Grand Prismatic Spring

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Grand Prismatic Spring.

The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world^[1], next to those in New Zealand.

1 History
2 Color
3 Physical structure
4 References
5 External links

[edit] History

There is no doubt that many Native American peoples were aware of the Grand Prismatic Spring long before Europeans first saw it, but the first records of the Spring are from early explorers and surveyors.

In 1839, a group of fur trappers from the American Fur Company crossed the Midland Geyser Basin and made note of a "boiling lake", most likely the Grand Prismatic Spring^[2], with a diameter of 300 feet (91 meters).

In 1870, the Washburn Party, led by General Henry D. Washburn, visited the Spring, noting a 50 foot (15 meter) geyser nearby (later named Excelsior^[3]).^[4]

[edit] Color

Grand Prismatic Spring from the air, the bright colors in the spring are created by mats of bacteria growing in the warm, mineral rich water. The bright blue area is boiling water too hot for bacteria; the successive green, yellow, red, and orange bands are bacteria growing at progressively lower temperatures.

The vivid colors in the spring are the result of pigmented bacteria in the microbial mats that grow around the edges of the water. The bacteria produce colors ranging through greens, yellows, oranges, and reds; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green.^[5] The center of the pool is sterile because of its heat.

The deep blue color of the water in the center of the pool results from a light-absorbing overtone of the Hydroxy stretch of water ^[6]. Though this effect is responsible for making all large bodies of water blue, it is particularly intense here as a result of the high purity and depth of the water in the middle of the spring.

[edit] Physical structure

The spring is approximately 250 by 300 feet (75 by 91 m) in size and is 160 feet (49 m) deep. The spring discharges an estimated 560 gallons (2000 l) of 160°F (71°C) water per minute.^[7]

[edit] References

^ Steam Explosions, Earthquakes, and Volcanic Eruptions—What’s in Yellowstone’s Future?. U.S. Geological Survey. Retrieved on 2005-09-14.
^ VII. "The Fire Hole": Era of the American Fur Company, 1833-1840. Colter's Hell & Jackson's Hole - The Fur Trappers' Exploration of the Yellowstone and Grand Teton Park Region. Retrieved on 2005-09-14.
^ Notes. Yellowstone National Park: Its Exploration and Establishment. Retrieved on 2005-09-14.
^ Part II: Definitive Knowledge - The Washburn Party (1870). Yellowstone National Park: Its Exploration and Establishment. Retrieved on 2005-09-14.
^ Thomas D. Brock. Colorful Yellowstone. Life at High Temperatures. Retrieved on September 14, 2005.
^ Braun, Charles L.; Sergei N. Smirnov (1993). Why Is Water Blue?. Retrieved on May 23, 2006.
^ Grand Prismatic Spring. Geyser Observation and Study Association (GOSA) (2006). Retrieved on May 23, 2006.