Scientists drilling deep into an iceberg off Greenland have discovered a fish with glowing green antifreeze coursing through its veins.
The juvenile variegated snail (Liparis gibbous) contained the “highest expression levels” of antifreeze proteins ever reported, according to a new study.
Similar to how antifreeze helps regulate the Temperature from a car’s engine under extreme conditions, some species have evolved to enjoy similar protection, especially those that live in frigid habitats such as the offshore polar waters Greenland.
“Antifreeze proteins stick to the surface of smaller ice crystals and slow or prevent them from growing into larger, more dangerous crystals,” said study co-author David Gruber, a research associate at the Museum. American Institute of Natural History (AMNH) and a distinguished professor of biology at Baruch College at the City University of New York, Live Science said in an email. “Fish from the North and South Poles independently evolved these proteins.”
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Antifreeze proteins were first discovered in some Antarctic fish almost 50 years ago, according to the national science foundation (opens in a new tab).
Unlike some species of cold-blooded reptiles and insects, fish are unable to survive when their body fluids freeze, which can cause grains of ice to form inside their cells and essentially turn them into popsicles of fish.
“The fact that these different antifreeze proteins evolved independently in a number of different – and not closely related – fish lineages shows[s] how critical they are to the survival of these organisms in these extreme habitats,” John Sparks, curator in the AMNH Department of Ichthyology and co-author of the study, told Live Science in an email. .
Snails produce antifreeze proteins “just like any other protein and then excrete them into their bloodstream,” Gruber said. However, snails appear to “produce antifreeze proteins in the top 1% of all other fish genes”.
Scientists discovered the tiny tadpole-like creature in 2019 during an expedition while exploring iceberg habitats off the coast of Greenland. During the trip – part of the Constantine S. Niarchos Expedition, a series of scientific expeditions led by the AMNH – scientists were baffled when they discovered the biofluorescent snail glowing green and d a brilliant red in the icy habitat.
“The snailfish was one of the few species of fish that lived among the icebergs, in the crevices,” Gruber said. “It was surprising that such a small fish could live in such a cold environment without freezing.”
It is also rare for arctic fish to exhibit biofluorescence, which is the ability to convert blue light to green, red, or yellow light, because there are long periods of darkness, especially in winter, at the poles. Normally, this characteristic is found in fish swimming in warmer waters. This is the first reported case of an arctic fish species exhibiting this adaptation, according to a AMNH post (opens in a new tab).
The scientists further examined the snail’s biofluorescent properties and found “two different types of gene families that code for antifreeze proteins,” according to a separate statement, an adaptation that essentially helps them avoid turning into rods. frozen fish.
This mind-boggling level of antifreeze production could help this species adapt to a sub-zero environment, the statement said. It also raises a question about how snails will behave as ocean temperatures rise due to global warming.
“Due to rapidly warming Arctic waters, these cold-water adapted species will also have to compete with warmer-water species that are now able to migrate north and survive at higher latitudes (and that won’t need to produce antifreeze proteins to survive in warmer Arctic waters),” Sparks said. “In the future, [antifreeze] protein may no longer provide a benefit.”
The results were published on August 16 in the journal Evolutionary bioinformatics (opens in a new tab).
Originally posted on Live Science.