Grand Prismatic springs of the US: Much more than just a hot water spring
Every luxury travel itinerary has one thing for sure: A trip to the spa. But have you ever been to a natural spa that gushes hot water throughout the year? Imagine a bubbling warm water bathtub on the ground, surrounded by steam. Well, there’s a name by which these natural spas are known as, all across the world: Hot springs or thermal springs.
They spew hot water through the cracks and fissures from the Earth’s surface that is originally heated by the magma in the volcanic rocks, in the Earth’s crust. In fact, the heat generated from these hot springs is often used to generate geothermal energy that can power buildings and greenhouses.
Now, there are several hot springs around the world, but are you aware of the Grand Prismatic Hot Springs? Turns out, they are the largest hot water springs in the USA and third largest in the world, right after the Frying Pan Lake in New Zealand and the Boiling Lake in Dominica.
Grand Prismatic hot springs: A bird’s eye view
Turns out, the Grand Prismatic hot springs are situated in the famous Yellowstone National Park, in Wyoming, USA. They are found midway between the Upper and the Lower Geyser Basins, along the Firehole River. These hot springs are 110 metres wide and 50 metres deep and spring out an estimated 560 gallons of water per minute! Unbelievable right?
Stunning geology
Not many know, but these springs sit on a bed of lightly-coloured rhyolite rocks (igneous rocks with volcanic characteristics), that too on the west side of the Yellowstone Caldera, the volcanic crater that is one of the major attractions of the Yellowstone National Park. These rocks contain high amounts of the element silica.
Now, as it happens, the spring water gets heated by the magma present underneath the rocks. The hot water dissolves the silica and circulates it to the surface of the spring. This mineral-rich spring water flows out and deposits the silica on the ground, in turn forming giving the surrounding landscape a greyish-white colour. Now, since this circulation is continuous, there is a constant supply of fresh hot water underneath, waiting to spurt. And guess what happens with this? The silica deposition too keeps on happening!
The rainbow appearance
The name of the Grand Prismatic spring was inspired by the amazing rainbow formation in the water, that was first detected during the Hayden Geological Expedition and Survey in 1871. But how are they formed? Let’s find out.
As you all would agree, nature never fails to amaze us. And this is especially true in case of the Grand Prismatic hot springs and their rainbow appearance. Well, it is the work of various species of thermophilic (heat-loving) and chemotropic (chemically charged) bacteria. As it turns out, these bacteria use chemicals as source of their energy, and when they do, they in turn multiply and form a third species of bacterium called cyanobacteria or blue-green algae. Now, as you can guess from the name, this gives the spring water its bluish and greenish shades. As for the other colours, that too forms thanks to the cyanobacteria.
So, here’s what happens. When they undergo aquatic photosynthesis, they end up producing various bands of colours that are visible in the spring waters, similar to the rainbow’s spectrum. Interestingly, the colours seen in these springs are red, orange, yellow, green, blue and brown. Now you know why the Grand Prismatic Springs is called so! After all, the spectacular show of colours does remind one of a prism, isn’t that right?