Sapphire Pool, in the Biscuit Basin area of the Upper Geyser Basin, Yellowstone National Park
![Sapphire Pool, in the Biscuit Basin area of the Upper Geyser Basin, Yellowstone National Park](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/FIgure%201%20Sapphire%20Pool.jpg?itok=nTetlwc9)
Detailed Description
Sapphire Pool, an alkaline (pH ~7.5) spring in the Biscuit Basin area of the Upper Geyser Basin, Yellowstone National Park. The vent (top image) is hot (~80°C), with white silica precipitating, but as the water cools down the outflow channel the temperature drops below the upper temperature threshold for photosynthesis (~72°C), as indicated by the sudden appearance of bright yellow-green from photosynthetic pigments produced by phototrophic bacteria (bottom image).
Sources/Usage
Public Domain.