1. Nutrient cycles
The water cycle is unique because it is a cycle of “phase changes” ie “physical changes”. In all stages, the water molecule is basically the same molecule.
Nutrient cycles are chemical cycles, so the chemical structure is changing at every stage.

2. 1) Nitrogen cycle
Many many molecules of living things require the atom Nitrogen (N)
Amino acids
Proteins
DNA

3. Ammonia NH3
Ammonium = NH4
Nitrates= NO2
Nitrates = NO3
*Atmospheric Nitrogen N2
*Fertilizers = NH4(Ammonium) NO3(Nitrates)

4. Nitrogen Cycle O2
Diazotrophs = nitrogen fixers Nitrogen gas to ammonia or proteins
Nitrobacteria = nitrite to nitrate
Nitrosomonus bacteria turn ammonia into nitrite

5. LOTS OF ORGANIC MOLECULES WITH NITROGEN LIKE PROTEINS NH3 NO21- NO31-
Ammonia NH3
Ammonium = NH4
Nitrates= NO2
Nitrates = NO3
*Atmospheric Nitrogen N2
*Fertilizers = NH4(Ammonium) NO3(Nitrates)
NO21-
NO31-

7. Ammonium = NH4
Nitrates= NO2
Nitrates = NO3
Atmospheric Nitrogen N2