草地学报 ›› 2026, Vol. 34 ›› Issue (2): 478-490.DOI: 10.11733/j.issn.1007-0435.2026.02.010

• 研究论文 • 上一篇    

不同冻融条件下高寒沼泽草甸土壤碳矿化及δ13C值特征

周祉蕴1,2,4, 王奕钧1,2, 章妮1,2,4, 纪伟1,2,4, 杜岩功3, 陈克龙1,2,4   

  1. 1. 青海师范大学地理科学学院/青海省自然地理与环境过程重点实验室, 青海 西宁 810008;
    2. 青海师范大学青藏高原地表过程与生态保育教育部重点实验室, 青海 西宁 810008;
    3. 高原科学与可持续发展研究院, 青海 西宁 810008;
    4. 国家林业和草原局青海湖湿地生态系统国家定位观测研究站, 青海 海北 812200
  • 收稿日期:2025-04-03 修回日期:2025-06-09 发布日期:2026-01-22
  • 通讯作者: 陈克龙,E-mail:ckl7813@163.com
  • 作者简介:周祉蕴(1999-),女,汉族,四川德阳人,博士研究生,主要从事湿地草地学研究,E-mail:824465275@qq.com;
  • 基金资助:
    第二次青藏高原综合科学考察研究项目(2019QZKK0405);青海省重点研发与转化计划(2020-QY-204);水位上升下青海湖湖滨带生态系统变化及其对碳循环影响研究项目(2023-ZJ-905T)资助

Characteristics of Soil Carbon Mineralization and δ13C Values in Alpine Marsh Meadow under Different Freeze-Thaw Conditions

ZHOU Zhi-yun1,2,4, WANG Yi-jun1,2, ZHANG Ni1,2,4, JI Wei1,2,4, DU Yan-gong3, CHEN Ke-long1,2,4   

  1. 1. Qinghai Province Key Laboratory of Physical Geography and Environmental Processes, College of Geographical Science, Qinghai Normal University, Xining, Qinghai Province 810008, China;
    2. Key Laboratory of Ministry of Education for Surface Processes and Ecological Conservation of the Qinghai-Tibet Plateau, Qinghai Normal University, Xining, Qinghai Province 810008, China;
    3. Institute of Plateau Science and Sustainable Development, Xining, Qinghai Province 810008, China;
    4. National Positioning Observation and Research Station of Qinghai Lake Wetland Ecosystem in Qinghai, National Forestry and Grassland Administration, Haibei, Qinghai Province 812200, China
  • Received:2025-04-03 Revised:2025-06-09 Published:2026-01-22

摘要: 为探究不同频次与强度的冻融作用对高寒沼泽草甸土壤碳矿化过程及其稳定碳同位素分馏特征的影响机制,本研究以青藏高原高寒沼泽草甸土壤为对象,设置-15~15℃(高强度)、-10~10℃(低强度)两种冻融强度(共15次冻融)及10℃对照,开展15 d室内连续监测,比较碳矿化动态及δ13C变化。结果表明:低强度冻融显著抑制碳矿化速率,使其下降7.67%;而高强度冻融则显著促进碳矿化累积量,增幅为2.70%。前3次冻融后各处理差异较小,第3次后低强度处理碳矿化增速明显放缓。不同冻融强度下δ13C值范围-21.49‰~-28.03‰,表现为-15~15℃>10℃>-10~10℃,且随冻融频次增加呈先降后升趋势。RDA显示,NH4+-N和MBN是调控碳矿化及同位素分馏的关键因子。-15~15℃处理下δ13C值与NO3--N显著正相关;而-10~10℃处理下碳矿化速率与MBN显著负相关,与MBC/MBN显著正相关;其稳定同位素与NH4+-N和MBC/MBN也显著正相关。综上,冻融强度减弱显著抑制土壤碳矿化过程并导致微生物代谢路径变化,未来需关注冻融强度持续减弱对高寒湿地碳汇功能的长期影响。

关键词: 土壤碳矿化, 稳定同位素, 冻融循环, 高寒沼泽草甸, 青海湖

Abstract: To investigate the mechanisms of the effects of different frequencies and intensities of freeze-thaw cycles on the soil carbon mineralization process and the characteristics of stable carbon isotope (δ13C) fractionation in alpine swamp meadows, this study focused on the soil of alpine swamp meadows on the Qinghai-Tibet Plateau. Two freeze-thaw intensities (-15 to 15℃ and -10 to 10℃, a total of 15 freeze-thaw cycles) and a control group at 10℃ were established. A 15-day indoor continuous monitoring experiment was conducted to compare the dynamics of carbon mineralization and changes in δ13C. The results showed that low-intensity freeze-thaw cycles significantly inhibited the rate of carbon mineralization, causing a decrease of 7.67%. In contrast, high-intensity freeze-thaw cycles significantly promote the cumulative carbon mineralization, with an increase of 2.70%. The differences among treatments were relatively small after the first 3 freeze-thaw cycles, but the growth rate of carbon mineralization significantly slowed down under the low-intensity treatment after the third cycle. The δ13C values under different freeze-thaw intensities ranged from -21.49‰ to -28.03‰, which showed -15-15℃>10℃>-10-10℃, and showed a trend of first decreasing and then increasing with the increase of freeze-thaw frequency. Redundancy analysis (RDA) showed that ammonium nitrogen (NH4+-N) and microbial biomass nitrogen (MBN) were the key factors regulating carbon mineralization and isotope fractionation. Under the -15-15℃ treatment, δ13C values were significantly positively correlated with nitrate nitrogen (NO3--N). In contrast, under the -10-10℃ treatment, the carbon mineralization rate was significantly negatively correlated with MBN and significantly positively correlated with microbial biomass carbon to microbial biomass nitrogen ratio (MBC/MBN). Additionally, its stable isotopes were significantly positively correlated with NH4+-N and MBC/MBN. Overall, the reduced freeze-thaw intensity significantly inhibits soil carbon mineralization processes and causes changes in microbial metabolic pathways. It is crucial to pay attention to the long-term impacts of the continued weakening in freeze-thaw intensity on the carbon sequestration function of alpine wetlands.

Key words: Soil carbon mineralization, Stable isotopes, Freeze-thaw cycle, Alpine swamp meadows, Qinghai Lake