土壤二氧化碳而非甲烷通量决定咸水湿地土壤碳排放对季节性降水分配的响应

doi:10.1093/jpe/rtaf138

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土壤二氧化碳而非甲烷通量决定咸水湿地土壤碳排放对季节性降水分配的响应

收稿日期:2025-03-30 接受日期:2025-08-22

Soil CO₂ not CH₄ flux determines soil carbon emission response to seasonal precipitation variation in a brackish wetland

Huiqi Zhang^a,b,c, Guangxuan Han^b,c, Wenli Jia^a,b,c, Wanxin Huang^b,c,f, Xiaoshuai Zhang^b,c, Xiaojie Wang^b,c, Mingliang Zhao^b,c, Baohua Xie^b,c, Feng Lu^e, Jianbin Song^e, Wei Zhang^g, Xiaojing Chu^b,c*

^aSchool of Geography and Environment, Liaocheng University, Liaocheng 252000, China

^bCAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, China

^cYellow River Delta Field Observation and Research Station of Coastal Marsh Ecosystem, Chinese Academy of Sciences, Dongying 257000, China

^eAdministration Bureau of the Yellow River Delta National Nature Reserve, Dongying 257091, China

^fSchool of Ecology, Hainan University, Hainan 570228, China g School of Environmental and Material Engineering, Yantai University, Yantai 264005, China

^*Corresponding author. E-mail: xjchu@yic.ac.cn

Received:2025-03-30 Accepted:2025-08-22
Supported by:
This work was funded by National Key Research and Development Program in China (2022YFF0802101), the Natural Science Foundation of China (42101117, 42071126, U2106209), the International Science Partnership Program of the Chinese Academy of Sciences (121311KYSB20190029) and the Natural Science Foundation of Shandong Province(ZR2019BC106)

摘要/Abstract

摘要： 全球气候变化导致的降水格局变化使咸水湿地土壤碳封存能力面临显著不确定性。为揭示季节性降水分配(Seasonal Precipitation Distribution, SPD)对土壤碳排放的调控机制，本研究在黄河三角洲咸水湿地开展了原位控制实验。基于历史降水数据(1961–2018年)，在维持年降雨量不变的前提下设置了5种SPD处理(+73%、+56%、CK、–56%和–73%)：其中CK组采用历史平均季节降水分布作为对照；实验通过正负梯度设计实现季节间降水再分配—春季降水增加处理(+73%和+56%)对应夏秋季降水等比例减少，而春季降水减少处理(–56%和–73%)则伴随夏秋季降水等比例增加；各处理冬季降水量保持恒定。结果表明，土壤CO₂通量对SPD变化表现出显著的季节敏感性，其中+56%处理对土壤CO₂排放的促进作用反而高于+73%处理，呈现非线性响应特征。相比之下，SPD对土壤甲烷(CH₄)通量无显著影响。机理分析表明，SPD通过调控水盐动态产生双重效应：春季增雨缓解土壤盐渍化胁迫，显著促进植被定植；而夏秋季减雨则通过降低淹水压力提升植被生产力。结构方程模型显示，SPD驱动的CO₂通量增加主要源于春季盐分胁迫解除和植被碳分配过程的协同作用。上述研究为完善气候变化背景下湿地碳循环模型的降水参数化方案提供了理论依据。

关键词: 季节性降水分配, 土壤二氧化碳通量, 土壤盐分, 细根生物量, 咸水湿地

Abstract: Global climate change-induced alterations in precipitation patterns have introduced uncertainty regarding soil carbon sequestration capacity in brackish wetlands. To investigate the effect of seasonal precipitation distribution (SPD) on soil carbon emissions, we conducted a field experiment in a brackish wetland in the Yellow River Delta, maintaining consistent annual precipitation but varying SPD (+73%, +56%, CK, –56%, and –73%). Increased precipitation during the spring was followed by decreased precipitation in the summer and fall (+73% and +56%), whereas decreased spring precipitation was followed by increased summer and fall precipitation (–56% and –73%). Precipitation remained consistent across all treatments during winter. The results revealed significant seasonal and inter-annual sensitivity of soil CO₂ fluxes to SPD, with the spring precipitation enhancement (+56%) treatment exerting a greater influence on emissions than the +73% treatment. In contrast, soil CH4 fluxes exhibited no statistically significant variations across seasons or in response to precipitation adjustments. Furthermore, hydrological mediation of SPD established inverse water-salt dynamics: increased precipitation in spring mitigated soil salinity, promoting vegetation colonization and growth, while reduced precipitation in summer and autumn alleviated inundation pressure, enhancing vegetation productivity. Increases in soil CO₂ fluxes driven by SPD were primarily attributed to alleviation of salinity stress and vegetation-mediated carbon partitioning, whereas CH₄ fluxes remained statistically constant across precipitation regimes. Therefore, we conclude that SPD predominantly affects soil carbon emissions in the brackish wetland by modifying soil CO₂ fluxes. These findings provide mechanistic insights for refining predictive models of wetland carbon cycling under climate-driven precipitation reconstruction.

Key words: seasonal precipitation distribution, soil CO₂ fluxes, soil salinity, fine root biomass, brackish wetland

. 土壤二氧化碳而非甲烷通量决定咸水湿地土壤碳排放对季节性降水分配的响应[J]. Journal of Plant Ecology, DOI: 10.1093/jpe/rtaf138.

Huiqi Zhang, Guangxuan Han, Wenli Jia, Wanxin Huang, Xiaoshuai Zhang, Xiaojie Wang, Mingliang Zhao, Baohua Xie, Feng Lu, Jianbin Song, Wei Zhang, Xiaojing Chu. Soil CO₂ not CH₄ flux determines soil carbon emission response to seasonal precipitation variation in a brackish wetland[J]. J Plant Ecol, DOI: 10.1093/jpe/rtaf138.