荒漠河岸林土壤呼吸温度敏感性与碳平衡研究

This project is based on the middle and lower reaches of Tarim River as the study area, the desert riparian forest as a research object, around its temperature sensitivity of soil respiration (Q10) characteristic of one order of magnitude below the global average, To ecosystem carbon process as the starting point, Through the investigation of components of soil organic carbon and soil respiration of separation and quantitative, Analysis of desert riparian forest soil organic carbon and soil respiration intensity distribution characteristics of temporal and spatial, As well as the coupling relationship between the two. By attribution and screening of the relevant factors that affect soil respiration, In biochemistry, soil aggregates , as well as ecosystem scale, Revealing the desert riparian forest soil respiration temperature sensitivity low intrinsic mechanisms . Construction of multi-parameter model of temperature sensitivity of soil respiration. Determination of desert riparian forest soil carbon emission intensity under the influence of low temperature sensitivity. By artificial warming, the humidifier control experiments, the joint monitoring of soil respiration and ecosystem respiration, Explore the desert riparian forest ecosystem carbon balance in the context of climate change, as well as the effectiveness of carbon deposition and its changing trend. Clarify future environmental changes desert riparian forest ecosystem carbon sources and sinks. And strive to achieve a breakthrough in the desert ecosystem carbon cycle response mechanism on climate change and its dynamic.

本项目以塔里木河中下游为研究区，以荒漠河岸林作为研究对象，围绕其土壤呼吸温度敏感性指标（Q10）低于全球平均值1个数量级的特点，以生态系统碳过程为切入，通过对土壤有机碳各组分调查及土壤呼吸的分离量化，分析荒漠河岸林土壤有机碳和土壤呼吸强度的时空分布特征及其两者之间的耦合关系；通过对影响土壤呼吸各相关因子的归因和甄别，揭示荒漠河岸林土壤呼吸在生物化学、土壤团聚体以及生态系统尺度上温度敏感性偏低的内在机制，构建多参数的土壤呼吸温度敏感性模型，确定弱温度敏感性影响下的荒漠河岸林土壤碳排放强度；通过人工增温、增湿的控制实验和土壤呼吸与生态系统呼吸的联合监测，探讨气候变化背景下荒漠河岸林生态系统碳平衡以及碳沉积有效性及其变化趋势，弄清未来环境变化下荒漠河岸林生态系统的碳源汇功能。力争在荒漠区生态系统碳循环对气候变化的响应机制及其动态方面取得突破。

土壤表面CO2释放作为陆地生态系统碳收支的第二大通量，正在逐渐受到人们的关注并成为研究热点，对环境变化极其敏感的脆弱生态系统CO2释放过程的研究是全球生物地球化学循环研究中重要一环，对了解和认识各类生态系统的碳源/汇功能具有重要意义。本项目以西北干旱区最干旱的一隅—塔里木河下游为靶区，以干旱区典型森林类型—胡杨林群落为研究对象，结合对塔里木河下游浅层地下水、土壤水、温度以及植物光合能力等相关因子观测，利用LI－8100和涡度相关监测胡杨林群落土壤CO2释放速率以及净生态系统碳通量，分析了胡杨林群落土壤CO2释放的变化特点及其时空变化特征及其与环境因子的关系，确定了土壤有机碳时空分布特征，分析土壤有机碳与土壤呼吸速率之间的关系，探讨土壤呼吸温度敏感性的变化，分析其变化的影响因子，解读研究区气候变化趋势，研究气候变化背景下，植被个体、群落及生态系统尺度上碳排放对气候变化的适应对策，探讨了人工措施影响下退化生态系统碳固定收益，并基于基础研究基础上，进行干旱荒漠区固碳技术研发，申报国家发明专利4项，获得2项授权。