Lignin Preservation and Microbial Carbohydrate Metabolism in Permafrost Soils

verfasst von

Thao Thi Dao, Robert Mikutta, Leopold Sauheitl, Norman Gentsch, Olga Shibistova, Birgit Wild, Jörg Schnecker, Jiří Bárta, Petr Čapek, Antje Gittel, Nikolay Lashchinskiy, Tim Urich, Hana Šantrůčková, Andreas Richter, Georg Guggenberger

Abstract

Permafrost-affected soils in the northern circumpolar region store more than 1,000 Pg soil organic carbon (OC), and are strongly vulnerable to climatic warming. However, the extent to which changing soil environmental conditions with permafrost thaw affects different compounds of soil organic matter (OM) is poorly understood. Here, we assessed the fate of lignin and non-cellulosic carbohydrates in density fractionated soils (light fraction, LF vs. heavy fraction, HF) from three permafrost regions with decreasing continentality, expanding from east to west of northern Siberia (Cherskiy, Logata, Tazovskiy, respectively). In soils at the Tazovskiy site with thicker active layers, the LF showed smaller OC-normalized contents of lignin-derived phenols and plant-derived sugars and a decrease of these compounds with soil depth, while a constant or even increasing trend was observed in soils with shallower active layers (Cherskiy and Logata). Also in the HF, soils at the Tazovskiy site had smaller contents of OC-normalized lignin-derived phenols and plant-derived sugars along with more pronounced indicators of oxidative lignin decomposition and production of microbial-derived sugars. Active layer deepening, thus, likely favors the decomposition of lignin and plant-derived sugars, that is, lignocelluloses, by increasing water drainage and aeration. Our study suggests that climate-induced degradation of permafrost soils may promote carbon losses from lignin and associated polysaccharides by abolishing context-specific preservation mechanisms. However, relations of OC-based lignin-derived phenols and sugars in the HF with mineralogical properties suggest that future OM transformation and carbon losses will be modulated in addition by reactive soil minerals.

Organisationseinheit(en)

Institut für Bodenkunde

Externe Organisation(en)

Martin-Luther-Universität Halle-Wittenberg
Russian Academy of Sciences (RAS)
Universität Wien
Stockholm University
University of South Bohemia
University of Bergen (UiB)
Aarhus University
Siberian Branch of the Russian Academy of Sciences
Universität Greifswald
Austrian Polar Research Institute

Typ

Artikel

Journal

Journal of Geophysical Research: Biogeosciences

Band

127

Anzahl der Seiten

22

ISSN

2169-8953

Publikationsdatum

01.2022

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Bodenkunde, Forstwissenschaften, Gewässerkunde und -technologie, Paläontologie, Atmosphärenwissenschaften, Aquatische Wissenschaften, Ökologie

Ziele für nachhaltige Entwicklung

SDG 13 – Klimaschutzmaßnahmen

Elektronische Version(en)

https://doi.org/10.1029/2020JG006181 (Zugang: Offen)