ermafrost, making their way to the surface through tube-like structures of gypsum, a salt composed of calcium sulfate. By the time the springs reach the air, they have picked up so much salt that they have three times the salinity of saltwater. The salt acts like an antifreeze, allowing the springs to stay liquid even when the weather is well below the normal freezing temperature of water.
Sources of liquid water may be the obvious places to look for life, but organisms can flourish even where water is perpetually frozen. I spent much of my time in the Arctic digging holes in the permafrost, collecting soil samples in a search for life.
Axel Heiberg may be harsh for most large life forms, save the occasional caribou or well-insulated Arctic hare. Look on a smaller scale, though, and you’ll find bacteria thriving in permafrost nearly a meter underground. Permafrost occurs on Mars, too, opening the doors for more analog studies.
On Earth, permafrost is characteristic of polar regions. It thaws during the summer, creating an “active layer” of soil. Dig through the layer of soft soil and you will eventually hit the solid, perfectly flat table of ice-cemented ground that exists in the Arctic and Antarctic. Analysis of our soil samples in laboratories back in the United States revealed the presence of metal-reducing and sulfur-reducing bacteria much like those found at the other end of the earth in Antarctic permafrost.
Frozen soil isn’t the only place on Axel Heiberg to find bacteria. Axel’s springs are another logical place to look for life — and indeed, the springs are surrounded by slimy layers of sulfur-reducing bacteria. Microorganisms even form colonies called endoliths inside giant chunks of rock or gypsum salt.
It seems as though life can find a niche no matter how unbelievable the environment. To me, a community of bacteria living where nothing else can is one of the most compelling scientific beauties I can imagine on Earth. I’d pick a barren, frozen desert over a teeming jungle any day, and Mars is the most enticing desert I know.