Thiobacillus as a key player for biofilm formation in oligotrophic groundwaters of the Fennoscandian Shield

Abstract Biofilm formation is a common adaptation for microbes in energy-limited conditions such as those prevalent in the vast deep terrestrial biosphere. However, due to the low biomass and the inaccessible nature of subsurface groundwaters, the microbial populations and genes involved in its form...

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Bibliographic Details
Published in:npj Biofilms and Microbiomes
Main Authors: Margarita Lopez-Fernandez, George Westmeijer, Stephanie Turner, Elias Broman, Magnus Ståhle, Stefan Bertilsson, Mark Dopson
Format: Article in Journal/Newspaper
Language:English
Published: Nature Portfolio 2023
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Online Access:https://doi.org/10.1038/s41522-023-00408-1
https://doaj.org/article/5ce784cb72c24af7916933071d01e1a0
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Summary:Abstract Biofilm formation is a common adaptation for microbes in energy-limited conditions such as those prevalent in the vast deep terrestrial biosphere. However, due to the low biomass and the inaccessible nature of subsurface groundwaters, the microbial populations and genes involved in its formation are understudied. Here, a flow-cell system was designed to investigate biofilm formation under in situ conditions in two groundwaters of contrasting age and geochemistry at the Äspö Hard Rock Laboratory, Sweden. Metatranscriptomes showed Thiobacillus, Sideroxydans, and Desulforegula to be abundant and together accounted for 31% of the transcripts in the biofilm communities. Differential expression analysis highlighted Thiobacillus to have a principal role in biofilm formation in these oligotrophic groundwaters by being involved in relevant processes such as the formation of extracellular matrix, quorum sensing, and cell motility. The findings revealed an active biofilm community with sulfur cycling as a prominent mode of energy conservation in the deep biosphere.