pleuston

1. (ecology) The organisms that live floating at the surface of water.Examples: "They^([Cnidarians]) are also the dominant organisms of the marine pleuston, providing food or substrate for a variety of other invertebrates living at the air-water interface[…]."; "These animals form the pleuston. Zaitsev (1971) differentiates between the neuston and the pleuston, while admitting that the distinction may be somewhat blurred. Both populations are associated with the surface film. That part of a pleuston animal which projects above the water surface can withstand prolonged desiccation and exposure to direct sunlight."uncountable

2. (botany) Plants that live floating at the surface of water.uncountable