Living organisms participate in Earth's carbon cycle by transforming carbon-containing molecules from one form to another, transferring them between the biotic and abiotic components of an ecosystem. The metabolic processes of photosynthesis and cellular respiration drive a large part of the carbon cycle.
In photosynthesis, plants and other photosynthetic organisms use energy from sunlight plus carbon dioxide and water to create sugars, releasing oxygen as a byproduct.
In this way, plants remove carbon from the atmosphere and bring it into the living organisms of an ecosystem. Because photosynthetic organisms "produce" sugar, an organic molecule, from inorganic atmospheric CO2, they are called producers.
This sugar molecule represents stored chemical energy that the producer can use. A consumer also uses the chemical energy of sugar. This energy is released to the cell via the process of cellular respiration. All organisms—producers and consumers—perform cellular respiration.
The carbon cycle is the movement of carbon through the living (biotic) and nonliving (abiotic) parts of an ecosystem. The atmosphere, oceans, and soil are abiotic reservoirs for carbon. Oceans absorb carbon dioxide (CO2) directly from the atmosphere and soils accumulate it during decomposition.
Carbon as carbon dioxide is transferred from the atmosphere to living things through photosynthesis, in which producers use sunlight to fuel the production of sugars from carbon dioxide and water.
The producers use and store the carbon. The carbon compounds are eventually passed on to consumers via the food chain. Some of these consumers are decomposers, which decompose organic material to acquire raw materials and energy.
All organisms perform cellular respiration, which breaks down carbon compounds into carbon dioxide, returning carbon to the atmosphere.
Humans unbalance the carbon cycle with activities that increase the amount of carbon dioxide in the atmosphere. The burning of fossil fuels and forest fires deliver more carbon dioxide to the atmosphere. Deforestation results in less carbon dioxide being removed from the atmosphere via photosynthesis.
Identify the main events of the carbon cycle by dragging the terms to their correct locations. You may use each term more than once.