Scientists are studying acidic streams in Dorset because of their similarity to the environment of Mars billions of years ago.

Reseachers from Imperial College London have found traces of fatty acids – which are key to the development of life – in Dorset’s acidic streams.

Applying their findings from St Oswald’s Bay, they predict there could be nearly 12,000 Olympic sized pools of organic matter on Mars representing traces of past life.

The researchers used Dorset’s highly acidic sulphur streams as a template for Mars and examined the rock deposits near them.

Rich in iron, the mineral goethite transforms to another called hematite which is very common on Mars and gives the planet its famous red colour.

The team hoped that if the iron-rich minerals harboured traces of life on Earth, then they could also hold clues to past microbial life on the Red Planet.

Their study found that goethite in St Oswald’s Bay hosted many microbes as well as traces of their fossilised organic remains.

The research, published in Scientific Reports, applied the results from Dorset to what they know about the Martian environment.

Composite of sunset in Dorset (L) and on Mars
Image:
A sunset in Dorset (L) and on Mars

Based on how much rock is from acid environments on Mars, and assuming the concentration of fatty acids found in Martian sediments is the same as it is on Earth, there could be thousands of metric tonnes of fatty acids preserved in Martian rock.

Although previous missions to the planet have used heat to inspect rocks for organic matter, the heat might have caused the minerals to react with that matter – destroying the evidence.

Fortunately, goethite and hematite would not react with organic matter when they are heated, meaning targeting those minerals could provide crucial evidence of Martian life.

Professor Mark Sephton, head of the university’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.”

The ICL team tests the Ph of the streams in Dorset
Image:
The ICL team tests the Ph of the streams in Dorset

Co-author Dr Jonathan Tan 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.”

If traces of life are found on Mars it is likely to be in the form of bacteria which can survive extreme environments like the acid streams on Earth, the authors said.

They hope that the next life-searching mission to Mars, Mars 2020, can be programmed to search for these ancient acidic streams and the sediments inspected for traces of fatty acids.



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