biostudies-literatureUnknown15(1)Sanchez-Roman MMicrobial impacts on early carbonate diagenesis, particularly the formation of Mg-carbonates at low temperatures, have long eluded scientists. Our breakthrough laboratory experiments with two species of halophilic aerobic bacteria and marine carbonate grains reveal that these bacteria created a distinctive protodolomite (disordered dolomite) rim around the grains. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) confirmed the protodolomite formation, while solid-state nuclear magnetic resonance (NMR) revealed bacterial interactions with carboxylated organic matter, such as extracellular polymeric substances (EPS). We observed a significant carbon isotope fractionation (average δ¹³C = 11.3‰) and notable changes in Mg/Ca ratios throughout the experiments. Initial medScientific reports561https://www.ebi.ac.uk/biostudies/studies/S-EPMC11696100biostudies-literatureThe hidden role of heterotrophic bacteria in early carbonate diagenesis.PMC11696100Sanchez-Roman MReijmer JVahrenkamp VAreias CChandra VMulder SfalseThe hidden role of heterotrophic bacteria in early carbonate diagenesis.Microbial impacts on early carbonate diagenesis, particularly the formation of Mg-carbonates at low temperatures, have long eluded scientists. Our breakthrough laboratory experiments with two species of halophilic aerobic bacteria and marine carbonate grains reveal that these bacteria created a distinctive protodolomite (disordered dolomite) rim around the grains. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) confirmed the protodolomite formation, while solid-state nuclear magnetic resonance (NMR) revealed bacterial interactions with carboxylated organic matter, such as extracellular polymeric substances (EPS). We observed a significant carbon isotope fractionation (average δ¹³C = 11.3‰) and notable changes in Mg/Ca ratios throughout the experiments. Initial med2025-01-01T00:00:00Z2025 Jan2025-04-22T08:59:30.685Z2025-04-05T22:52:27.441ZS-EPMC116961003974761810.1038/s41598-024-84407-y