BBC Science Focus

Ultra-black deep-sea fish that can absorb 99.9 per cent of light


You might be able to apply black make-up, dye your hair a dusky tone and drape yourself in black leather, but you’ll never be as goth as some species of deep sea fish.

A team of scientists from Duke University and the Smithsonia­n National Museum of Natural History have found that the skin of some deep sea fish absorbs more than 99.9 per cent of the light that hits them, making them appear ultra black. In the dark environmen­t in which they live, where even a tiny bit of reflected light can attract unwanted attention, this intense black colour improves their chances of survival.

Duke University's Dr. Karen Osborn, who co led the research, first discovered the incredible properties of the fish when she tried to photograph some of the specimens that she'd brought up from the deep sea. Despite high tech equipment, she could not see any detail in the images. "It didnot matter how you set up the camera or lighting s they [the fish] Lust sucked up all the light," she said.

The researcher­s found that the secret to the ultra-black colour is melanin - the same pigment that gives human skin and hair its colour - and its distributi­on within the fish skin.

The melanin is located inside structures called melanosome­s, which are densely packed into cells on the fish skin. Thanks to the shape and arrangemen­t of the melanosome­s, any light that reaches a melanosome will be redirected towards another in the cell, to absorb it. "These pigment containing structures are packed into the skin cells like a tiny gumball machine, where all of the gumballs are of Lust the right siza and shape to trap light within the machine," said Alexander Davis, a co author of the study and doctoral student at Duke University.

5o far, the researcher­s have found 1 species of fish that use this method to appear ultra black in the deep sea. As the species are not closely related, it could be a relatively common strategy. It is thought that engineers could take inspiratio­n from the fish to create ultra black substances for sensitive optical equipment, which is currently expensive and fiddly to produce.

 ??  ?? Some deep-sea fish, like this Anoplogast­er cornuta absorb almost all the light, making them appear ultra-black
Some deep-sea fish, like this Anoplogast­er cornuta absorb almost all the light, making them appear ultra-black

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