Prominent Biofluorescence Discovered in Arctic Fish

by johnsmith

New research published in the American Museum Novitates is the first to document biofluorescence in Arctic fishes.

A juvenile variegated snailfish (Liparis gibbus) imaged under white light (A, B) and under fluorescent lighting (C, D) conditions. White light: (A) dorsal view; (B) ventral view. Fluorescent lighting: (C) dorsal view, showing both green and red fluorescence; (D) ventral view, showing green fluorescence and red fluorescent sucking disk. (C, D) note red fluorescent pectoral fin sticking out dorsally. Image credit: Gruber & Sparks.

A juvenile variegated snailfish (Liparis gibbus) imaged under white light (A, B) and under fluorescent lighting (C, D) conditions. White light: (A) dorsal view; (B) ventral view. Fluorescent lighting: (C) dorsal
view, showing both green and red fluorescence; (D) ventral view, showing green fluorescence and red fluorescent sucking disk. (C, D) note red fluorescent pectoral fin sticking out dorsally. Image credit: Gruber & Sparks.

Biofluorescence results from the absorption of electromagnetic radiation at one wavelength by an organism, followed immediately by its reemission at a longer, lower-energy, wavelength.

In clear ocean water, the light spectrum bandwidth progressively narrows with increasing depth, reaching a wavelength peak of 465 nm and a narrow bandwidth of 20 nm at the maximum depth of penetration.

Marine organisms biofluoresce by absorbing the dominant ambient blue light via a variety of fluorescent compounds and reemit it at longer wavelengths, visually resulting in green, orange, and red fluorescence.

American Museum of Natural History’s Professor John Sparks and Professor David Gruber previously identified more than 180 new species of fishes that biofluoresce.

Although this ability is now well documented in tropical fishes that live in regions where there is an even amount of daylight year-round, it was unknown how prolonged periods of darkness in the Arctic might affect fish biofluorescence.

“Overall, we found marine fluorescence to be quite rare in the Arctic, in both invertebrate and vertebrate lineages,” Professor Sparks said.

“So we were surprised to find these juvenile snailfish brightly fluorescing in not just one, but two different colors, which is very unusual in a single species.”

In their research, the authors documented prominent biofluorescence in two juveniles of the variegated snailfish (Liparis gibbus) collected from the coastal waters of Eastern Greenland as well as in an adult kelp snailfish (Liparis tunicatus) collected in the Bering Strait off of Little Diomede Island.

Surprisingly, variegated snailfish exhibited both green (523-530 nm) and red (674-678 nm) biofluorescence on discrete anatomical areas — a rare example of multiple fluorescent colors emitted from a single individual.

“Finding a red and green biofluorescent snailfish on a dive among icebergs at night felt like a moment straight from The Life Aquatic with Steve Zissou,” Professor Gruber said.

“We are now focusing our efforts on determining the function of fluorescence in various fish groups, including catsharks, where we have shown that bright green fluorescence enhances contrast in their pigmentation pattern, making it easier for individuals to see each other at depth,” Professor Sparks concluded.

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David F. Gruber & John S. Sparks. 2021. First report of biofluorescence in Arctic snailfishes and rare occurrence of multiple fluorescent colors in a single species. American Museum Novitates 3967; http://digitallibrary.amnh.org/handle/2246/7257

Source link: https://www.sci.news/biology/arctic-fish-biofluorescence-10657.html

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