We arrive at the northeast entrance of Yellowstone via Gardiner. Here the worlds first national park was founded in 1872 and became role-model for thousands of nature reserves in many countries on earth. In the park you find the worlds highest concentration of geysers, hot pools, fumaroles, and mudpots, powered by magmatic heat from deep underground. Three huge volcanic eruptions, the last one 640,000 years ago, spewed out millions of tons of debris and formed a 30 to 45 miles caldera thats nowadays in the middle of the park.
In the visitor centre one of five we get to know which roads are already closed for winter season. The first attraction is Mammoth Hot Springs. Hot thermal water becomes enriched with calcium carbonate on its way to the surface and the white limestone is deposited in the form of travertine as terraces and other forms. Besides the continuously changing limestone terraces the worlds largest there are three more hydrothermal formations in the park: A big accumulation of the fumaroles called steam vents are found 20 km south at Roaring Mountain. Hot pools are the most common phenomenon. The most impressive creation is geysers, hot pools with narrow spaces in their plumbing, usually near the surface. These constrictions prevent hot water from circulating and cause boiling water and steam eruptions.
There are many small pools and geysers in Norris Geyser Basin a bit more south on the western park road. They are habitat for different heat loving microorganisms. Those are mainly bacteria, Achaea that were assumed in former times to be bacteria, but have a different genetic structure, and viruses. There are Eukarya as well, single- or multi-cellular plants, animals or fungi. Different thermophiles live in different temperature ranges and have different glowing colours: The hottest areas between 140 and 181° F can be recognized by their yellow colour and their smell like rotten eggs when hydrogen sulphide is converted to sulphur. Iron processing bacteria and Achaea with brown to red colours live in water below 140° F. You can determine the coldest parts below 133° F based to their emerald-green colour from algae and bacteria containing chlorophyll, exchanging sunlight into energy.
The most spectacular geyser called Steamboat is at home in Norris Basin. It is the worlds tallest active geyser. It throws more than 100 m / 300 ft high, followed by thunders of steam for hours. Unfortunately the eruptions are entirely unpredictable and Steamboat can sleep for days, months, or even years. The last time it happened was 2005.