Microbial carbonates in time and space

Microbes (bacteria, small algae, fungi) are widespread on aquatic substrates. Carbonate<br>precipitation, locally augmented by grain trapping, results in their accretion and preservation as<br>microbial carbonates. Extracellular polymeric substances (EPS), produced by microbes for<br>attachment and protection, provide nucleation sites and facilitate grain trapping.