What is the community of organisms that reside on or in the substrate of a body of water called?

The community of organisms that reside on or in the substrate of a body of water is known as the benthic community. This terminology specifically refers to the diverse range of organisms, including bacteria, fungi, invertebrates, and small fish, that inhabit the bottom of aquatic ecosystems such as lakes, rivers, and oceans. These organisms play essential roles in the ecosystem, including the decomposition of organic matter, nutrient cycling, and serving as a food source for larger animals.

Understanding the benthic community is crucial as it reflects the health of aquatic environments and indicates the quality of the water. The term captures the range of life that interacts closely with the substrate, distinguishing it from other communities that may be present in the water column or in different ecological niches. Other options, like aquatic assemblage or plankton community, refer to broader or different groups of organisms in the water or its layers, while waterway association does not specifically identify the substrate-dwelling organisms.