Tardigrades, also known as water bears or moss piglets, are famous for surviving almost anything. In their dormant state, the microscopic animals have endured the vacuum of space, extreme cold, and intense radiation. But when researchers placed active tardigrades into simulated Martian regolith — the dusty material that covers Mars’ surface — their movement quickly slowed.
Within two days, activity significantly dropped in one version of the simulated soil. Yet when researchers rinsed that same material with water before introducing the animals, most of the damage disappeared. The results, published in the International Journal of Astrobiology, indicate the soil may contain something harmful to living organisms, but that the problem might be manageable. That matters if humans ever hope to grow food on Mars, and if they want to avoid accidentally contaminating the planet with life from Earth.
“When considering sending people to non-Earth environments, we need to understand two things: how the environment will impact the people and how the people will impact the environment,” said Corien Bakermans, who co-led the international research team, in a press release.
Read More: Unique Protein That Helps Tardigrades Endure Deadly Radiation Could Help Us Fight Cancer
Testing Mars’ Surface on Tardigrades
The team focused on simulated Martian regolith, laboratory-made material designed to match the mineral and chemical makeup of soil sampled by NASA’s Curiosity rover at Gale Crater.
Researchers tested two versions: one meant to represent Martian regolith broadly and another designed to more closely mimic the specific chemistry of the Rocknest deposit. They mixed active, hydrated tardigrades into samples of each simulant and monitored their movement under a microscope over several days.
In the simulant known as MGS-1, tardigrade activity was significantly reduced within 48 hours. In the second simulant, OUCM-1, activity also declined but to a lesser degree. This is important considering that whether the animals are moving, feeding, and functioning, is a key measure of their health.
Is Martian Soil Toxic to Life, or a Natural Defense?
Tardigrades can survive extreme conditions when they enter a dehydrated, dormant state. Once rehydrated and active, however, they are more sensitive, though still resilient compared to most animals.
In this case, the MGS-1 simulant appeared to be especially harsh on them.
The researchers suspected something specific in the material might be responsible. When they rinsed MGS-1 with water and then introduced fresh tardigrades, activity levels were largely restored.
The finding raises the possibility that if Martian regolith naturally inhibits biological activity, it could act as a kind of built-in defense against contamination from Earth, a major concern in planetary protection. At the same time, anything harsh enough to slow tardigrades could also complicate efforts to use Martian soil to grow food or support human habitats.
What This Means for Life Beyond Earth
Planetary protection aims to prevent microbes from Earth from contaminating other worlds, while also protecting Earth from potential extraterrestrial materials. Understanding how regolith interacts with living organisms is part of that equation.
Water is scarce on Mars, so rinsing soil is not a simple fix. But knowing that harmful components may be water-soluble offers insight into how extraterrestrial materials might be managed.
The study also highlights how little is known about how Martian-like environments affect animals, even microscopic ones. Most previous research has focused on bacteria and fungi.
“Regolith isn’t the only component, of course,” Bakermans said. “But we’re beginning to tease apart components of this overall system where any single piece could be a drawback or benefit the larger understanding of planetary protection.”
Future work will examine additional stressors, including temperature and atmospheric pressure, to better understand how life — human or otherwise — might interact with Martian terrain.
For now, even one of Earth’s toughest microscopic survivors has revealed that Mars’ dusty surface may be more complicated than it looks.
Read More: Tardigrades May Still Be Living on the Moon After Lunar Lander Crash
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a recent study published in the International Journal of Astrobiology: Short-term survival of tardigrades (Ramazzottius cf. varieornatus and Hypsibius exemplaris) in martian regolith simulants (MGS-1 and OUCM-1)
