2026-03-13 中国科学院（CAS）
Whole-ecosystem warming experiment shows that moss-associated biological nitrogen fixation is a key pathway supporting vegetation growth in permafrost ecosystems under climate warming. (Image by BAI Yufei)
＜関連情報＞
- https://english.cas.cn/newsroom/research-news/202603/t20260313_1152650.shtml
- https://www.pnas.org/doi/10.1073/pnas.2516443123
永久凍土生態系における温暖化下での植物成長のための窒素補給におけるコケの重要な役割 Key role of moss in supplementing nitrogen for plant growth under warming in a permafrost ecosystem
Wei Zhou, Yuxuan Bai , Yuhong Xie, +6 , and Yuanhe Yang
Proceedings of the National Academy of Sciences Published:February 18, 2026
DOI:https://doi.org/10.1073/pnas.2516443123
Significance
Permafrost ecosystems store vast amounts of carbon that are vulnerable to microbial decomposition, potentially reinforcing climate change. Although warming can stimulate plant growth and partially offset soil carbon losses, this compensation depends on adequate N supply. Based on a whole-ecosystem warming experiment on the Tibetan Plateau, we find that plants need more N to sustain growth under warming. Mosses, through associations with N-fixing bacteria, emerge as important sources of extra N. These N inputs partly satisfy elevated N requirements within the experimental period, but may be transient as moss cover declines with continued warming. To better characterize biological N fixation (BNF) dynamics, Earth system models should incorporate moss traits and microbial processes, which could improve projections of permafrost carbon-climate feedback.
Abstract
Enhanced plant productivity under climate warming may partially offset soil carbon losses in cold ecosystems, but this compensation depends on whether soil nitrogen (N) supply can keep pace with the increased N demand associated with accelerated plant growth. However, it remains unclear whether existing soil N supply processes are sufficient to support this rising plant N demand. Based on a unique whole-ecosystem warming experiment in the permafrost region on the Tibetan Plateau, we assess 43 variables encompassing plant N demand and soil N supply. After 2 y of warming, plant N demand significantly increases, while leaf N resorption remains unchanged, indicating a heightened reliance on external soil N inputs. Among all quantified N-supply processes, moss-associated biological N fixation is the only process that responds positively to warming, providing partial compensation for the elevated plant N demand over the two experimental years. This enhancement is associated with warming-driven changes in moss functional traits that likely expand colonization niches and increase carbon availability for diazotrophs, coupled with a warming-induced increase in the breadth and intensity of taxon-level 15N incorporation into the DNA of N-fixing bacteria. These findings highlight that moss-associated N fixation may act as an early contributor in helping satisfy the elevated plant N demand under warming, offering insights into understanding the dynamics of vegetation productivity and permafrost carbon-climate feedback through the lens of moss–soil–microbial interactions.
