Decomposers play a crucial ecological role in the nutrient cycle by breaking down organic matter, such as dead plants and animals, into simpler compounds. This process releases essential nutrients back into the soil, making them available for uptake by plants. Without decomposers, ecosystems would become overwhelmed by organic waste, which would hinder soil health and plant growth. This recycling of nutrients is vital for maintaining biodiversity and supporting various trophic levels within an ecosystem, ultimately contributing to overall ecosystem stability.