1. NITROGEN CYCLE

2. What does this have to do with me?

3. Nitrogen Cycle
The series of processes by which nitrogen and its compounds are exchanged between the environment and living organisms.

4. Two Purposes Helps to keep the environment clean
Replenishes and balances the supply of nitrogen in the ecosystem

5. Can’t we just breathe it in?
Why Do We Need Nitrogen?
It is a necessary component of all proteins.
It is necessary for the formation of nucleic acids. ←
DNA
Our atmosphere is about 78% nitrogen gas (N2).
Can’t we just breathe it in?

6. We Cannot Break the Bond in N2
Atmospheric nitrogen (N2) is a stable molecule and requires a lot of energy to break apart.
Lightning
Volcanic activity

7. But the majority of the nitrogen used by living things is made available by...
Bacteria

8. } Six Processes The processes of the nitrogen cycle are:
Nitrogen Fixation
Decomposition
Ammonification
Nitrification
Assimilation
Denitrification
Making Nitrogen Useable
← Using Nitrogen
← Getting Rid of Unused Nitrogen

10. Nitrogen Fixation
This is a process where some soil bacteria convert atmospheric nitrogen (N2) to ammonia (NH3).
These bacteria can either live free in the soil, or they can live inside the roots of some legumes.

11. Nitrogen Fixing Bacteria in Roots
Legumes such as peas, beans, alfalfa, clover, and peanuts have many of these bacteria living in root nodules. Both the bacteria, and the plants benefit from this relationship. ←

12. Decomposition
This is the process by which bacteria and fungi break down dead organic matter

13. Decomposed Organic Matter
Ammonification
Bacteria and fungi turn nitrogen products of decomposition into ammonia (NH3).
Ammonia (NH3) ↔ ←
Decomposed Organic Matter
Ammonium (NH4+)

14. Nitrification
Nitrification is the conversion of ammonia (NH3) to nitrite (NO2-), and then to nitrate (NO3-).The bacteria gain the energy that they need, and give off nitrate (NO3-) as a waste product.

15. Assimilation
• Plants absorb ammonia (NH3) and nitrate (NO3-), and use them to build amino acids (building blocks of proteins), and nucleic acids.
• Animals eat plants and assimilate their nitrogen into more organic molecules

16. Denitrification Why do we need this step?
Not all fixed nitrogen is used by plants and animals. Some is converted back into nitrogen gas (N2).
Some bacteria use nitrogen from Nitrate (NO3-) for their cellular respiration instead of oxygen. Release nitrogen gas (N2) as product
Why do we need this step?

17. The Nitrogen Cycle Also Works Under Water
Nitrogen Cycle in an Aquarium
The same processes also take place in aquatic ecosystems with nitrogen that is dissolved in water.

18. Expanded Nitrogen Cycle

19. Haber Bosch Process
Nitrogen fixation commercially for fertilizer production
Uses a combination of Nitrogen Gas (N2) and Hydrogen gas (H2) under high temperatures and pressures in order to produce ammonia (NH3)

20. Scishow

21. To Make Plants Grow Better,
We Add Fertilizers
These can include:
Animal manure
Plant compost
Ammonia
Commercially prepared nitrates
“Chemical fertilizers” can disrupt fragile ecosystems.
“Natural fertilizers” adds nutrients slowly through decomposition and ammonification.