title: Increased Electron-Accepting and Decreased Electron-Donating Capacities of Soil Humic Substances in Response to Increasing Temperature.
abstract: The electron transfer capacities (ETCs) of soil humic substances (HSs) are linked to the type and abundance of redox-active functional moieties in their structure. Natural temperature can affect the chemical structure of natural organic matter by regulating their oxidative transformation and degradation in soil. However, it is unclear if there is a direct correlation between ETC of soil HS and mean annual temperature. In this study, we assess the response of the electron-accepting and -donating capacities (EAC and EDC) of soil HSs to temperature by analyzing HSs extracted from soil set along glacial-interglacial cycles through loess-palaeosol sequences and along natural temperature gradients through latitude and altitude transects. We show that the EAC and EDC of soil HSs increase and decrease, respectively, with increasing temperature. Increased temperature facilitates the prevalence of oxidative degradation and transformation of HS in soils, thus potentially promoting the preferentially oxidative degradation of phenol moieties of HS or the oxidative transformation of electron-donating phenol moieties to electron-accepting quinone moieties in the HS structure. Consequently, the EAC and EDC of HSs in soil increase and decrease, respectively. The results of this study could help to understand biogeochemical processes, wherein the redox functionality of soil organic matter is involved in the context of increasing temperature.
authors.forename: Wenbing
authors.initials: W
authors.lastname: Tan
authors.affiliation: School of Environmental and Municipal Engineering, Lanzhou Jiaotong University , Lanzhou 730070, China.
authors.forename: Beidou
authors.identifier: 0000-0003-1930-017X
authors.initials: B
authors.lastname: Xi
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University , Beijing 100193, China.
authors.forename: Guoan
authors.initials: G
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Beijing Forestry University , Beijing 100083, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jiang
authors.forename: Xiaosong
authors.identifier: 0000-0001-7447-4848
authors.initials: X
authors.lastname: He
authors.affiliation: School of Resource and Environmental Science, Wuhan University , Wuhan 430079, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Mao
authors.forename: Rutai
authors.initials: R
authors.lastname: Gao
authors.forename: Caihong
authors.initials: C
authors.lastname: Huang
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University , Beijing 100193, China.
authors.forename: Yufu
authors.initials: Y
authors.lastname: Jia
authors.forename: Ying
authors.initials: Y
authors.lastname: Yuan
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhao
mesh_terms: D004583:Electrons; D006812:Humic Substances; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D006812:Humic Substances; D012987:Soil