I’ve heard that soil microbes are living in Antarctica. How can that be?

The polar regions of the globe are often very cold for the most of the year. In the dead of winter, these environments can experience air temperatures well below -50° F! The coldest temperature on record (-128° F) was measured in Antarctica in 1983.

Soil with a permafrost layer beginning at 60 cm near the center of the photograph. Photo: Near Dead Horse, Alaska by Mary Tiedeman

Soils located in polar regions are unique to those found elsewhere, as they contain permafrost. Permafrost is a thick subsurface layer of soil that is frozen year round. In Antarctica, during the coldest parts of the year, the entire soil system is frozen solid. Because of this, the soil is actually very dry, like in deserts! If this is true, wouldn’t it be impossible for living creatures to survive there? Antarctica surely looks like a lifeless, barren area…

The Dry Valleys region of Antarctica is one of the most inhospitable places on earth. Scientists studying soils around the lake discovered that microbial activity dominates biological functioning in this ecosystem and that a diverse microbial population in the soil actively cycles carbon and nutrients. Photo: E Gregorich

Amazingly, there is life in Antarctic soils. Even in these extreme environments, scientists have been able to find soil microorganisms alive and thriving.

What scientists have found is that these tiny organisms are able to survive by living in microscopic films of water that stick to soil particles (adherence). The bond energy between water molecules and soil particles is so great that it prevents the thin layer of water from freezing, even at extremely low temperatures. Microbes live in this unfrozen water, which allows them to stay alive even during the long deep freeze of winter.

These microbes aren’t just surviving, either. During the winter, they are still consuming organic matter, “exhaling” carbon dioxide (CO₂) and maintaining their populations. They are actually alive, not even hibernating!

You may wonder why scientists are willing to spend their time researching soil microbiology in such remote areas. Studying organisms in extreme and inhospitable environments like the Arctic and Antarctic allows scientists to make inferences about life on other planets. This type of research is also important for understanding how cold ecosystems function now, and how that might change in response to global climate change. Scientists are already starting to observe increased microbial activity in the polar regions. As temperatures rise, microorganisms are predicted to consume more soil organic matter, which could lead to the release of even more CO₂ (a greenhouse gas) into the atmosphere.

Most of us don’t live in Antarctica, but in the northern parts of the hemisphere, it’s pretty cold in February. If you think you’ve got it bad, try to be inspired by the mighty polar microbes. They are some pretty tough organisms, and because of this, they can teach us very much.

By Mary Tiedeman and Ed Gregorich

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