An iron-dependent burst of hydroxyl radicals stimulates straw decomposition and CO2 emission from soil hotspots: Consequences of Fenton or Fenton-like reactions

Plant residues in soil create temporal and spatial hotspots of extremely high microbial activities leading to very intensive greenhouse gas (GHG) fluxes that challenge our mechanistic understanding and predictive power. Using a series of well-controlled soil microcosm experiments, we examine how abiotic processes (e.g., iron reduction-oxidation cycling) at residue/soil interfaces contribute to hotspot dynamics. We quantify for the first time the contributions of microbially-initiated Fenton reactions, which produce strongly oxidizing hydroxyl radicals (HO[rad]), to organic matter solubilization and mineralization in hotspots 0–3 mm from the litter surface. The concentrations of ferrous iron (Fe2+), hydrogen peroxide (H2O2) and HO[rad] were 2.1–3.0, 3.0–9.0 and 2.6–2.8 times higher, respectively, at the straw-soil interface than in the bulk soil. Thus, iron minerals, especially in concert with microorganisms, produce a burst of hydroxyl radicals that explain extremely high GHG fluxes from soil hotspots. Our findings highlight how Fe minerals and microorganisms synergistically influence global carbon cycling. These synergistic effects should be accounted for mechanistic understanding of processes in soil hotspots. © 2020 Elsevier B.V.

Authors
Du H.-Y.1, 2 , Chen C.-M.1, 3 , Yu G.-H.1 , Polizzotto M.L.4 , Sun F.-S.1 , Kuzyakov Y. 5, 6, 7
Journal
Publisher
Elsevier
Language
English
Status
Published
Number
114512
Volume
375
Year
2020
Organizations
  • 1 Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
  • 2 Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, College of Resources & Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
  • 3 Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, DE 19711, United States
  • 4 Department of Earth Sciences, University of Oregon, Eugene, OR 97403, United States
  • 5 Department of Agricultural Soil Science, University of Göttingen, Göttingen, Germany
  • 6 Institute of Environmental Sciences, Kazan Federal University, Kazan, 420049, Russian Federation
  • 7 Agro-Technology Institute, RUDN University, Moscow, Russian Federation
Keywords
Detritusphere; Greenhouse gas fluxes; Hydroxyl radical; Interfacial process; Iron minerals; Soil hotspots
Date of creation
02.11.2020
Date of change
02.11.2020
Short link
https://repository.rudn.ru/en/records/article/record/64376/
Share

Other records