1. The Carbon, Nitrogen and Phosphorus Cycles
Nutrient Cycling
The Carbon, Nitrogen and Phosphorus Cycles

2. Carbon Stores Carbon stores are also known as carbon sinks.
- organic matter become buried
on land and under the oceans.
under great pressure over many years, coal, oil, and gas form.
- Layers of shells also are deposited in sediments on the ocean floor
Carbon stores are also known as carbon sinks.

3. So How does carbon Cycle?
Photosynthesis: is a chemical reaction and atmospheric carbon dioxide gas into chemical energy:
6CO2 + 6H2O + sunlight  C6H12O6 + 6O2
Cellular respiration: plants and animals obtain energy by converting carbohydrates and oxygen into carbon dioxide and water.
C6H12O6 + 6O2  6CO2 + 6H2O + energy
The energy released is used for growth, repair, and other life processes.

4. Decomposition - decomposers break down large quantities of cellulose
- Cellulose is a carbohydrate most other organisms cannot break down.

5. Ocean Mixing CO2 dissolves in cold, northern waters and sinks
Ocean currents flow to the tropics where the water rises and releases CO2.
Eruptions and forest fires – can also release CO2.

6. The Whole Carbon Cycle:

7. Nitrogen - In animals, proteins are vital for muscle function
- in the structure of DNA and proteins
- In animals, proteins are vital for muscle function
- In plants, nitrogen is important for growth

8. - Approximately 78 percent of Earth’s atmosphere is N2 gas.

9. So How does Nitrogen Cycle?
Nitrogen is cycled through 4 processes
Nitrogen fixation
Nitrification
Uptake
Denitrification

10. 1. Nitrogen FiXation
Nitrogen fixation is the conversion of N2 gas into compounds containing nitrates (NO3-)and ammonium (NH4+).
Two ways of fixing nitrogen:
Lightning - N2 reacts with O2 to get NO3-
Nitrogen-fixing bacteria
e.g. Rhizobium converts
N2 to NH4+

11. 2. Nitrification! 3. Uptake 4. Denitrification
Nitrifying bacteria converts Ammonium (NH4+) is to nitrite (NO2–), and then to nitrate (NO3-).
Usable forms of Nitrogen (nitrates/ammonium) are taken up by plant roots and used for plant proteins
Nitrogen is returned to the atmosphere by denitrifying bacteria
- Nitrates (NO3-) to Nitrogen (N2)
3. Uptake
4. Denitrification

12. The Whole Nitrogen Cycle:

13. The Phosphorous Cycle Phosphorus is not stored in the atmosphere.
Phosphorus is essential for life processes in plants and animals.
- a part of the molecule that carries energy in cells
- promotes root growth, stem strength, and seed production.
Phosphorus is not stored in the atmosphere.
- trapped in phosphates (PO43–, HPO42–, H2PO4–) found in rocks and in the sediments on the ocean floor.

14. The Phosphorous Cycle Weathering releases phosphates from rocks.
Weathering does not occur until there is geologic uplift, exposing the rock
Two types:
- chemical weathering, via acid precipitation or lichens
- physical weathering, including wind, water and freezing

15. Nutrient Cycles: Phosphorous Cycle

16. How Changes in Nutrient Cycles Affect Biodiversity
Any significant changes to any of these nutrients (C, N, or P) can greatly affect biodiversity.
Carbon cycle changes can contribute to climate change and global warming.
Increased levels of nitrogen & phosphorus can allow certain plant species to outcompete other species, decreasing resources for every species in the food webs.

17. Food Chain Song