This is a pretty cool phenomemon that not too many people have seen because 1. you have to be out and about in early winter, 2. you have to have a lot of herbaceous perennials, 3. just the right weather conditions, basically a very frosty night after milder weather, and 4. you have to be somewhere with all of these things together. Without going into a lot of detail, basically when root pressure continues to push water up a stem which has been cut or ruptured by freezing, the water can form elaborate ribbons of ice as it freezes in cold air. And hey, they sort of look like flowers. Obviously the ground temperature has not yet reached winter temperatures. At any rate some of these formations are pretty cool and have caught the imagination of a geologist here in the upper midwest. More pictures and more information here via Jim Carter.
Earth Day: Pogo and our responsibility
5 weeks ago in Doc Madhattan
3 comments:
Cool! I only just recently heard about this phenomenon. Lots of pretty pictures here: http://www.kuriositas.com/2012/12/frost-flowers-natures-exquisite-ice.html
TPP, I've seen these on dead wood, stumps, and coming up through gravel and rocks. Your comment about root pressure may be somewhat true, but it may not have any role to play, either. The ice forms at the interface of the luquid stage inside the object, and the liquid water feeds the expanding solid phase at that point. I don't think active transpiration or other "pushing" is needed. The solid ice pulls the liquid to the point where it can phase shift to solid. BTW, I belive the liquid is super-cooled at this point, as well, and is just waiting for an initiating event to convert to solid form.
Well, Dr. Chips really makes some good points as he usually does; dead stumps definitely don't have root pressure. I'd only ever seen them on herbaceous perennials. And I hadn't thought about super-cooled water. Guess that's my problem: it's more physics than biology. Drat!
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