Pleuston are the organisms that live in the thin surface layer existing at the air-water interface of a body of water as their habitat.[1] Examples include some cyanobacteria, some gastropods, the ferns Azolla and Salvinia and the seed plants Lemna, Wolffia, Pistia, Eichornia and Hydrocharis. The term pleuston was first used by Carl Schroeter in 1896.