When I first saw a sea sapphire I thought I was hallucinating. The day had been anything but normal, but this part will always stand out. I’d spent the afternoon on a small dingy off the coast of Durban, South Africa. It was muggy, and I’d been working for hours–-throwing a small net out, and pulling in tiny hauls of plankton that I’d then collect in jars. As I looked through one jar, the boat rocking up and down, I saw for an instant a bright blue flash. Gone. Then again in a different place. An incredible shade of blue. Maybe I’d been in the sun too long? Maybe I was seeing things? It wasn’t until I got back to the lab that I discovered the true beauty and mystery of these radiant flashes...
The small creature I’d found was a Sapphirina copepod, or as I like to call it, a sea sapphire. Copepods are the rice of the sea, tiny shrimp-like animals at the base of the ocean food chain. And like rice, they are generally not known for their charisma. Sea sapphires are an exception. Though they are often small, a few millimeters, they are stunningly beautiful...
...The secret to the sea sapphire’s shine is in microscopic layers of crystal plates inside their cells. In the case of blue sea sapphires, these crystal layers are separated by only about four ten thousandths of a millimeter; about the same distance as a wavelength of blue light. When blue light bounces off these crystal layers, it is perfectly preserved and reflected. But for other colors of light, these small differences in distance interfere, causing the colors to cancel out. So while white light is composed of all colors, only blue light is reflected back. This type of coloration is known as structural coloration, and though resembling a gem in hue, a sea sapphire’s color has more in common with an oil sheen than a pigmented jewel. Combine this nifty trick with the sea sapphire’s impressively transparent body, and you have an animal as radiant as a star in one moment, and invisible in the next...
I think I saw something like this once in Lake Erie, but it could have been some trash wrapped in aluminum foil.
Hat tip: BadBlue Tech News
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