The natural and anthropogenic microbiota of Glerá, a sub-arctic river in northeastern Iceland

Abstract The river Glera in Northern-Iceland presents a convenient model for the evaluation of anthropogenic effects on sub-Arctic river microbiota. The river originates in a pristine valley, flows past a landfill site where leachate merges into the river, and subsequently through a small urban area. Our aim was to characterize the river microbiota in both its pristine and anthropogenically impacted state, particularly focusing on prospective surfactant degraders whose activity in the river water might contribute to the river's self-purification capacity. We sampled river water and riverbed sediment at 10 sampling sites that spanned the river from its pristine source to the estuary for culturable bacteria and extractable DNA. A few other biotopes in the catchment area were also sampled. A confirmed pure and viable culture collection of 170 isolates was generated and partially analyzed for identification by 16S rRNA gene sequencing, and for biodegradation of selected surfactants as well as glycans, protein and triglyceride. Protein-degrading pseudomonads are strongly represented in the culture collection, many of whom can also degrade selected surfactants. The collection also contains other members of the Gammaproteobacteria as well as the Alphaproteobacteria, Betaproteobacteria, Bacilli, Actinobacteria, Flavobacteria, and Sphingobacteria. Several isolates of all classes, except the Betaproteobacteria, displayed biodegradative activity.