“…The primary driver for calcification in biofilms is the local increase in calcium carbonate supersaturation, which may result from specific microbial metabolisms, for instance, photosynthesis, ureolysis, or sulfate reduction [e.g., Saghaï et al, 2016, White et al, 2016. This active, biologically induced CaCO 3 mineralization process occurs concurrently with passive binding of Ca 2+ ions on the EPS matrix of the biofilm, which may favor CaCO 3 heterogeneous nucleation, and influence mineral properties such as morphology, size, or structure [Dupraz et al, 2009, Görgen et al, 2021, Lyu et al, 2020. Interestingly, it is now recognized that microbially induced CaCO 3 precipitation may not be limited to heavily calcifying, mat-building environmental communities such as those forming stromatolites, but can also occur in biofilms of bacteria previously studied as pathogens in a medical context [e.g., Pseudomonas aeruginosa or Proteus mirabilis; Li et al, 2016aLi et al, , 2015.…”