Only the toughest organisms can thrive in one of the coldest springs on earth. That’s why in the summers of 2017 and 2019, Lyle Whyte flew a helicopter to Lost Hammer Spring, in the depopulated Arctic region of Nunavut, Canada. Snow, ice, coarse salt, rocks, and permafrost surround the modest spring, which lies between nearly arid, treeless mountains on the island of Axel Heiberg, a few hundred miles from the North Pole. He had traveled to this place outside of this world to study the microbes that live in its salt, icy, and low-oxygen water in hopes of learning what life would have been like if it had never emerged in similar places, on Mars. .
In a new document a The International Society for Microbial Ecology Journal, Whyte and colleagues write that microorganisms that live a few inches down in spring sediment can survive in the harsh environment. Most terrestrial species depend directly or indirectly on solar energy. But these microbes can survive with a source of chemical energy: they eat and breathe inorganic compounds such as methane and hydrogen sulfide, which make the area smell like rotten eggs, even from a distance. (The pilot of the research team calls the site “smelly sources”). “You have these rock-eating insects that basically eat simple inorganic molecules, and they do it in conditions very similar to Mars, in this frozen world,” says Whyte, an astrobiologist at McGill University in Montreal, Canada.
The search for extraterrestrial life has often focused on the Red Planet. Scientists believe that more than 3 billion years ago, Mars was warmer and wetter than it is today, and had a more protective atmosphere. Although the planet is now almost completely inhospitable to life, researchers imagine that past Martian microbes develop life, or even bloom, in the cold, muddy bottom of some pond. Scientists have been sending rovers to roll over the surface to look for evidence of long-extinct alien microorganisms, and a drone copter to explore the path ahead. But it is expensive — and difficult — to send a sampling expedition to Mars. Canada is much closer and not a bad middleman.
The Lost Hammer Spring has a number of unique attributes that mimic parts of the Martian landscape, Whyte says. First, there is the sub-zero temperature (about -5 degrees Celsius), as well as the extreme salinity of the water: 25 percent salinity, about 10 times saltier than seawater. (Salt keeps water liquid, preventing it from freezing.) Mars has been found to have deposits of salt here and there, some of which may have been in brine for eons, which may have been the last habitable places on the planet. . . Lost Hammer water has almost no oxygen, less than 1 part per million, which is rare on Earth but not in other worlds. Any creature that stays there counts as “extremophile,” because it survives in bleak conditions on the brink of where life may exist.
On each of their trips to the remote Canadian region, Whyte and colleagues collected samples of salt mud, each weighing a few grams. Back in their lab, they used machines to isolate microbial cells and sequence their genomes and RNA to find out what microbes use to get energy and how they tolerate spring conditions. This could help astronomers ’efforts to find out where and how microbes could be kept on Mars or in other worlds.