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

Why we care about nitrogen…Nitrogen is an essential

component of _____________________.The building blocks of life.

DNA, RNA and Proteins

How does atmospheric nitrogen (N2) get changed into a form that can be used by

most living organisms?By traveling through one of the ________

processes in the Nitrogen Cycle!

Nitrogen Cycle

(1) Nitrogen Fixation

(2) Ammonification(3) Nitrification

(4) Denitrification

Four

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 _______________.

NN

H

N HH

N2

Nitrogen Fixation

“fixed”hydrogen oxyge

n

Ammonia (NH3) Nitrous Oxide (N2O)

Three ways to “fix” NitrogenMain 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)

bacteria

some

Lightning

Chemical

Process 2: Ammonification_____________________ - After all the living organisms have used the ___________________, decomposer bacteria convert the nitrogen to _______________.

NH

H

H

Ammonificationorganic nitrogen

ammonia

Bacteria Ammonia

Organic Nitrogen (proteins)

Process 3: Nitrification_______________ 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? _____________________ N

N

NH

H

H

O O

O

O O

Nitrification

mostcan

Both

Bacteria!

Process 4: Denitrification_______________: 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.

N2ONO3

N2

Denitrificationconvert back

bacteriaburning

Nitrogen Cycle

(4) Denitrification

(1) Nitrogen Fixation

(2) Ammonification

Nitrates in Soil Organic nitrogen is converted to ammonia.

N2

NH3NO3

N2O

Ammonia is converted to nitrites and nitrates.

(3) Nitrification

Nitrogen inthe air

animal protein

dead plants & animalsurine & feces

ammonia

nitrites

nitrates

plant madeprotein

decomposition by bacteria & fungi

bacteria

(nitrifying bacteria)

nitrates absorbed

denitrifyingbacteriaroot nodules

(containing nitrogen fixing bacteria)

nitrogen fixing planteg pea, clover

bacteria

Human Impact___________________, 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.

Combustion

Commercial Fertilizers

mineral depositsmunicipal sewage

Commercial Fertilizers

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 ________________.

#1

limiting factor

twice as much

food chain

CFA1. 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?