1. Nicole Carter, Sarah Kish, Natalie Knapton
Nitrogen Cycle
Nicole Carter, Sarah Kish, Natalie Knapton

2. What is Nitrogen?
Nitrogen (N) is not only a macronutrient, but a limiting nutrient that most organisms need to thrive and sustain life
It is dispersed throughout the atmosphere as N2, but organisms cannot access Nitrogen with it being in this form
Once the N2 is converted into ammonia (NH3), it becomes available to primary producers (plants)

3. Importance
Forms amino acids (building blocks of humans) and nucleic acids (building blocks of DNA and RNA)
Makes up 3% of human’s total body weight
Moves from within the soil, into plants, and back into the atmosphere---NITROGEN CYCLE

4. Nitrogen Fixation
Very few organisms can directly convert N2 gas into ammonia (NH3) using nitrogen fixation
First step in the nitrogen cycle
Nitrogen-fixing organisms have specialized enzymes within that break N2 bonds to add Hydrogen which forms NH3 and finally to NH4+ located in soil

5. Nitrogen Fixing Organisms
Cyanobacteria (algae)
Bacteria that live within plant roots such as:
Few tree Species
Bean plants
Pea Plants

6. What To Do Next With Fixed Nitrogen?
Organisms synthesize their own tissues using the fixed Nitrogen
These ions, depending on location, can end up in water or aquatic locations or in plant’s roots

7. Nitrogen Fixed Through Abiotic Pathways
Nitrogen gas can be fixed with combustion such as lightning, fire building, and the burning of fossil fuels
The gas is con0verted into NO3- (nitrate), which plants can use
Nitrate can be carried to the Earth’s surface in precipitation

8. N2 Conversions in Fertilizers
Synthetic Nitrogen fertilizers lead to increased crop yields and growth
Through this process, vast amounts of energy is used
With this, more Nitrogen is fixed than Nitrogen fixed in nature

9. Step 2: Assimilating Nitrogen
In their tissues
Primary consumers feed on producers which then allows Nitrogen to be assimilated into tissue and waste
Inevitably, death will result and the decomposing releases Nitrogen

10. Ammonification and Nitrification
Step 3 and Step 4
Decomposers use waste and bodies to create ammonium (released through waste)
This then is converted into nitrite, NO2- and finally into nitrate, NO3- (Nitrification)

11. Leaching
Negatively charged nitrate ions do not bind well to the particles in soil because they too are negatively charged which repel each other
-nitrate is transported through the soil with water

12. Denitrification
Nitrogen is converted back into N2 which completes the Nitrogen cycle
Leached nitrates settle in oceans and other aquatic ecosystems in which bacteria converts it into Nitrous oxide )N2O) and N2

13. Excess Nitrogen
Studies have shown that species can die off in areas with too much Nitrogen due to the fact of competition between thriving plants under such conditions
Others have shown that plants experience changes in their composition because of this
“In ecosystems containing species that have adapted to their environments over thousands of years (or longer), changes in conditions are likely to cause changes in biodiversity as well as in the movement of energy through, and the cycling of matter within, those ecosystems”

14. The Nitrogen Cycle in an Ecosystem

15. The Nitrogen Cycle Working Within Soil

16. Basic Diagram of the Nitrogen Cycle