Abstract:

Coastal wetlands serve as crucial carbon sinks with significant carbon sequestration potential in coastal zones, offering a long-term solution for mitigating global climate change. As one of the most important invasive species in Chinese coastal wetlands, Spartina alterniflora has biological characteristics such as strong adaptability, high reproduction rate, rapid growth, and fast spreading compared to native vegetation. This poses a threat to the survival of native wetland vegetation in salt marshes and mangroves and subsequently affects the soil carbon budget, including soil carbon sequestration, carbon decomposition, and lateral carbon transfer. Following photosynthetic carbon assimilation by vegetation, organic carbon is inputted into the soil as litter, root residues, and root exudates. Inorganic carbonates are generated during soil carbon assimilation to achieve fixation of soil inorganic carbon (SIC) fixation. This study summarizes the differences in photosynthetic carbon assimilation capacity between Spartina alterniflora and native vegetation, changes in soil organic carbon in vegetation sources caused by Spartina alterniflora invasion in coastal wetlands, and the effects of Spartina alterniflora invasion on soil inorganic carbon storage in coastal wetlands. In this study, the changes and influencing mechanisms of greenhouse gas carbon dioxide (CO₂) and methane (CH₄) emissions after Spartina alterniflora invasion of coastal wetlands were explored, and the effects of Spartina alterniflora invasion on soil lateral carbon transfer in the form of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC) in coastal wetlands were analyzed. Finally, this study presents future research prospects and suggestions regarding the impact of invasion on soil carbon budget. It included four aspects: establishing a field observation network in coastal wetlands to expand the research scale, focusing on spatiotemporal variability and driving mechanisms of soil carbon stocks under the invasion of Spartina alterniflora, developing ecosystem dynamics models to systematically quantify and predict the consequences of the invasion, and formulating locally adapted ecological management schemes for coastal wetlands.

Key words: coastal wetlands, coastal blue carbon, Spartina alterniflora, soil, greenhouse gas, lateral carbon transfer

摘要：

滨海湿地是海岸带蓝碳生态系统的重要组成部分，其碳汇功能与固碳潜力已成为缓解全球气候变化的长期解决方案之一。互花米草（Spartina alterniflora）作为中国滨海湿地最重要的入侵物种之一，与本土植被相比具有适应性强、繁殖率高、生长迅速、传播速度快等生物特性，威胁盐沼和红树林等滨海湿地本土植被的生存，并随之影响滨海湿地土壤碳固存、碳分解、横向碳迁移等垂直和水平方向上的碳收支过程。植被光合碳同化后以凋落物、根系残留物及其分泌物等形式将有机碳输入到土壤中，土壤碳同化过程生成无机碳酸盐实现土壤无机碳（SIC）固定。该文概述了互花米草和本土植被的光合碳同化能力差异、互花米草入侵滨海湿地引起的植被源土壤有机碳变化以及互花米草入侵对滨海湿地土壤无机碳储量的影响；探究了互花米草入侵滨海湿地后土壤垂直方向上温室气体二氧化碳（CO₂）和甲烷（CH₄）排放的变化规律及其影响机制，并分析了互花米草入侵在溶解无机碳（DIC）、溶解有机碳（DOC）、颗粒有机碳（POC）等形式进行的滨海湿地土壤横向碳迁移中产生的影响。最后，指出了未来互花米草入侵在土壤碳收支方面的研究方向：建立滨海湿地野外观测网络以扩大研究尺度；重视与加强互花米草入侵下土壤碳固定和分解的时空变化及其驱动机制；发展生态系统动力学模型系统量化和预测互花米草入侵后果；制定和实践因地制宜的滨海湿地生态管理方案。

关键词: 滨海湿地, 海岸带蓝碳, 互花米草, 土壤, 温室气体, 横向碳迁移