Microorganisms (bacteria and archaea) are widely suggested to influence the formation of minerals. But how do we know? Is the evidence for microbial involvement in mineral formation truly robust in every case?

The mechanisms by which microorganisms may affect mineral formation are diverse: do they simply alter their environment through metabolic activity, driving the surrounding fluid to supersaturation with respect to a particular mineral phase? Or can they mediate the nucleation and growth of a mineral that is already supersaturated in the fluid but whose formation is kinetically inhibited? And how might these different processes manifest in the sedimentary record?

These controversial questions call for an open and unbiased debate. This Geopanel provides a forum for such a discussion from a multidisciplinary perspective, bringing together panellists representing mineralogical, geochemical, microbiological and sedimentological viewpoints.

The aim is not to promote a particular interpretation, but to critically examine the evidence, clarify the mechanisms involved, and develop a more differentiated understanding of the role of microorganisms in mineral formation — helping the field to build a stronger scientific foundation.