中国科学院植物研究所杨元合团队近日揭示了青藏高原冻土生态系统中土壤氮储量随气候变暖而逐渐下降。该研究于2025年9月2日发表在《自然—地球科学》杂志上。
永久冻土区含有地球土壤氮的很大一部分，易受气候变化的影响。这种重要的氮储量对变暖的响应可能通过改变植物生产力、微生物分解和氧化亚氮排放来影响永久冻土-气候反馈。然而，土壤氮储量响应变暖的长期轨迹仍不清楚。
研究组反复测量了土壤氮储量至50 cm深度，评估28个氮循环变量，探索影响土壤氮储量的三条主要途径，包括氮输入、微生物氮转化和氮损失。该研究结果表明，尽管在试验的最初几年没有观察到变化，但经过8年的变暖，暖地的表层土壤氮储量有所下降（相对于对照地平均减少7.7%）。这种减少与多年生植物生物量氮固存增强、生态系统氮淋失和土壤气态氮损失增加有关。该发现强调了永久冻土地区土壤N储量对持续变暖的脆弱性，并表明潜在的永久冻土-气候反馈可能比先前预期的更强。
附：英文原文
Title: Progressive decline in soil nitrogen stocks with warming in a Tibetan permafrost ecosystem
Author: Wei, Bin, Zhang, Dianye, Voigt, Carolina, Zhou, Wei, Bai, Yuxuan, Zheng, Zhihu, Xie, Yuhong, Zhao, Chunbao, Wang, Feiqi, Huang, Luyao, Yang, Guibiao, Kou, Dan, Peng, Yunfeng, Luo, Yiqi, Peuelas, Josep, Yang, Yuanhe
Issue&Volume: 2025-09-02
Abstract: Permafrost regions contain a substantial fraction of Earth’s soil nitrogen, which is vulnerable to climate change. The response of this crucial N stock to warming could impact the permafrost–climate feedback by altering plant productivity, microbial decomposition and nitrous oxide emissions. However, the long-term trajectory of soil N stocks in response to warming remains unclear. Here we present results from a ten-year field warming experiment in a permafrost ecosystem on the Tibetan Plateau. We made repeated measurements of soil N stocks to 50cm depth and assessed 28 N-cycling variables to explore three primary pathways affecting soil N stocks, including N inputs, microbial N transformations and N losses. Our results reveal that, despite no changes being observed during the initial years of the experiment, warmed plots experienced a decline in surface soil N stocks (an average 7.7% reduction relative to control plots) after eight years of warming. This decrease is associated with the enhanced N sequestration in perennial plant biomass, increased ecosystem N leaching and gaseous N losses from soils. Our findings underscore the vulnerability of soil N stocks in permafrost regions to ongoing warming, and suggest that the potential permafrost–climate feedback may be stronger than previously anticipated.
DOI: 10.1038/s41561-025-01786-1
Source: https://www.nature.com/articles/s41561-025-01786-1