Mismatch of N release from the permafrost and vegetative uptake opens pathways of increasing nitrous oxide emissions in the high Arctic - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Global Change Biology Année : 2022

Mismatch of N release from the permafrost and vegetative uptake opens pathways of increasing nitrous oxide emissions in the high Arctic

Sönke Zaehle
Silvia Caldararu
Jörg Schaller
Peter Stimmler
David Holl
Lars Kutzbach
  • Fonction : Auteur
Mathias Göckede

Résumé

Abstract Biogeochemical cycling in permafrost‐affected ecosystems remains associated with large uncertainties, which could impact the Earth's greenhouse gas budget and future climate policies. In particular, increased nutrient availability following permafrost thaw could perturb the greenhouse gas exchange in these systems, an effect largely unexplored until now. Here, we enhance the terrestrial ecosystem model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which simulates fully coupled carbon (C), nitrogen (N) and phosphorus (P) cycles in vegetation and soil, with processes relevant in high latitudes (e.g., soil freezing and snow dynamics). In combination with site‐level and satellite‐based observations, we use the model to investigate impacts of increased nutrient availability from permafrost thawing in comparison to other climate‐induced effects and CO 2 fertilization over 1960 to 2018 across the high Arctic. Our simulations show that enhanced availability of nutrients following permafrost thaw account for less than 15% of the total Gross primary productivity increase over the time period, despite simulated N limitation over the high Arctic scale. As an explanation for this weak fertilization effect, observational and model data indicate a mismatch between the timing of peak vegetative growth (week 26–27 of the year, corresponding to the beginning of July) and peak thaw depth (week 32–35, mid‐to‐late August), resulting in incomplete plant use of nutrients near the permafrost table. The resulting increasing N availability approaching the permafrost table enhances N loss pathways, which leads to rising nitrous oxide (N 2 O) emissions in our model. Site‐level emission trends of 2 mg N m −2 year −1 on average over the historical time period could therefore predict an emerging increasing source of N 2 O emissions following future permafrost thaw in the high Arctic.
Fichier principal
Vignette du fichier
Global Change Biology - 2022 - Lacroix.pdf (9.6 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04225235 , version 1 (02-10-2023)

Identifiants

Citer

Fabrice Lacroix, Sönke Zaehle, Silvia Caldararu, Jörg Schaller, Peter Stimmler, et al.. Mismatch of N release from the permafrost and vegetative uptake opens pathways of increasing nitrous oxide emissions in the high Arctic. Global Change Biology, 2022, 28 (20), pp.5973-5990. ⟨10.1111/gcb.16345⟩. ⟨hal-04225235⟩
5 Consultations
2 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More