Abstract
Manganese (Mn) is an essential plant micronutrient that plays a critical role in the litter decomposition by oxidizing and degrading complex organic molecules. Previous studies report a negative correlation between Mn concentrations and carbon (C) storage in organic horizons and suggest that high Mn concentrations in leaf litter reduce soil C storage in forest ecosystems, presumably by stimulating the oxidation of lignin by fungal enzymes. Yet, the relationship between Mn and C in the litter layer and organic soil remains poorly understood and restricted to a few biomes, hampering our ability to improve mechanistic understanding of soil C accumulation. To examine plant-soil interactions that underlie observed relationships between Mn and C across a wide range of biomes, we extracted biogeochemical data reported for plants and soils from the National Ecological Observatory Network (NEON) database. We found that increased C and nitrogen (N) storage in organic horizons were associated with declines in Mn concentrations across diverse ecosystems at the continental scale, and this relationship was associated with the degree of organic matter decomposition (i.e., Oi, Oe, and Oa). Carbon and N stocks were more strongly correlated with Mn than with climatic variables (i.e., temperature and precipitation). Foliar Mn was strongly correlated with foliar lignin, and both these parameters increased with a decrease in soil pH, indicating links between soil pH, foliar chemistry, and litter decomposability. Our observations suggest that increased Mn bioavailability and accumulation in foliage under moderately acidic soil conditions support fungal decomposition of lignin-rich litter and contributes to lower soil C stocks.
| Original language | English |
|---|---|
| Article number | e2022GB007412 |
| Journal | Global Biogeochemical Cycles |
| Volume | 37 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2023 |
Funding
We thank the reviewers for their helpful comments and suggestions. The National Ecological Observatory Network (NEON) is a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part upon work supported by the National Science Foundation through the NEON Program. This work was sponsored by the Laboratory‐Directed Research and Development Program of the Oak Ridge National Laboratory (ORNL), managed by UT‐Battelle, LCC for the US Department of Energy (DOE) under contract DE‐AC05‐00OR22725, project number 9958, and by the ORNL Critical Interfaces Science Focus Area sponsored by the DOE Office of Science Biological and Environmental Research Program. This manuscript has been authored by UT‐Battelle, LLC, under contract DE‐AC05‐00OR22725 with the US DOE. The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). We thank the reviewers for their helpful comments and suggestions. The National Ecological Observatory Network (NEON) is a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part upon work supported by the National Science Foundation through the NEON Program. This work was sponsored by the Laboratory-Directed Research and Development Program of the Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LCC for the US Department of Energy (DOE) under contract DE-AC05-00OR22725, project number 9958, and by the ORNL Critical Interfaces Science Focus Area sponsored by the DOE Office of Science Biological and Environmental Research Program. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US DOE. The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).
Keywords
- carbon
- lignin
- manganese
- plant-soil interactions
- soil organic matter