The Grand Prismatic Spring in
Yellowstone National Park is the largest
hot spring
A hot spring, hydrothermal spring, or geothermal spring is a Spring (hydrology), spring produced by the emergence of Geothermal activity, geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow ...
in the United States, and the third largest in the world, after
Frying Pan Lake
Frying Pan Lake (renamed Waimangu Cauldron in 1963 though not widely used) is the world's largest hot spring. It is located in the Echo Crater of the Waimangu Volcanic Rift Valley, New Zealand and its acidic water maintains a temperature of about ...
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 most of those seen in 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 four 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 . In 1870 the
Washburn–Langford–Doane Expedition visited the spring, noting a
geyser nearby (later named
Excelsior).
Color
The bright, vivid colors in the spring are the result of
microbial mats of
thermophilic
A thermophile is a type of extremophile that thrives at relatively high temperatures, between . Many thermophiles are archaea, though some of them are bacteria and fungi. Thermophilic eubacteria are suggested to have been among the earliest bact ...
bacteria around the edges of the mineral-rich water. The mats produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of
chlorophyll
Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy ...
to
carotenoids and on the temperature gradient in the runoff. 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
intrinsic blue color of water. The effect is strongest in the center of the spring, because of its sterility and depth.
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Physical structure
The spring is approximately in diameter and is deep. The spring discharges an estimated of water per minute.
References
{{Wyoming
Geothermal features of Yellowstone National Park
Hot springs of Wyoming
Geothermal features of Teton County, Wyoming
Hot springs of Teton County, Wyoming