With the aid of diagrams, briefly describe the following processes of environmental balance:
(i) Nitrogen cycle.
(ii) Carbon cycle
Sure! Here's a brief description of the nitrogen cycle and the carbon cycle, along with diagrams to help visualize the processes.
(i) Nitrogen Cycle:
The nitrogen cycle is a crucial process that converts nitrogen, an essential element, into different forms that can be used by living organisms. Here's a step-by-step breakdown:
1. Nitrogen Fixation:
Nitrogen gas (N2) makes up 78% of the Earth's atmosphere, but it cannot be directly used by most organisms. Nitrogen fixation is the process by which certain bacteria, called nitrogen-fixing bacteria, convert atmospheric nitrogen into ammonia (NH3) or ammonium ions (NH4+) that can be used by plants.
2. Nitrification:
Ammonia produced by nitrogen-fixing bacteria is further converted into nitrite (NO2-) and then into nitrate (NO3-). This process, called nitrification, is carried out by nitrifying bacteria. Nitrate is the form of nitrogen that plants can readily absorb from the soil.
3. Assimilation:
Plants take up nitrate from the soil through their roots and use it to produce amino acids, proteins, and other organic compounds necessary for growth. Animals obtain nitrogen by consuming plants or other animals that have incorporated nitrogen into their tissues.
4. Ammonification:
When plants and animals die or produce waste, nitrogenous compounds like proteins and nucleic acids remain. During ammonification, decomposer bacteria break down these organic compounds, releasing ammonia back into the soil.
5. Denitrification:
Denitrifying bacteria convert nitrate back into atmospheric nitrogen, completing the cycle. This happens primarily in oxygen-depleted environments, such as wetlands or waterlogged soils.
Here's a diagram summarizing the nitrogen cycle:
```
Nitrogen Fixation
↓
Ammonia
↓
Nitrification
↓ ↓
Nitrite Nitrate
↓
Assimilation
↓
Ammonification
↓
Denitrification
↓
Atmospheric Nitrogen
```
(ii) Carbon Cycle:
The carbon cycle describes the movement of carbon atoms between the atmosphere, living organisms, oceans, and the Earth's interior. Here's a simplified version of the carbon cycle:
1. Carbon Dioxide Absorption:
Green plants, algae, and some bacteria undergo photosynthesis, using sunlight, water, and carbon dioxide (CO2) to produce glucose (C6H12O6) and oxygen (O2). This process helps remove carbon dioxide from the atmosphere.
2. Respiration:
All living organisms, including plants, animals, and decomposers, undergo respiration. This process releases carbon dioxide back into the atmosphere as a byproduct.
3. Combustion:
When organic material such as fossil fuels (coal, oil, natural gas) or biomass (wood, crops, garbage) is burned, carbon stored in those substances is released into the atmosphere as carbon dioxide.
4. Decomposition:
Decomposers break down dead plants and animals, returning carbon to the soil as organic matter. Over time, this organic matter may transform into fossil fuels through processes like heat and pressure.
5. Carbon Sequestration:
Some carbon is stored for long periods, such as in forests, oceans, and carbonate rocks. These reservoirs, known as sinks, store carbon for extended periods, reducing the amount of CO2 in the atmosphere.
Here's a diagram summarizing the carbon cycle:
```
Carbon Dioxide
↓
Photosynthesis
↓
Organic Carbon
↓
Respiration
Combustion/Decomposition
↓
Carbon Dioxide
```
Remember, these explanations and diagrams provide a simplified overview of the processes involved. The nitrogen cycle and carbon cycle have more intricate details, interactions, and feedback loops that help maintain environmental balance.