At the North Pole, the diversity of fish species is limited because only a few populations have adapted to the adverse conditions. All the more interesting is a type of disc bellies that has special abilities. But it is precisely these that could soon be fatal to the animals.
David Gruber and John Sparks reported a year ago that this inconspicuous fish is something special: At that time, researchers at the American Museum of Natural History in New York wrote that young fish of the Liparis gibbus species can glow in the dark – red and green . This makes them the only fish in the Arctic for which fluorescence has been detected. Now the research duo is following suit: According to this, the species produces large amounts of anti-frost proteins.
She probably needs that too, because the species, which belongs to the family of the disc bellies (Liparidae), lives off the coast of Greenland surrounded by icebergs at a water temperature of around -2 degrees Celsius. “Similar to how the antifreeze in your car keeps the water in the radiator from freezing when it’s cold, some animals have amazing mechanisms that protect them from frost,” biologist Gruber is quoted as saying in a statement from the museum.
The anti-frost proteins prevent the formation of ice crystals, as the researchers write in the journal “Evolutionary Bioinformatics”. Genetic analyzes showed that these substances are formed in extreme amounts. “We knew that this small disk belly, which lives in extremely cold water, produces anti-frost proteins,” says Gruber. “But we didn’t realize how gorged he is on it – and how much effort he puts into producing these proteins.”
The proteins, which are mainly formed in the liver, have been known in some fish for a good 50 years. So far, five gene groups responsible for them have been registered. According to the researchers, two groups of genes are active in the disk belly L. gibbus. The fish are usually a good 10 centimeters long and reach a maximum of about 50 centimeters.
Possibly, the authors fear, the adjustment they have made to the extreme cold could be fatal for the fish in the future. Because the Arctic is currently warming up much faster than the rest of the planet. According to forecasts, the region could be ice-free in summer by the middle of the century – the lack of the protective light-colored layer of ice should then warm the water even more.
“The Arctic Sea doesn’t support a large diversity of fish species,” says co-author Sparks. The study suggests that with increasing temperatures, species such as the disc belly face increasing competition “from species from more temperate zones that previously could not survive in these more northerly latitudes”.
The disc-bellied family includes about 420 species that live in the Atlantic and Pacific – often in extreme environments. A few years ago, three new species were discovered in the Pacific Atacama Trench at a depth of about 7500 meters, and another species at a depth of about 8000 meters in the Mariana Trench.