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What role organisms play in :(1) carbon cycle (2) nitrogen cycle

Answer» \tThe Carbon Cycle:Carbon is an important constituent of organic compounds found in all living beings in the form of carbohydrates, fats, proteins and nucleic acids. Carbon is trapped in the surrounding air and water in the form of carbon dioxide. The consumers devour the organic carbon compounds that producers manufacture. Through respiration, both consumers and producers return carbon to the non-living environment in the form of carbon dioxide. Some carbon accumulates in wood for many years and is eventually returned to the atmosphere by fires or through consumption and respiration by fungi, bacteria and other detrivores.\xa0The utilisation of glucose to provide energy to living things involves the process of respiration in which oxygen may or may not be used to convert glucose back into carbon dioxide. This carbon dioxide then goes back into the atmosphere. Another process that adds to the carbon dioxide in the atmosphere is the process of combustion where fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial processes. Carbon is thus cycled repeatedly through different forms by the various physical and biological activities.\xa0\tThe Nitrogen Cycle:The continuous process by which nitrogen is exchanged between organisms and the environment is called nitrogen cycle. Nitrogen is an essential nutrient, needed to make amino acids and other important organic compounds, but most organisms cannot use free nitrogen, which is abundant as a gas in the atmosphere. The decomposers help in decomposing the dead bodies of plants and animals, and hence act as cleansing agents of environment. The decomposers also help in putting back the various elements of which the dead plants and animals were made, back into the soil, air and water for reuse by the producers like crop-plants, e.g. the decomposers like purifying bacteria and fungi decompose the dead plants and animal bodies into ammonia. This ammonia is converted into nitrates by nitrifying bacteria present in soil. These nitrates act as fertilizer in the soil and are again absorbed by the plants for their growth. Thus, the nitrates act as fertilizer in the biosphere so that the process of life may go on and on like an unending chain.


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