Question

How do decomposers convert energy for an ecosystem?

Answer 1

Decomposers break down dead, dying, or decaying organic material (ex dead animals) into their original organic components (ex. Carbon, phosphates, nitrates, etc.) and returns them to the soil. They can then be used by producers and or autotrophs for growth, which then are passed on to consumers, etc. --

Do you get the gist of it now?

Answer 2

They eat dead things so the ecosystem's not filled with rotting corpses all the time. Think worms. ^The other guy is correct, I'm just replying in a more simple manner.