Brinicles

A superb TV series is currently taking people in the UK by storm. It is called ‘Frozen Planet’ and narrated by Richard Attenborough – it really is a classic and has relied heavily on the use of new technologies to aid its filming.

The programme focuses in on life in the Antarctic and Arctic and has so far covered the seasons. Last night it was Winter and some superb footage was released of a ‘brinicle’.

Unfortunately, if you live outside the uK you are not able to access clips on the BBC website – however, this was so amazing that it is all over YouTube (embedded clip below)

A ‘brinicle’ is a name that has been dubbed to this unique feature. From what I can understand, the brinicle is an icicle that has been formed from the freezing effect of brine. At the surface, where the temperature is extremely cold, sea water freezes to form ice. It leaves behind the salt. This salt effectively becomes concentrated at the ice / water boundary and as it is denser than water it sinks. The sea water is supersaturated brine and so it has a lower freezing point than the surrounding sea water.

Because it has a lower freezing point it is in effect colder than the other sea water and as the it sinks, it causes the seawater to freeze. A sheath of ice forms around it and it grows down to the sea floor where it freezes everything it comes into contact with – the clip shows this in all of its deadly beauty.

[youtube]LMhBuSBemRk[/youtube]

Three further points:

1. The clip can also be viewed here (if you live in the UK)
2. There is a good wikipedia article on ‘Ice Stalactites’ that explains the phenomena much more succinctly than me.
3. Is that a sea urchin with ear muffs entering the left hand side of the screen at 1 min 18 sec?! 😆