The hues are also influenced by how light interacts with the water’s depth—turning it yellow and orange in the shallows and green in the deep end.
The team’s mathematical model helps predict and explain Morning Glory’s color (and that of other springs in Yellowstone) “based on the interplay between light and the microbial mats,” reports Hoffman. The researchers published their findings in the Journal of Applied Optics.
“Our paper describes a very simple, 1-dimensional model, that gives the first clue if you really want to do more,” one of the study’s authors told the Optical Society. The researchers hope to collaborate with biologists to keep an eye on the chemical and biological composition of these pools and better develop the role optics might play in such research.
It seems like it'd be easy to reverse this effect: remove the trash from Morning Glory’s heat source in an attempt to restore its old, blue self. But there’s no formal word so far on whether such efforts would be possible—or effective. But you can bet that Yellowstone officials will take a firm hand to anyone caught making a lucky-penny wish into the pool. After all, no one likes a litterbug—except, perhaps, some of Morning Glory’s cooler water-loving microbes.