Nitrogen Cycle vs Carbon Cycle
In ecosystem, biochemical cycles are important in order to maintain the natural balance. For many elements in an ecosystem, a cycle can be drawn which summarises the movement of the element through the living components of the eco system. During the cycle, elements are converted to complex molecules and later broken down in decomposition to simpler molecules. All cycles have a larger reservoir pool, which is abiotic usually. Nitrogen cycle, carbon cycle, hydrological cycles are some of the important biochemical cycles in nature. Understanding the cycling of matter and maintaining of effective cycling is important to save the environment from pollution.
The main nitrogen reservoir is atmospheric nitrogen. Atmosphere has about 78% nitrogen gas, but it cannot be used by any organisms. So nitrogen should be converted to forms which can be used by plants. This process is known as nitrogen fixation. Nitrogen fixation is done in several ways. One method is the biological fixation. Symbiotic bacteria like Rhizobium who live in the root nodules of the leguminous plants can fix atmospheric nitrogen. Also, there are some free living bacteria like Azotobacter who can fix nitrogen. Another method of nitrogen fixation is the industrial nitrogen fixation. Through Heber process, nitrogen gas can be converted to ammonia which is used to make fertilizer and explosives. Other than this, naturally nitrogen is converted to nitrate when lightning strikes. Most plants depend on a supply of nitrate from the soil for their nitrogen source. Animals depend on plants directly or indirectly to get their nitrogen supply. When the plant and animals die, their nitrogen containing compounds like proteins are oxidized back into nitrates by saprotrophic bacteria and fungi. This happens through a series of oxidation reactions where protein converts to amino acids amino acids convert to ammonia. This process is known as nitrification, and Nitrosomonas and Nitrobacter bacteria are participating in this. Nitrification can be reversed by denitrification bacteria. They reduce nitrate in soil to nitrogen gas.
The main carbon source for living organisms is carbon dioxide present in the atmosphere or dissolved in the surface waters. Photosynthetic plants, algae, and blue green bacteria can convert carbon dioxide into carbonic compounds like carbohydrates. Carbohydrates become the building blocks for most other organic compounds they need, for their structures and functions. Animals get carbon from the plants directly or indirectly. The carbon dioxide absorbed by the plants for photosynthesis is counter balanced by the respiration of both plants and animals. Therefore, photosynthesis and respiration is the main mechanism to maintain the natural balance of the carbon cycle. Some of the fixed carbon dioxide through photosynthesis is stored in the bodies of living organisms, and when they die, carbon is released to the soil and water bodies. When these dead matters accumulate for a longer time fossil fuel deposits are formed. When, people burn fossil fuel carbon dioxide is released back to the atmosphere.
What is the difference between Nitrogen and Carbon Cycles?
• Nitrogen cycle shows how nitrogen is cycled in the environment whereas carbon cycle shows the cycling of carbon.
• The reservoir for nitrogen cycle is atmospheric nitrogen whereas for carbon it is carbon dioxide gas.
• Nitrogen reservoir is much larger compared to carbon reservoir.
• A disturbance in the carbon cycle can be much more affected to humans and animals rapidly compared to a disturbance in the nitrogen cycle.