With the aid of diagrams, briefly describe the following processes of environmental balance:
(i) Nitrogen cycle.
The nitrogen cycle is a vital process in maintaining environmental balance. It involves the conversion and movement of nitrogen in various forms through different components of the ecosystem. Let's briefly describe the nitrogen cycle with the aid of diagrams.
1. Nitrogen Fixation:
The first step is nitrogen fixation, where atmospheric nitrogen (N2) is converted into a usable form called ammonia (NH3) or nitrate (NO3-) by nitrogen-fixing bacteria. These bacteria live in the soil or form symbiotic relationships with certain plants, such as legumes. The diagram would show arrows indicating the conversion of atmospheric nitrogen (N2) to ammonia (NH3) or nitrate (NO3-) with the help of nitrogen-fixing bacteria.
2. Nitrification:
Ammonia (NH3) produced during nitrogen fixation is then converted into nitrite (NO2-) and then into nitrate (NO3-) through the process of nitrification. This is accomplished by nitrifying bacteria in the soil. The diagram would illustrate the conversion of ammonia (NH3) to nitrite (NO2-) and then to nitrate (NO3-) with arrows depicting the involvement of nitrifying bacteria.
3. Assimilation:
Nitrate (NO3-) is taken up by plants through their root systems and assimilated into organic nitrogen compounds, such as amino acids and proteins. This process allows plants to convert inorganic nitrogen into organic forms, making it available for consumption by animals and other organisms. The diagram would include the transfer of nitrate (NO3-) from the soil to plants, with arrows representing the assimilation process.
4. Ammonification:
When plants and animals die or produce waste, organic nitrogen compounds are broken down by decomposers, such as bacteria and fungi, through the process of ammonification. This converts organic nitrogen compounds back into ammonia (NH3). The diagram would show the breakdown of organic nitrogen compounds into ammonia (NH3) with the involvement of decomposers.
5. Denitrification:
Finally, denitrifying bacteria convert nitrate (NO3-) back into atmospheric nitrogen (N2) through denitrification. This occurs in anaerobic conditions, such as waterlogged soils. The diagram would display the conversion of nitrate (NO3-) into atmospheric nitrogen (N2) with arrows representing the role of denitrifying bacteria.
By understanding and visualizing these processes, we can appreciate the importance of the nitrogen cycle in maintaining environmental balance and ensuring the availability of nitrogen for living organisms.