Interestingly, bones and teeth and other biominerals consist of similar assemblies of building blocks. But their synthesis in our bodies is tightly regulated by proteins—not one or two random proteins, but scores and scores of precise biological molecules that order each tiny crystal where to sit and how to behave. By comparison, the Ney Spring waters self-organize into complex structures without any extra help. (Well, not nearly as complex, to be honest, but still interesting.)

Back in time and far in space

On present-day Earth, the Ney Spring is a rare geochemical specimen. However, similar environments might have been common on early Earth and other faraway planets. This raises an important caution. When we find a curious-looking object on Earth or Mars or Europa, we will want to characterize it with extra confidence before declaring it is, or was, alive.

This argument goes the other way round as well. We should not immediately discredit a potential fossil because it looks like something made in the lab. There are other ways, besides morphology, that scientists use to scrutinize potential fossils. But even measurements such as isotope fractionation and chemical analysis are fraught with difficulties. Clearly, searching for life is easier said than done…

Not too long ago, the boundaries between geochemical and biological structures were perceived as sharp and well defined. These boundaries are now more blurred than ever, and scientists from various disciplines are cooperating to meet the coming challenges.

Acknowledgements

Full details of the study can be found here. The study was lead by Prof. Juan Manuel Garcia-Ruiz and performed in cooperation with Prof. Oliver Steinbock, Electra Kotopolou, Leonardo Tamborrino, and Dr. Elias Nakouzi. Special thanks to the Mount Shasta Trail Association. This study was funded by the European Research Council and the National Science Foundation.