The variegated snail is packed with natural antifreeze proteins at never-before-seen levels that help it survive in sub-freezing waters, new research has found. The the snail, known as the Liparis gibbus, is too distinctive thanks to biofluorescence, which causes it to glow green and red.
Study authors David Gruber and John Sparks, both researchers American Museum of Natural History scientists in New York, were part of the Constantine S. Niarchos Scientific Expedition in 2019 when they spotted a glowing snail off the east coast of Greenland.
Biofluorescence occurs when animals have the ability to convert blue light into green, red or yellow light. This trait is incredibly rare in arctic fish, which live in long periods of darkness. So far, the variegated snail is the only polar fish known to have this glow.
Gruber and Sparks collected a juvenile snailfish only about 3/4 inch (1.9 cm) long – about the size of a fingernail – compared to the average length of 4.5 inches (11. 4 cm) of an adult.
Scientists wanted to learn more about the snail’s biofluorescent properties when they came across something else in fish genetics: the highest expression levels of antifreeze proteins ever observed.
“In the same way that the antifreeze in your car keeps the water in your radiator from freezing in cold weather, some animals have developed amazing machines that keep them from freezing, like antifreeze proteins, which prevent the formation of crystals of ice,” said Gruber, a researcher. associate at the American Museum of Natural History and professor emeritus of biology at Baruch College at the City University of New York, in a statement.
“We already knew that this little snail, which lives in extremely cold waters, produced antifreeze proteins, but we didn’t realize just how full of these proteins it is – and how much effort it goes into making. these proteins.
As Arctic waters continue to warm due to the climate crisis, the future of the variegated snail, with its remarkable cold adaptation, is uncertain. said study co-author John Burns, principal investigator at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine.
The polar oceans are extreme environments for marine life and only creatures that have adapted to live in freezing temperatures can survive there.
Some species of insects and reptiles can survive if they experience partial freezing of their body fluids, but fish cannot. Antifreeze proteins, produced largely in the liver, prevent the formation of large grains of ice in their cells and body fluids.
Scientists first discovered antifreeze proteins in fish nearly 50 years ago. The researchers traced the proteins to five different genetic families.
The snail is particularly intriguing because it has two different types of gene families that encode antifreeze proteins: type I and type IV.
“The genes encoding type I antifreeze proteins are likely recent additions to the fish genome and can be actively extended to additional copies,” Burns said. “It’s like capturing evolution in action.”
The fact that scientists discovered so many genetic details in a juvenile snail reflects what happens as the fish grows and develops, Burns said.
“We see that in addition to growth, this juvenile fish also needs to invest heavily to protect itself from freezing,” Burns said. “The amount of RNA fish make to protect themselves from freezing is on par with what they invest in the fundamental cellular machinery, the stuff that makes their cells in the first place.”
Until now, scientists do not know if there is a link between biofluorescence and antifreeze proteins.
But warming temperatures in the Arctic could pose a threat to the very creatures that have adapted to survive there, meaning all the energy they put into protecting themselves from freezing temperatures is wasted effort, Burns said. .
Some scientists predict that if Arctic sea ice continues to decline at its current rate, the Arctic will be ice-free within the next three decades, according to the study authors.
“Arctic seas do not support a high diversity of fish species, and our study hypothesizes that with warmer ocean temperatures, ice specialists such as this snail may encounter increased competition from more temperate species that were previously unable to survive in these higher northern latitudes,” said Sparks, curator in the Department of Ichthyology at the American Museum of Natural History and professor at the museum’s Richard Gilder Graduate School, in a communicated.
Better understanding antifreeze proteins could help scientists translate their findings into biotech uses, such as protecting cultures from freezing or better determining the freezing properties of meat, Burns said.