Neuston(redirected from neustonic)
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the organisms that attach themselves to the surface film of water and move on either the top of the film (supraneuston) or the underside (infraneuston). The neuston includes protozoans, unicellular algae, water striders, Gyrinidae (whirligig beetles), gnat larvae, some Cladocera (water fleas), Pulmonata, and other small, for the most part freshwater, organisms. The marine infraneuston also includes inhabitants of the top of the water (0–5 cm), which occupy that region at all times or only at night (small crustaceans, fish fry).