Precipitation of High Mg-Calcite and Protodolomite Using Dead Biomass of Aerobic Halophilic Bacteria

Qigao Fan, Deng Liu, Dominic Papineau, Xuan Qiu, Hongmei Wang, Zhenbing She, Linduo Zhao

Research output: Contribution to journalArticlepeer-review


The microbial dolomite model has been used to interpret the origin of sedimentary dolomite. In this model, the formation of low-temperature protodolomite, an important precursor to sedimentary dolomite, can be facilitated either by actively metabolizing cells of anaerobic microbes and aerobic halophilic archaea or by their inactive biomass. Aerobic halophilic bacteria are widely distributed in (proto-)dolomite-depositing evaporitic environments and their biomass might serve as a template for the crystallization of protodolomite. To test this hypothesis, carbonation experiments were conducted using dead biomass of an aerobic halophilic bacterium (Exiguobacterium sp. strain JBHLT-3). Our results show that dead biomass of JBHLT-3 can accelerate Mg2+ uptake in carbonate mineral precipitates. In addition, the amount of Mg incorporated into Ca-Mg carbonates is proportional to the concentration of biomass. High Mg-calcite is produced with 0.25 or 0.5 g/L biomass, whereas protodolomite forms with 1 g/L biomass. This is confirmed by the main Raman peak of Ca-Mg carbonates, which shifts towards higher wavenumbers with increased Mg substitution. Microbial cells and their imprints are preserved on the surface of high Mg-calcite and protodolomite. Hence, this study furthers our understanding of the dolomitization within buried and dead microbial mats, which provides useful insights into the origin of ancient dolomite.

Original languageEnglish (US)
Pages (from-to)456-466
Number of pages11
JournalJournal of Earth Science
Issue number2
StatePublished - Apr 2023


  • Mg-hydration effect
  • biosignature
  • high Mg-calcite
  • microbial dead biomass
  • paleobiology
  • protodolomite

ASJC Scopus subject areas

  • General Earth and Planetary Sciences


Dive into the research topics of 'Precipitation of High Mg-Calcite and Protodolomite Using Dead Biomass of Aerobic Halophilic Bacteria'. Together they form a unique fingerprint.

Cite this