pleuston
noun
pleus·ton ˈplü-stən 
-ˌstän
: organisms living in the thin surface layer existing at the air-water interface of a body of water
pleustonic
plü-ˈstä-nik
adjective 
Word History
Etymology
International Scientific Vocabulary pleus- (irregular from Greek plein to sail, float) + -on (as in plankton)
First Known Use
1909, in the meaning defined above