From Peter Watson, Ottawa, Canada
Your excellent article on water starts off by saying that if it behaved like a normal liquid and became denser as it cooled, lakes would freeze from the bottom up, killing all the fish (2 June, p 26). But freezing kills living things because water expands when it turns to ice and hence breaks the cell walls around it. If it were a “normal” liquid, it would contract, and freezing would be harmless. Those animals that must survive freezing have various ingenious biochemical tricks to keep the water liquid and high density.
The editor writes:
• We should perhaps have said that cell rupture is not the only problem. Freezing would deprive fish, and the organisms they feed on, of food on the sea or lake floor: they would probably starve.
Advertisement
