Temporal variations of δ13C-CH4 in rice paddies dominated by the plant-mediated pathway
The stable carbon isotope signature of methane (δ<sup>13</sup>C-CH<sub>4</sub>) helps constrain CH<sub>4</sub> emissions on regional to global scales, yet observations in rice paddies remain limited. The temporal dynamics of δ<sup>13</sup>C-CH<sub>4</sub> and its drivers in rice paddies are still not fully understood. Here, we conducted continuous <i>in situ</i> observations of CH<sub>4</sub> and δ<sup>13</sup>C-CH<sub>4</sub> at three canopy heights throughout a rice growing season. We investigated the emission source signature (δ<sup>13</sup>C<sub>source</sub>) and partitioned it into plant-mediated (δ<sup>13</sup>C<sub>P</sub>) and non-plant-mediated (δ<sup>13</sup>C<sub>NP</sub>) pathways. δ<sup>13</sup>C<sub>source</sub> exhibited significant temporal and vertical variability, influenced by transport pathways and external sources. We found that temporal variations in δ<sup>13</sup>C<sub>source</sub> were strongly correlated with rice photosynthesis and predominantly driven by δ<sup>13</sup>C<sub>P</sub>. Our results show that plant-mediated transport, rather than CH<sub>4</sub> production, dominates δ<sup>13</sup>C<sub>source</sub> variability. These findings provide new insight into the δ<sup>13</sup>C<sub>source</sub> dynamics in rice paddies and will be crucial for improving regional-to-global estimates of CH<sub>4</sub> fluxes from rice agriculture.
Authors
- Shushi Peng (ORCID: https://orcid.org/0000-0001-5098-726X)
- Jing M. Chen (ORCID: https://orcid.org/0000-0002-8682-1293)
- Guirui Yu (ORCID: https://orcid.org/0000-0002-1859-8966)
- Huilin Chen (ORCID: https://orcid.org/0000-0002-1573-6673)
- Weimin Ju
- Xuguang Chi (ORCID: https://orcid.org/0009-0007-1036-8166)
- Philippe Ciais (ORCID: https://orcid.org/0000-0001-8560-4943)
- Yongguang Zhang (ORCID: https://orcid.org/0000-0001-6584-9062)
- Zeqing Ma (ORCID: https://orcid.org/0000-0003-1197-8066)
- Aijun Ding (ORCID: https://orcid.org/0000-0003-4481-5386)
- Wenping Yuan
Institutions
- Fujian Normal University (CN)
- Centre National de la Recherche Scientifique (FR)
- Cyprus Institute (CY)
- University of Toronto (CA)
- Université de Versailles Saint-Quentin-en-Yvelines (FR)
- Chinese Academy of Sciences (CN)
- Peking University (CN)
- Ministry of Natural Resources (CN)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Université Paris-Saclay (FR)
- Laboratoire des Sciences du Climat et de l'Environnement (FR)
- CEA Paris-Saclay (FR)
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application (CN)
- Institute of Geographic Sciences and Natural Resources Research (CN)
- University of Chinese Academy of Sciences (CN)
- Nanjing University (CN)
Publication Details
- Journal
- iScience
- Published
- 2025-06-16
- DOI
- https://doi.org/10.1016/j.isci.2025.112886
- Primary Topic
- Atmospheric and Environmental Gas Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Government of Jiangsu Province
- Jiangsu Collaborative Innovation Center for Climate Change
- National Key Research and Development Program of China
- Fundamental Research Funds for the Central Universities