Sea sparkle (Noctiluca scintillans) is a single-celled dinoflagellate that is heterotrophic; they eat algae and even small zooplankton. For a single-celled, the sea sparkle is enormous, up to one millimetre in size. Sea sparkles looks like a sphere with a tentacle. With this tentacle the sea sparkle makes a mucous thread with which the food is collected, which is absorbed and digested in the cell. Sea sparkles can also live in symbiosis with diatoms that live inside the cell and provide energy through photosynthesis.
Sea sparkles are best known for its ability to give light through bioluminescence. After a disturbance the cell gives a blue light pulse. Why they do this is not entirely certain, perhaps to scare off enemies. The “light of the sea” caused by sea sparkle is especially visible on warm, windless summer evenings. Even during a night dive it is beautiful, turn off your diving torch, take your hand through the water and you will be surrounded by a cloud of blue sparks!