sea sapphire, the mystery of the invisible crustacean

The sea sapphire also called sapphirina is a really small crustacean which belong to the genius of parasitic copepods. Those critters which feed directly on phytoplankton take their nickname: “sapphire of the ocean” from the fact their transparent skin is iridescent, in other word they can change color according to the light.

Some time you can observe hundreds of sapphirina at the surface of the ocean, in those situations the sea seems to be covered by diamonds. Depending of the light its color can vary from gold to pure blue. This characteristic is due to microscopic hexagonal plates that reflect only some wavelengths of light. For the same reason, the crustacean can become invisible to the human eye, depending on the angle illuminated. All Sapphirina do not have this power, only males can become as luminous as precious stones, females, which parasitize gelatinous organisms, are much less luminous. These copepods live in most oceans, found in Asia, in America and in Africa. So don’t be surprise next time you see diamonds underwater!