infauna

marine zoology

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June 29, 2026

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Infauna refers to benthic fauna that live within the soft bottom sediments of the seafloor, as opposed to living on the surface. These organisms are a part of the larger group known as benthos, which are all organisms inhabiting the seafloor. Infauna can range in size from microscopic to larger forms, and their specific composition varies based on environmental factors like latitude, depth, and substrate type. They are a crucial part of marine ecosystems, feeding on plankton and organic debris that sinks from the water column above.123

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benthos
…upon bottom objects; the so-called infauna live within the sediments of the seafloor. By far the best-studied benthos are the macrobenthos, those forms larger than 1 mm (0.04 inch), which are dominated by polychaete worms, pelecypods, anthozoans, echinoderms, sponges, ascidians, and crustaceans. Meiobenthos, those organisms between 0.1 and 1 mm…
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…upon bottom objects; the so-called infauna live within the sediments of the seafloor. By far the best-studied benthos are the macrobenthos, those forms larger than 1 mm (0.04 inch), which are dominated by polychaete worms, pelecypods, anthozoans, echinoderms, sponges, ascidians, and crustaceans. Meiobenthos, those organisms between 0.1 and 1 mm…
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bivalve
Ecology and habitats
…to the adoption of a burrowing mode of life, which is achieved by a muscular foot. Primitive forms were detritivorous, whereas modern bivalves are suspension feeders that collect food particles from seawater using ciliated ctenidia (modified gills). The burrowing, filter-feeding mode of life restricts bivalves to aquatic environments.
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…to the adoption of a burrowing mode of life, which is achieved by a muscular foot. Primitive forms were detritivorous, whereas modern bivalves are suspension feeders that collect food particles from seawater using ciliated ctenidia (modified gills). The burrowing, filter-feeding mode of life restricts bivalves to aquatic environments.
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