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The significance of microbial processes in hydrogeology and geochemistry

Hydrogeology Journal

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Abstract

Microbial processes affect the chemical composition of groundwater and the hydraulic properties of aquifers in both contaminated and pristine groundwater systems. The patterns of water-chemistry changes that occur depend upon the relative abundance of electron donors and electron acceptors. In many pristine aquifers, where microbial metabolism is limited by the availability of electron donors (usually organic matter), dissolved inorganic carbon (DIC) accumulates slowly along aquifer flow paths and available electron acceptors are consumed sequentially in the order dissolved oxygen > nitrate > Fe(III) > sulfate > CO2 (methanogenesis). In aquifers contaminated by anthropogenic contaminants, an excess of available organic carbon often exists, and microbial metabolism is limited by the availability of electron acceptors. In addition to changes in groundwater chemistry, the solid matrix of the aquifer is affected by microbial processes. The production of carbon dioxide and organic acids can lead to increased mineral solubility, which can lead to the development of secondary porosity and permeability. Conversely, microbial production of carbonate, ferrous iron, and sulfide can result in the precipitation of secondary calcite or pyrite cements that reduce primary porosity and permeability in groundwater systems.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The significance of microbial processes in hydrogeology and geochemistry
Series title:
Hydrogeology Journal
Volume
8
Issue:
1
Year Published:
2000
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrogeology Journal
First page:
41
Last page:
46
Number of Pages:
6