Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies

Abstract δ 15 3 - δ 15 δ 15 15 N signature to nitrate. However, the potential to observe these thaw signals at the mouths of rivers depends on the spatial scale of thaw sites, permafrost degradation, and recycling mechanisms. In contrast with the Kolyma, with near 100 % continuous permafrost extent, the Ob River, draining large areas of discontinuous and sporadic permafrost, shows large seasonal changes in both nitrate and DON isotopic signatures. During winter months, water percolating through peat soils records isotopically heavy denitrification signals in contrast with the lighter summer values when surface flow dominates. This early year denitrification signal was present to a degree in the Kolyma, but the ability to relate seasonal nitrogen signals across Arctic Rivers to permafrost degradation could not be shown with this study. Other large rivers in the Arctic show different seasonal nitrogen trends. Based on nitrogen isotope values, the vast majority of nitrogen fluxes in the Arctic rivers is from fresh DON sourced from surface runoff through organic-rich topsoil and not from permafrost degradation. However, with future permafrost thaw, other Arctic rivers may begin to show nitrogen trends similar to the Ob. Our study demonstrates that nitrogen inputs from permafrost thaw can be identified through nitrogen isotopes, but only on small spatial scales. Overall, nitrogen isotopes show potential for revealing integrated catchment wide nitrogen cycling processes.

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch

Bibliographic citation
Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies ; volume:20 ; number:2 ; year:2023 ; pages:365-382 ; extent:18
Biogeosciences ; 20, Heft 2 (2023), 365-382 (gesamt 18)

Creator
Francis, Adam
Ganeshram, Raja S.
Tuerena, Robyn E.
Spencer, Robert G. M.
Holmes, Robert M.
Rogers, Jennifer A.
Mahaffey, Claire

DOI
10.5194/bg-20-365-2023
URN
urn:nbn:de:101:1-2023033008074379678534
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
14.08.2025, 10:44 AM CEST

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Associated

  • Francis, Adam
  • Ganeshram, Raja S.
  • Tuerena, Robyn E.
  • Spencer, Robert G. M.
  • Holmes, Robert M.
  • Rogers, Jennifer A.
  • Mahaffey, Claire

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