"Below the surface, the bottom of Pavilion Lake is dotted with something resembling coral reefs: domes and cones and weird shapes much like artichokes. These are not corals, though, which are colonies of tiny animals: they are rock formations called microbialites, made by and coated in cyanobacteria. Sometimes misleadingly referred to as 'blue-green algae', these bacteria probably even made the rocks they live on, absorbing nutrients from the water and leaving stone behind. Like plants, they live on sunlight, and they thrive in shallow waters down the steep underwater slope to the point where sunlight fades to gloom.
They are the reason for NASA's interest, and my visit. The people I've come here to see have even bigger things in mind. They want to know what the rare formations in Pavilion Lake might tell us about the origins of life on Earth, life on other worlds and, indeed, what life is, exactly."
If we met new life – on this planet or the next – would we know it when we saw it? Matthew Francis investigates.
Written by Matthew Francis, read and produced by Barry J Gibb.
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