Trebouxiaceae – the perfect space travellers?

"We don't really know much about microalgae, even though they are present in environments all over our planet," says Principal Investigator Marta Pérez-Rodrigo, a PhD candidate at the Universitat de València. "Knowing that they can resist Martian conditions helps us to explore theories of whether organisms could travel from one planet to another. And if we can culture these microalgae in autonomous systems on Mars, or during space missions, then it opens up many possibilities, from providing astronauts with food and oxygen, to protecting them from harmful radiation."

The results showed that these lichen microalgae can completely withstand individual stresses, including exposure to UV radiation, freezing temperatures (-80°C), simulated Martian soil with high levels of iron oxide and a simulated Martian atmosphere. The microalgae recover rapidly after exposure and return to healthy growth. Some species also tolerate the cellular (osmotic) stress associated with drought or extremely salty water.

The lichen microalgae have molecular mechanisms that allow them to respond to these challenging conditions, including the production of high levels of sugar alcohols. It would be possible to transport them to Mars and maintain them there, and their high nutritional value makes them a good choice for producing food in space.