The Grand Prismatic Spring in

Yellowstone National Park Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowston ...

is the largest

hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, and the third largest in the world, after Frying Pan Lake in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and

Boiling Lake The Boiling Lake is a flooded fumarole located in Morne Trois Pitons National Park, a World Heritage Site on the island of Dominica. The lake, located east of Dominica's capital Roseau, is filled with bubbling greyish-blue water that is usually e ...

Dominica Dominica ( or ; Kalinago: ; french: Dominique; Dominican Creole French: ), officially the Commonwealth of Dominica, is an island country in the Caribbean. The capital, Roseau, is located on the western side of the island. It is geographically ...

. It is located in the

Midway Geyser Basin The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at 10, ...

. Grand Prismatic Spring was noted by geologists working in the

Hayden Geological Survey of 1871 The Hayden Geological Survey of 1871 explored the region of northwestern Wyoming that later became Yellowstone National Park in 1872. It was led by geologist Ferdinand Vandeveer Hayden. The 1871 survey was not Hayden's first, but it was the first ...

, and named by them for its striking coloration. Its colors match most of those seen in the

rainbow A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows c ...

dispersion of white light by an optical

prism Prism usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentary ...

: red, orange, yellow, green, and blue. Grand Prismatic Springs in July

History

Aerial image of Grand Prismatic Spring (view from the south)

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 The American Fur Company (AFC) was founded in 1808, by John Jacob Astor, a German immigrant to the United States. During the 18th century, furs had become a major commodity in Europe, and North America became a major supplier. Several British co ...

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 The Washburn Expedition of 1870 explored the region of northwestern Wyoming that two years later became Yellowstone National Park. Led by Henry D. Washburn and Nathaniel P. Langford, and with a United States Army, U.S. Army escort headed by Lt. G ...

visited the spring, noting a

geyser A geyser (, ) is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only in ...

nearby (later named

Excelsior Excelsior, a Latin comparative word often translated as "ever upward" or "even higher", may refer to: Arts and entertainment Literature and poetry * "Excelsior" (Longfellow), an 1841 poem by Henry Wadsworth Longfellow * ''Excelsior'' (Macedo ...

Color

The bright, vivid colors in the spring are the result of

microbial mat A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts. ...

s 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 (also chlorophyl) 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 allow plants to a ...

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...

s 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.

Physical structure

The spring is approximately in diameter and is deep. The spring discharges an estimated of water per minute.

References

External links

{{Wyoming Geothermal features of Yellowstone National Park Hot springs of Wyoming Geothermal features of Teton County, Wyoming Hot springs of Teton County, Wyoming