Ultrablack Fish

[Recusant]

Studying deep sea fish from various species, researchers have learned about how their skin achieves its extremely un-reflective surface.

"How Deep-Sea, Ultra-Black Fish Disappear – Science Behind Skin That Absorbs More Than 99.5% of Light" | SciTechDaily

The ultra-black Pacific blackdragon (Idiacanthus antrostomus), the second-blackest fish studied by the research team. These fish have a bioluminescent lure that they use to attract prey, and if not for their ultra-black skin and transparent, anti-reflective teeth, the reflection of their lure would scare prey away. The Pacific blackdragon also has light-producing organs below their eyes that scientists expect might be used as a searchlight to spot prey. In the July 16 issue of the journal Current Biology, a team of scientists led by Smithsonian's National Museum of Natural History research zoologist Karen Osborn and Duke University biologist Sönke Johnsen report on how a unique arrangement of pigment-packed granules enables some fish to absorb nearly all of the light that hits their skin, so that as little as 0.05% of that light is reflected back. Image credit: Karen Osborn, Smithsonian

Deep in the ocean, where sunlight barely reaches, Smithsonian scientists and a team of collaborators have discovered one of the blackest materials known: the skin of certain fish. These ultra-black fish absorb light so efficiently that even in bright light they appear to be silhouettes with no discernible features. In the darkness of the ocean, even surrounded by bioluminescent light, they literally disappear.

In the July 16 issue of the journal Current Biology, a team of scientists led by Smithsonian's National Museum of Natural History research zoologist Karen Osborn and Duke University biologist Sönke Johnsen report on how a unique arrangement of pigment-packed granules enables some fish to absorb nearly all of the light that hits their skin, so that as little as 0.05% of that light is reflected back. Mimicking this strategy could help engineers develop less expensive, flexible and more durable ultra-black materials for use in optical technology, such as telescopes and cameras, and for camouflage, Osborn said.

[. . .]

The near-complete light absorption of ultra-black fish depends on melanin, the same pigment that colors and protects human skin from sunlight. Osborn and her colleagues discovered that this pigment is not just abundant in the skin of ultra-black fish, it is distributed in a unique way. Pigment-filled cellular compartments called melanosomes are densely packed into pigment cells and these pigment cells are arranged very close to the surface of an ultra-black fish's skin in a continuous layer. The size, shape and arrangement of the melanosomes cause them to direct any light they do not immediately absorb toward neighboring melanosomes within the cell, which then suck up the remaining light.

"Effectively what they've done is make a super-efficient, super-thin light trap," Osborn said. "Light doesn't bounce back; light doesn't go through. It just goes into this layer, and it's gone."

[Continues . . .]

The paper is open access:

"Ultra-black Camouflage in Deep-Sea Fishes" | Current Biology

[jumbojak]

The link seems to lead to a blank page.

[Dark Lightning]

Hmm. I got lucky and saw the page, I guess. It may have changed since I viewed it. That's very cool technology, is all I can say! Yeah, I know that it's biology, but still.

[Recusant]

The link seems to lead to a blank page.

Every link I gave? Hmm, I don't know how that happened.

[jumbojak]

The link seems to lead to a blank page.

Every link I gave? Hmm, I don't know how that happened.

Oh, I just clicked on the Current Biology link. Still steering clear of the pop-sci sites but the girlfriend is fascinated by the deepest blacks and I was trying to send it to her.

Where's that innuendo thread again...

[Randy]

That is quite interesting. I wonder if scientists will be able to replicate this. I know they have made some pretty black material in the past.

[Recusant]

The link seems to lead to a blank page.

Ah, OK. Maybe your computer doesn't like the redirects involved. I used a DOI link, because I wasn't sure the address it directs to will work on its own. We'll try that address and see if you have any better results:

"Ultra-black Camouflage in Deep-Sea Fishes"