous processes.
Nitrogen is incorporated into plant proteins / nucleic acids.

18. Return to Environment:
Bacterial action:
NO3- N2 to atmosphere
Organic cmpds NH4+
(decomposition / ammonification)

19. Animal Action:
Excretion of NH4+ / NH3 in urea or uric acid.

21. The Phosphorus Cycle In nature: no gaseous state :. Non atmospheric
stored in rocks:
Erosion P in soil
P in water

22. In organisms:
plants:
root absorption from soil
animals:
consumption of plants and/or primary consumers

23. Return to the Environment:
Decomposers
Excretion of P by animals

24. The Phosphorus Cycle

25. The Water Cycle
In nature:
oceans
air (vapor)
groundwater
glaciers

26. In organisms:
plants:
absorption from soil
animals:
drinking
eating plants / other animals

27. Return to Environment:
Transpiration in plants
Animal / Plant Decomposition

30. What distinguishes the Water Cycle from the others??