Why don't fish freeze in Antarctic water?

07 September 2008

Question

Why is it that fish don’t freeze solid in Antarctic water and can we exploit the fact that they don’t freeze?

Answer

Helen: Wonderful question, thank you very much. The seas around Antarctica get incredibly cold. Because of the salt in it they can actually go down to -1.9 degrees centigrade. So how on Earth can things live there? In the 1980s scientists discovered that Antarctic cod or ice fish actually have antifreeze inside their blood. Since then scientists have been poking around trying to find out how it works. We're still not quite sure. It basically seems to be something to do with these things called glycopeptides. They're a protein covered in sugar which seem to stop ice crystals from growing any bigger by various ways of interacting with the water there. It also seems that the cod are able to survive with little tiny crystals in their blood. Their blood flows even if there's some little ones, as long as they don't grow any bigger they're ok. What can we do with it? It's something that it's possible we might be able to use these antifreezes for preserving donor organs. It's the idea of how do we stop things from freezing and not deteriorating whilst they are frozen? It could also be a better, more environmentally sensitive way of actually doing antifreeze for things like roads. Someone's actually started putting the genes for it inside of yeast so they can create it artificially and create lots of it. It's a possibility we might be using it. And on cars, perhaps!

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