It is said that the role of decomposers in biogeochemical cycles is very important. Explain

Decomposers play a major role in biogeochemical cycles. They decompose the dead plants and excreta of animals.
During this process, complex organic compounds are broken down into simple or usable forms. These compounds are released into nutrient pool (soil, waterbodies and atmosphere) where these nutrients are reutilised by the plants from the soil.