What is Nitrogen?
Nitrogen makes up about 78%
of our atmosphere.
Nitrogen in the atmosphere it is mostly in the
N2 which is a compound that plants
form of ______,
and animals cannot use.
The process of converting nitrogen into
compounds that can be used by plants and
animals is called the ______________________.
Nitrogen Cycle
Why we care about nitrogen…
Nitrogen is an essential
component of
DNA, RNA and Proteins
_____________________.
The building blocks of life.
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
Process 1: Nitrogen Fixation
Nitrogen Fixation
___________________
is the process in
which the N2 compound in the atmosphere
breaks and combines with other compounds.
“fixed”
The nitrogen is _________
when it combines
hydrogen
oxygen
with ______________
or _______________.
N
H
H
N
N
N2
H
Ammonia (NH3)
Nitrous Oxide (N2O)
Three ways to “fix” Nitrogen
bacteria
Main process: Special ____________
convert the nitrogen gas (N2) to
ammonia (NH3), which only ________
some
plants can use (peas, beans).
Lightning
_________________
strikes convert
N2 to N2O or NO3.
Chemical
Industrial production. ____________
manipulation turns N2 into NH3
(Fertilizer)
Process 2: Ammonification
Ammonification
_____________________
- After all the living
organic nitrogen
organisms have used the ___________________,
decomposer bacteria convert the nitrogen to
ammonia
_______________.
H
N
H
Bacteria
Organic Nitrogen (proteins)
H
Ammonia
Process 3: Nitrification
Nitrification
_______________
is the process that
converts ammonia (NH3) into nitrites
(NO2) and nitrates (NO3) which most
____
can
plants _______
use.
Both
Note: Ammonia comes from ______
nitrogen fixation and ammonification
How is it done?
Bacteria!
_____________________
H
H
O
N
H
N
O
O
O
N
O
Process 4: Denitrification
_______________:
Denitrification
Process in which nitrogen
convert back
compounds _____________________
into
atmospheric nitrogen (N2 or N2O).
The main process is performed by
bacteria
_____________________
in the soil. It can
also happen by _____________
burning fossil fuels.
N2
NO3
N2O
N2
N2O
(1) Nitrogen Fixation
(4) Denitrification
Nitrogen
Cycle
(2) Ammonification
(3) Nitrification
Ammonia is converted
to nitrites and nitrates.
NO3
NH3
Nitrates in Soil
Organic nitrogen is
converted to ammonia.
Nitrogen in
the air
nitrogen fixing plant
eg pea, clover
animal protein
plant made
protein
root nodules
(containing nitrogen
fixing bacteria)
denitrifying
bacteria
nitrates absorbed
dead plants & animals
urine & feces
decomposition by bacteria & fungi
nitrates
bacteria
(nitrifying bacteria)
ammonia
nitrites
bacteria
Human Impact
Combustion
___________________,
releases toxic nitrogen
compounds into the atmosphere.
Commercial Fertilizers
____________________________
release
nitrous oxide into the atmosphere and introduce
excess nitrogen into the environment.
Remove nitrogen from the soil when we mine it
mineral deposits
for nitrogen rich __________________________.
Discharge of ___________________________
municipal sewage
releases excess nitrogen into the water ecosystems
which disrupts the aquatic balance and kills fish.
Commercial Fertilizers
#1 contributor of new nitrogen in
Are the ______
the nitrogen cycle.
limiting factor
Added because nitrogen is a ________________
for plant growth.
Problems: hard to apply fertilizer and keep it in
one area. Runoff, evaporation, etc.. So farmers
twice as much
apply about ___________________
as they
need.
food chain
Extra nitrogen disrupts the ________________.
CFA
1. What are the four main processes
of the nitrogen cycle?
2. What is it called when bacteria
convert nitrogen into ammonia?
3. What organism is required for
every step of the nitrogen cycle?