In Andy Weir’s novel-turned-Matt-Damon-movie The Martian, the protagonist endures the harsh terrain of Mars by using his own shit to grow potatoes. The idea isn’t that outlandish—over the last few years, a NASA-backed project has been attempting to simulate Martian potato farming by growing taters in the Peruvian desert. While early results were promising, new research suggests that survival of any life on Mars—much less potato-growing humans—might be more difficult than we thought. I blame Matt Damon.
Scientists at the University of Edinburgh tested how the bacteria Bacillus subtilis would react to perchlorates, which were first discovered in Martian soil back in 2008. Perchlorates are naturally-occurring (and sometimes, man-made) chemicals that are toxic to humans, but they’re not always so bad for microbes. In fact, in the Atacama Desert in Chile, some microbes use perchlorates in the soil as an energy source. On Mars, perchlorates allow water to exist in a briny liquid form despite the planet’s low atmospheric pressure.
However, when the researchers put B. subtilis in a bath of magnesium perchlorate solution similar to the concentrations found on Mars, and exposed the microbes to similar levels of UV radiation, the bacteria died within 30 seconds. Even when the researchers repeated the experiment on a Martian rock environment they made of silica, most of the bacteria still died. The depressing research has been published in Scientific Reports.
“Although the toxic effects of oxidants on the Martian surface have been suspected for some time, our observations show that the surface of present-day Mars is highly deleterious to cells, caused by a toxic cocktail of oxidants, iron oxides, perchlorates and UV irradiation,” the researchers wrote. “However, we show the bacteriocidal effects of UV-irradiated perchlorates provide yet further evidence that the surface of Mars is lethal to vegetative cells and renders much of the surface and near-surface regions uninhabitable.”
Not all hope is lost, however. For one thing, the study only tested one species of bacteria—it’s unclear how others would have fared under the same circumstances. Lynn Rothschild of NASA Ames Research Center told Gizmodo she and her team recently conducted research that suggests “bacteria could withstand the perchlorates and salts on Mars.” We’ve reached out for additional information and will update this post when we hear back. Of course, it’s always possible that life forms on Mars are so biologically different, they’ve found a way to adapt to perchlorates in the soil, and even thrive.
Obviously, more research must be done before we give up on Martian potatopia. Still, it does sense that a giant unused litter box orbiting the sun wouldn’t be a great for potato farming. Goddamn you, Matt Damon.