Lichens might survive on Mars

This video is about lichens.

Translated from Griet Nijs’ Dutch in Belgium:

Life on Mars after all?

Message from Natuurpunt Study (Belgium) on Tuesday, April 3, 2012

For many years, science has been asking itself whether there is life on Mars. In an attempt to finally get out of this impasse, researchers have exposed several lichens to space conditions and have monitored whether they survived. The results are at least surprising.

Research into life on Mars is not new. During the last twenty years, it has been proved several times that prokaryotes, cells without nuclei such as bacteria, can survive under simulated or real space conditions. They can survive a high dose of UV radiation, extreme temperatures and even vacuums. Some prokaryotes would even survive the extreme conditions on Mars.

Over the past decade there were also the first experiments with eukaryotes, organisms with a more developed cell structure, including humans, animals and plants. Lichens also belong to the eukaryotes. Lichens are essentially a symbiosis (a form of society with mutual benefit) between a fungus and a green alga or cyanobacteria. The mold retains water and provides protection while the algae take care of the production of sugars through photosynthesis.

When scientists exposed some lichens, such as Xanthoria elegans, a lichen also of alpine and polar regions, and Fulgensia bracteata, to conditions like in space, they were found to have high resistance against this. When the algal symbionts were separated and therefore could not benefit from protection by the fungus, they lost their capacity for growth. The physiological capacities were reduced to 42%. This suggests that the symbiosis between the fungus and the algae increases the ability of both partners to survive under space conditions.

Based on the results of the simulated space conditions, Xanthoria elegans, Aspicilia fruticulosa and Rhizocarpon geographicum were then subjected to a real space test. It showed that after ten days in space, only a minimal effect occurred. An exposure of eighteen months in space brought more effects. While A. fruticulosa and Xanthoria elegans still showed photosynthesis and physiological activity, it turned out that Rhizocarpon geographicum was slightly damaged.

These results inspired the researchers to go one step further. They decided to expose Xanthoria elegans to a range of parameters such as those found on Mars. The atmosphere, extreme temperatures, humidity, UV radiation and available minerals were simulated. Xanthoria elegans, which also occurs here in Flanders, showed an exceptional survival capacity when it was exposed to these conditions for four days. From these results one can deduce that eukaryotic symbionts may be able to survive in regions of Mars where liquid water is present.

The results of this study show that not only the most primitive life forms could survive on the surface of planets in our solar system. We do not know if they have reached those planets. But life as we know it would therefore be possible on other planets …

Source: de Vera JP, Lichens as survivors in space and on Mars, Fungal Ecology (2012), doi: 10.1016/j.funeco.2012.01.008

Lichen Can Survive in Space: Space Station Research Sheds Light On Origin of Life; Potential for Better Sunscreens: here.

Lichens of Dutch Ameland island: here.

Algal blooms can cause serious – even fatal – problems in our waterways, but scientists know little about what causes them: here.