The World Below the Icy Blanket

When I think of winter, what comes to mind is a quiet, gloomy time between the fall and spring seasons. The days are shorter, the air is cold and crisp, and nature seems to be waiting for the warmer months to come. Many animals go into hibernation, and the forests are filled with nothing but a layer of sparkling white snow. But beneath the snow lies a hidden world that is filled with life. 

This small ecosystem is known as the subnivium and is able to constantly stay one degree above freezing through the cold winter months, allowing microbes, insects, and even small mammals to thrive. This system is very similar to a frozen pond. When a pond freezes during the winter, the fish and organisms living in the pond aren’t frozen as well, right? Just like how the ice is a barrier for the fish in a pond, it also serves as a barrier for animals on land.  Additionally, the subnivium does not only affect animals, but it is also essential for plants as well. When plants lose their leaves in the fall, they remain on the forest floors. The decomposers in the subnivium eat the organic matter all winter, leaving fertile soil for the spring months. Without the subnivium, the forest ecosystems would be severely disrupted even during the rest of the year because it provides a haven for small animals and maintains fertile soil. 

However, due to global warming, there is less snowfall, which is a major threat to the subnivium and the ecosystems that experience colder temperatures. It may seem counterintuitive, but in reality, less snowfall can make the ground colder. As I previously stated, the snowpack serves as a blanket for the ground, so if there is less snowfall it won't be able to trap the heat underneath. According to a 2019 study in Nature Climate Change, there will be 10 more days every winter where the ground is frozen and bare if temperatures continue to rise at the rate they currently are. This will be detrimental to the subnivium and thus the forest ecosystems for the rest of the year.