Nitrogen Cycle

 

THE CARBON CYCLE

In this planet called earth, there are a lot of chemical elements found in living things, non-living things and the atmosphere. These includes, sodium, carbon, and nitrogen among others. One of the most common elements is carbon.

Carbon is the sixth element on the periodic table. It has three isotopes i.e. Carbon – 12, carbon 13 and Carbon – 14. It can be found in food (carbohydrates, fats and proteins), the soil, water, in plants and animals. It can also be found in the atmosphere in the form of carbon dioxide. Other carbon based compounds includes Methane (CH₄), Bicarbonates of sodium (NaHCO₃) and others.

Carbon cycle refers to the process through which carbon passes through living and non-living things and the atmosphere.

This process occurs through four basic processes and in all carbon dioxide (CO₂) plays a pivotal role in each of them. Before we look at these processes, let’s look at the role carbon play in our system and environment.

Ø  Plants and other living organisms called autotrophs prepare their food using carbon dioxide, water and energy from the sun. This enables these organisms to get food.

Ø  Animals and other living organisms that cannot prepare their own food (heterotrophs) depends on autotrophic organisms for food. Carbon forms the basis of all foods for living things.

Ø  Carbon is found in the water we drink in the form of bicarbonates

Ø  When living things die and decay, these carbon compounds are released into the soil and they form carbon based compounds such as fossil fuels, diamond and others.

Ø  We use these fossil fuels to power our machines such as generators and vehicles and release smoke which contain carbon dioxide or carbon monoxide.

Ø  Carbon dioxide can be used as a refrigerant i.e to fill fridges and air conditions for cooling systems.

Ø  Carbon dioxide can be also used as fire extinguishers.

Ø  Carbon in the atmosphere act as a greenhouse gas to warm the surface of the earth to give earth it’s optimum temperature to help organisms survive.

Now let us look at the four basic processes involved in the carbon cycle. These are Photosynthesis, respiration, combustion and decomposition.

PHOTOSYNTHESIS

Photosynthesis refers to the process where green plants prepare their own food from simple raw materials such as carbon dioxide and water with energy from the sunlight. Photosynthesis is a very crucial in the carbon cycle as it removes carbon from the atmosphere in the form of carbon dioxide.

Too much carbon dioxide in the atmosphere can cause too much heat on earth and this can cause the melting of ice at the poles of the earth and cause rise in the ocean levels which can cause flooding. It can also cause drought at areas away from the oceans because of high temperatures and cause loss of lives.

Chemically photosynthesis can be represented as 6CO₂ + 6H₂O                  C₆H₁₂O₆ + 6O₂.

RESPIRATION

Respiration is the process through which food is broken down to release energy with or without oxygen.

Respiration that uses oxygen is known as aerobic respiration whilst anaerobic respiration does not involve oxygen. Both processes release carbon dioxide into the atmosphere after energy is produced.

This means that when plants and animals need energy, they break down the glucose in their cells to produce carbon dioxide and water (during aerobic respiration) or lactic acid (in animals) or alcohol (in plants) and carbon dioxide so that they can get energy for their life processes.

DECOMPOSITION

This refers to the breakdown of dead organic matter into smaller compounds. This process makes the carbon from these carbon life forms available in the soils and water bodies. The deposited carbon compounds accumulate to form other chemicals and substances such as fossil fuels like gasoline, diesel, coal, bitumen and kerosene. Did you know that carbons can combine in special structures to form precious gems such as diamond? I entreat you to read more about them.

COMBUSTION

This refers to the process of breaking down substances in the presence of oxygen. It is also called burning. When fuel (wood, gasoline etc) comes in the presence of oxygen, It produces heat, light, ash and carbon dioxide. There are two types of combustion i.e Complete and incomplete combustion.

Complete combustion occurs in the presence of enough oxygen. The fuel burns completely releasing only carbon dioxide and water vapour.

Incomplete combustion occurs in the presence of little oxygen and the fuel doesn’t burn completely leaving pollutants like carbon monoxide and soot.

During combustion, carbon dioxide or monoxide is produced and released into the atmosphere. It is used to power cars, machines, generators and also to get rid of waste substances such as plastics.

From the above processes it can be observed that Photosynthesis is the only process that remove carbon from the atmosphere whiles the other processes releases carbon based compounds into the atmosphere. The amount of carbon produced by these processes must be taken by photosynthesis to maintain the right amount of carbon in the atmosphere. This means that as we increase respiration, combustion and decomposition, we must as well be able to plant more trees to remove these carbon from the atmosphere. However, some human activities causes a disruption in the carbon cycle which affects living things on earth. Examples of such activities are treated below.

HUMAN ACTIVITIES THAT DISRUPTS THE CARBON CYCLE

·         Deforestation: This refers to the felling of trees. This activity destroys the habitat of many organisms. As the trees are felled without replacement, the amount of carbon dioxide in the atmosphere increases.

·         Industrialization: As humans increase in number and there is technology on the rise, So is industrialization.  This has caused most forests to be destroyed and a lot of houses and industries has been built in their place. These industries burn fuels and release carbon dioxide into the house atmosphere.

·         Urbanization: Humans by nature love to explore and move to areas where they can acquire properties and wealth. This has caused the vegetation around such areas to be cleared. More houses are built to accommodate them, roads and other amenities are built which will replace the forestation at those places. This cause rise in carbon concentrations in those places as more vehicles, machines and living things produce more carbon dioxide to disrupt the cycle.

HOW THE DISRUPTION OF CARBON CYCLE AFFECTS LIVING THINGS

The amount carbon dioxide in the atmosphere already is enough to maintain balance in the atmosphere. This means that the amount of carbon dioxide produced on earth must be also removed in order to maintain balance. If there is too much carbon dioxide in the atmosphere, it will lead to greenhouse effect, i.e. these gases will trap heat to warm the earth’s surface. When the heat trapped is above normal, the ice at the poles of the earth will melt causing the rise in the levels of the oceans and can cause flooding at coastal areas. Too much heat can also cause droughts at the land locked areas. This can affect plant and animal lives greatly as it will lead to hunger, and respiratory diseases among others.

When the amount of carbon dioxide reduces in the atmosphere, It can lead to very cold temperatures which will cause oceans and water bodies to freeze causing aquatic organisms to lose their lives. Animals and plants may also die due to the cold weather.

This means that we must do everything to protect our environment and maintain balance in the carbon cycle.

I will entreat you to discuss measures to be taken to prevent disruptions in the carbon cycle.