Mars Might Not Be The Potato Utopia We Hoped

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.

Image: 20th Century Fox

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 have 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.

WATCH MORE: Science & Health News


    No need to blame Matt Damon: These are really two separate problems. The bacterial research looked at bacteria growing in Martian-like soil with UV irradiation similar to what would be experienced on the surface of Mars. That proved to be toxic to the bacterial used in the experiment. However, Matt Damon grew his potatoes underground (where most potatoes grow) and inside his space house - which protected both him and his potatoes from the effects of UV irradiation. In fact, the bacterial researchers explored growing their bacterial partially protected from the UV (as if they were a little underground) and found that they were not killed as quickly. Almost certainly bacteria living more deeply under ground would not be killed by the UV. Of course, this doesn't confirm that you CAN grow potatoes on Mars - that would be a separate experiment.

      It's not just the UV that's the problem. Perchlorates, found in the soil, are toxic to most living things.

      They may be able to be washed out and recovered (perchlorates are used in solid rocket motors), but this may also wash nutrients out of the soil as well.

      A colony may be able to take fertiliser to sustain early crops, relying on recycling waste to make new fertiliser for future crops.

      Lots of water will need to be taken with them to act as shielding to protect from radiation on the journey, so they can have plenty to use to wash the toxins from the soil before use

    Running low on ideas for stories?
    An almost identical story was published just days ago...

      There's been a fair bit of recycling lately, I noticed a big bunch of old stories that were months old popping up on Friday.

      Pro tip though. Look at the tags at the top of the story near the byline (in this case, 'bummer'). If that list of metatags doesn't include Australian Story, its a reprint from one of the associated sites.

      So I suspect both authors unknowingly wrote similar stories for different versions of Giz, and someone up the chain decided to just repost the US version as a filler. It happens.

        Ah ok, my fault, I forget this interwebs thingy is world wide ;)


    Since stuff already doesn't grow there, we kind of already knew that.

    You can't grow potatoes on salt flats on earth either. Magnesium perchlorate is strongly water soluble so simply wash it out of the dirt. Magnesium perchlorate can be heated to 220C to release oxygen, always useful stuff. And perchlorates can be used as oxidiser for rocket fuel, again useful stuff.
    So just take you martian dirt, wash all the salts out out. Sieve out the fine silt from the gravel. Make expanded clay pebbles from the silt by baking to 1200C.
    Mix the gravel, clay pebbles, foodscraps, some poop , and some piss together and it makes a good artificial soil, same as used in aquaponics/hydroponics, (bring a teaspoon of de-nitrifying bacteria from earth), and away you go!.

    I wonder what perchlorates would do to potatoes or any other crop. It might not be something people want or can eat. There are some perchlorates in the Atacama Desert, but what food for human consumption actually grows there? Perchlorates ingested can cause hypothyroid problems. As far as the radiation, food would have to be grown indoors - Mars is so dry I can't imagine anything else. On the brighter side, perchlorates could be made into rocket fuel to bring people back to Earth who realized their colossal mistake moving to Mars or to provide transportation to other places.

      Apparently the Incas farmed potatoes in the Atacama desert, though it may have been a different species to the one originally domesticated in the Andes. They also cultivated Maize and Quinoa.

      That said the issue there wasn't perchlorates, it was lack of water.

Join the discussion!