The Nitrogen Cycle

Significance of the Nitrogen Cycle to Organisms  Allows nitrogen to be available in a usable form to organisms that need it  Provides nitrogen absorbed by chlorophyll molecules for further growth of plants and for them to perform photosynthesis in order to manufacture food.  When nitrogen containing plants are consumed by omnivorous animals it is broken down in their body to generate biochemical for life processes.  Allows animals which consume nitrogenous animals to be able to make proteins and nucleic acids ( DNA and RNA). It forms the building blocks of proteins. We need proteins because they make up our skin, hair and allows us to digest food.

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

Basic Chemical and Formula Equation  The formula for Biological Nitrogen Fixation is: –N2 + 6 H+ + 6 e− → 2 NH 3 Firstly ammonia is converted into nitrites by Nitrosomonas and Nitrococcus bacteriaFirstly ammonia is converted into nitrites by Nitrosomonas and Nitrococcus bacteria 2NH 3 +3O 2 Nitrosomonas 2NO 2 ¯ + 2H + + 2H 2 O 2NH 3 +3O 2 Nitrosomonas 2NO 2 ¯ + 2H + + 2H 2 O Nitrococcus Nitrococcus The nitrites are then converted into nitrates by Nitrobacter and Nitrocystis, which are now available for plant absorption.The nitrites are then converted into nitrates by Nitrobacter and Nitrocystis, which are now available for plant absorption. 2NO O 2 Nitrobacter -2NO Energy 2NO O 2 Nitrobacter -2NO Energy Nitrocystis Nitrocystis  The denitrification process: 2NO e- + 12H+  N2 + 6H2O 2NO e- + 12H+  N2 + 6H2O

How is Nitrogen returned to the Atmosphere

 Denitrification : When nitrites are reduced into largely inert gas. This is conducted in anaerobic conditions so these bacteria are active in poorly aerated, waterlogged soils.  Anaerobic ammonium oxidation: nitrite and ammonium are converted directly into dinitrogen gas. This process makes up a major proportion of dinitrogen conversion in the oceans.  When animals and plants die, decomposers feed on their remains and is converted to ammonia. This is then converted to nitrites and then is converted to nitrates. The nitrogen is then returned to atmosphere by denitrifying bacteria.  NO2 enters the atmosphere by combustion processes.

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

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

How Humans Influence the Nitrogen Cycle  Human extensively produce legumes by the use of chemical fertilizers. Use of this doubles the use of nitrogen in biological processes by the emission of gases from vehicles and industrial plants and increases the trace of nitrogen from land to oceans and earth to atmosphere.  The Increase of nitrogen catalyses or breaks down of the ozone layer  Increases ammonia in atmosphere which acts as aerosol thus the air quality decreases and clings on water droplets resulting in acid rain  Sewage facilities: releases large amounts of nitrogen by discharging through drain field into the ground.

Organic Compounds  Species of element nitrogen: amino acid, protein, amino sugars, urea

Biological Fixation  Done by lightning, micro organisms, blue algae.  Symbiosis with micro organisms with higher plants, example: rhizobia with legumes and legumes bacteria.

 The intensification of the nitrogen cycle due to anthropogenic effects, causes ecological problems: regionally increasing concentration of volatile nitrogen compounds(NO x, N 2 O and NH 3 ) in the troposphere and stratosphere. There is a greater exchange of nitrogen compounds between the layers, thus increasing the concentration of the oxygen, consuming nitrogen compounds. Higher levels of nitrates in ground and surface water is generated. Carcinogenic conditions(cancer causing)