Two young earthworms are the first animals to be born in Mars-like soil conditions. The worms could be crucial for a garden-like ecosystem if we ever want to establish a Martian colony.

Overview of the pots with rucola and Mars soil simulant and Earth control. Image credits: Wieger Wamelink.

If we want to send people long-term to Mars (or on any other planet, really), it’s vital to establish a sustainable agricultural system — a garden of sorts. Now, such an ecosystem would be much more complex than it seems at a first glance, including not only plants, soil, and water, but also crucial microorganisms and worms. The poop and pee of the (human) Martian will also have to be used to fertilize the soil, and making all of that function on Mars of all places is no easy feat.

Within this ecosystem, worms break down and recycle dead organic matter. They’re very important for healthy and fertile soils, which is why researchers were thrilled to find two of them in a Mars soil experiment at Wageningen University & Research. The Mars soil simulant was already used to grow rucola (rocket), and researchers just added adult worms and fertilizer in it (they used pig slurry instead of the human excrements that would be available on Mars, for hygiene reasons). Aided by the manure, the worms started to breed, and biologists now report the first offspring in this soil.

“Clearly the manure stimulated growth, especially in the Mars soil simulant, and we saw that the worms were active. However, the best surprise came at the end of the experiment when we found two young worms in the Mars soil simulant”, said Wieger Wamelink of Wageningen University & Research.

Young worm, born in mars soil simulant. Image credits: Wieger Wamelink.

The manure helped, which was expected, but researchers were surprised to see just how much it improved the quality of the Mars soil simulant.

“The positive effect of adding manure was not unexpected’, added Wamelink, ‘but we were surprised that it makes Mars soil simulant outperform Earth silver sand,” Wamelink continued. “We added organic matter from earlier experiments to both sands. We added the manure to a sample of the pots and then, after germination of the rucola, we added the worms. We therefore ended up with pots with all possible combinations with the exception of organic matter which was added to all of the pots.”

Nowadays biologists are able to grow over a dozen crops, though some have proven more difficult to grow (ahem, I’m looking at you, spinach). However, crops such as green beans, peas, radish, tomato, potato, rucola, carrot and garden cress have all been successful. If the overall quality of the ecosystem can also be improved, a Martian garden might not be so far after all.