Microbial precipitation of dolomite in methanogenic groundwater

Geology
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Abstract

We report low-temperature microbial precipitation of dolomite in dilute natural waters from both field and laboratory experiments. In a freshwater aquifer, microorganisms colonize basalt and nucleate nonstoichiometric dolomite on cell walls. In the laboratory, ordered dolomite formed at near-equilibrium conditions from groundwater with molar Mg:Ca ratios of <1; dolomite was absent in sterile experiments. Geochemical and microbiological data suggest that methanogens are the dominant metabolic guild in this system and are integral to dolomite precipitation. We hypothesize that the attached microbial consortium reacts with the basalt surface, releasing Mg and Ca into solution, which drives dolomite precipitation via nucleation on the cell wall. These findings provide insight into the long-standing dolomite problem and suggest a fundamental role for microbial processes in the formation of dolomite across a wide range of environmental conditions.

Publication type Article
Publication Subtype Journal Article
Title Microbial precipitation of dolomite in methanogenic groundwater
Series title Geology
DOI 10.1130/G20246.2
Volume 32
Issue 4
Year Published 2004
Language English
Publisher Geological Society of America
Contributing office(s) Toxic Substances Hydrology Program
Description 4 p.
First page 277
Last page 280
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