A rainbow viewed from above    Grand Prismatic Spring in the United States

Text by / MOOK Scenic Spots Travel Life Network Editorial Department, compiled and reported by Liao Qiyu

 

The colorful pool (Grand Prismatic Spring), also known as the Grand Prismatic Spring, located in Yellowstone National Park, is the largest hot spring in the United States and the third largest in the world. It spans 75–91 meters in width and reaches a depth of 49 meters, discharging approximately 2,000 liters of 71-degree hot water per minute. The Grand Prismatic Spring resembles a huge, deep blue eye hidden within the Earth’s misty veil, surrounded by radiant, vivid flames.

What’s special is that the surface color of the Grand Prismatic Spring changes with the seasons. In spring, the pool shifts from green to brilliant orange-red. This is due to the algae and pigmented bacteria living in the mineral-rich water—microorganisms whose ratio of chlorophyll to carotenoids changes with the seasons, resulting in varying water colors. In summer, when chlorophyll levels are relatively low, the pool displays orange, red, or yellow hues. In winter, due to limited sunlight, these microorganisms produce more chlorophyll to suppress the colors of carotenoids, making the water appear deep green.

Additionally, the warm water flowing from the hot spring pools erodes the surrounding soil and rocks over time, creating layered grooves and patterns on the water’s surface. These are adorned with the vibrant colors formed by microorganisms, resembling a surreal, earthy picture book.