epibenthic

Epibenthic refers to organisms that inhabit the surface of the seabed or riverbed, occupying the interface between the benthic substrate and the overlying water column. In marine biology, epibenthos denotes the community of such organisms on the seabed surface; it is distinct from infauna, which live within sediments, and from pelagic organisms that inhabit the water column away from the bottom. Epibenthic habitats occur on hard substrates (rocks, coral, shells) and on soft sediments, where organisms may attach to the surface or move across it.

The epibenthos includes a wide range of taxa. Sessile or slow-moving forms such as barnacles, bryozoans, sponges, and encrusting algae often dominate hard-substrate environments, while mobile invertebrates such as crustaceans, echinoderms, mollusks, and some fish traverse or feed on the surface of the bottom. Feeding modes are diverse, including suspension feeding, scraping, grazing, and predation.

Ecologically, epibenthic communities contribute to habitat structure, primary and secondary production, and energy transfer between the benthos and the overlying water. They can influence sediment stability, nutrient cycling, and serve as prey for larger organisms. Their composition and abundance reflect environmental conditions such as substrate type, depth, currents, and pollution.

Researchers study epibenthic communities to monitor ecosystem health and biodiversity. Sampling methods include underwater video and photography, suction samplers, sleds or grabs for removing surface-dwelling organisms, and targeted surveys along substrate and depth gradients.