Walking uphill from the previous steaming pool, we came to the biggest hot spring in the park, the Grand Prismatic Spring. I have to say, I was a bit disappointed by this one – this was a feature I'd been anticipating for a long time, but you can only get a partial idea of the range of colors it contains from the ground (and in this picture), but to really appreciate its prism-ness, you need an aerial view. (Or one from space).
This is what you can see from ground level. The overflow from the spring travels in thin sheets across the ground, so the only place it's safe to walk is along a raised boardwalk.
The mineral-rich water deposits thin layers of crust as it cools. The crust is pretty fragile, which is another reason the NPS wants you to stay on the boardwalk.
These little terraces are home to dense mats of microbes.
The vivid blue of the center of the pool is just the blue of clear, deep water; but the brilliant oranges and reds of the periphery are the photosynthetic pigments of vast multitudes of thermophilic archaebacteria (what we old-timers used to call 'cyanobacteria', or just plain old 'blue-green algae').
Posted by David Fleck at 07 April 2007 07:01 PM
There are archaebacteria in the picture; there are almost certainly cyanobacteria there as well, since they are almost everywhere, at least everywhere there is even a little water.
From your remark, I gather that the archaebacteria used to be grouped with the cyanobacteria. Or do I misunderstand you? Were they in the same bacteria phylum? In my very quick search, I didn't find that connection.
Posted by: Jim Miller on April 7, 2007 06:56 PM
Jim-
Back when I was either being a student of this stuff or forcing it upon hapless pupils, all our texts asserted that there were five, count' em, five, kingdoms, and everything that wasn't a eukaryote was lumped together in the Monera. As a vertebrate-oriented guy, I decided that that one term (Monera) was all the mental real estate that I was prepared to devote to the little buggers.
Posted by: David Fleck on April 10, 2007 08:20 PM
David,
There is a way to see the Grand Prismatic from above. As you come out of the car park for Excelsior and Grand Prismatic, turn right and drive for about one mile. There is a turnoff on the right for the Fairy Falls Trail car park. Leave the car there and you will find a metal bridge across the river. Follow the trail and you will eventually see the Prismatic on your right. Keep an eye open for small footpaths where others have made their way up the hill. There is no official footpath, but make sure you are right alongside the Spring before you start climbing. If you get the opportunity to go back to Yellowstone it's worth doing.
Best regards
Sheila Parsons
Posted by: Sheila Parsons on April 30, 2007 08:50 AM