What is Carbon Cycle? | Types, Definition, Structure, Function & Facts

What is Carbon Cycle?

One of the most important elements of life on planet Earth is carbon. All living organisms have carbon as the basis for life. This is so important that animals are often referred to as “carbon-based” life forms.

How much Carbon is in the Human Body?

Carbon makes up about 18% of the human body. So if you weigh 100 pounds, your body contains about 18 pounds of carbon.

The Carbon Cycle

Some carbon atoms are always in motion. Indeed, carbon atoms are used by all kinds of processes on our planet. Some of these processes release carbon into the atmosphere (air) and others remove carbon. The carbon cycle is often closely related to the oxygen cycle.

Taking Carbon out of the Atmosphere

Nature is continuously extracting carbon from the atmosphere. These processes are sometimes called carbon sinks.

Photosynthesis – Plants use photosynthesis to produce energy and grow. They absorb carbon dioxide (CO2), sunlight, and water and turn them into oxygen and sugar. Vast areas of vegetation like rainforests remove a lot of carbon from the atmosphere.

The Ocean – Sea water does a lot to remove excess carbon from the atmosphere. Carbon dioxide in the air reacts with seawater to produce carbonic acid in the ocean. However, if there is too much carbonic acid, it can cause acid rain, which is not good. Some of the carbon dioxide in the ocean is good because carbon combines with calcium to form calcium carbonate, which is used by marine organisms to make their shells. These shells will eventually become sedimentary rocks such as limestone.

Moving Carbon into the Atmosphere

While some natural processes remove carbon from the air, others add more carbon to the air. These processes are called sources.

Respiration (breathing) – Every time you breathe you turn oxygen into carbon dioxide. This is true of every animal on Earth.

Decay – When plants and animals die they decay. When this happens, the carbon in their body will either be released into the atmosphere or stored in ground as fossil fuels.

Combustion (burning) – When plants, trees, or fossil fuels are burned, carbon is released into the atmosphere.

The Carbon Cycle Balance

Carbon is essential to life, and nature has done a great job of balancing carbon availability throughout the carbon cycle. Carbon is also needed in the atmosphere because it helps keep the Earth warm. Without it, we would all be frozen.

How Man Alters the Carbon Cycle

While nature does a great job of balancing carbon throughout the carbon cycle, when humans are involved, we can upset the balance. By burning fossil fuels like coal, gas and oil, a lot of carbon is released into the air. In addition, cutting down trees for growth reduces the amount of plants available to remove carbon from the air.