What Causes a Brinicle to Form?

[Monique]

Amazing footage by BBC Nature, I had to share:

 

[Ryan_m_b]

This absolutely brilliant documentary series (Frozen Planet) is on tonight at 9 on BBC 1. Well worth a watch!

 

[turbo]

I love David Attenborough's voice! I bought the BBC version of Planet Earth just because he narrated it - not the US Susan Sarandon version.

 

[turbo]

I love David Attenborough's voice! I bought the BBC version of Planet Earth just because he narrated it - not the US Susan Sarandon version.

We have "Planet Earth" queued up for the holiday so we can revisit this classic over a period of days and avoid the tripe that the networks are selling as "classics".

I'm no business-entertainment guru, but I'll be willing to bet that if a cable channel would loop Planet Earth continuously, parents would set their cable channel permissions accordingly. Their children would at least be a bit better educated.

Perhaps I'm a bit optimistic regarding the motivations of the parents...

 

[Andy Resnick]

whoa...

 

[SW VandeCarr]

whoa...

Can someone explain the physics involved here? I can understand seawater being liquid at say -3 C, and fresh water would freeze at this temperature, although not as fast as it appears to here. Why would fresh water sink in seawater? Fresh water has a maximum density at +4 C and becomes less dense at lower temperatures. That's why ice forms on the surface and floats.

EDIT: OK. I missed the first sentence the first time I saw this. This is a stream of liquid brine at a lower temperature than the seawater. Because of its high salinity the brine "finger" remains liquid, but the less saline seawater has a higher freezing point and freezes around the liquid column as the heavy brine descends. Fascinating.