These worksheets look at how carbon, a vital element to living things, is recycled naturally.

These worksheets look at just about every aspect of the Carbon cycle. This is the process that moves carbon through all different types of mediums including the atmosphere, soil, living things, and bodies of water. We look at how this element is recycled and how oxygen seems to affect the progress of the cycle. We also take a look at several compounds and process that seemingly affect the efficiency of this process. We look at how food chains also affect the process. We also look at how forms of human pollution are having long term consequences for the planet. The worksheets are organized into reading passage followed by question worksheets to help both students and teacher learn more about this amazing process.

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Print Carbon Cycle Worksheets

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The Cycle Worksheet

The Cycle

The ocean also takes a lot of excess carbon out of the atmosphere because CO2 in the air reacts with sea water.

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Cycle Questions Worksheet


Processes that put carbon into the air are called sources. Human respiration puts it back into the atmosphere when we exhale CO2. Carbon also returns to the environment through the process of the decay of plants and animals.

What Is Carbon Worksheet

What Is Carbon?

It forms a major part of rock formations like limestone and marble. It dissolves in large bodies of water, including the ocean. It is also found in fossil fuels like coal, natural gas, and petroleum.

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What Is Carbon Question Worksheet


Almost every human industry uses it in some way. Any industry that uses coal, methane gas, or crude oil (a precursor of gasoline) uses carbon.

Oxygen Cycle Worksheet

The Oxygen Cycle

Oxygen is the most common element in the human body where it exists primarily in the form of water. While carbon accounts for 18% of the human body, oxygen makes up 65% of it.

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Oxygen Cycle Question Worksheet

Question Set: The Oxygen Cycle

Cellular respiration (which is also part of the C cycle) is not the only natural process that uses oxygen. Decomposition, which releases carbon from dead plants and animals back into the soil and the atmosphere uses up oxygen.

Photosynthesis Worksheet


Photosynthesis and cellular respiration are opposite reactions. During photosynthesis, photosynthetic organisms use the energy from sunlight to convert CO2 and water into the simple sugar glucose.

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Photosynthesis Question Worksheet

Question Set: Photosynthesis

Because all living things breathe in some way, all living things contain some form of carbon. Activities like eating and excretion are also contribute to this cycle, as the element is being taken into and passed back out of living organisms.

Atmospheric Carbon Dioxide Worksheet

Atmospheric CO2

The layer of gases that surrounds the Earth is called the atmosphere. The Earth's atmosphere is made up of nitrogen, oxygen, water vapor, and very small amounts of other gases like argon and CO2.

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Atmospheric Carbon Dioxide Question Worksheet

Question Set: Atmospheric CO2

Carbon removed by the ocean becomes calcium carbonate, which some aquatic organisms use in order to make their shells. When these organisms die, the carbon in their shells returns to the environment in the form of sedimentary rock. If too much of it is removed from the air by the ocean, it can become carbolic acid and reenter the atmosphere in the damaging from of acid rain.

Food Chain Worksheet

Food Chains

Plants are considered to be at the bottom of the food chain because they create usable energy through the process of photosynthesis.

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Food Chain Question Worksheet

Questions: Food Chains

When animals eat plants, the energy in the plants, as well as the carbon in the plants, becomes available for the animal's body to use.

Ocean Worksheet


There are many ongoing processes on Earth that are part of the carbon cycle: photosynthesis, eating, excreting, decomposition, burning, etc.

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Oceans Questio Worksheet

Oceans Question Series

About half of the CO2 removed from the atmosphere is dissolved on the surface of the ocean. Because the ocean takes more carbon from the atmosphere than it puts back into it, the ocean is sometimes called a carbon sink.

Changes Worksheet

Changes in the Carbon Cycle

For many millions of years the level of carbon in the atmosphere has remained relatively constant.

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Changes Question Worksheet

Question Set: Changes in the Cycle

Human activity is not the only change that has occurred in the carbon cycle. The amount of CO2 in the Earth's atmosphere has increased several times during prehistoric times because of volcanic eruption, which sends gases like CO2 into the atmosphere.

Carbon Cycle and Energy Worksheet

The Carbon Cycle and Energy

Plants use ATP to sustain their own lives. Because plants produce ATP, they are known as producers in the food chain. When terrestrial or aquatic animals eat plants, their bodies digest the plants in order to make the chemical energy stored there available for their own bodies to use.

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Energy Question Worksheet

Energy Questions

When living organisms die, the carbon (and the energy) that is stored in their bodies returns to the environment, where it becomes available to new plants in the form of nutrients.

Deforestation Worksheet


If there aren't enough trees to keep the amount of CO2 in the atmosphere at the right levels, the planet's climate changes, something which is happening right now.

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Deforestation Question Worksheet

Deforestation Questions

Deforestation is having a negative effect on the carbon cycle, a process on which all life on Earth depends.

What Is the Carbon Cycle?

Carbon is a non-metallic element that has a great deal of significance for living things. It is an element that has an incomparable ability to bind to an unusually high number of different elements. The elements unique structure of have four available electrons to form bonds helps it form multiple stable bonds with other small elements. This helps living things form complex molecules like amino acids, proteins, and DNA. The carbon cycle is the process whereby Mother Nature will constantly recycle this element. It plays a vital role in the homeostasis of all living things on Earth. Since it is cycle, you can pretty much view it from any angle, but I would say it begins with plants. Plants use carbon dioxide that is found in Earth's air to make energy from sunlight. Animals love tasty green things, so they eat the plants and breathe in oxygen. They also breathe out with more carbon dioxide than they breathed in. The plants then use all this extra carbon dioxide to keep it going. As the plants and animals die, decomposers break down their remains and return nutrients to the soil and carbon dioxide to the atmosphere. Carbon is crucial for life, and it must be replenished often. You’ll see how that happens through the carbon cycle.

The carbon cycle traces the movement of carbon atoms within this world. Carbon atoms undergo many processes and transformations to move from atmosphere to the ground, ground to the atmosphere, and organism to organism. The cycle ensures the recycling of carbon atoms.

If you keep reading this article, you’ll be able to follow the journey that carbon atoms take across the Earth. I’ll also explain what makes this cycle so important.

Understanding Where Carbon Atoms Come From

To understand the carbon cycle, you first need to know where all the carbon atoms come from and go. These destinations in the carbon cycle journey are what we call reservoirs or sinks. They are termed such because these are where carbon atoms are usually stored.

Here are a few examples of these places:

  • Living organisms
  • Rocks and sediments
  • The ocean
  • The atmosphere

Let’s discuss each of these in greater detail.

Living Organisms

Humans, plants, animals, fungi, protozoa, and many other living organisms have carbon as the backbone of life. It makes up our cells, bones, and many other parts. When we die and decompose, this carbon is released.

Rocks and Sediments

Carbon is stored in rocks and minerals, usually in the form of carbonate. When organisms die and decay, they release carbon atoms that may eventually become rocks. They may also become fossils and later become fossil fuels.


Aside from the marine organisms that use and comprise carbon, the ocean is a large sink for carbon storage. Carbon exchange at the surface allows carbon atoms to dissolve into the water and react with it. This leads to the formation of other ions like bicarbonate.


Many carbon atoms are stored in the atmosphere as carbon dioxide. Carbon dioxide helps maintain the Earth’s temperature. However, too much of it contributes to global warming and other drastic environmental effects.

Processes in the Carbon Cycle

Carbon goes through many processes as it moves across the Earth. Through these processes, it combines with other elements to form compounds.

Let’s discuss some of the processes involved in the carbon cycle.

Ground to Atmosphere

Here are processes that allow carbon to move from the ground to the atmosphere:

  • Respiration. As living beings exhale, they release carbon dioxide.
  • Fire. The combustion or burning of carbon compounds releases them as carbon dioxide.
  • Human Emissions. A product of burning fossil fuels is carbon dioxide.
  • Decomposition. As organisms decay, some carbon atoms are released into the air.
  • Eruption. Volcanic eruptions release a significant amount of carbon dioxide.

Atmosphere to Ground

Carbon dioxide from the atmosphere can return to the land through these processes:

  • Photosynthesis. Plants use carbon dioxide to make their food through photosynthesis.
  • Carbon sequestration. Because of global warming, scientists are looking for artificial ways to sequester carbons and prevent them from entering the atmosphere.
  • Rain. Carbon can react with water to form carbonic acid that falls with the rain.

Ground to Ground

Carbon dioxide moves along the ground, whether it’s transported from organism to organism or from an organism to the Earth:

  • Consumption. The food web is a way to trace the movement of carbons; as one organism consumes the other, carbon atoms are passed along.
  • Decomposition. Especially when buried or unexposed to the atmosphere, carbon from decomposing organisms is trapped in the Earth.


  • Dissolution. The exchange of elements on the ocean’s surface leads to the dissolution of carbon atoms in the water. The carbon atoms can react with the water molecules and form bicarbonate, making the ocean acidic.
  • Respiration and decomposition. Marine organisms also respire and decompose like other organisms, thus, promoting the movement of carbon atoms.

Why Is the Carbon Cycle Important?

The carbon cycle is important because it affects the distribution of carbon atoms on the Earth. These carbon atoms are the building blocks of life and the regulators of temperature in our atmosphere. Any changes to its distribution could affect many life processes.

Disturbing the carbon cycle is now reflected in our present environmental issues.

Global warming has led to climate change, melting ice sheets, rising ocean levels, and many other drastic effects.

Thus, monitoring the carbon cycle and controlling the distribution of carbon dioxide in the atmosphere is crucial to maintaining the balance in our world.

Final Thoughts

The carbon cycle describes the movement of carbon atoms across the Earth. Its journey is like a loop that allows it to move from the atmosphere to the ground and from organism to organism. This journey affects life itself.