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ORIGINAL RESEARCH article

Front. Mol. Biosci.

Sec. Metabolomics

Volume 12 - 2025 | doi: 10.3389/fmolb.2025.1621357

This article is part of the Research TopicAdvances in Mass Spectrometry: Transforming Analytical Chemistry in Molecular and Spatial Biology, Multimodal Omics, and BioanalysisView all 7 articles

Tracing Priming Effects in Palsa Peat Carbon Dynamics Using a Stable Isotope-Assisted

Provisionally accepted
  • 1University of Arizona, Tucson, United States
  • 2Michigan Technological University, Michigan, United States
  • 3Pacific Northwest National Laboratory, Richland, United States
  • 4Lawrence Livermore National Laboratory, Livermore, United States
  • 5Stockholm University, Stockholm, Sweden
  • 6University of New Hampshire, Durham, United States
  • 7Ohio State University, Columbus, United States

The final, formatted version of the article will be published soon.

Peatlands store up to a third of global soil carbon, and in high latitudes their litter inputs are increasing and changing in composition under climate change. Although litter significantly influences peatland carbon and nutrient dynamics by changing the overall lability of peatland organic matter, the physicochemical mechanisms of this impact-and thus its full scope-remain poorly understood. We applied multimodal metabolomics (UPLC-HRMS, 1 H NMR) paired with 13 C Stable Isotope-Assisted Metabolomics (SIAM) to track litter carbon and its potential priming effects on both existing soil organic matter and carbon gas emissions. Through this approach, we achieved molecule-specific tracking of carbon transformations at unprecedented detail. Our analysis revealed several key findings about carbon dynamics in palsa peat. Microbes responded rapidly to litter addition, producing a short-term increase in CO2 emissions, fueled nearly exclusively by transformations of litter carbon. Litter inputs significantly contributed to the organic nitrogen pool through amino acids and peptide derivatives, which served as readily accessible nutrient sources for microbial communities. We traced the fate of plant-derived polyphenols including flavonoids like rutin, finding evidence of their degradation through heterocyclic Cring fission, while accumulation of some polyphenols suggested their role in limiting overall decomposition. The SIAM approach detected subtle molecular changes indicating minimal and transient priming activity that was undetectable through conventional gas measurements alone. This transient response was characterized by brief microbial stimulation followed by rapid return to baseline metabolism. Pre-existing peat organic matter remained relatively stable; significant priming of its consumption was not observed, nor was its structural alteration. This suggests that while litter inputs temporarily increase CO2 emissions, they don't sustain long-term acceleration of stored carbon decomposition or substantially decrease peat's carbon store capacity. Our findings demonstrate how technological advancements in analytical tools can provide a more detailed view of carbon cycling processes in complex soil systems.

Keywords: Isotopic tracer, high resolution mass spectrometry, Metabolomics, NMR, Palsa, carbon cycling, Stable isotope-assisted metabolomics, Litter decomposition

Received: 30 Apr 2025; Accepted: 04 Aug 2025.

Copyright: © 2025 Ayala-Ortiz, Hough, Eder, Hoyt, Chu, Toyoda, Blazewicz, Crill, Varner, Saleska, Rich and Tfaily. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Malak M Tfaily, University of Arizona, Tucson, United States

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