江西省水库温室气体释放及其影响因素分析

Greenhouse gas flux at reservoirs of Jiangxi Province and its influencing factors

对江西省柘林、白云山、陡水、洪门、仙女湖5个水库表面N_2O、CH_4和CO_2这3种温室气体的溶存浓度进行测定,估算出这3种温室气体在水-气界面的释放速率分别为0.29~1.05、3.65~39.42和-51.56~1383.21μg/(m^2·h).与其他环境因素的相关性分析表明,总氮浓度是控制N2O释放速率的决定性因素;CH_4的释放速率与水体温度、透明度以及总磷浓度的相关性显著;而CO_2的释放速率与叶绿素a、总有机碳浓度等环境因素均未发现单一的相关性.根据温室气体的全球变暖潜能值计算得到5个水库温室气体总的CO_2等效释放速率(TFeq-CO_2)范围为237.83~2267.83μg CO_2-e/(m^2·h).N2O、CH_4和CO_2的CO_2等效释放速率在TFeq-CO_2中所占比例范围分别为13.94%~83.26%、20.54%~175.21%和-140.43%~60.99%.N_2O和CH_4的CO_2等效释放速率对TFeq-CO_2的贡献基本相当;在柘林和仙女湖水库中CO_2的贡献为负值,而在其余3个水库中CO_2是水库所释放的最为主要的温室气体.本实验中5个水库温室气体的TFeq-CO_2相当于10.52~377.10 t C/a的碳排放,占产生相同电能燃煤发电站年碳排放量的0.05%~1.12%.

Five reseiToirs located in the Jiangxi Province（ Zhelin, Baiyunshan,Doushui, Uongmen and Xiannuhu Reservoirs） were sampled in order to estimate the concentrations of greenhouse gas（G11G） in the surface of these reservoirs. The calculation for dif-fusive fluxes of nitrous oxide（ N2O） , methane（ C114 ） and carbon dioxide（ CO2 ） at the water-air interface indicated that the surface of the reservoirs was a source of CO2 and CU4 during the sampling period（ from 0.29 to 1.05, 3.65 to 39.42 pg/（ m2 h） , respec-tively）. Zhelin Reservoir（-51.56 pg/（ m2 .h） ） and XiannUhu Reservoir（-589.50 pg/（ m2 .h） ） surfaces constituted sinks for CO2. In contrast, the surface of all the other reservoirs were sources of CO2（ from 342.53 to 1383.21 pg/（m2 .h） ）. A significant correlation was observed between the magnitude of N2O diffusive fluxes and the TN. Water temperature, transparency and TP should affect the Cl4 fluxes. There was no relationship between the CO2 emission and other environmental factors. Taking into ac-count the global warming potential of N2O and CU4 , the total fluxs of CO2 equivalents was estimated that ranged from237.83-2267.83 pg CO2e /（ m2 -h） .The contribution of N2O, Cl 4 and CO2 to TFeq-CO2 range from 13.94% to 83.26% , 20.54% to 175.21% and from -140.43% to 60.99% , respectively.The contribution of N2O to TFeq-CO2 were similar to that of CU4 in all res-ervoirs. For Zhelin and XiannUhu Reservoirs, the contribution of CO2 to TFeq-CO2 was negative, but it was the most significant in the other reservoirs. The TFeq-CO2 from each reservoir were equivalent to the 10.52-377.10 t C/a of the carbon emissiom that were much lower than the annual CO2 emissions from themal power plants burning coal（ from 0.05% to 1.12% ） .