about the carbon cycle

Carbon is a significant constituent of minerals and biological compounds.“ The carbon cycle explains how carbon moves by photosynthesis, respiration, and decomposition. This biogeochemical cycle explains nature’s basic method of recycling carbon atoms as they migrate ”from the atmosphere to the cells and the ground, and then back into the atmosphere“ (Wigley & Schimel, 2000). Carbon dioxide reaches the atmosphere through oxygen-using respiration and combustion processes. Respiration is a metabolic mechanism in which body cells produce energy by mixing glucose and oxygen, resulting in the release of carbon dioxide, water, and energy.

The equation for respiration is;

Glucose + oxygen = Carbon dioxide + water + energy

C6H12O6 + 6O2 = 6CO2 + 6H2O + ATP

Photosynthesis is the next step of the carbon cycle and takes place in the chloroplasts found in leaves. Here, chlorophyll absorbs solar energy that is used in splitting of water molecules which combine with CO2 to make food in form of carbohydrates. The by-product of this process is oxygen. The chemical equation for photosynthesis is given as

CO2 + H2O + Light Energy = CH2O + O2

Animals feed on these plants passing carbon compounds along the food chains. This carbon is exhaled by animals as carbon dioxide. When plants and animals die, they decompose and emit carbon dioxide. The carbon atoms found in dead organisms is therefore returned to the atmosphere as carbon dioxide. Additionally, burning of decomposing organisms release CO2. Carbon dioxide is also dissolved in seawater and emitted as carbon dioxide into the atmosphere. The ocean-atmosphere carbon exchange is significant to the carbon cycle explained by the enormous seawater bodies hence having the potential of storing and releasing huge amounts of carbon dioxide.

Human Activity that has impacted on the Carbon Cycle

One of the primary human activities that has influenced the carbon cycle is the burning of fossil fuels. Fossil fuels including natural gas, petroleum and coals release buried carbon into the atmosphere having a profound impact on the carbon cycle. As such, automobiles, natural gas and coal plants involved in the production of electricity both for residential and industrial use emit massive carbon dioxide into the atmosphere. The process of synthesizing artificial fertilizers leads to a rise in the level of carbon. Deforestation is another human activity that has continued to have a detrimental impact on the carbon cycle. Widespread activities of deforestation culminate into less carbon sequestered via photosynthesis. Furthermore, a lot of carbon gets released from the decomposition process of cut plants. Clearing forests for agricultural land and timber harvest are acts of deforestation that interfere with the carbon cycle (Wigley & Schimel, 2000). Moreover, a concern arising from the increase in carbon dioxide levels emanate from the greenhouse effect. Greenhouse gas traps infrared radiation from the surface of the earth which would otherwise escape into the atmosphere and therefore insulating the planet. Temperatures increase upsetting the carbon cycle and causing drastic changes in the global climate. This affects the weather, agriculture, biodiversity and the entire health of the ecosystem. Deforestation makes less photosynthesis to occur, and consequently, the little amount of oxygen is released into the atmosphere making fewer amounts of carbon dioxide to be absorbed. Hence, carbon dioxide increases.

Reference

Wigley, T., & Schimel, D. (2000). The carbon cycle. Cambridge, England: Cambridge University Press.