The geological search for ancient life frequently zeroes in on fossilized organic structures or biominerals that can serve as “biosignatures,” that survive in the rock record over extremely long time scales. Mineral elements such as sulfur are often formed through biological activity. Microbes can also produce a variety of telltale extracellular structures that resemble sheaths and stalks.
However, according to new findings published in the journal Nature Communications, carbon-sulfur microstructures that would be recognized today by some experts as biomaterials are capable of self-assembling under certain conditions, even without direct biological activity. These “false” biosignatures could potentially be misinterpreted as signs of biological activity due to their strong resemblance to microbial structures.
“Surprisingly, we found that we could create all sorts of biogenic-like materials that have the right shape, structure and chemistry to match natural materials we assume are produced biologically,” said Associate Professor Alexis Templeton of CU Boulder’s Department of Geological Sciences and senior author of the new study. Paper. (public access) – Julie Cosmidis, Alexis S. Templeton. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments. Nature Communications, 2016; 7: 12812 DOI: 10.1038/ncomms12812 More.
Did you ever write away for a kit that promised you an underwater garden that was actually crystal salts building up? Really nice and very instructive, but not life.
See also: What we know and don’t know about the origin of life
What can we hope to learn about animal minds? (What makes it life?)
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