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Research article - Peer-reviewed, 2023

Molecular C-14 evidence for contrasting turnover and temperature sensitivity of soil organic matter components

Jia, Juan; Liu, Zongguang; Haghipour, Negar; Wacker, Lukas; Zhang, Hailong; Sierra, Carlos A.; Ma, Tian; Wang, Yiyun; Chen, Litong; Luo, Ao; Wang, Zhiheng; He, Jin-Sheng; Zhao, Meixun; Eglinton, Timothy I.; Feng, Xiaojuan

Abstract

Climate projection requires an accurate understanding for soil organic carbon (SOC) decomposition and its response to warming. An emergent view considers that environmental constraints rather than chemical structure alone control SOC turnover and its temperature sensitivity (i.e., Q(10)), but direct long-term evidence is lacking. Here, using compound-specific radiocarbon analysis of soil profiles along a 3300-km grassland transect, we provide direct evidence for the rapid turnover of lignin-derived phenols compared with slower-cycling molecular components of SOC (i.e., long-chain lipids and black carbon). Furthermore, in contrast to the slow-cycling components whose turnover is strongly modulated by mineral association and exhibits low Q(10), lignin turnover is mainly regulated by temperature and has a high Q(10). Such contrasts resemble those between fast-cycling (i.e., light) and mineral-associated slow-cycling fractions from globally distributed soils. Collectively, our results suggest that warming may greatly accelerate the decomposition of lignin, especially in soils with relatively weak mineral associations.

Keywords

compound-specific C-14; physical fractions; soil organic carbon; temperature sensitivity; turnover time

Published in

Ecology Letters
2023, Volume: 26, number: 5, pages: 778-788
Publisher: WILEY

    UKÄ Subject classification

    Ecology

    Publication identifier

    DOI: https://doi.org/10.1111/ele.14204

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/121787