Friday, November 24, 2006

Methane clathrates off NZ coast

NIWA has just finished an expedition off the coast apparantly and tracked some indigenous methane clathrate deposits off the east coast of the Nth Island while studying the biology of the local inhabitants (which run entirely off the methane energy - no sunlight required. That's pretty cool all by itself).
The article is mistaken by referring to the deposits as 'frozen methane' although it's a pretty understandable mistake (for a journo major). A clathrate is a far more interesting beastie than plain old frozen methane (which freezes at -182.5 degrees Celcius -uumm did the reporter wonder why the water was still liquid...).
Clathrates get a good Wiki write-up here, complete with a very cool 'burning ice' photo. The methane molecule is literally trapped in a cage of water molecules. I'm not sure of the details (and i'm not sure the details are particularly clear to anyone) but some structures become more stable when they're built around scaffolding - to a chemist replace structure with 'hydrogen bonded water molecules' and scaffold with 'molecule'. Unlike say, a stone arch where you can remove the scaffolding after construction and still retain the structure, clathrates will collapse without both ingrediants.
The ice is trying to freeze which would normally create 'normal' ice (last time i checked there were at least a dozen structures for ice and an acquaintance at Oxford just made a name for himself by finding a brand new one) but in the presence of the methane, it self-assembles into a cage. As the ice starts to melt (by bringing it to the surface of the ocean) the methane is released. How cool is that?

It wouldn't surprise me in the least if NZ's methane clathrate reserves made Maui look like a puddle...

There plenty of energy sloshing around, we just haven't bothered to look for it.

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