sea water glows during night mainly due to occurence of

1. gonyaulax
2. noctiluca
3. euglena
4. cyclotella

The correct option is 2.
Noctiluca scintillans, commonly known as the Sea Sparkle, and also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence, when disturbed. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase reaction that takes place in thousands of spherically shaped organelles, called scintillons, located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these scintillons.