This is a picture of sea ice from the plane when I went to help with the Magic Project of taking pictures of emperor pengions from 2500 feet.

Sea ice is a mass of frozen seawater that forms aroudn the margins of Antarctica. Pure water freezes at 0C however, seawater with a salinity of 35 parts per thousand is -1.91C. As water freezes at the ocean surface, the dissolved solids cannot fit into the crystalline structure of the ice so the salts are left behind to dissolve in surrounding sea water. The density and salnity of the surrounding water therefore increases and the greater salinity lowers the freezing point of the remaining water. The denser lower temperature water not in the ice sinks replaced by warmer less dense water creating circulation that enhances the formation of sea ice. Freezing is aided by low salinity and calm water conditions.

Sea ice forms as small needlelike crystals of a hexagonal shape eventually creating a slush that forms into a thin sheet broken by wind and waves creating disc shaped pancake ice. As furter freezing occurs the pancakes form ice floes. The rate at which this occurs is temperature dependant. Brine channels form in the sea ice but as it gets older these disperse and the ice becomes more pure.