Which organisms are characterized as bottom-dwelling in aquatic ecosystems?

Bottom-dwelling organisms in aquatic ecosystems are referred to as benthos. These organisms inhabit the substrate at the bottom of water bodies, such as lakes, rivers, and oceans. Benthos include a variety of life forms such as fish, crustaceans, mollusks, and aquatic plants that are adapted to living on or near the bottom. Their existence plays a critical role in the ecosystem as they contribute to nutrient cycling and serve as food for others, forming a fundamental part of the aquatic food web.

In contrast, nekton refers to organisms that actively swim in the water column, such as fish and squid, and are not bottom-dwellers. Zooplankton consists of small, often microscopic animals that drift with currents in the water, while phytoplankton are tiny plant-like organisms that photosynthesize and also float in the upper layers of water. All these groups occupy different niches within the aquatic ecosystem, but it is the benthos that are specifically associated with the bottom-dwelling lifestyle.