Metagenomic insights into diazotrophic communities across Arctic glacier forefields

Maisie V. Nash*, Alexandre M. Anesio, Gary Barker, Martyn Tranter, Gilda Varliero, Emiley A. Eloe-Fadrosh, Torben Nielsen, Thomas Turpin-Jelfs, Liane G. Benning, Patricia Sánchez-Baracaldo

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

34 Citations (Scopus)
310 Downloads (Pure)


Microbial nitrogen fixation is crucial for building labile nitrogen stocks and facilitating higher plant colonisation in oligotrophic glacier forefield soils. Here, the diazotrophic bacterial community structure across four Arctic glacier forefields was investigated using metagenomic analysis. In total, 70 soil metagenomes were used for taxonomic interpretation based on 185 nitrogenase (nif) sequences, extracted from assembled contigs. The low number of recovered genes highlights the need for deeper sequencing in some diverse samples, to uncover the complete microbial populations. A key group of forefield diazotrophs, found throughout the forefields, was identified using a nifH phylogeny, associated with nifH Cluster I and III. Sequences related most closely to groups including Alphaproteobacteria, Betaproteobacteria, Cyanobacteria and Firmicutes. Using multiple nif genes in a Last Common Ancestor analysis revealed a diverse range of diazotrophs across the forefields. Key organisms identified across the forefields included Nostoc, Geobacter, Polaromonas and Frankia. Nitrogen fixers that are symbiotic with plants were also identified, through the presence of root associated diazotrophs, which fix nitrogen in return for reduced carbon. Additional nitrogen fixers identified in forefield soils were metabolically diverse, including fermentative and sulphur cycling bacteria, halophiles and anaerobes.

Original languageEnglish
Article numberfiy114
Number of pages12
JournalFEMS Microbiology Ecology
Issue number9
Early online date13 Jun 2018
Publication statusPublished - 1 Sept 2018


  • Nitrogen fixation
  • Metagenomics
  • Forefield
  • Arctic
  • Diversity
  • Diazotrophs


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