How temperature and aridity drive lignin decomposition along a latitudinal transect in western Siberia

authored by

Thao Thi Dao, Robert Mikutta, Birgit Wild, Leopold Sauheitl, Norman Gentsch, Olga Shibistova, Jörg Schnecker, Nikolay Lashchinskiy, Andreas Richter, Georg Guggenberger

Abstract

Climate change drives a northward shift of biomes in high-latitude regions. This might have consequences on the decomposition of plant litter entering the soil, including its lignin component, which is one of the most abundant components of vascular plants. In order to elucidate the combined effect of climate and soil characteristics on the decomposition pattern of lignin, we investigated lignin contents and its degree of oxidative decomposition within soil profiles along a climosequence in western Siberia. Soil samples were collected from organic topsoil to mineral subsoil at six sites along a 1500-km latitudinal transect, stretching from tundra, through taiga and forest steppe to typical steppe. The stage of lignin degradation, as mirrored by decreasing organic carbon-normalized lignin contents and increasing oxidative alteration of the remnant lignin (acid-to-aldehyde ratios of vanillyl- and syringyl-units [(Ac/Al)_V and (Ac/Al)_S]) within soil horizons, increased from tundra to forest steppe and then decreased to the steppe. Principal component analysis, involving also climatic conditions such as mean annual temperature and aridity index, showed that the different states of lignin degradation between horizons related well to the activity of phenoloxidases and peroxidases, enzymes involved in lignin depolymerization that are produced primarily by fungi and less importantly by bacteria. The low microbial lignin decomposition in the tundra was likely due to low temperature and high soil moisture, which do not favour the fungi. Increasing temperature and decreasing soil moisture, facilitating a higher abundance of fungi, led to increased fungal lignin decomposition towards the forest-steppe biome, while drought and high pH might be responsible for the reduced lignin decomposition in the steppe. We infer that a shift of biomes to the north, driven by climate change, might promote lignin decomposition in the northern parts, whereas in the south a further retardation might be likely.

Organisation(s)

Institute of Soil Science

External Organisation(s)

Electric Power University (EPU)
Martin Luther University Halle-Wittenberg
Stockholm University
University of Vienna
Austrian Polar Research Institute
Siberian Branch of the Russian Academy of Sciences

Type

Article

Journal

European journal of soil science

Volume

74

ISSN

1351-0754

Publication date

20.09.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Soil Science

Sustainable Development Goals

SDG 13 - Climate Action

Electronic version(s)

https://doi.org/10.1111/ejss.13408 (Access: Open)