How do decomposers recycle materials in inland water ecosystems?

In inland water ecosystems, decomposers—including bacteria, fungi, and small invertebrates—recycle materials by breaking down dead organisms and organic wastes into simpler components. This process is essential for nutrient cycling, as it converts complex organic matter back into inorganic nutrients that primary producers can utilize for growth.12

Decomposers often utilize a process called absorptive nutrition, where they excrete enzymes to digest nonliving organic matter, known as detritus, into simpler molecules that are then absorbed for nutrition. For example, certain fungi and bacteria are highly efficient at breaking down complex plant materials like cellulose. In freshwater environments, water molds (Oomycetes) also serve as critical decomposers of both plant and animal material.3

Through these metabolic activities, decomposers facilitate the return of essential elements to the ecosystem. While energy is ultimately degraded to heat, these nutrients are recycled, allowing them to move repeatedly between biotic and abiotic components of the hydrosphere.12