The Nitrogen CycleThe Nitrogen Cycle

Significance of the Nitrogen Cycle to OrganismsSignificance of the Nitrogen Cycle to Organisms

Allows nitrogen to be available in a usable form to organisms that need itAllows nitrogen to be available in a usable form to organisms that need it

Provides nitrogen absorbed by chlorophyll molecules for further growth Provides nitrogen absorbed by chlorophyll molecules for further growth of plants and for them to perform photosynthesis in order to manufacture of plants and for them to perform photosynthesis in order to manufacture food.food.

When nitrogen containing plants are consumed by omnivorous animals it When nitrogen containing plants are consumed by omnivorous animals it is broken down in their body to generate biochemical for life processes. is broken down in their body to generate biochemical for life processes.

Allows animals which consume nitrogenous animals to be able to make Allows animals which consume nitrogenous animals to be able to make proteins and nucleic acids (proteins and nucleic acids (DNA and RNA). It forms the building blocks of DNA and RNA). It forms the building blocks of proteins. We need proteins because they make up our skin, hair and allows us to proteins. We need proteins because they make up our skin, hair and allows us to digest food.digest food.

Recycles nitrogen so that it can be used over again by organisms that Recycles nitrogen so that it can be used over again by organisms that need itneed it

Basic Chemical and Formula EquationBasic Chemical and Formula Equation

The formula for Biological Nitrogen Fixation is:The formula for Biological Nitrogen Fixation is:– N2 + 6 H+ + 6 e− → 2 NHN2 + 6 H+ + 6 e− → 2 NH33

• Firstly ammonia is converted into nitrites by Nitrosomonas and Firstly ammonia is converted into nitrites by Nitrosomonas and Nitrococcus bacteria Nitrococcus bacteria

   2NH2NH33+3O+3O22 NitrosomonasNitrosomonas 2NO 2NO22¯̄

+ 2H+ 2H+ + + 2H+ 2H22OO

NitrococcusNitrococcus• The nitrites are then converted into nitrates by Nitrobacter and The nitrites are then converted into nitrates by Nitrobacter and

Nitrocystis, which are now available for plant absorption. Nitrocystis, which are now available for plant absorption.

2NO2NO--22 + O + O22 NitrobacterNitrobacter -2NO -2NO--

33 + Energy + Energy

NitrocystisNitrocystis The denitrification process:The denitrification process: 2NO3- + 10e- + 12H+ 2NO3- + 10e- + 12H+ N2 + 6H2O N2 + 6H2O

How is Nitrogen returned to the AtmosphereHow is Nitrogen returned to the Atmosphere

How is Nitrogen returned to the AtmosphereHow is Nitrogen returned to the Atmosphere

Denitrification : When nitrites are reduced into largely inert gas. This is Denitrification : When nitrites are reduced into largely inert gas. This is conducted in anaerobic conditions so these bacteria are active in conducted in anaerobic conditions so these bacteria are active in poorly aerated , waterlogged soils. poorly aerated , waterlogged soils.

Anaerobic ammonium oxidation:Anaerobic ammonium oxidation: nitrite and ammonium are converted nitrite and ammonium are converted directly into dinitrogen gas. This process makes up a major proportion directly into dinitrogen gas. This process makes up a major proportion of dinitrogen conversion in the oceans.of dinitrogen conversion in the oceans.

When animals and plants die, decomposers feed on their remains and When animals and plants die, decomposers feed on their remains and is converted to ammonia. This is then converted to nitrites and then is is converted to ammonia. This is then converted to nitrites and then is converted to nitrates. The nitrogen is then returned to atmosphere by converted to nitrates. The nitrogen is then returned to atmosphere by denitrifying bacteria.denitrifying bacteria.

NO2 enters the atmosphere by combustion processes. NO2 enters the atmosphere by combustion processes.

Major Components of the Earth’s Global System Major Components of the Earth’s Global System association with the nitrogen cycleassociation with the nitrogen cycle

Biosphere: this consists of all living things. In the nitrogen cycles the Biosphere: this consists of all living things. In the nitrogen cycles the organisms associated with the cycle are plants, animals and organisms associated with the cycle are plants, animals and decomposers. The plants make use of the nitrogen cycle to grow and decomposers. The plants make use of the nitrogen cycle to grow and manufacture food, the animals digest the nitrogen containing plants for manufacture food, the animals digest the nitrogen containing plants for their biological processes and decomposers break these organisms their biological processes and decomposers break these organisms when they die in order to create ammonia. These organisms are the when they die in order to create ammonia. These organisms are the major components of the nitrogen cycle because the make use the major components of the nitrogen cycle because the make use the nitrogen cycle so that does not accumulate in the atmosphere.nitrogen cycle so that does not accumulate in the atmosphere.

Hydrosphere: this consists of all water bodes. It is associated with the Hydrosphere: this consists of all water bodes. It is associated with the nitrogen cycle because it allows the cycle to be conducted so as to be nitrogen cycle because it allows the cycle to be conducted so as to be used by fish. Also it is needed for in order for it provided anaerobic used by fish. Also it is needed for in order for it provided anaerobic conditions for denitrification to take place for nitrogen to return to the conditions for denitrification to take place for nitrogen to return to the atmosphere.atmosphere.

Atmosphere: This consists of all gases. It has 78-80% nitrogen gas. It Atmosphere: This consists of all gases. It has 78-80% nitrogen gas. It is necessary for Nitrogen cycle because it has the nitrogen for this is necessary for Nitrogen cycle because it has the nitrogen for this cycle to be conducted. Without it the nitrogen cycle would not exist at cycle to be conducted. Without it the nitrogen cycle would not exist at all. This is also where the nitrogen gas is returned to by the denitrifying all. This is also where the nitrogen gas is returned to by the denitrifying bacteria.bacteria.

Lithosphere: consists of the soil and rocky crust of the earth. It is Lithosphere: consists of the soil and rocky crust of the earth. It is necessary for the nitrogen cycle for it provides conditions for most necessary for the nitrogen cycle for it provides conditions for most plants to live. Leguminous plants receive nitrogen when it is converted plants to live. Leguminous plants receive nitrogen when it is converted to nitrates by nitrogen fixing bacteria and is absorbed by the plants to nitrates by nitrogen fixing bacteria and is absorbed by the plants when it is dissolved in the soil.when it is dissolved in the soil.

How Humans Influence the Nitrogen CycleHow Humans Influence the Nitrogen Cycle

Human extensively produce legumes by the use of chemical fertilizers. Human extensively produce legumes by the use of chemical fertilizers. Use of this doubles the use of nitrogen in biological processes by the Use of this doubles the use of nitrogen in biological processes by the emission of gases from vehicles and industrial plants and increases emission of gases from vehicles and industrial plants and increases the trace of nitrogen from land to oceans and earth to atmosphere.the trace of nitrogen from land to oceans and earth to atmosphere.

The Increase of nitrogen catalyses or breaks down of the ozone layerThe Increase of nitrogen catalyses or breaks down of the ozone layer

Increases ammonia in atmosphere which acts as aerosol thus the air Increases ammonia in atmosphere which acts as aerosol thus the air quality decreases and clings on water droplets resulting in acid rainquality decreases and clings on water droplets resulting in acid rain

Sewage facilities: releases large amounts of nitrogen by discharging Sewage facilities: releases large amounts of nitrogen by discharging through drain field into the ground.through drain field into the ground.

Organic CompoundsOrganic Compounds

Species of element nitrogen: amino acid, Species of element nitrogen: amino acid, protein, amino sugars, ureaprotein, amino sugars, urea

Biological FixationBiological Fixation

Done by lightning, micro organisms, blue Done by lightning, micro organisms, blue algae.algae.

Symbiosis with micro organisms with higher Symbiosis with micro organisms with higher plants, example: rhizobia with legumes and plants, example: rhizobia with legumes and legumes bacteria.legumes bacteria.

The intensification of the nitrogen cycle due to The intensification of the nitrogen cycle due to anthropogenic effects, causes ecological problems: anthropogenic effects, causes ecological problems: regionally increasing concentration of volatile regionally increasing concentration of volatile nitrogen compounds(NOnitrogen compounds(NOx x , N, N22O and NHO and NH33) in the ) in the

troposphere and stratosphere. There is a greater troposphere and stratosphere. There is a greater exchange of nitrogen compounds between the exchange of nitrogen compounds between the layers, thus increasing the concentration of the layers, thus increasing the concentration of the oxygen, consuming nitrogen compounds. Higher oxygen, consuming nitrogen compounds. Higher levels of nitrates in ground and surface water is levels of nitrates in ground and surface water is generated. Carcinogenic conditions(cancer causing)generated. Carcinogenic conditions(cancer causing)