which of the following types of organisms are required to complete the nitrogen cycle, including the process of denitrification?
which of the following types of organisms are required to complete the nitrogen cycle, including the process of denitrification?
Answer: To complete the nitrogen cycle, including the process of denitrification, various types of microorganisms are required. Denitrification is the biological conversion of nitrates (NO3-) and nitrites (NO2-) into atmospheric nitrogen (N2) or, in some cases, nitrous oxide (N2O). The microorganisms responsible for denitrification are primarily bacteria. Here’s how these microorganisms contribute to the nitrogen cycle:
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Ammonification: The nitrogen cycle begins with the decomposition of organic matter, such as dead plants and animal remains. Decomposer bacteria, such as certain species of Bacillus and Clostridium, break down the organic nitrogen found in these materials and convert it into ammonia (NH3) and ammonium ions (NH4+).
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Nitrification: Ammonia (NH3) and ammonium ions (NH4+) produced during ammonification are converted into nitrites (NO2-) and nitrates (NO3-) through a two-step process called nitrification. Two groups of bacteria are involved: ammonia-oxidizing bacteria (AOB), which convert ammonia to nitrites, and nitrite-oxidizing bacteria (NOB), which further convert nitrites to nitrates.
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Assimilation and Plant Uptake: Plants take up nitrates (NO3-) and ammonium ions (NH4+) from the soil, incorporating them into their biomass. This process is called assimilation.
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Denitrification: Denitrification is the final step of the nitrogen cycle, where specialized bacteria known as denitrifying bacteria convert nitrates (NO3-) and nitrites (NO2-) back into atmospheric nitrogen (N2) gas. These bacteria are often found in anaerobic (low-oxygen) environments, such as waterlogged soils or sediments. Common denitrifying bacteria include Pseudomonas and Paracoccus species.
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Nitrogen Gas: The end result of denitrification is the release of atmospheric nitrogen (N2) gas, which returns to the atmosphere, completing the nitrogen cycle.
So, to complete the nitrogen cycle, including denitrification, various types of bacteria play crucial roles in converting different forms of nitrogen compounds. These microorganisms ensure that nitrogen is recycled in ecosystems, making it available for plants and other organisms while maintaining a balance in the nitrogen cycle.