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

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DOI

  • Thomas Turpin-Jelfs, Bristol University
  • ,
  • Katerina Michaelides, Bristol University, University of California, Santa Barbara
  • ,
  • Joshua Blacker, University of Leeds, United Kingdom
  • Liane G. Benning, University of Leeds, GFZ German Research Centre for Geosciences, Free University of Berlin, United Kingdom
  • James Williams, University of Bristol, United Kingdom
  • Alexandre M. Anesio
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
JournalAnnals of Glaciology
Volume59
Issue77
Pages (from-to)87-94
Number of pages8
ISSN0260-3055
DOIs
Publication statusPublished - 2018

    Research areas

  • Arctic glaciology, CARBON, CHRONOSEQUENCE, DAMMA GLACIER, FIXATION, FORELAND, LOVENBREEN, ORGANIC-MATTER, PHOSPHORUS, PRIMARY SUCCESSION, VEGETATION, biogeochemistry, microbiology, moraine

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