Nitrogen Cycle – What is? – Explain | Diagram & Drawing

The nitrogen cycle is an important component of the ecosystem. In this essay, we will look into it. We will study What is the nitrogen cycle, Explain the stages of the nitrogen cycle, diagrams and drawings, and other facts. This is a vital topic for your UPSC preparation, so let’s start.

What is the Nitrogen Cycle?

• The Nitrogen Cycle is a biogeochemical process in which Nitrogen is transformed into various forms before traveling from the atmosphere to the soil to the organism and back into the atmosphere.
• Nitrogen fixation, nitrification, denitrification, degradation, and putrefaction are some of the processes involved. There are biological and inorganic types of nitrogen gas. 
• Organic Nitrogen is found in living species and is transferred up the food chain through the eating of other living organisms. Nitrogen inorganic forms are abundant in the atmosphere. 
• Symbiotic bacteria that can convert inert Nitrogen into proper forms, such as nitrites and nitrates – make this Nitrogen available to plants.
• To keep the environment in balance, Nitrogen undergoes different transformations. This process also affects a variety of biomes, with the ocean nitrogen cycle being one of the most complex biogeochemical cycles.
• All proteins, hormones, chlorophylls, vitamins, and DNA include nitrogen atoms.
• Plants and bacteria compete for the minimal Nitrogen available in the soil, making it a limiting factor in both natural and agricultural ecosystems. It also exists in the atmosphere as N2.

Definition of Nitrogen Cycle

“The nitrogen cycle is a biogeochemical process that converts inert nitrogen in the atmosphere into a form that living organisms may use.”

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Explain the Stages In Nitrogen Cycle:

The nitrogen cycle is made up of various processes. Nitrogen fixation, nitrification, denitrification, degradation, and putrefaction are examples of these processes. Also, Nitrogen undergoes a number of techniques and transformations in order to preserve ecosystem balance.

Stage 1: Nitrogen Fixation Process

• The nitrogen cycle begins with this phase.
• In this process, inert Nitrogen from the surrounding atmosphere is transformed into helpful Ammonia (NH3).
• The gas is transferred from the atmosphere onto soils and surface waters mostly by precipitation.
• The symbiotic bacteria complete the entire nitrogen fixation process. Diazotrophs are the bacteria that fix Nitrogen.
• Nitrogen fixation can occur either through air fixation (lightening) or through industrial fixation (producing Ammonia at high temperatures and pressures). This can also be corrected by man-made processes, notably industrial activities that produce Ammonia and nitrogen-rich fertilizers.
• Nitrogen fixation can be classified into atmospheric fixation, industrial nitrogen fixation, and biological nitrogen fixation.

Nitrogen Fixation Types

1. Atmospheric fixation: It is a natural phenomenon in which lightning energy breaks Nitrogen into nitrogen oxides, which plants then utilize.
2. Industrial nitrogen fixation: It is a man-made substitute that uses Ammonia to help in nitrogen fixation. The direct combining of Nitrogen and hydrogen produces Ammonia. Also, It then turns into urea and other fertilizers.
3. Biological nitrogen fixation: We obviously know that plants and animals do not consume Nitrogen directly from the air. Bacteria like Rhizobium and blue-green algae convert the useless form of Nitrogen into more valuable molecules. These microorganisms repair these nitrogen molecules in the soil.

Stage 2: Nitrification

• Ammonia is transformed into nitrate during this procedure. This is done due to the presence of microorganisms in the soil.
• The oxidation of Ammonia produces nitrites, which is accomplished with the help of Nitrification bacteria species known as Nitrosomonas.
• Nitrobacter then converts the nitrites generated into nitrates. Because ammonia gas is hazardous to plants, this conversion is required.
• Therefore, The following is the reaction that occurs during the nitrification process:

2NH4+ + 3O2 → 2NO2– + 4H+ + 2H2O

2NO2– + O2→ 2NO3–

Stage 3: Assimilation

• Plants that are primary producers absorb nitrogen molecules from the soil. This is accomplished through their roots.
• Ammonia, nitrite ions, nitrate ions, and ammonium ions are all forms of Nitrogen. After that, these are used to make animal and plant proteins.
• Chlorophyll, amino acids, and nucleic acids are all made up of Nitrogen.
• As a result, Nitrogen enters the food web when the main consumer eats the plant.
• Nitrogen is only obtained by plants through the absorption process.

Stage 4: Ammonification

• The decaying process includes ammonification.
• The Nitrogen (cycle) in organic matter is released back into the soil when plants or animals die.
• Decomposers in the soil, such as bacteria or fungi, turn organic matter back into ammonium.
• As a result, Ammonia is produced during the decomposition process, which is then required in other biological processes.

Stage 5: Denitrification

• Denitrification is the process through which nitrogen compounds make their way back into the atmosphere.
• Nitrate (NO3-) is transformed into nitrogen gas (N).
• The nitrogen cycle comes to a close here.
• This occurs in the absence of oxygen.
• Denitrifying bacterium species carry out the process of denitrification. These bacteria then break down nitrate to produce oxygen while also releasing free nitrogen gas as a byproduct.
• The steps in the conversion of nitrate to dinitrogen:

N03 → N02 → NO → N20 → N2

Importance of Nitrogen Cycle

• The Nitrogen Cycle aids plants in the production of chlorophyll from nitrogen molecules.
• The bacteria engaged in the ammonification process aid in the decomposition of animal and plant materials. This finally contributes to the cleanup of our environment.
• The nitrogen cycle is beneficial because it aids in the conversion of inert nitrogen gas that cannot be used directly into a useable form for plants via biochemical activities.
• Nitrites and nitrates are released back into the soil during the cycle. This discharge contributes to the enrichment of the soil for agriculture by releasing the nutrients essential for the process.
• Nitrogen is an essential component of the cell. It is found in a variety of essential chemicals and elements.

Human activity has an impact on the nitrogen cycle

• One of the primary causes of eutrophication in water systems is the overuse of fertilizers in agriculture. Amounts of nutrients in agricultural runoff are uncontrolled, and the natural cycle cannot balance them.
• Factory-emitted nitrogen gases and aerosols can be directly hazardous to specific plant species, impacting the physiology and growth of plants in close proximity to substantial sources of nitrogen pollution. 
• Plant species may also change as nitrogen compound accumulation raises its availability in the ecosystem, ultimately modifying species composition, plant variety, and the nitrogen cycle.
• Human activities can produce nitrate accumulation in the natural water environment, which can have negative health consequences. Excessive use of nitrogen fertilizer in agriculture is one of the leading causes of nitrate pollution in groundwater & surface water, which can lead to nitrate poisoning.

Nitrogen Cycle: Explain with Diagram and Drawing

The nitrogen cycle is shown in this diagram and drawing.

Nitrogen Cycle: Key Points

• The nitrogen cycle is a collection of biogeochemical processes that occur on Earth that cause nitrogen to undergo chemical reactions, change its form, and flow through various reservoirs, including living organisms.
• Nitrogen is necessary for all species’ survival and growth since it is a component of DNA, RNA, and protein. However, most species are unable to utilize atmospheric nitrogen, which is the most significant reserve.
• Microorganisms drive the nitrogen cycle’s five processes: fixation, uptake, mineralization, nitrification, and denitrification.
• Humans primarily impact the global nitrogen cycle through the use of nitrogen-based fertilizers.

Conclusion– Nitrogen Cycle

To summarise, despite the fact that N2 makes up the majority of the air we breathe, molecular nitrogen cannot be used directly to sustain life. This module explains the nitrogen cycle, which is one of the primary biogeochemical cycles. The cycle’s five basic processes are described. Also, The module investigates the impact of humans on the nitrogen cycle, including diagrams and drawings, as well as other information. Here is the link to the UPSC official website for the exam information.

FAQ– Nitrogen Cycle