Yellowstone's Morning Glory Pool

The pool has barely retained its blue color.
Photo by Miguel Hermoso Cuesta

Yellowstone National Park is home to some of the most amazing natural sights in the world, not least of which is the Morning Glory Pool. The Morning Glory Pool is a hot spring that attracts quite a few visitors. It is known for its vibrant color.  However, much of that has diminished over the past decades. Nonetheless, the pool is still stunning to behold. The change in the pool’s color is also very interesting in that it gives us a first hand look at the effect that pollution can have on the world that surrounds us.

The Morning Glory Pool is located on the northern edge of the Upper Geyser Basin. It was named in 1883 for its magnificently deep blue color that nearly matched the flower for which it was named.

This pool is roughly 23 feet by 26 feet and is about 23 feet deep. Currently, the temperature of the water in the Morning Glory Pool is around 171.6 degrees Fahrenheit. The water is clear enough that you can see the way that the sides taper down into its depths. Viewed from some angles, this gives the illusion that the pool is in fact running down into the center. This also makes the pool seem as if it has a “stem,” which makes its name that much more appropriate.

Unfortunately, the pool has changed color over the years because of the acts of uncaring or unwitting visitors. Tons (yes, tons) of trash have been thrown into the pool, effectively blocking the vents that keep the pool so hot. Thermophilic bacteria that need high temperatures to survive cause the blue color of the pool.

When the vents became blocked by trash, the temperature in the pool started to drop, thus killing some of these bacteria. The drop in temperature also made it possible for other bacteria to thrive in the Morning Glory Pool. These new bacteria are red, yellow and orange and are changing the pool’s color from the outside in. As the pool gets cooler, the new bacteria move closer to its center. Given enough time, the entire pool could change if the vents do not get opened back up.

An old road used to go directly by the Morning Glory Pool, so there were many more visitors to it in the past. Today that road is gone. Visitors must walk or bicycle for 1.5 miles both ways to get to the pool; a three-mile trip total. This means fewer visitors and fewer opportunities to steal pieces of the edge of the pool or throw trash into its depths.

Because the Morning Glory Pool is a geyser it is hoped that it will one day blow the trash loose and thus remove the blockage from its thermal vents. However, whether it will do so or not is uncertain, especially with the amount of trash that is in it. For now, we can only hope that some effort on our part or some natural occurrence will return the pool to its original, magnificent state.