摘要: |
城市湿地作为区域碳氮循环的重要成分,研究城市湿地不同界面的温室气体排放通量,可为区域碳收支估算和温室气体减排提供依据。本研究选取西宁市海湖湿地、宁湖湿地和北川河湿地作为研究对象,通过静态暗箱法采集并测定湿地不同时期、不同界面的温室气体,分析湿地不同界面温室气体排放通量特征,通过采集样点内的表层土壤、水体、沉积物并测定,分析理化性质与温室气体排放通量的相关关系。研究结果表明,海湖湿地土-气界面的平均甲烷(CH4)排放通量最大,为6.25-16.48 μg·m-2·h-1,宁湖湿地水-气界面的平均CH4排放通量最大,为27.36-86.41 μg·m-2·h-1。海湖湿地在土-气界面和水-气界面上的的平均二氧化碳(CO2)排放通量都为最大值,分别为7.95-35.55 mg·m-2·h-1和3.95-22.49- mg·m-2·h-1,宁湖湿地氧化亚氮(N2O)排放通量为土-气界面最大和水-气界面最小。湿地理化性质方差分析结果中,受到不同湿地和时期影响的指标主要有土壤pH值、全氮(Total Nitrogen,TN)、总有机碳(Total Organic Carbon,TOC),以及沉积物和水体的氨氮(NH3-N)、全磷(Total Phosphorus,TP)、TN、TOC等。冗余分析结果显示,影响湿地温室气体排放的主要因子为温度、容重、pH值、TOC、TP、TN等。此外,湿地的温室气体排放通量排序为海湖湿地>宁湖湿地>北川河湿地,不同湿地水-气界面CH4排放通量均高于土-气界面,而水-气界面CO2排放通量低则于土-气界面,N2O排放通量则是土-气界面略大于水-气界面,不同时期的温室气体排放通量丰水期均要大于平水期和枯水期,温室气体的排放主要受到湿地内水热条件的影响。 |
关键词: 高原城市湿地 温室气体 排放通量 冗余分析 |
DOI: |
投稿时间:2024-10-14修订日期:2025-05-24 |
基金项目:青海省科技厅项目(2023-HZ-802) |
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Characterization of greenhouse gas emission fluxes at different interfaces and influencing factors in Xining wetlands |
Zhou shipeng, Zhang xiaoyan, Tian jiawei, Kang jiawen, Qin biyu, Lu sujin
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(Qinghai University) |
Abstract: |
Urban wetlands, as critical components of regional carbon and nitrogen cycles, play a significant role in estimating regional carbon budgets and guiding greenhouse gas (GHG) emission reduction strategies. This study focuses on three urban wetlands in Xining City: Haihu Wetland, Ninghu Wetland, and Beichuan River Wetland. Using the static dark box method, GHG emissions from different interfaces (soil-air and water-air) were collected and measured across varying hydrological periods. Concurrently, surface soil, water, and sediment samples were analyzed to investigate correlations between physicochemical properties and GHG flux variations. Key findings reveal that Haihu Wetland exhibited the highest average methane (CH4) emission flux at the soil-air interface (6.25-16.48 μg·m-2·h-1), while Ninghu Wetland showed the highest CH4 flux at the water-air interface (27.36-86.41μg·m-2·h-1)). For carbon dioxide (CO2), Haihu Wetland recorded the maximum fluxes at both soil-air (7.95-35.55 mg·m-2·h-1)) and water-air interfaces (3.95-22.49 mg·m-2·h-1)). Nitrous oxide (N2O) emissions were highest at the soil-air interface in Ninghu Wetland but lowest at its water-air interface.Variance analysis of physicochemical properties identified significant differences in soil pH, total nitrogen (TN), total organic carbon (TOC), as well as ammonia nitrogen (NH3-N), total phosphorus (TP), TN, and TOC in sediments and water across wetlands and seasons. Redundancy analysis highlighted temperature, bulk density, pH, TOC, TP, and TN as primary factors influencing GHG emissions. Overall, GHG emission fluxes followed the order: Haihu Wetland > Ninghu Wetland > Beichuan River Wetland. CH4 emissions at water-air interfaces consistently exceeded those at soil-air interfaces, whereas CO2 fluxes were lower at water-air interfaces. N2O emissions were marginally higher at soil-air interfaces. Seasonal variations showed GHG fluxes during the wet season surpassed those in normal and dry seasons, driven predominantly by hydrothermal conditions within the wetlands. This study provides critical insights into the mechanisms of GHG emissions in urban wetlands, offering a scientific foundation for regional carbon management and climate mitigation strategies. |
Key words: Plateau urban wetlands greenhouse gas emission fluxes redundancy analysis |