Colors of thermal pools at Yellowstone National Park

The vibrant colors observed in Yellowstone National Park's thermal pools are primarily shaped by microbial mats at the pool bottoms, with their spectral properties linked to water temperature. Deeper pools, however, derive their hues mainly from wavelength-dependent absorption and scattering within the water itself. Researchers used a 1D radiative transfer model to simulate these colors, incorporating data on water attenuation, microbial mat reflection, and surface reflection. The study also utilized thermal imaging to map water skin temperatures, confirming that shallow-water features' colors are dominated by microbial activity, while deeper pools exhibit color variations due to light interaction with the water column.

Nugent, P. W., Shaw, J. A., & Vollmer, M. (2014). Colors of thermal pools at Yellowstone National Park. Applied Optics, 54(4), B128. https://doi.org/10.1364/ao.54.00b128