Distribution of soil nitrogen and nitrogenase activity in the forefield of a High Arctic receding glacier

Thomas Turpin-Jelfs*, Katerina Michaelides, Joshua J. Blacker, Liane G. Benning, James M. Williams, Alexandre M. Anesio

*Corresponding author for this work

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

2 Citations (Scopus)
245 Downloads (Pure)

Abstract

Glaciers retreating in response to climate warming are progressively exposing primary mineral substrates to surface conditions. As primary production is constrained by nitrogen (N) availability in these emerging ecosystems, improving our understanding of how N accumulates with soil formation is of critical concern. In this study, we quantified how the distribution and speciation of N, as well as rates of free-living biological N fixation (BNF), change along a 2000-year chronosequence of soil development in a High Arctic glacier forefield. Our results show the soil N pool increases with time since exposure and that the rate at which it accumulates is influenced by soil texture. Further, all N increases were organically bound in soils which had been ice-free for 0-50 years. This is indicative of N limitation and should promote BNF. Using the acetylene reduction assay technique, we demonstrated that microbially mediated inputs of N only occurred in soils which had been ice-free for 0 and 3 years, and that potential rates of BNF declined with increased N availability. Thus, BNF only supports N accumulation in young soils. When considering that glacier forefields are projected to become more expansive, this study has implications for understanding how ice-free ecosystems will become productive over time.
Original languageEnglish
Pages (from-to)87-94
Number of pages8
JournalAnnals of Glaciology
Volume59
Issue number77
Early online date24 Jan 2019
DOIs
Publication statusE-pub ahead of print - 24 Jan 2019

Keywords

  • Arctic glaciology
  • biogeochemistry
  • microbiology
  • moraine

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