青海湖流域河源湿地生态系统碳交换对模拟增温的响应

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

为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。

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.