Also known as sea sparkle, Noctiluca scintillans is a large dinoflagellate that lives near the surface of the ocean, where it feeds on other planktonic organisms. It has a flattened spherical body but no protective test. It is colorless, although the presence of photosynthetic organisms within the Noctiluca scintillans may give it a pink or greenish tinge. Usually only one of the two flagella is visible. The flagellum is not used in locomotion but instead sweeps food into the oral cavity and removes waste matter. To control its buoyancy, Noctiluca scintillans can adjust the concentration of its cell contents. This species, which is bioluminescent in some areas (noctiluca means “shining lantern”), may also form red tides and has been linked to fish and invertebrate deaths. Little is known of its complex life cycle. Reproduction can be either sexual or asexual by simple division.
Bioluminescence in Noctiluca scintillans
Floating just below the surface of the water at night, dinoflagellates, and in particular Noctiluca scintillans, are the most common cause of bioluminescence in the open ocean. Millions of Noctiluca scintillans cells twinkle in the waves, hence the common name sea sparkle. The blue-green light is emitted from small organelles within the cells and is generated by a chemical reaction. Unlike many bioluminescent fish, Noctiluca scintillans does not depend on light-emitting bacteria.