Friday, July 1, 2011

Rising Above Grand Prismatic

There is so much to see and experience at Yellowstone National Park that even if I were to spend a lifetime here I could never see it all. In light of this situation, you might think I would never consider going back to someplace I’ve already visited.

Au contraire! Especially if the experience is from another perspective. Early in my summer season I had gone to check out Midway Geyser Basin and particularly Grand Prismatic Spring. At the time I ended up seeing very little of the thermal features at Midway due to the frigid air temperature, fogged glasses and a continuous snootful of steam. This 200–foot wide gem of a hot spring is the largest in North America and the deepest (111 feet) in Yellowstone, and I was determined to see it sometime in clearer air. Fellow park ranger Amy and I could not have picked a better last day of June for my return and her first visit.

FireholeRiver(a)
Firehole River At Midway Geyser Basin
AmyAtMidway GeyserBasin
Amy on the bridge

GrandPrismatic(a)
Boardwalk at Grand Prismatic Spring
GrandPrismatic(b)
Grand Prismatic Spring



 











Midway Geyser Basin extends for about a mile along the Firehole River. Besides Grand Prismatic there is Excelsior Geyser Crater, which last erupted as a geyser in 1888 but as of 1994 was continuing to pump out a constant flow of around 4000 gallons of boiling water each minute. The last witnessed eruptions of Excelsior in 1888 were so violent that they blew out all the constrictions in the “plumbing” of the geyser. This allowed the water to flow freely to the surface as a hot spring – Excelsior will not erupt as a geyser until something once again constricts the water’s path to the surface.

ExcelsiorGeyser Crater(a)
Excelsior Geyser Crater

ExcelsiorGeyser Crater(b)
Excelsior Geyser Crater






















Smaller but no less exquisite pools at Midway include Turquoise and Opal.

TurquoisePool_ MidwayGeyser Basin(b)
Turquoise Pool
OpalPool_MidwayGeyserBasin
Opal Pool



















The boardwalk at Grand Prismatic does not go all the way around it but traverses only one edge, so it is difficult to see the entire pool because it is so big. However, there is a path that climbs to a nearby ridge, allowing jaw-dropping views of many of the hydrothermal features at Midway. Amy and I were soon toodling up the steep path, pulling ourselves over tree roots, downed trunks, and obsidian outcrops while stopping frequently for photo ops until we reached the high point along the ridge.

GrandPrismatic(d)
Grand Prismatic Spring
 
OnTheWayUp
Yours Truly with a birds-eye view
AmyAndThe Obsidian
Amy at the obsidian


























Communities of thermophiles, or heat-loving micro-organisms, give the edges and runoff channels of these hot springs their diverse colors. Some bacteria called thermocrinus form orange filaments and streamers at temperatures above 167°F (75°C) – these bacteria can also be pink, or yellow, or gray. Other orange cyanobacteria are believed to be similar to the first life forms on earth that were capable of photosynthesis – these form long filaments that entwine themselves into mats and live at temperatures between 113°F and 167°F (45°C and 75°C). Olive–green cyanobacteria mats mix with iron in runoff channels and cooler areas of the springs at temperatures less than 167°F (75°C).

The deep turquoise blue at the center of many thermal pools is a result of all the prismatic colors of the sunlight spectrum being absorbed by the water except for blue, which is reflected outward. Water is near the boiling point (≈199°F at these Yellowstone elevations). Photosynthetic organisms are unable to survive at this high temperature, but as the water gradually cools outward towards the edges of the pools, varied communities of colorful microorganisms not only live but thrive.

Now that I’ve been to Midway Geyser Basin twice, should that mean I don’t want to go back?

MidwayGeyser Basin
   Grand Prismatic Spring at Midway Geyser Basin  


2 comments:

  1. THANKS RANGER N,

    I APPRECIATE THE INFORMATION ON THE COMMUNITIES OF THERMOPHILES. IT REALLY IS INTERESTING FOR SOMEONE LIKE ME WHO KNEW ABSOLUTELY NOTHING ABOUT HOW THE VARIOUS COLORS DEVELOPED.

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  2. Except for the fact that's there So much else to see at Yellowstone, why not go back. The hike was worth it for that awesome view.

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