A recently published study shows accurately how Yellowstone National Park's well-known thermal springs appeared decades ago before it suffered pollution due to tourism.

The study is published this week in the journal Applied Optics, Vol. 54, Issue 4. Yellowstone's hot springs and its water present at Old Faithful are quite the sight to be seen. With high number of daily tourists, the landscape of Yellowstone National Park has changed drastically.

Lead author of the study, and professor at Montana State University, Joseph Shaw said there are people at his university who are world experts in the biological side of what's happening in the pools. "As a result of coins, trash, and rocks thrown into the pool over time, the vent has become partially blocked, leading to a lower temperature and altered color pattern", Joseph Shaw added.

The prime suspect for the thermal spring's chameleon meniscus is the 'wishing well' practice, which is so regular amongst other spring-like bodies of water. Combining this with the popularity of tourist throwing other big remains into the pools and also anything from big rocks to bottle caps has made the water cooler.

Yellowstone's thermal springs had a homeostatic temperature at 180 degrees Fahrenheit before the introduction of these foreign bodies. Now they run a bit cooler, 40 degrees cooler, to be accurate. The study was the collaborative work between researchers at Montana State University and Germany's Brandenburg University of Applied Science.

With the help of one-dimensional models and microbial mapping, the team of researchers was able to optically recreate how the pools looked before the decades of accumulated waste. Despite the important findings the study revealed, the researchers said it was their inquisitive natures that led them to this conclusion.