What ecosystem role do decomposers primarily fulfill?

Decomposers play a crucial role in ecosystems by breaking down dead material, which includes deceased plants, animals, and organic matter. This process of decomposition is vital for nutrient cycling within the ecosystem. When decomposers such as fungi, bacteria, and insects break down this organic material, they release essential nutrients back into the soil, making them available for uptake by plants. This cycle supports plant growth and, by extension, the entire food web that relies on plants for energy. Without decomposers, the accumulation of dead matter would disrupt ecosystems and deplete nutrient availability, ultimately affecting all organisms within the environment.