Permafrost degradation and its consequences for carbon storage in soils of Interior Alaska

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Patrick Liebmann - , Leibniz University Hannover (LUH) (Author)
  • Jiří Bárta - , University of South Bohemia (Author)
  • Cordula Vogel - , Institute of Soil Science and Site Ecology, Chair of Soil Resources and Land Use, TUD Dresden University of Technology (Author)
  • Tim Urich - , University of Greifswald (Author)
  • Alexander Kholodov - , University of Alaska Fairbanks (Author)
  • Milan Varsadiya - , University of South Bohemia, University of Bayreuth (Author)
  • Ole Mewes - , Leibniz University Hannover (LUH) (Author)
  • Stefan Dultz - , Leibniz University Hannover (LUH) (Author)
  • Muhammad Waqas - , University of South Bohemia (Author)
  • Haitao Wang - , University of Greifswald (Author)
  • Olga Shibistova - , Leibniz University Hannover (LUH) (Author)
  • Georg Guggenberger - , Leibniz University Hannover (LUH) (Author)

Abstract

Permafrost soils in the northern hemisphere are known to harbor large amounts of soil organic matter (SOM). Global climate warming endangers this stable soil organic carbon (SOC) pool by triggering permafrost thaw and deepening the active layer, while at the same time progressing soil formation. But depending, e.g., on ice content or drainage, conditions in the degraded permafrost can range from water-saturated/anoxic to dry/oxic, with concomitant shifts in SOM stabilizing mechanisms. In this field study in Interior Alaska, we investigated two sites featuring degraded permafrost, one water-saturated and the other well-drained, alongside a third site with intact permafrost. Soil aggregate- and density fractions highlighted that permafrost thaw promoted macroaggregate formation, amplified by the incorporation of particulate organic matter, in topsoils of both degradation sites, thus potentially counteracting a decrease in topsoil SOC induced by the permafrost thawing. However, the subsoils were found to store notably less SOC than the intact permafrost in all fractions of both degradation sites. Our investigations revealed up to net 75% smaller SOC storage in the upper 100 cm of degraded permafrost soils as compared to the intact one, predominantly related to the subsoils, while differences between soils of wet and dry degraded landscapes were minor. This study provides evidence that the consideration of different permafrost degradation landscapes and the employment of soil fractionation techniques is a useful combination to investigate soil development and SOM stabilization processes in this sensitive ecosystem.

Details

Original languageEnglish
Pages (from-to)199-223
Number of pages25
JournalBiogeochemistry
Volume167
Issue number3
Publication statusPublished - Mar 2024
Peer-reviewedYes

External IDs

ORCID /0000-0002-6525-2634/work/167215333

Keywords

Sustainable Development Goals

Keywords

  • Climate change, Microbial decomposition, Permafrost thaw, Soil development, Soil fractions, Soil organic matter