By studying a stream on the UK coast, scientists have calculated how much organic matter we might find in connection with life on Mars, and where to look.
According to Imperial College London, scientists have found traces of fatty acids – key building blocks of biological cells – in Dorset’s acidic streams. They say that because of the similarity of acidic streams in Dorset and on Mars, their findings hint that life on Mars may have once existed.
By applying their findings to the Red Planet, the researchers concluded that there could be nearly 12,000 Olympic sized pools of organic matter on Mars that could represent traces of past life.
How can Dorset provide the information needed?
Dorset is home to highly acidic sulphur streams that host bacteria which thrive in extreme conditions. One such environment, in St Oswald’s Bay, mimics the conditions on Mars billions of years ago.
Researchers have treated the landscape as a template for Mars and examined the organic matter preserved in the rock deposits. The iron-rich mineral goethite transforms to haematite which is very common on Mars, giving the planet its red colour. If these iron-rich minerals harbour traces of life on Earth, then they may hold clues to past microbial life on the Red Planet.
This study, funded by the UK space agency, found that goethite in St Oswald’s Bay hosted many microbes as well as traces of their fossilised organic remains.
Researchers applied these results to a Martian environment: based on how much rock is from acid environments on Mars, and assuming the concentration of fatty acids found in Martian sediments matches that of Earth, there might be up to 2.86×1010 kg of fatty acids preserved within Martin rock.
Missions to Mars
Previous missions to find traces of life on Mars have used heat to inspect rock for the presence of organic matter. Scientists suspect the heat might have caused minerals to react with any organic matter, explaining why we haven’t yet found traces of life.
Heating goethite or haematite does not destroy any organic matter that is there, meaning that these minerals could be good targets to use when searching for life.
Co-author Professor Mark Sephton, Head of Imperial’s Department of Earth Science & Engineering said: “Mars harboured water billions of years ago, meaning some form of life might have thrived there. If life existed before the water dried up, it would probably have left remains that are preserved to this day in Martian rock.
“However, we have yet to find convincing traces of organic matter that would indicate previous life on the Red Planet.”
Co-author Jonathan Tan, also from the Department of Earth Science & Engineering, said: “St Oswald’s Bay is a present-day microcosm of middle-aged Mars. As the acid streams dry up, like during Mars’ ‘drying period’, they leave goethite minerals behind which preserve fatty acids that act as biological signatures.”
The authors say that if traces of life on Mars were found, it will probably be in the form bacteria that can thrive in extreme environments – like the acid streams on Earth.