Morning Glory Pool, located in the Upper Geyser Basin near Old Faithful in Yellowstone National Park, used to look like the dazzling crystal-clear blue that inspired its name. But after decades of visitors throwing coins, trash, and other debris into it, Morning Glory now resembles many of the other prismatic thermal pools in the park, with a dark green center that flows into a yellow ring.
“There are some lovely quotes about its beauty and striking blue colors, likening it to the Morning Glory flower,” said Yellowstone National Park historian Alica Murphy. Cowboy State JournalMurphy explained that when tourists first started visiting in the 1880s, the concepts of conservationism and “leave no trace” didn't yet exist, and people viewed the park's colorful thermal pools essentially as “wishing wells.”
“I think a lot of people like to throw things into pools,” he continued. “Wishing wells are a long-standing tradition. You throw a coin into a wishing well and make a wish. There's something about a pool of water that gives people a strange instinct to throw things into it.”
As for the scientific reason for the color change, decades of littering the pool has caused the temperature of the water to physically cool.
“Temperature is a huge factor,” said Mike Poland, chief scientist at the Yellowstone Volcano Observatory. “Hotter pools are usually bright blue, and cooler pools can be more colorful because bacteria can grow there. At Morning Glory, the temperature dropped because people threw objects in and the channel partially blocked, and the temperature dropped, allowing different types of bacteria to grow.”
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Until the early 1990s, Yellowstone's thermal pools were cleaned by crews, but this process was very laborious, both to ensure the safety of park employees and to prevent further disruption of the thermal pools' delicate balance.
Former Yellowstone ranger Jeff Henry, who has worked at the park for nearly 50 years, was part of the last crew to clean up Morning Glory Pool in 1991. But he said it won't happen again.
“We used a couple of fire trucks to lower the water level of the pool and launch it into the Firehole River,” Henry recalls. “A guy was in a climbing harness so he wouldn't fall into the pool, and he was out there with a long-handled net, fishing things out of the water deep down into the crater of the pool.”
“We found tons of coins, probably thousands of them,” he continued. “The main parkway runs right past Morning Glory, so that may account for some of the metal pieces that looked like car parts that had been thrown at the bottom of the pool. There were a lot of rocks that didn't belong there, and I think we found some hats that had blown off people's heads and fallen into the pool. And they wisely didn't try to get them.”
But aside from the inherent dangers of cleaning the thermal pools, Henry said another reason they no longer go through the process is that park visitors are generally more responsible these days. And given that Yellowstone has naturally adapted to man-made change, officials are now trying to preserve the park in its current state.
“I don't see as many coins in the pools as I did in my early days at the park,” Henry explained. “The bottoms of the more accessible sources used to be covered in coins, but it's pretty rare to see anything thrown into the pools anymore.”
“I remember one time I was cleaning Old Faithful and I found an old tire,” he added. “Pool cleaning used to be done regularly. It was like harvesting a crop. But values are changing and they don’t clean the pools anymore, at least not as often and on the scale that we do.”