A new study recently published in the journal Applied Optics shows how some of the Yellowstone National Park’s thermal springs really looked like before they were polluted by tourists. Using simple mathematical models, scientists were able to simulate the initial colors of the Morning Glory Pool (photo), one of Yellowstone’s hot springs pools that had been dark blue before getting the colors we see today.
Scientists said that the hot springs changed colors mainly because the chemistry of their waters went through several transformations while tourists kept throwing make-a-wish coins, rocks and trash in Yellowstone’s thermal pools.
The group of scientists that conducted the study are not chemists or biologists, but optics experts from Montana State University and Brandenburg University of Applied Sciences in Germany. However, they said that their findings were of great interest to other fields too, thus they were hoping for a future collaboration.
“We didn’t start this project as experts on thermal pools. We started this project as experts on optical phenomena and imaging, and so we had a lot to learn. There are people at my university who are world experts in the biological side of what’s going on in the pools. They’re looking for ways to monitor changes in the biology – when the biology changes, that causes color changes – so we’re actually looking at possibilities of collaborating in the future,”
Joseph Shaw, co-author of the study and professor at Montana State University, said.
Mr. Shaw also explained what really happened in the pools that made them change color. It seems that before the 1940s, most of the pools had a deep blue color. However after that date, layers of refuse have been accumulating at the bottom and started obstructing the underwater vent that fueled the pools with warmth and fresh water.
Gradually the water temperature has started cooling down and the microbial mats in it started changing composition. Since these mats are responsible for Yellowstone hot springs’ dazzling colors, their colors also altered.
The Morning Glory Pool, for instance, had a very soothing dark blue color more than 70 years ago. But today, decades of irresponsible tourism changed its color into an orangey greenish tint.
Scientists said that they reached these findings by very simple methods. For instance, they gathered data about Yellowstone’s Grand Prismatic Spring, Morning Glory Pool and Sapphire Pool on a bright sunny day using only a digital SLR camera, portable spectrometers and a long wave infrared camera. The infrared camera was designed to measure water temperatures with no additional water sampling.
These data were later used by a computer app that simulated a one dimensional model of how it really looked like the pools before tourists stepped in.
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