Fish in the frigid waters in Antarctica have a special protein in their blood that acts like antifreeze in a car, keeping ice crystals small enough so the vehicle does not freeze.
According to the Washington Post, the researchers found that this protein does them little good in warmer temperatures. In fact, warm water can be problematic for the fish, because the ice crystals do not melt at their given melting point, they become "superheated."
Published in the journal Proceedings of National Academy of Sciences, the new study may have observed "superheating" for the first time in nature.
"We discovered what appears to be an undesirable consequence of the evolution of antifreeze proteins in Antarctic notothenioid fishes," study co-author Paul Cziko, a doctoral student at the University of Oregon, said in a press release. "What we found is that the antifreeze proteins also stop internal ice crystals from melting. That is, they are anti-melt proteins as well."
Another author on the study and an animal biology professor at the University of Illinois, Arthur DeVries first discovered these antifreeze proteins in the Antarctic's fish in the 1960s. The researchers expected the proteins to melt in Antarctica's warmer summer waters, but it was not the case. Instead they found the proteins were also responsible for disallowing the ice crystals to melt.
"Since much of the ice accumulates in the fishes' spleens, we think there may be a mechanism to clear the ice from the circulation," Cziko said. "This is just one more piece in the puzzle of how notothenioids came to dominate the ocean around Antarctica.
"It also tells us something about evolution. That is, adaptation is a story of trade-offs and compromise. Every good evolutionary innovation probably comes with some bad, unintended effects."
