The organisms that primarily decompose dead matter are known as decomposers, including bacteria, fungi, and some insects. These organisms play a vital role in nutrient cycling within ecosystems by breaking down organic matter and recycling essential nutrients back into the soil. This process facilitates plant growth and promotes overall ecosystem health. Decomposers ensure the functioning of food webs, allowing energy and matter to flow through different trophic levels. Understanding their contributions is important for ecological studies and sustainable environmental practices.