Rare but active taxa contribute to community dynamics of benthic biofilms in glacier-fed streams

Linda Wilhelm, Katharina Besemer, Christina Fasching, Tim Urich, Gabriel A. Singer, Christopher Quince, Tom J. Battin

Research output: Contribution to journalArticlepeer-review

85 Citations (Scopus)


Glaciers harbour diverse microorganisms, which upon ice melt can be released downstream. In glacier-fed streams microorganisms can attach to stones or sediments to form benthic biofilms. We used 454-pyrosequencing to explore the bulk (16S rDNA) and putatively active (16S rRNA) microbial communities of stone and sediment biofilms across 26 glacier-fed streams. We found differences in community composition between bulk and active communities among streams and a stronger congruence between biofilm types. Relative abundances of rRNA and rDNA were positively correlated across different taxa and taxonomic levels, but at lower taxonomic levels, the higher abundance in either the active or the bulk communities became more apparent. Here, environmental variables played a minor role in structuring active communities. However, we found a large number of rare taxa with higher relative abundances in rRNA compared with rDNA. This suggests that rare taxa contribute disproportionately to microbial community dynamics in glacier-fed streams. Our findings propose that high community turnover, where taxa repeatedly enter and leave the 'seed bank', contributes to the maintenance of microbial biodiversity in harsh ecosystems with continuous environmental perturbations, such as glacier-fed streams.

Original languageEnglish
Pages (from-to)2514-2524
Number of pages11
JournalEnvironmental Microbiology
Issue number8
Publication statusPublished - Aug 2014

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