The largest hot spring in Yellowstone National Park, the Grand Prismatic Spring reaches temperatures of up to 189º F at its center—far too hot to sustain most life. But like a freshly baked muffin, it's cooler near the edges. Every band of slightly cooler water provides a chance for a different species of thermophilic, or heat-loving, bacteria to set up camp. Just outside the deep blue, bacteria-sparse center is a band of Synechococcus bacteria, which glow a bright yellow instead of their usual green due to the stresses of high water temperatures, and also to protect themselves from the harsh UV light. Beyond that band, Synechococcus is joined by a population of chloroflexi bacteria, which appear orange for the same sun-protection purposes. The coolest ring, closest to the water's edge, is home to a wide variety of bacteria, and the mix of their individual hues creates a deep red-brown color. The result is a spectacular display of rainbow hues. Discover other rainbows in unexpected natural places below.
The Grand Prismatic Spring Creates Rainbow Rings
Get a full view of this majestic sight from overhead.
The Element That Makes Rainbow Crystals
Check out the spellbinding crystals that bismuth forms.
Key Facts In This Video
Bismuth has a low melting point for a metal: 271 degrees Celsius (520 degrees Fahrenheit). 00:18
A layer of oxidation gives bismuth crystals their rainbow colors. 01:27
See a man-made bismuth "geode": 02:28
Caño Cristales: The River of Five Colors
Find out what gives this river its dazzling hues.
Wake up with the smartest email in your inbox.
Our Best Articles Daily