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Fluorescence and antifreeze: How fish brave the arctic cold

Fluorescence and antifreeze: How fish brave the arctic cold

Travel and antifreeze
How fish brave the arctic cold

In the Arctic, the diversity of fish species is limited because only a few groups have adapted to adverse conditions. Even more interesting is the kind of disc bellies that have special abilities. But this is exactly what could soon be fatal to animals.

David Gruber and John Sparks already know that this inconspicuous fish is something special I mentioned a year ago: At the time, researchers at the American Museum of Natural History in New York wrote that juveniles are fish species Liberis Gebus It can glow in the dark – that is, red and green. This makes it the only arctic fish in which fluorescence has been detected. Now the research duo follows suit: according to this, the species produces large amounts of anti-frost proteins.

You probably need them too, because the family of disc bellies (liberida) lives off the coast of Greenland surrounded by icebergs at a water temperature of about -2 ° C. “Similar to the way the antifreeze in your car prevents the water in the radiator from freezing when it’s cold, some animals have amazing mechanisms that protect them from frost,” biologist Gruber was quoted as saying in a statement from the museum.

Packed with anti-freeze proteins

Image of Liberis gibbos growing in white light.

(Photo: J. Sparks, Dr. Gruber/D.B.)

Antifreeze proteins prevent the formation of ice crystals, such as Journal researchers Write “evolutionary bioinformatics”. Genetic analyzes showed that these substances are formed in large quantities. “We learned that this little discoid belly, which lives in very cold water, produces anti-frost proteins,” says Gruber. “But we didn’t realize how much he was devouring them — and how much effort it was going to put in to make these proteins.”

Proteins that form mainly in the liver have been known in some fish for 50 years, and so far five gene groups responsible for these proteins have been recorded. on the belly of the disc El Jebus According to the researchers, two sets of genes are active. The fish is usually 10 cm in length and reaches a maximum length of about 50 cm.

Perhaps, the authors fear, their modification to extreme cold may prove fatal to fish in the future. Because the North Pole is currently warming much faster than the rest of the planet. According to predictions, the area could be ice-free in summer by the middle of the century – the lack of a protective, light-colored layer of ice should warm the water even more.

Danger from the climate crisis

“The Arctic Sea does not support a great diversity of fish species,” says co-author Sparks. The study notes that as temperatures rise, species like the discoid belly are facing increased competition “from species from more temperate regions that previously could not have survived in these northern latitudes.”

The disc-bellied family includes about 420 species that live in the Atlantic and Pacific Oceans – often in harsh environments. A few years ago, three new species were discovered in the Pacific Atacama Trench at a depth of about 7,500 m, and another species at a depth of about 8,000 m in the Mariana Trench.

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