1. CARBON CYCLE

Carbon, being the main component of living organisms, is vital to life. It is a fundamental element for all organic polymers such as carbohydrates, proteins and lipids. Carbon dioxide and methane, are examples of carbon compounds that circulate in the atmosphere and influence global climates. Through the processes of photosynthesis and respiration, carbon is also circulated between living organisms and nonliving components of the ecosystem.

Fast Carbon Cycle: Fast carbon cycle is the movement of carbon through biotic components in the environment. Plants and other organisms that are capable of photosynthesis, obtain carbon dioxide from their environment and use it to build biological substances. Plants, animals, and decomposers such as bacteria and fungi, return the carbon dioxide to the atmosphere by respiration.

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  Carbon enters the atmosphere as carbon dioxide through respiration and combustion.

 

 

 

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  Carbon dioxide is absorbed by plants and other photosynthetic organisms to make carbohydrates, in photosynthesis. (Oxygen is released in this process)

 

 

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  Carbon compounds are passed along the food chain when animals feed on plants. Most of this carbon is then released as carbon dioxide during respiration. The plants and animals eventually die.

 

 

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  The decomposers then consume these dead organisms, returning the carbon in their bodies to the atmosphere as carbon dioxide. In certain conditions where decomposition is blocked, the plant and animal material can then be available as fossil fuel in the future for possible combustion.

 

 

Slow Carbon Cycle: The movement of carbon through the abiotic elements in the environment such as rocks, soil, and oceans forms the slow carbon cycle. Moving of carbon through these abiotic elements can take as long as 200 million years.

 

 

 

2. NITROGEN CYCLE

Nitrogen is also an essential component of biological molecules such as amino acids and nucleic acids. Although nitrogen is abundant in the atmosphere, nitrogen in this form cannot be used by most living organisms to synthesise organic compounds.

Hence, nitrogen must first undergo fixation and be converted into ammonia by certain types of bacteria.

• As organisms like nitrogen fixing bacteria use nitrogen to synthesise the biological molecules needed for survival, atmospheric nitrogen has to be first converted to ammonia by nitrogen fixing bacteria in aquatic and soil environments.

• Ammonia is then converted to nitrite and nitrate by the bacteria.

• Plants obtain nitrogen from the soil by absorbing ammonium (NH4-) and nitrate through their roots. Nitrate and ammonium are then used to produce organic compounds.

• Animals then consume plants and thus attain the nitrogen in the organic compounds. The nitrogen in organic form is then passed down the food chain when other animals these animals.

• Decomposers then return ammonia into the soil by decomposing solid waste and dead or decaying matter.

• Nitrifying bacteria convert ammonia to nitrite and nitrate.

• Denitrifying bacteria then convert nitrite and nitrate to nitrogen, releasing nitrogen back into the atmosphere.

 

 

3. OXYGEN CYCLE: 

Oxygen is another vital element in life and is essential to us in many ways. Oxygen can be dissolved in water and support aquatic life. It is also needed for the decomposition of organic waste. Wastes from living organisms are called biodegradable as there are aerobic bacteria that convert these organic waste materials into stable inorganic materials and these aerobic bacteria requires oxygen.

 

• Majority of the oxygen found in the atmosphere is derived from the process of photosynthesis, where plants and other photosynthetic organisms use Carbon dioxide, water and light energy to produce Oxygen and glucose.

• The glucose formed is then used to synthesise organic molecules while Oxygen is released into the atmosphere.

• Oxygen is then removed from the atmosphere through processes of decomposition and respirations in organisms.

 

 

4. PHOSPHORUS CYCLE

Phosphorus is an element that can be found in several compound forms in water, soil and sediments. Phosphorus is an essential nutrient needed for plant growth and animals as well. It has a vital role in cell development and is a key component of molecules that store energy such as Adenosine Triphosphate (ATP), Deoxyribonucleic Acid (DNA) and lipids.

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  Rocks when in contact with rainwater, release phosphate ions and other minerals over time. This inorganic phosphate is then distributed in soils and water.

• Plants then take up inorganic phosphate from the soil, and these plants may then be consumed by animals.

• The phosphate is then incorporated into organic molecules such as DNA, and when plants or animals die and decay, the organic phosphate is returned to the soil.

• Bacteria in the soil then breaks down the organic matter into forms of phosphate that is absorbable by plants. It is also a process called mineralisation.

• Phosphorus in the soil can then end up in waterways and oceans, and can be incorporated into sediments over time.

 

5. OTHERS

Other cycles include the Sulphur cycle, Oxygen cycle, Hydrogen cycle, and many more.

Sulphur cycle: Sulphur is a solid in its natural form and in this form, it is restricted to the sedimentary cycle. It can be transported by physical processes such as wind, erosion by water, and geological events like volcanic eruptions. It can also be transported by the ocean and to atmosphere, land and back to the oceans through its compounds such as sulphur dioxide, sulphuric acid, salts of sulphate or organic sulphur by rainfall and rivers.

Hydrological cycle: Water is the most essential chemical of life for all living organisms. In the atmosphere, water is usually in the gas state, in the form of water vapour but condenses to liquid water and is able to solid when temperatures are 0^oC to form ice.