I went on a road trip for a week and did some junk I've not done/junked before.
This is an impressive hot spring located in the Upper Geyser Basin in Yellowstone National Park, the Wyoming part I think. Stinks a wee bit but it is GORgeous.
The distinct colours originate from temperature sensitive algae/bacteria that live in the warm waters. The striking blue hue is a result of the heat loving bacteria, whereas the yellow is due to colder conditions. The overall effect is of a big oil spill real close up. Whilst cooking eggs.
The park has put a lot of emphasis on how visitor carelessness over the years has caused irreparable damage to many of the areas features, including the colour of this hot spring. Countless cases of coins and other debris being tossed into Morning Glory have blocked vents underground, causing certain parts of it to cool near the surface. This is why the colour has become less vibrant blue and more yellow over the years.
So the moral of the story is that unless your one true wish is to destroy naturey shit, stop throwing money into centuries old pools of boiling sulphur water.