Nitrogen Cycle of biosphere

 The nitrogen forms many components like nucleic acids, proteins, amino acids etc. It is the inert gas and is the most abundant gas present in the atmosphere. It plays an important role in the fixation of nitrogen .They play a vital role in the formation of protoplasm. It is present in the inorganic form and is changed into the organic form. This conversion is done by the plants. The organic nitrogen act as a food for the animals and the inorganic nitrogen act as a food for the plants and they store in the form of nitrates and ammonium ions. They occur in the soil. They cannot be recreated from the nitrates which are present in the rocks. The rocks occur everywhere and liberate nitrogen by the process of weathering. It is a slow process. The nitrogen is mainly provided by the atmosphere and they make more than 80 percent of the air. The nitrogen can occur in the form of element or molecule. In the process of nitrogen fixation this nitrogen is changed into the other compounds of nitrogen. The nitrogen fixation can be atmospheric, biological or industrial. In the atmospheric nitrogen fixation the oxygen combines with the nitrogen. This combination does occur with the process of photochemical and electrochemical reactions. It gives rise to oxides of nitrogen. They dissolve in the rain water and are settled in the soil. They combine with the other salts and form nitrates. This process adds around 35 mille gram per meter per year of the nitrogen. The biological nitrogen fixation involves the different types of bacteria. They can be free living or symbiotic or blue green algae. They have the ability to utilize the nitrogen from atmosphere and change it to ammonia. The ammonia combines with the organic acids to form the amino acids. This type of nitrogen fixation adds around 400 mille gram per meter per year of the nitrogen. It raises the total amount to 175 million tones making nearly 2/3rd of the total supply. The industrial nitrogen fixation produces the ammonia. In this nitrogen is combined with the hydrogen at high temperature and at constant pressure. The plants absorb the nitrate ions and change it to ammonia and which is used to make the amino acids. This type of ammonia is of direct type. The amino acids form proteins and nucleotides. They give rise to nucleic acid later on. The animals make use of the organic nitrogen with the help of plants. The products like nucleic acids and proteins are used by the animals. When the proteins are metabolized they produce multiple nitrogenous wastes like ammonia, urea along with the uric acid. They are excreted out. The dead bodies of plants along with the animals have a nitrogenous compounds and the ammonifying bacteria act on it. These are also known as the decomposers. They include the Actinomycetes, fungi and bacilli. They use the organic acids and release the ammonia. It helps in the building of body. The ammonia may also come into the atmosphere and the volcanic eruptions are also a good source of ammonia. This ammonia is acted by the nitrifying organisms which change them into the nitrate. In this case the nitrites are formed first and are followed by the nitrate. This helps the plants in the process of absorption. The nitrifying bacteria are the nitrosomonas, nitrococcus, nitrobacter and penicillium. The nitrate is available for the absorption. Some potassium salts are added to the soil which acts as a fertilizer. Some nitrate is also lost by the process of precipitation and leaching. It forms the rocks and they release the nitrogen very slowly. The anaerobic areas and in the water rich areas the bacteria utilize the oxygen of nitrates. The nitrates reduce to form the nitrogen gas which comes into the atmosphere. This step is referred as the denitrification. The common bacteria included in this group are pseudomonas and thiobacillus.