Answer & explanation:
Soil carbon transformations have two phases: The first one is the atmospheric carbon dioxide (CO₂) fixation phase, which is performed by photosynthetic organisms, in which there is synthesis of organic compounds.
These compounds return to the soil and are used by organisms that regenerate CO₂ during respiratory oxidation reactions, using energy for their maintenance and growth.
After this, the regeneration phase begins, which corresponds to the stages of decomposition of organic molecules by the action of the soil microbiota.
Thus, soil microbiota (mainly fungi and bacteria) use waste components as a substrate for energy and also as a carbon resource in the synthesis of new cells. Energy is supplied to microbial cells by the oxidation of organic compounds. The end product is CO₂, which is released into the atmosphere.