Grand Prismatic Spring

Grand Prismatic Spring
An aerial view of Grand Prismatic Spring
Location	Midway Geyser Basin, Yellowstone National Park, Teton County, Wyoming
Coordinates
Elevation	7,270 feet (2,220 m)
Type	Hot spring
Discharge	560 US gallons (2,100 L) per minute
Temperature	160 °F (70 °C)
Depth	160 feet (50 m)

The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin.

Grand Prismatic Spring was noted by geologists working in the Hayden Geological Survey of 1871, and named by them for its striking coloration. Its colors match the rainbow dispersion of white light by an optical prism: red, orange, yellow, green, and blue.

History

The first records of the spring are from early European explorers and surveyors. In 1839, a group of fur trappers from the American Fur Company crossed the Midway Geyser Basin and made note of a "boiling lake", most likely the Grand Prismatic Spring, with a diameter of 300 feet (90 m). In 1870 the Washburn–Langford–Doane Expedition visited the spring, noting a 50-foot (15 m) geyser nearby (later named Excelsior).

Color

The vivid colors in the spring are the result of pigmented archaea in the microbial mats that grow around the edges of the mineral-rich water. The archaea produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids and on the temperature of the water which favors one archaea over another. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green. The center of the pool is sterile due to extreme heat.

The deep blue color of the water in the center of the pool results from the scattering of blue light by particles suspended in the water. This effect is particularly visible in the center of the spring due to the lack of archaea that live in the center and the depth of the water.

Physical structure

The spring is approximately 370 feet (110 m) in diameter and is 121 feet (40 m) deep. The spring discharges an estimated 560 US gallons (2,100 L) of 160 °F (70 °C) water per minute.

Gallery

• Grand Prismatic Spring in Yellowstone.jpg
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• GrandPrismaticSpring.jpg
• Grand Prismatic Spring 2013.jpg
• Yellowstone Grand Prismatic Spring p1110210.jpg