As we have discussed in previous posts, healthy soil is essential for a healthy life. The soil, in winter, can help keep microbes, animals, and plant roots from freezing. As the air temps drop below freezing, the water that’s in the top soil layer will freeze and form a frost layer. You may believe that life in the soil stops when the ground freezes, but you would be wrong.
Though the frost layer may go down several feet, other factors determine just how far down it can go. When snow covers the ground in early winter, it can be utilized as a blanket for the soil below. Also, heat is created underground as organic matter decomposes. This organic matter can consist of leaves, compost, or mulch and serves as an insulation for the root systems.
Some shrubs, trees, and grasses are perennial and can withstand freezing temperatures. They grow their roots down past the layer of frost. The roots do several things to protect themselves from freezing. Perennial plant roots send out water into the soil around them from their cells, allowing them to withstand the cold temps without the water in their cells expanding and killing the cells in the roots. There is also a high concentration of salts and sugars in these plants which lowers their freezing point.
Animals that live in the soil will generally burrow beneath the frost layer during the winter. They will either hibernate or live underground on the food stores they have throughout the winter months. Some of these animals include gophers, worms, turtles, snakes, frogs, and insects.
Here is something that is fascinating: many animals that live in the soil have the ability to survive at below freezing temperatures. In North America, there are at least five species of frogs that produce their own kind of antifreeze. Because of this, they are able to be frozen completely for an extended period of time without their cells suffering damage. Quite amazing!
Many of the fungi and bacteria in the soil can stay active during the winter too. In the permafrost grounds of Antarctica, microbial life has been found. When Spring comes in North America, the microbes activate and do their job more vigorously in order to ensure biodiversity.
So the next time you are out for a winter stroll, think about what’s happening underground. Though you may not can see it, there is life beneath the frozen earth.