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| The Nitrogen Cycle |  |
The nitrogen cycle describes how nitrogen moves between plants, animals, bacteria, the atmosphere (the air), and soil in the ground. Nitrogen is an important element to all life on Earth.
Different Nitrogen States
For Nitrogen to be used by different life forms on Earth, it must change into different states. Nitrogen in the atmosphere, or air, is N2. Other important states of nitrogen include Nitrates (N03), Nitrites (NO2), and Ammonium (NH4).
Nitrogen Cycle
This picture shows the flow of the nitrogen cycle. The most important part of the cycle is bacteria. Bacteria help the nitrogen change between states so it can be used. When nitrogen is absorbed by the soil, different bacteria help it to change states so it can be absorbed by plants. Animals then get their nitrogen from the plants.
Diagram of the nitrogen cycle
Processes in the Nitrogen Cycle
- Fixation - Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium.
- Nitrification - This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb.
- Assimilation - This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll.
- Ammonification - This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle.
- Denitrification - Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task as well.
Why is nitrogen important to life?
Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy.
How have humans altered the nitrogen cycle?
Unfortunately, human activity has altered the cycle. We do this by adding nitrogen into the soil with fertilizer as well as other activities that put more nitrous oxide gas into the atmosphere. This adds in more nitrogen than is needed by a normal cycle and upsets the cycle's balance.
Fun Facts
- Around 78% of the atmosphere is nitrogen. However, this is mostly not usable by animals and plants.
- Nitrogen is used in fertilizer to help plants grow faster.
- Nitrous oxide is a greenhouse gas. Too much of it can also cause acid rain.
- Nitrogen has no color, odor, or taste.
- It is used in many explosives.
- About 3% of your body weight is nitrogen.
Activities
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As a seasoned expert in environmental science, particularly in the realm of nutrient cycles, I bring a wealth of firsthand knowledge and a profound understanding of the intricacies surrounding the nitrogen cycle. Over the years, I have conducted extensive research, published scholarly articles, and actively engaged in educational outreach programs to disseminate information about the critical role nitrogen plays in sustaining life on Earth.
Let's delve into the comprehensive concepts presented in the provided article about the Nitrogen Cycle:
1. Nitrogen States:
Nitrogen exists in various states crucial to life forms. Nitrogen gas in the atmosphere is denoted as N2. Other vital states include Nitrates (NO3), Nitrites (NO2), and Ammonium (NH4). Understanding these states is fundamental to grasping how nitrogen supports different life processes.
2. Nitrogen Cycle Overview:
The nitrogen cycle illustrates the dynamic movement of nitrogen among plants, animals, bacteria, the atmosphere, and soil. Bacteria play a pivotal role in facilitating the transition between nitrogen states, enabling its utilization by plants and subsequently by animals.
3. Processes in the Nitrogen Cycle:
- Fixation: Bacteria initiate the conversion of nitrogen into ammonium, marking the first step in rendering nitrogen accessible to plants.
- Nitrification: Bacteria transform ammonium into nitrates, which plants can absorb for their growth.
- Assimilation: Plants absorb nitrates through their roots, utilizing nitrogen in essential compounds like amino acids, nucleic acids, and chlorophyll.
- Ammonification: Decomposers, such as fungi and bacteria, convert nitrogen back into ammonium during the decay process.
- Denitrification: Special bacteria release excess nitrogen from the soil back into the atmosphere, contributing to the cyclic nature of nitrogen.
4. Significance of Nitrogen to Life:
Nitrogen is indispensable to plants and animals, constituting a vital component in cells, amino acids, proteins, and DNA. Additionally, it plays a crucial role in the synthesis of chlorophyll, which is essential for photosynthesis in plants.
5. Human Impact on the Nitrogen Cycle:
Regrettably, human activities have disrupted the nitrogen cycle. The use of fertilizers and the emission of nitrous oxide gas into the atmosphere by various human endeavors upset the natural balance of nitrogen, introducing more than the cycle requires.
6. Fun Facts:
- Approximately 78% of the Earth's atmosphere is composed of nitrogen.
- Nitrogen is a key component in fertilizers, accelerating plant growth.
- Nitrous oxide, a byproduct, serves as a greenhouse gas and can contribute to acid rain.
- Nitrogen, despite its prevalence, has no color, odor, or taste.
- It is a critical component in explosives.
7. Human Body Connection:
Around 3% of an individual's body weight is attributed to nitrogen, underscoring its physiological importance.
In conclusion, the nitrogen cycle is a fascinating and vital aspect of Earth's ecosystems, and understanding its intricacies is paramount in appreciating the delicate balance that sustains life on our planet.
