Ontario Grade 9 Science Class Practice Exam 2025 - Free Grade 9 Science Practice Questions and Study Guide

Decomposers play a crucial role in ecosystems by breaking down dead organic matter, such as fallen leaves, dead plants, and animal remains. This process of decomposition is essential because it recycles nutrients back into the soil, making them available for plants and other producers to use. When decomposers, which include organisms like bacteria, fungi, and certain insects, break down this organic matter, they facilitate the flow of energy and matter through the ecosystem, thus maintaining its health and stability.

The recycling of nutrients by decomposers supports plant life, which is foundational for maintaining food chains and ecosystems. Without decomposers, dead material would accumulate and essential nutrients would be trapped in that matter, leading to a reduction in soil fertility and negatively impacting the entire ecosystem. In essence, decomposers are vital for nutrient cycling, which sustains the productivity of the ecosystem.