青海湖流域河源湿地生态系统碳交换对模拟增温的响应

左弟召　陈克龙　刘娟

摘要 為了探究河源湿地生态系统碳交换过程对增温的响应，2017年9月采用LI-6400便携式光合仪和静态箱法对生长季末期的河源湿地生态系统碳通量各组分进行测定。结果表明，河源湿地生态系统表现为碳汇，增温处理降低了生态系统净交换（NEE）的碳吸收能力。增温处理促进了河源湿地生态系统呼吸（ER），且对生态系统总初级生产力（GEP）的日变化速率具有重要影响。NEE主要受控于土壤温度且与不同深度土壤温度具有极显著的正相关关系，ER主要受控于土壤体积含水量且与不同深度土壤体积含水量具有显著的正相关性。土壤体积含水量可能是生长季末期河源湿地生态系统碳源汇转换的关键因子。在未来全球气候变化背景下，可能会导致河源湿地生态系统碳吸收和碳排放的转变。

关键词 生态系统碳交换;模拟增温;静态箱法;青海湖流域

中图分类号 X 171文献标识码 A

文章编号 0517-6611（2020）23-0001-05

doi：10.3969/j.issn.0517-6611.2020.23.001

Response of Carbon Exchange to Simulated Warming of River Source Wetland Ecosystem in Qinghai Lake Basin

ZUO Di-zhao1，2，3，CHEN Ke-long2，3，4，LIU Juan1，2，3

（1.College of Geographical Sciences，Qinghai Normal University，Xining，Qinghai 810008;2. MOE Key Laboratory of Tibet Plateau Land Surface Process and Ecological Conservation，Qinghai Normal University， Xining，Qinghai 810008;3.Key Laboratory of Natural Geography and Environmental Processes of Qinghai Province，Qinghai Normal University，Xining，Qinghai 810008;4. Science and Technology Department，Qinghai Normal University，Xining，Qinghai 810008）

Abstract In order to investigate the response of carbon exchange process of river source wetland ecosystem to temperature increase，in September 2017，LI-6400 portable photosynthesis system and static chamber method were used to measure the carbon flux components of the river source wetland ecosystem at the end of the growing season.The results showed that river source wetland ecosystems behave as carbon sinks，and warming treatment reduced the carbon absorption capacity of the net ecosystem exchange （NEE）.The warming treatment promotes the ecosystem respiration （ER） of the river source wetland ecosystem，and had an important impact on the daily change rate of the total primary productivity （GEP） of the ecosystem. NEE was mainly controlled by soil temperature and had a significantly positive correlation with soil temperature at different depths. ER was mainly controlled by soil volumetric water content and had a significant positive correlation with soil volumetric water content at different depths. Soil volumetric water content may be a key factor in carbon source-sink transition of river source wetland ecosystem at the end of the growing season. In the context of future global climate change，it may lead to changes in carbon absorption and carbon emissions in river source wetland ecosystems.

Key words Ecosystem carbon exchange;Simulated warming;Static chamber method;Qinghai Lake Basin

随着大气CO2浓度增加和人类活动的加剧，全球变暖趋势进一步持续。近年来，青藏地区暖湿化特征明显，其增温速率明显高于全球和全国平均水平，升幅为0.37  ℃/10 a[1]。湿地生态系统与气候之间存在着密切的联系，与其他陆地生态系统相比，湿地生态系统对气候变化异常敏感。在气候变化下，受纬度、海拔的影响，高寒地区生态系统具有极高的敏感性[2]。因此，加强对高海拔地区湿地生态系统与气候变化的响应研究显得尤为重要。

现有关模拟增温对生态系统碳交换影响的研究多集中于高寒草原生态系统[3]、高寒草甸生态系统[4]、高寒湖滨湿地生态系统[5]和高寒人工草地生态系统[6]，而对高寒河源湿地生态系统碳交换的研究较少。……