南京典型水体春季温室气体排放特征研究

利用静态箱-气相色谱法对南京4条河流(内秦淮河、外秦淮河、金川河、团结河)和1座水库(丁解水库)的春季水-气界面CO2、CH4、N2O 3种温室气体通量进行包括昼夜变化的持续观测,对其变化趋势及影响因素加以分析.结果表明,春季团结河CO2和CH4的排放量最大,分别为1023.34,89.45mg/(m2·h),金川河两种气体排放量次之,内、外秦淮河CO2排放量相当,而内秦淮CH4的排放量比外秦淮小1个量级.丁解水库该2种温室气体排放量最小.金川河N2O的排放量最高,为151.31μg/(m2·h),团结河N2O排放量次之[111.74μg/(m2·h)],其他2条河流和丁解水库N2O的排放量均在一个量级上(101).水-气界面温室气体的排放受温度、压力、风速等环境因子影响.温室气体的昼夜变化分析结果表明,除了金川河N2O的排放趋势为昼间排放、夜间吸收外,其余河流及丁解水库均为温室气体的排放源.内秦淮和丁解水库的排放趋势受人为因素影响较大,外秦淮河的排放趋势主要受水位的高低变化影响,团结河的排放量受风速和温度的共同影响.金川河主要受微生物活性影响3种温室气体均呈明显的昼夜变化.5种水体在春季是大气3种温室气体的主要排放源.

Greenhouse gases emission characteristics of Nanjing typical waters in Spring

Employing floating static chamber-chromatography method, the greenhouse gases(GHGs) fluxes, which include CO2, CH4 and N2O, at the water-air interface of four rivers(Tuanjie River, Jinchuan River, Inner and Outer Qinhuai River)and Dingjie Reservoir were continuously monitored in Nanjing during spring in 2012. And based on these observed data, the variation and influencing factors of GHGs fluxes were analyzed. The results showed that the CO2 and CH4 emission fluxes of Tuanjie River were top, which were 1023.34mg/(m2·h) and 89.45mg/(m2·h), respectively, and Jinchuan River followed; CO2 fluxes from Inner and Outer Qinhuai River were at the same magnitude;CH4 fluxes emitted from Inner Qinhuai were one magnitude less than Outer Qinhuai; and CO2 and CH4 fluxes from Dingjie Reservoir were the lowest among the waters. As for N2O fluxes, Jinchuan River was the highest [151.31μg/(m2·h)], followed by Tuanjie River (111.74μg/m2·h), and Inner/Outer Qinhuai River and Dingjie Reservoir perform modest with 101 magnitude. In addition, all of the waters were GHGs emission sources except Jinchuan River being N2O sink. We also concluded that the mainly influencing factors on GHGs fluxes of Inner Qinhuai/Dingjie Reservoir, Outer Qinhuai ,Jinchuan and Tuanjie River were human’s activities, water level, microbial activity and joint actions of wind speed and temperature, separately. The five waters studied in this paper were emission sources of the three major GHGs in spring.