YELLOWSTONE NATIONAL PARK — In Yellowstone National Park (YNP), the autumn brings a change of color not just to leaves, but to the microbes in the area’s hydrothermal features.

According to the Park’s Facebook page, the bacteria in YNP use light to make energy just like leaves on a tree do. Because of this, both groups experience a change to darker colors as the days become shorter and the sun hits at a lower angle, as a way to absorb light.

An example of this change can be seen at Mammoth Hot Springs, where a summer photo shows a paler microbe coloring in comparison to the darker green patches of microbes in the winter photo.

The microbes at Mammoth Hot Springs in the summer versus the winter. Photo: Courtesy of YNP’s Facebook

YNP confirms a number of these microbes are similar to the first life forms capable of photosynthesis, which is the process of using sunlight to convert water and carbon dioxide to oxygen, sugars and other by-products. Because of the uniqueness and fragility of these features, visitors are always reminded to remain on boardwalks and avoid touching any hydrothermal features in YNP.

River Stingray is a news reporter with a passion for wildlife, history and local lenses. She holds a Master's degree in environmental archaeology from the University of Cambridge and is also a published poet, dog mom and outdoor enthusiast.