An unusual underwater phenomenon they called “icicle of death” has been filmed by BBC crew in Antarctica. This has equipped with high end time-lapse cameras, the group recorded salt water being excluded from the sea ice and sinking down to the ocean floor. The temperature of this brine is less than 0C, leading water to freeze in an icy casing called “brinicle.” When “brinicle” met the sea bed, a web of ice formed that froze the whole thing it touched, as well as sea urchins and starfish. The strange phenomenon was filmed for the first time by cameramen Hugh Miller and Doug Anderson for the BBC One series Frozen Planet. The icy phenomenon is mainly caused by cold, sinking brine, which is more-dense than the rest of the sea water. It forms a brinicle as it contacts warmer water below the surface. It’s a bit of a race against time because no-one really knew how fast they formed. The location underneath the ice offs the foothills of the volcano Mount Erebus, in water as cold as -2C – really not easy to access.