Sulphate-controlled Diversity of Subterranean Microbial Communities over Depth in Deep Groundwater with Opposing Gradients of Sulphate and Methane
Journal article, 2014

The groundwater system in Olkiluoto, Finland, is stratified with a mixing layer at a depth of approximately 300m between sulphate-rich, methane-poor and sulphate-poor, methane-rich groundwaters. New sequence library data obtained by 454 pyrotag sequencing of the v4v6 16S rDNA region indicated that sulphate-reducing bacteria (SRB) dominated the mixing layer while SRB could not be detected in the deep sulphate-poor groundwater samples. With the indispensable support of the sequence data, it could be demonstrated that sulphate was the only component needed to trigger a very large community transition in deep sulphate-poor, methane-rich groundwater from a non-sulphate-reducing community comprising Hydrogenophaga, Pseudomonas, Thiobacillus, Fusibacter, and Lutibacter to a sulphate-reducing community with Desulfobacula, Desulfovibrio, Desufobulbaceae, Desulfobacterium, Desulfosporosinus, and Desulfotignum. Experiments with biofilms and planktonic microorganisms in flow cells under in situ conditions confirmed that adding sulphate to the sulphate-poor groundwater generated growth of cultivable SRB and detectable SRB-related sequences. It was also found that the 16S rDNA diversity of the biofilms was conserved over 103 d and that there was great similarity in diversity between the microorganisms in the biofilms and in the flowing groundwater. This work demonstrates that the presence/absence of only one geochemical parameter, i.e., sulphate, in the groundwater significantly influenced the diversity of the investigated subterranean microbial community.

granitic groundwater






deep biosphere




introduced organic-compounds

crystalline bedrock

fennoscandian shield

gen. nov.

16S rDNA

reducing bacterium



Karsten Pedersen

Chalmers, Civil and Environmental Engineering, GeoEngineering

A. F. Bengtsson

J. S. Edlund

L. C. Eriksson

Geomicrobiology Journal

0149-0451 (ISSN) 1521-0529 (eISSN)

Vol. 31 7 617-631

Subject Categories

Earth and Related Environmental Sciences



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