1. What is Nitrogen? Nitrogen makes up about 78% of our atmosphere.
Nitrogen in the atmosphere it is mostly in the form of ______, which is a compound that plants and animals cannot use.
The process of converting nitrogen into compounds that can be used by plants and animals is called the ______________________. N2
Nitrogen Cycle

2. Why we care about nitrogen…
Nitrogen is an essential component of _____________________.The building blocks of life.
DNA, RNA and Proteins

3. How does atmospheric nitrogen (N2) get changed into a form that can be used by most living organisms?
Four
By traveling through one of the ________ processes in the Nitrogen Cycle!
(1) Nitrogen Fixation
(4) Denitrification
Nitrogen Cycle
(3) Nitrification
(2) Ammonification

4. Process 1:
Nitrogen Fixation
___________________ is the process in which the N2 compound in the atmosphere breaks and combines with other compounds. The nitrogen is _________ when it combines with ______________ or _______________.
“fixed”
hydrogen
oxygen N N H N2 N H H
Nitrous Oxide (N2O)
Ammonia (NH3)

5. Three ways to “fix” Nitrogen
bacteria
Main process: Special ____________ convert the nitrogen gas (N2) to ammonia (NH3), which only ________ plants can use (peas, beans).
_________________ strikes convert N2 to N2O or NO3.
Industrial production. ____________ manipulation turns N2 into NH3 (Fertilizer)
some
Lightning
Chemical

6. Process 2:
_____________________ - After all the living organisms have used the ___________________, decomposer bacteria convert the nitrogen to _______________.
Ammonification
organic nitrogen
ammonia H N H H
Ammonia
Bacteria
Organic Nitrogen (proteins)

7. _____________________
Process 3: H
_______________ is the process that converts ammonia (NH3) into nitrites (NO2) and nitrates (NO3) which ____ plants _______ use.
Note: Ammonia comes from ______ nitrogen fixation and ammonification
How is it done?
_____________________
Nitrification N H H
most
can
both O O N O N
Bacteria! O O

8. Process 4:
_______________: Process in which nitrogen compounds _____________________ into atmospheric nitrogen (N2 or N2O).
The main process is performed by _____________________ in the soil. It can also happen by _____________ fossil fuels.
Denitrification
convert back
bacteria
burning N2
NO3
N2O

9. decomposition by bacteria & fungi
Nitrogen in
the air
nitrogen fixing plant
Eg: pea, clover
animal protein
plant made
protein
dead plants & animals
urine & feces
denitrifying
bacteria
root nodules
(containing nitrogen
fixing bacteria)
decomposition by bacteria & fungi
nitrates absorbed
nitrates
ammonia
bacteria
nitrites
bacteria
(nitrifying bacteria)

10. Human Impact Combustion Commercial Fertilizers mineral deposits
___________________, releases toxic nitrogen compounds into the atmosphere.
____________________________ release nitrous oxide into the atmosphere and introduce excess nitrogen into the environment.
Remove nitrogen from the soil when we mine it for nitrogen rich __________________________.
Discharge of ___________________________ releases excess nitrogen into the water ecosystems which disrupts the aquatic balance and kills fish.
Commercial Fertilizers
mineral deposits
municipal sewage

11. Commercial Fertilizers#1
Are the ______ contributor of new nitrogen in the nitrogen cycle.
Added because nitrogen is a ________________ for plant growth.
Problems: hard to apply fertilizer and keep it in one area. Runoff, evaporation, etc.. So farmers apply about ___________________ as they need.
Extra nitrogen disrupts the ________________.
limiting factor
twice as much
food chain

12. Fritz Haber German Jew (1868-1934) Nobel prize 1918 for the
synthesis of ammonia from
nitrogen
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)

13. The irony of Fritz Haber
Gas warfare in WWI

14. Zyklon B

15. Dead zones

16. Ocean Dead Zones Double Every 10 Years
Eutrophication

17. Dead zones