Antifreeze proteins depress the equilibrium freeze point, separating the freeze point from the melting point, creating a thermal hysteresis gap. In this gap, continual ice growth is inhibited and preventing freezing of the organism. Beyond this gap, freezing is inevitable. This can be observed with the nanoliter osmometer (a)–(c). (a) Above the equilibrium freeze/melting point ice crystals are absent. (b) After isolating individual ice crystals, within the gap ice crystals are seen to neither grow nor melt. (c) Beyond the gap, explosive growth of numerous ice crystals increases the opacity of the droplet, blocking microscope light.
