艾比湖高盐湖泊湿地土壤二氧化碳排放影响机制研究

Soil carbon storage capacity and carbon dioxide emissions rules of seasonal changes of High salt lake wetland , especially the freezing and thawing process research on carbon emission mechanism is less. In this study, Ebinur Lake with the largest Salt Lake in arid region of Xinjiang as the study area, the choice of high, low Lake Wetland reed root zone, there is no root zone, and bare land, soil carbon flux measurement system of LI-8100A application, the annual Yu Yue winter, spring bud stage, middle stage, vigorous growth, withering period, the diurnal variation of monitoring soil respiration monitoring system, at the same time, soil physical and chemical properties, reed growth process parameters, groundwater level, soil water and salt dynamics, soil freezing and thawing process, seasonal changes of the Ebinur Lake Wetland revealed high salt soil respiration, the intrinsic mechanism of study on soil physicochemical properties, the dynamics of soil water and salt, groundwater level and crop growth process on the high salt lake Ebinur Lake wetland soil respiration effect, provides the support for the study of carbon cycling in arid area of lake.

通过对艾比湖高盐湖泊湿地芦苇有根、无根区、裸地区的土壤呼吸季节变化规律的研究，分析其湖泊湿地在越冬期，春季萌芽期，中期，旺盛生长期，枯黄期的土壤呼吸特征，同时系统监测土壤理化性质、芦苇生长过程参数、地下水位动态、土壤水盐动态、土壤冻融过程，揭示艾比湖高盐湖泊湿地土壤呼吸的季节变化规律，探讨土壤理化性质、土壤水盐动态、地下水位及作物生长过程等对艾比湖高盐湖泊湿地土壤呼吸影响的内在机制，为干旱区湖泊碳循环研究提供支撑。

为研究干旱区高盐湖泊湿地土壤CO2、CH4和 N2O排放的时空变化及影响因素，以艾比湖湿地为研究对象，采用静态暗箱气相色谱法，于2015-2017年的环湖一周，于春夏秋冬的不同月分测定不同植物群落下土壤的CO2、CH4和 N2O通量，分析土壤温室气体通量变化的影响因素。结果表明：（1）艾比湖湖泊湿地土壤CO2和N2O排放通量的季节变化的最大值出现在夏季，最小值出现在冬季，且CO2和N2O在冬季表现为弱吸收。夏季土壤CH4吸收通量明显高于其它季节；与山前绿洲区、城镇绿洲区、绿洲-荒漠湿地过渡带对比，绿洲-荒漠湿地过渡带各月均为土壤 CO2 的排放“源”，山前绿洲区各月均为土壤 CH4的吸收“汇”，研究区各月均为土壤 N2O的排放“源”。（2）艾比湖湿地年均排放CO2和N2O最大值出现在西北部梭梭-柽柳群落，东南部胡杨群落年均吸收CH4通量最大。土壤CO2和N2O扩散通量深层高于浅层土壤的空间分布特征，芦苇土壤CO2、N2O扩散通量显著高于柽柳和裸地。（3）对环境因子的分析发现，土壤温度、空气温湿度、土壤有机质是影响艾比湖高盐湖泊湿地土壤CO2、CH4、N2O通量的主要因子。随着季节更替，温度、湿度变化对土壤温室气体CO2、N2O、CH4累积排放影响显著，呈现夏季最大，冬季最小。（4）在百年时间尺度上，不同典型植物群落下土壤的综合增温潜势表现为：梭梭-柽柳群落>梭梭群落>胡杨群落>芦苇群落。综合来看，艾比湖高盐湖泊湿地土壤总体上是温室气体的排放“源”，即对全球变暖有促进作用。