Several species of wild Antarctic fish bring on their own “ antifreeze ” protein that obligate to ice crystals and stop them from growing in the blood line . While this help Pisces come through in icy amnionic fluid , those same protein also terminate ice crystals from melting even when temperatures warm up up , according to a newstudypublished inProceedings of the National Academy of Sciencesthis week . The build - up of protein - stabilized ice quartz in their bodies could damage tissue during warm experimental condition .
Five families of notothenioid fishes inhabit the wintry Southern Ocean and make up more than 90 percent of the fish biomass of the part . In the 1960s , researcher discover how protein bind to crank crystals in the blood to prevent these Pisces from freezing , allowing them to dominate the ocean around Antarctica . But , “ adaption is a account of trade - offs and compromise,”saysPaul Cziko from the University of Oregon . “ Every good evolutionary innovation belike come up with some bad , unintended effect . "
Cziko and colleagues wanted to see if the ice crystals obligate to antifreeze proteins inside Pisces would melt during warmer season . They evaluate brine temperatures for 11 years using temperature - logging machine in McMurdo Sound , one of the world ’s coldest Antarctic fish habitats . They also tested the antifreeze proteins in the laboratory .
" We discovered what appear to be an unwanted consequence of the evolution of antifreeze proteins in Antarctic notothenioid fishes , " Cziko say in anews liberation . " The antifreeze proteins also lay off inner ice crystals from melting . That is , they are anti - melt proteins as well . "
A tenner is a substantial portion of the notothenioid lifespan , and not once in that time did temperatures increase enough to overcome the anti - melting core and rid the Pisces the Fishes of their internal ice totally . Even those swim in relatively warmer Antarctic summertime water – at temperature where they would be expected to be free of ice – had chalk crystals . When the researchers warm them up to temperatures above the look melting gunpoint , some internal ice crystal still failed to melt . When ice does n’t mellow out at its normal melting full stop , it ’s called " superheated , " and this body of work may be the first model of ice superheating in nature .
The investigator distrust that the accretion of ice could be serious and maybe even fatal , but no untoward physiologic consequences have been hear yet . If the fish are destine to carry ice-skating rink crystals around all their lives , ice mote could obstruct diminished capillaries or trigger unsought inflammatory responses , saysstudy coauthorChi - Hing Christina Cheng of the University of Illinois , Urbana - Champaign . The potential danger is like the threat pose by asbestos in the lungs or blood clots in the brain , Cziko explains . But since a caboodle of the ice accumulates in the spleen , maybe the fish have a mechanics to clear up it from circulation .
image : Paul Cziko ( top ) , Elliot DeVries ( middle )
