What is the role of decomposers in the ecosystem?

The microorganisms, comprising bacteria and fungi, that break-down the dead remains and waste products of organisms are called decomposers. They break-down the complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants. Thus they help to clean up by decomposing dead remains and also maintain the nutrient cycle by returning the plant nutrients back into the soil.