Tourists blamed for ruining Yellowstone thermal pool with 'weird' ritual

A once brilliant blue pool of water in Yellowstone National Park has been transformed into a mishmash of colours following years of pollution.

With millions of tourists visiting every year, they have been blamed for its less attractive brown, yellow and green look, but if we overlook the masses of people flocking to it, how could a tourist alter its appearance?

First of all, a little bit of history.

The Morning Glory Pool was discovered back in the 1880s and was named for its likeness of the morning glory flower, a plant with rich purple-blue petals.

It is a hot spring found in the Yellowstone Upper Geyser Basin and has an average temperature of 159.3°F, with the heat for the hydrothermal features coming from the Yellowstone Supervolcano.

But the temperature has cooled down significantly for the same reason it changed colour - tourism.

So what are, or should I say have, tourists been doing to pollute the once-crystal clear body of water?

Well, I'll first let you guess what it is; the "weird" ritual involves making a wish.

For more than a century, visitors have been throwing coins into the spring, which has been known to erupt like a geyser following earthquakes or other nearby seismic activities.

The Morning Glory Pool pictured just 33 years ago looks drastically different to how it does today (Wolfgang Kaehler/LightRocket via Getty Images)

They clearly weren't environmentally conscious, although I suppose no one really knew the harm they were inflicting on the planet back in those days.

Speaking about the phenomenon to Cowboy State Daily, Yellowstone National Park historian Alica Murphy said: "I think many people like to throw things into pools.

"Wishing wells are a time-honored tradition. Flip a coin into a wishing well and make a wish. There is something about a pool of water that gives humans a weird instinct to throw things into it."

But at one point in its history, it was cleaned out by a crew assisted by fire engines.

Back in 1991, former Yellowstone ranger Jeff Hendry was part of that team.

Recalling the experience, he told the outlet: "We used a couple of fire trucks to pump down the pool's water level and shoot it into the Firehole River.

The hot spring looks completely different to how it would have looked back in the 1800s (Getty/Steven Wares)

"A guy was hooked up to a climbing harness so that he wouldn't fall into the pool, and he was out there with a long-handled net, fishing things out of the water far down into the crater of the pool.

“There were a lot of rocks that didn't belong there, and I think we found some hats that probably had blown off people's heads and landed in the pool. And they, wisely, didn't try to retrieve them.”

He went onto say how almost everything had been thrown into the spring recently as he explained anything from decades ago would have been embedded into the rock.

While impressive, the pool is dangerous and can be lethal; one man died after slipping into the Morning Glory Pool back in 2016, and was tragically boiled alive before being completely dissolved.