Though the geyser basins may look like barren moonscapes, they’re often full of life! Don’t assume the vivid colors around the hot springs are minerals. There are some microscopic organisms that actually thrive in extremely hot water. They’re called thermophiles.
These communities of bacteria, algae and archaea live in the runoff water from the hot springs. In fact, different colors indicate different communities that thrive at different temperatures. Usually the colorless and lightest colors are closest to the center of the spring where the water is hottest. As the water gets further away from the spring and cools, different, darker organisms set up shop. Some even thrive in acidic springs!
Tiny black ephydrid flies can often be seen feeding on the bacterial mats or laying their salmon-colored clumps of eggs so their larvae can feed on the microbes. They then become food for spiders, mites, beetles, and dragonflies and the food chain continues with birds like killdeer and swallows. Even bison, elk and other large animals or at least their tracks and scat are seen in the hydro-thermal basins.
Some plant species such as hot springs panic grass and Ross’s bentgrass live in the extreme environs of the geyser basins, sometimes with the help of thermo-tolerant fungi. Yellow monkey flower and purple fringed gentian are commonly seen as well. In fact, the thermal basins can create microclimates, extending the growing season for some plants. Many of the organisms and plants are the subject of ongoing research.
We can only guess what we may uncover in the future. These thermophile communities are a reminder that we have much to learn about Yellowstone’s wonders. With continued preservation of the geyser basins, not only will we be able to marvel at the beautiful colors, but also preserve opportunities for scientific research and exciting new discoveries.