What role does soil play in the carbon cycle?

Soil plays a crucial role in the carbon cycle by acting as a carbon sink, which means it sequesters carbon from the atmosphere and stores it in organic matter. This process occurs through the decomposition of plant material and other organic matter, where decomposers break down these materials, releasing carbon into the soil in the form of organic carbon compounds. Various soil microorganisms contribute to this process, absorbing carbon dioxide from the atmosphere during photosynthesis and ultimately cycling it through the ecosystem.

Additionally, the carbon stored in the soil can be released back into the atmosphere through processes like respiration by plants and microorganisms or through land-use changes such as deforestation. Therefore, the ability of soil to store carbon has significant implications for climate change mitigation, as maintaining healthy soils can enhance carbon sequestration and reduce the concentration of greenhouse gases in the atmosphere.

Other options do not accurately represent the role of soil in the carbon cycle. Soil does not solely release carbon without also being a site of storage, nor does it have no role in the cycle. Furthermore, while nitrogen storage is another important soil function, it does not diminish the significance of carbon storage in soil management and ecosystem health.