You don’t have to travel to another dimension and back to produce a creature that can turn invisible. They already swim in all the world’s tropical and sub-tropical oceans. “Sea sapphires,” as science writer Rebecca Helm calls them, are tiny crustaceans that seem to blink in and out of existence, each time flashing a brilliant blue or red or gold before vanishing. They are nature’s Invisible Woman.
Sea sapphires, or Sapphirina copepods, are only millimeters long and look like miniature shrimp. But unlike Susan Storm, who can redirect light around herself to render her invisible, Sapphirina have a more passive super power. The secret is in their skin.
Sapphirina bodies are almost completely transparent — when they aren’t flickering they are gone save for the slight, Predator-like distortion they produce in the water. But it wouldn’t quite be a superpower if Storm or the sapphires couldn’t reappear.
Sapphires shine thanks to hexagonal, crystalline structures in their skin cells, spaced just far enough away to perfectly reflect wavelengths of blue/gold/red light at certain angles. When the lighting is just right, the ocean twinkles as tiny copepods drift and spin in ocean currents. When it isn’t, poof, gone.
Only male sea sapphires sparkle, however. The females instead have ginormous eyes relative to the males that they presumably use to pick out the quick flash in the ocean that signals a potential mate. Or maybe females look on while males battle in shiny armor, watching for a victor, as Helm suggests.
Either way, we have something in common with a rice-sized crustacean — we are transfixed by the shimmering sea sapphire.
IMAGE: New Scientist
HT: Deep Sea News