[MarkusQ]

This is like saying "wood burns, even when the tree is dead" but much, much slower.

The disequilibrium (sugars and free O₂) were produced by living organisms, and this is just the gradual drift back to a lower energy state. CO₂ is common in the universe, and not at all a sign of life. O₂ and sugars are rare.

[conductr]

This seems like the better explanation of my laybrain reading this and thinking; why would you start with soil? If it were a true geological phenomenon then shouldn’t they use a sterile jar of granite dust or something that only existed on earth prior to life? It seems like pointing at a jar of bio matter and saying we can’t stop it is not really a good methodology to base much upon. I barely ever even took a chemistry class in my life but something just feels wrong with this approach to me. I assume that’s what the other scientists who doubt the sterilization were thinking too.

[mrguyorama]

Indeed.

They suggest that the soil can somehow catalyze metabolic reactions and break down complex carbohydrates without life but where would the complex carbohydrates come from?

I'm also curious how they could demonstrate that there isn't some sort of very constrained extremophile producing all their results that doesn't exactly colonize very well but will still function.

[LarsAlereon]

This is honestly what I'm thinking. Carbohydrates and hydrocarbons will oxidize to CO2 and water in our atmosphere, and especially quickly at warm temperatures, in the presence of energy sources like sunlight, or in the presence of ozone or elevated oxygen levels. In general biological processes like aerobic decay are so much more effective that we ignore this, but it still happens.