• The Yellowstone Ecosystem


    An ecosystem is defined as a community of organisms and their environment, interacting physically, chemically, and in regard to energy. The Yellowstone ecosystem includes living animals from bison and grizzly bears to microscopic thermophiles and a physical environment that includes a giant live volcano over a huge reservoir of molten rock, mountain ranges, high plateaus, lakes, rivers and river valleys covering over 18 million acres of Wyoming, Montana and Idaho, forming an area roughly the size of West Virginia. It is one of the largest wild temperate zone ecosystems on the planet.

    The smallest living things in Yellowstone are the most recently discovered. In 1966 Dr. Thomas Brock discovered a bacterium in the Lower Geyser Basin of Yellowstone Park, near Great Fountain Geyser and White Dome Geyser. Three years later they were to name it Thermus Aquaticus, meaning an organism that can live in extremely hot water. Since its discovery, other thermophiles, meaning heat loving, and thermotolerant species of bacteria and archaea, another type of microorganism, have been discovered in Yellowstone’s hot springs, geysers, fumaroles and mudpots. Some form streamers and others live in mats, which may include thermophilic fungi as well, and the varied colors of mudpots are due to thermophiles’ pigments, such as chlorophyll and carotenoids. The latter is similar to the vitamin A that gives carrots their orange color. Species of thermophiles can be identified in the various thermal features by their colors. They can be pink, yellow, black, green, orange or white.

    Some thermophiles thrive not only in extreme heat but also in highly acidic or alkaline conditions, or in solutions of chemicals such as sulfur. The bacteria are thought related to the cyanobacteria, the earliest bacteria to inhabit the planet, and the organismsm responsible for making our atmosphere oxygen-rich. Archeae predate even the cyanobacteria. Both encourage speculation about life forms that might be able to inhabit planets with conditions our species considers severe.

    At one time it was thought that all life on Earth depended upon photosynthesis in one way or another, but T. aquaticus and some of the other thermophiles are exceptions to this rule, relying upon processing chemicals to get energy. Some thermophiles change hydrogen or sulfur into forms other thermophiles can use. Some thermophiles, on the other hand, do photosynthesize, providing oxygen for other thermophiles. Cyanobacteria and non-sulfur green bacteria are among the photosynthesizers.

    Around the thermal features of Yellowstone, diatoms are found in the soil. Diatoms make the soil unique, since in other parts of the world they are found only in water environments. Thermophilic fungi and bacteria also inhabit the hot soil around hot springs and other heated water.