Divergent changes in particulate and mineral-associated organic carbon upon permafrost thaw

Permafrost thaw can stimulate microbial decomposition and induce soil carbon (C) loss, potentially triggering a positive C-climate feedback. However, earlier observations have concentrated on bulk soil C dynamics upon permafrost thaw, with limited evidence involving soil C fractions. Here, we explor...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Liu, Futing, Qin, Shuqi, Fang, Kai, Chen, Leiyi, Peng, Yunfeng, Smith, Pete, Yang, Yuanhe
Format: Article in Journal/Newspaper
Language:English
Published: NATURE PORTFOLIO 2022
Subjects:
Multidisciplinary Sciences
SOIL CARBON
MATTER FORMATION
CLIMATE-CHANGE
STABILIZATION
PERSISTENCE
NITROGEN
BIODEGRADABILITY
DECOMPOSITION
MECHANISMS
RELEVANCE
Science Citation Index Expanded (SCI-EXPANDED)
permafrost
Thermokarst
Online Access:http://ir.ibcas.ac.cn/handle/2S10CLM1/28833
https://doi.org/10.1038/s41467-022-32681-7
Description
Summary:Permafrost thaw can stimulate microbial decomposition and induce soil carbon (C) loss, potentially triggering a positive C-climate feedback. However, earlier observations have concentrated on bulk soil C dynamics upon permafrost thaw, with limited evidence involving soil C fractions. Here, we explore how the functionally distinct fractions, including particulate and mineral-associated organic C (POC and MAOC) as well as iron-bound organic C (OC-Fe), respond to permafrost thaw using systematic measurements derived from one permafrost thaw sequence and five additional thermokarst-impacted sites on the Tibetan Plateau. We find that topsoil POC content substantially decreases, while MAOC content remains stable and OC-Fe accumulates due to the enriched Fe oxides after permafrost thaw. Moreover, the proportion of MAOC and OC-Fe increases along the thaw sequence and at most of the thermokarst-impacted sites. The relatively enriched stable soil C fractions would alleviate microbial decomposition and weaken its feedback to climate warming over long-term thermokarst development. Based on observations from thermokarst-impacted sites on the Tibetan Plateau, the authors find substantial particulate organic carbon loss but stable mineral-associated organic carbon and enriched iron-bound organic carbon upon permafrost thaw.

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