The Great Fountain Geyser is a fountain-type geyser located in the Firehole Lake area of Lower Geyser Basin of Yellowstone National Park

Yellowstone National Park

Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

, Wyoming. It is the only predicted geyser in the Lower Geyser Basin.

Eruption

The geyser erupts every 9 to 15 hours. Great Fountain's maximum height ranges from about 75 feet (22.9 m) to over 220 feet (67.1 m). Its duration is usually about one hour but durations of over two hours have been seen. The duration of an eruption affects the interval that will elapse before the next eruption, so that if the duration of an eruption is recorded, the time of the following eruption can be predicted to a precision of about two hours. The prediction can be refined, to plus or minus 15 minutes or so, through observation of overflow from the crater during the period between eruptions. While this pattern of behavior is observed most of the time, there are occasional episodes of so-called "wild-phase" activity during which the eruptions are of greatly extended duration and intervals between eruptions may be as long as three days. The geyser is then unpredictable until wild-phase activity ceases and more normal eruptions resume.

Nearby White Dome Geyser

White Dome Geyser

White Dome Geyser is a geyser located in the Lower Geyser Basin in Yellowstone National Park in the United States.White Dome is a conspicuous cone-type geyser located only a few feet from Firehole Lake Drive, and accordingly, seen by many visitors to the park as they wait for eruptions of nearby...

, which erupts considerably more frequently (albeit less powerfully) from a large geyserite

Geyserite

Geyserite is a form of opaline silica that is often found around hot springs and geysers. Botryoidal geyserite is known as fiorite. It is sometimes referred to as sinter.-References:*...

 cone, is easily seen from the same parking lot that affords a viewpoint for Great Fountain. The thermophilic

Thermophile

A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122  °C . Many thermophiles are archaea...

 bacterium Thermus aquaticus

Thermus aquaticus

Thermus aquaticus is a species of bacterium that can tolerate high temperatures, one of several thermophilic bacteria that belong to the Deinococcus-Thermus group...

, important because it produces an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 used in polymerase chain reaction

Polymerase chain reaction

The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

 laboratory procedures central to modern molecular biology

Molecular biology

Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

, was first isolated from Mushroom Pool, a non-eruptive hot spring

Hot spring

A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...

 a few hundred feet from White Dome Geyser.