Networks of mineral-associated organic matter fractions in forest ecosystems

Bin Niu; Qiuyu Chen; Hongzhe Jiao; Xiaoqin Yang; Ming Shao; Jian Wang; Guicai Si; Tianzhu Lei; Yibo Yang; Gengxin Zhang; Georg Guggenberger

doi:10.1016/j.scitotenv.2023.165555

Networks of mineral-associated organic matter fractions in forest ecosystems

Sci Total Environ. 2023 Nov 10:898:165555. doi: 10.1016/j.scitotenv.2023.165555. Epub 2023 Jul 15.

Authors

Bin Niu¹, Qiuyu Chen², Hongzhe Jiao¹, Xiaoqin Yang¹, Ming Shao³, Jian Wang⁴, Guicai Si⁵, Tianzhu Lei⁵, Yibo Yang⁶, Gengxin Zhang⁷, Georg Guggenberger⁸

Affiliations

¹ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China.
² State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Manchester, Manchester M139PL, UK.
³ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
⁴ Land and Resource College, China West Normal University, Nanchong 637009, China.
⁵ Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
⁶ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
⁷ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zhangg@itpcas.ac.cn.
⁸ Institute of Soil Science, Leibniz Universität Hannover, Hanover 30419, Germany.

PMID: 37454842
DOI: 10.1016/j.scitotenv.2023.165555

Abstract

Mineral-associated organic matter (MAOM), the largest soil carbon pool, is formed through a series of organo-mineral interaction mechanisms. However, different organo-mineral fractions relevant to specific stabilization mechanisms and their response to environmental variables are poorly understood, which hinders accurate prediction of MAOM preservation under climate change. We applied sequential chemical extraction to separate MAOM into different organo-mineral fractions. To assess of response of different organo-mineral fractions to climate change, alpine forest soils with high environmental sensitivity along a controlled environmental gradient were selected. Residual OM and weakly adsorbed OM were the primary organo-mineral fractions, accounting for approximately 45.1-67.7 % and 16.4-30.6 %, respectively, of the total organic carbon (TOC). Climate exerted considerable indirect effects on the preservation of organo-mineral fractions through weathering and edaphic and biotic variables. Moreover, organo-mineral fractions were closely associated with metal cations (mainly Fe³⁺/Al³⁺) and secondary minerals, forming complex networks. Water-soluble OM (WSOM), weakly adsorbed OM and Fe/Al oxyhydroxides-stabilized OM were tightly linked, occupying the central position of the networks, and were closely related to soil pH, moisture and prokaryotic composition, indicating that edaphic and biotic factors might play important roles in maintaining the network structure and topology. In addition, Fe/Al-OM complexes, oxyhydroxides-stabilized OM and residual OM in the network were greatly impacted by climate and weathering factors, including precipitation, temperature and the plagioclase index of alteration (PIA). The complex network among organo-mineral fractions sheds light on MAOM dynamic stabilization for better predicting MAOM preservation under climate change.

Keywords: Climate change; Forest soil; Mineral-associated organic matter; Network; Organo-mineral fractions.