Study Shows How Yellowstone National Park's Thermal Pools Have Changed Due To Coin-Tossing Tourists
Over the past century and more, tourists to Yellowstone National Park have marveled at the colors in the park's hot springs. Unfortunately, some of those visitors can't resist tossing coins, trash and other foreign objects into the thermal pools. Scientists have wondered how all that activity may have changed the composition and appearance of those springs, and a recently-released study offers some answers to those questions.