Montana-Wyoming 2011 - July 16, 2011 - Yellowstone - "A symphony of fire and water"

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A current video about Yellowstone calls the park "a symphony of fire and water" and I can't come up with a better description. Water is everywhere - flowing, spouting, steaming and gurgling. Water has shaped the landscape and provided much of the explosive energy that has created such features as the West Thumb limb of Yellowstone Lake. It constantly percolates down from the surface into the porous and cracked rock underneath, reaching great depths where pressure can result in water remaining in the liquid form at temperatures higher than 400 degrees. Water in the form of glaciers formed many of the valleys and left behind rock piles known as moraines, as well as large boulders strewn about haphazardly.

But one of the most visible activities of water is to emerge from underground as one of the various thermal features. The hottest of these are fumaroles and steam vents, where only steam and hot gases emerge, sometimes with a loud roar. These may deposit crystals of sulphur around the vent, but are relatively uninteresting. Of more interest to the casual viewer are the hot pools and spring and the geysers.

In hot springs and pools, the water comes up very hot but without any restriction of flow, so it just flows out. Sometimes there is some bubbling from hot gases coming up with the water, and less commonly actual boiling (which occurs at 199 degrees at this altitude). When there is a constriction of flow, then a geyser may form. The constriction prevents water from heading toward the surface as fast as it would like, and the pressure causes water and steam to be ejected violently from the surface, with streams of water going as high as 300' for the largest geysers. Geysers may be either fountain geysers, typically erupting through pools of hot water in spasmodic bursts, or cone geysers, which push steady jets of water skyward in a more uniform fashion.

Old Faithful is the best known of the geysers, and is a cone type geyser. It is certainly not the largest and not even the most dependable of the geysers, but combines the dependability with a large display that gets it all the press. It currently erupts at about 93 minute intervals, somewhat lengthened since the 1959 Hebgen Lake earthquake which altered many of the thermal features in the park.

The largest geyser is Steamboat Geyser, and its major eruptions with jets of water going up to 300' make it the largest currently active geyser in the world. The expression "currently active" is somewhat misleading. It does continue to erupt, but at intervals ranging from one month to 50 years. It was completely dormant from 1911 to 1961, and its last major eruption was in 2005.

The largest spring is Grand Prismatic Spring, which is over 300' across, making it impossible to see the entire thing except from the air. Like all such springs, it has multiple colors. The hottest water in the center is blue and clear, since the water absorbs all frequencies except blue. As you get out to the edges, you begin to see yellows and oranges, which are mats of thermoacidophilic bacteria. These can exist in some of the most extreme conditions on earth, in water with a pH of 3 and a temperature of 130 degrees. One species, Thermus aquaticus, contains a polymerase enzyme which can remain active at high temperatures, and this capacity has been exploited worldwide now to make polymerase chain reactions more efficient for use in DNA fingerprinting, forensic analysis, and disease detection, highlighting the iportance of preserving even the most seemingly insignificant species.

During our visit, we were lucky enough to be around at the right time to see eruptions of both Giant Geyser and Great Fountain Geyser, which erupt about twice a day or less and are much less predictable than some other geysers. To say they were spectacular is a grand understatement.

Another type of feature in the park is mud pots. In these, sulphur processing bacteria produce highly acidic conditions which degrade the rock into a fine clay. Water and steam then bubble through the clay and produce either foul-smelling bubbling vats or areas where bubbles slowly erupt through thicker clay with a plop, producing fantastic landscapes.

In some of the geysers basins, the hot runoff goes directly into the Firehole River. In the summer this can raise the water temperatures in the river to 80 degrees, forcing the local trout to retreat into cooler tributaries.

One sad image is that of Morning Glory Pool. I am including a picture I took in 1981 and one from this trip. You can clearly see the loss of the deep blue center and much less beauty as a result of tourists throwing coins and other objects into the pool, stopping up the plumbing and reducing the heat, thus allowing the colorful bacterial mats to encroach on the center and losing he beautiful blue center from very hot water there.

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