Article

 

Long-term litter decomposition controlled by manganese redox cycling Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/db78td75m

Descriptions

Attribute NameValues
Creator
Abstract
  • Litter decomposition is a keystone ecosystem process impacting nutrient cycling and productivity, soil properties, and the terrestrial carbon (C) balance, but the factors regulating decomposition rate are still poorly understood. Traditional models assume that the rate is controlled by litter quality, relying on parameters such as lignin content as predictors. However, a strong correlation has been observed between the manganese (Mn) content of litter and decomposition rates across a variety of forest ecosystems. Here, we show that long-term litter decomposition in forest ecosystems is tightly coupled to Mn redox cycling. Over 7 years of litter decomposition, microbial transformation of litter was paralleled by variations in Mn oxidation state and concentration. A detailed chemical imaging analysis of the litter revealed that fungi recruit and redistribute unreactive Mn²⁺ provided by fresh plant litter to produce oxidative Mn³⁺ species at sites of active decay, with Mn eventually accumulating as insoluble Mn³⁺/⁴⁺ oxides. Formation of reactive Mn³⁺ species coincided with the generation of aromatic oxidation products, providing direct proof of the previously posited role of Mn³⁺-based oxidizers in the breakdown of litter. Our results suggest that the litter-decomposing machinery at our coniferous forest site depends on the ability of plants and microbes to supply, accumulate, and regenerate short-lived Mn³⁺ species in the litter layer. This observation indicates that biogeochemical constraints on bioavailability, mobility, and reactivity of Mn in the plant–soil system may have a profound impact on litter decomposition rates.
  • Keywords: climate change, terrestrial carbon cycle, forest soil ecosystems, soil-atmosphere interactions, nutrient cycling
Resource Type
DOI
Date Available
Date Issued
Citation
  • Keiluweit, M., Nico, P., Harmon, M. E., Mao, J., Pett-Ridge, J., & Kleber, M. (2015). Long-term litter decomposition controlled by manganese redox cycling. Proceedings of the National Academy of Sciences, 112(38), E5253-E5260. doi:10.1073/pnas.1508945112
Journal Title
Journal Volume
  • 112
Journal Issue/Number
  • 38
Rights Statement
Funding Statement (additional comments about funding)
  • Keiluweit acknowledges funding through a Lawrence Scholar Fellowship awarded by the Lawrence Livermore National Laboratory (LLNL). Funding for M. E. H. and the long-term litter decomposition experiment was provided by a National Science Foundation grant to the H. J. Andrews Long-Term Ecological Research Program (Grant DEB-0823380). Analytical work was performed under the auspices of the US Department of Energy (DOE) by LLNL under Contract DE-AC52-07NA27344. Funding was provided by LLNL Laboratory Directed Research and Development Award 10-ERD-021 "Microbes and Minerals: Imaging C Stabilization" (to J.P.-R., P.N., and M. Kleber), and the work of P.N. was supported by Lawrence Berkeley National Laboratory Award IC006762 as sub-award from LLNL and DOE-Biological and Environmental Research Sustainable Systems scientific focus area. M. Kleber acknowledges support through a research fellowship from the Institute of Soil Landscape Research at the Zentrum für Agrarlandschaftsforschung. Use of the Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, US DOE under Contract DE-AC02-05CH11231. Use of SSRL at the Stanford Linear Accelerator Center National Accelerator Laboratory is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract DE-AC02-76SF00515.
Publisher
Peer Reviewed
Language
Replaces

Relationships

Parents:

This work has no parents.

Items