What does epifauna mean?
Epifauna refers to the animals that inhabit the surface of the seabed and other underwater surfaces — rocks, shells, sediment, pilings, and even the bodies of other organisms — rather than burrowing into them. The word is chiefly a technical term in marine biology and benthic ecology, where it is paired with its counterpart infauna, the animals that live hidden within soft sediment. Typical members of the epifauna include sponges, barnacles, mussels, bryozoans, sea anemones, sea stars, and many kinds of encrusting worms. Scientists study epifaunal communities to assess habitat quality, monitor pollution, and track recovery after disturbance, because these surface dwellers respond visibly to environmental change. Although rarely heard outside scientific contexts, the word captures an elegant ecological idea: an entire animal community living exposed upon the floor of the ocean, forming the visible architecture of the benthic world.
nounThe animals that live on the surface of the seabed or of submerged substrates such as rocks, sediments, and other organisms. The term is used chiefly in marine biology and ecology, often contrasted with infauna, which live buried within the sediment.
- The community of animals living on the surface of the seabed or other submerged substrates, as distinct from those burrowing within it.
"The rocky reef supports a rich epifauna of sponges, barnacles, and sea stars."
"Dredging can strip an entire epifauna of sponges and bryozoans from the seabed."
"Researchers compared the epifauna colonising oyster shells at each sampling site."
Epifauna is a collective noun referring to a group of animals; it does not take a separate plural form, though it may take plural verbs depending on emphasis.
"The epifauna were surveyed along transects at each depth."
Every barnacle glued to a rock and every starfish sprawled across a reef belongs to the epifauna — the animal city built on top of the seafloor rather than inside it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of epifauna
Epifauna derives from the Greek prefix epi-, meaning 'on' or 'upon', combined with fauna, from Faunus, the Roman god of fertility and herds, whose name came to denote animal life collectively. The compound follows the pattern of other ecological terms such as infauna ('within-fauna') and periphyton. It arose in scientific usage during the nineteenth century, when naturalists were systematically classifying bottom-dwelling marine life.
Related word forms
How epifauna is actually used
A technical term of marine ecology and benthic studies, rarely used outside scientific writing. It functions as a collective plural noun; 'epifaunal' serves as the adjective.
Easily confused with epifauna
Infauna are animals living within the sediment itself, whereas epifauna live on top of the seabed or substrate.
Periphyton refers to attached microorganisms and algae growing on submerged surfaces, while epifauna are animals.