Ice sheet likely source of methane on Mars, scientists find

Pablo Tucker
April 3, 2019

On Monday, scientists published their findings about the first independent confirmation about methane on Mars in the Nature Geoscience journal.

The researchers now hope to better understand how methane is removed from the atmosphere.

Their model suggests the release may have come from Aeolis Mensae, a geological feature some 300 miles east of Gale Crater. The probe has since found that the levels of the gas varies, rising and falling with Martian seasons.

On Earth, methane is typically a sign of life. On gas and ice giants such as Jupiter, Saturn, Uranus and Neptune, plenty of methane is produced via chemical processes.

The study, led by Dr. Marco Giuranna of Italy's National Astrophysics Institute, examined measurements from NASA's Curiosity rover and Europe's Mars Express taken a day apart in June 2013, definitively showing the presence of trace amounts of the compound in the atmosphere above the Gale Crater, a 154 kilometer-wide formation located along the Martian equator and previously considered to be a dried out lake.

'Prior to our study, methane detections on Mars, being either in situ, from orbit, or from Earth-based telescopes, were not confirmed by independent observations. But even if methanogenic forms of life have not developed on Mars, methane can be produced by abiotic processes that are likely on the Red Planet.

A methane "burp" on Mars that has divided scientists but could be evidence of life on the Red Planet really was detected by a Nasa rover in 2013, say scientists. The next day, ESA's Mars Express probe captured air samples with a methane concentration of 15.5 parts per billion as it whizzed through the atmosphere above Gale Crater. Comparing the data from Curiosity with the data from Mars Express, the team was able to determine that the methane in question probably came from a ground release some distance from Curiosity's location at Gale Crater.

Researchers indicate that they are not afraid of extreme temperature changes and intense radiation, which the organisms use as a source of energy.

At the time of the Curiosity detection, it was speculated that the methane originated north of the rover, because the prevailing winds were southward, and that the release likely occurred inside the crater.

"Remarkably, we saw that the atmospheric simulation and geological assessment, performed independently of each other, suggested the same region of provenance of the methane".

"Despite various detection's reported by separate groups and different experiments, and although plausible mechanisms have been proposed to explain the observed abundance, variability and lifetime of methane in the current Martian atmosphere, the methane debate still splits the Mars community". Methane can be made as a downstream product of serpentinisation. Since permafrost is an excellent seal for methane, it is possible that the ice here could trap subsurface methane and release it episodically along the faults that break through this ice.

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