Microorganisms play a vital role in sustaining Earth’s life-support systems by participating in the decomposition of organic matter, which is crucial for nutrient cycling. As decomposers, bacteria and fungi break down dead plants and animals, transforming them into simpler compounds that enrich the soil with essential nutrients like nitrogen, phosphorus, and potassium. This process not only recycles nutrients but also supports plant growth, forming the foundation of food webs that sustain all terrestrial life.
In addition to decomposition, microorganisms often engage in symbiotic relationships with larger organisms, enhancing ecosystem stability. For example, certain bacteria live in the root nodules of legumes, where they fix atmospheric nitrogen, making it available for plant use—a process essential for soil fertility. Similarly, mycorrhizal fungi form partnerships with plant roots to improve nutrient uptake while receiving carbohydrates in return. These interactions highlight how microorganisms are integral to maintaining ecological balance and supporting biodiversity across various habitats on Earth.