Life is capable of thriving in the most inhospitable places. The photograph above, which I took on my recent trip to Yellowstone National Park, shows Morning Glory Pool, a hot spring that is a short hike from Old Faithful. It’s named after the purplish-blue morning glory flower, but the pool no longer has that color, which was due to a particular type of thermophilic (heat-loving) microbe. That is because ignoramuses threw coins and other debris into the pool, blocking the vents and lowering its temperature, which allowed microbes of other colors to grow.