You would be forgiven for thinking that the vibrant, perhaps lurid, colors of the Morning Glory Pool in the Upper Geyser Basin of the Yellowstone National Park in the US were completely natural. After all, it has been a popular tourist destination for tourists for many a decade. However, only four decades ago the pool was a completely different color. Cue much scratching of heads.
It should first be noted that the somewhat risqué name of the pool comes from an innocent source. Back in 1883 the wife of the Assistant Park Superintendant, Charles McGowan, named it Convolutus. This is the Latin name for the morning glory flower – which the spring resembled. However, the common name of the flower became more popular than its latinate equivalent and it stuck.
Take a look at this picture from 1960. There you can see the wonderful deep blue color that Morning Glory used to be. From the picture of the flower on the left you can, additionally, see why Mrs McGowan chose to call the pool that name.
It is, contrary to occasional belief, anything to do with the fact that the pool erupts, geyser like, on occasion. So why the change of color in the intervening years?
Unsurprisingly enough, human hand is to blame, but not quite in the way you might expect.
By 1970 – as above – the discoloration was already underway.
Now, the colors of the Morning Glory Pool have changed completely. However, you don’t have to be Sherlock Holmes to solve this particular detective story. The Morning Glory Pool is not the victim of environmental pollution, as you might expect. Rather it is the victim of the hopes and aspirations of the many visitors it has received over the decades. Marking their making of a wish, many tourists would then throw a coin in to the pool, as if to pay the spirits in residence for making it come true.
The coins – not to mention other human detritus – eventually blocked the heat vents which keep the temperature of the pool high. As the temperature lowered then it allowed bacteria to grow which had been unable to thrive previously – plus chemicals on the coins have helped too.
So now the edge of the pool is a golden yellow while the untainted blue of the interior has turned a shade of green. While these colors, due to thermophilic bacteria – a kind of algae which photosynthesizes at high temperatures, are attractive to many they nevertheless represent nature being once more abruptly and permanently changed by the hand of man.
Image Credit Morning Glory Flower - Flickr User Photoholic
