城市小型景观水体CO_(2)与CH4排放特征及影响因素  

Spatiotemporal variations and influencing factors of CO_(2) and CH_(4) emissions from urban small landscape waters

作　　者：黄婷 王晓锋 刘婷婷 庞吉丽[3] 陈彦蓉 吴文洁 赵舒宁 吴胜男 王继龙 HUANG Ting;WANG Xiaofeng;LIU Tingting;PANG Jili;CHEN Yanrong;WU Wenjie;ZHAO Shuning;WU Shengnan;WANG Jilong(Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River,Chongqing 401331,China;Three Gorges Reservoir Area Earth Surface Ecological Processes of Chongqing Observation and Research Station,Chongqing 405400,China;College of Geography and Tourism,Chongqing Normal University,Chongqing 401331,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China)

机构地区：[1]长江上游湿地科学研究重庆市重点实验室,重庆401331 [2]三峡库区地表生态过程重庆市野外科学观测研究站,重庆405400 [3]重庆师范大学地理与旅游学院,重庆401331 [4]华东师范大学河口海岸研究所,上海200241

出　　处：《生态学报》2021年第15期6024-6037,共14页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41807321);重庆市基础研究与前沿探索项目(cstc2018jcyjAX0672);重庆市教委科学技术研究项目(KJZDK202000502);地理科学重庆市本科一流专业立项建设项目。

摘　　要：淡水生态系统被认为是大气温室气体排放的重要来源,尤其在人类活动影响下,其排放强度可能进一步增强。城市小型景观水体是城市生态系统的重要组成,具有面积小、数量大以及人类干扰强的特征,其温室气体排放特征及影响因素尚不清楚。选择重庆市大学城8个景观水体和周边2个自然水体为对象,于2019年1、4、7、10月,利用漂浮箱和顶空法分析了水体CO_(2)与CH_(4)的溶存浓度及排放通量,旨在揭示城市小型景观水体CO_(2)与CH_(4)排放强度、时空变异特征以及影响因素。结果表明,10个小型水体CO_(2)、CH_(4)的溶存浓度范围分别为10.75—116.25μmol/L和0.09—3.61μmol/L(均值分别为(47.6±29.3)μmol/L、(1.13±0.56)μmol/L),均为过饱和状态;漂浮箱法实测的8个景观水体CO_(2)和CH_(4)排放通量均值分别为(72.7±65.9)mmol m-2 d-1和(2.31±3.48)mmol m-2 d-1(顶空法估算值为(69.7±82.0)mmol m-2 d-1和(3.69±2.92)mmol m-2 d-1),是2个自然水体的3.5—6.1和2.0—4.5倍,呈较强的CO_(2)、CH_(4)排放源;居民区景观水体CO_(2)和CH_(4)排放略高于校园区,均显著高于对照的自然水体;CO_(2)排放夏季最高,秋季次之,冬、春季最低,CH_(4)呈夏季>秋季≈春季>冬季的季节模式,温度和水体初级生产共同影响CO_(2)和CH_(4)排放的季节模式;水生植物分布对景观水体CO_(2)、CH_(4)排放有显著影响,有植物分布的水域比无植物水域平均高1.97和2.94倍;漂浮箱法和顶空法测得气体通量线性关系较好,但顶空法测得CO_(2)通量在春季明显偏低,而CH_(4)则普遍偏高。相关分析表明,景观水体碳、氮浓度、pH值以及DO等对CO_(2)排放具有较好的指示性,CH_(4)排放通量主要与水体中碳、磷浓度有关。城市小型景观水体CO_(2)、CH_(4)排放通量远高于大部分已有自然水体的研究结果,呈一种较强的大气温室气体排放源,在区域淡水系统温室气体排放清单中具有重要贡献,未来�Freshwater ecosystem,as sink of the terrestrial and anthropogenic carbon,is the most active bioreactor for global carbon biogeochemical processes and an important emitter of greenhouse gases(i.e.CO_(2)and CH_(4))to atmosphere,and then influences the global climate change and carbon cycling.CO_(2)and CH_(4)emissions from freshwaters have been extensively attentional in recent years given their importance,particularly that the emissions would be further enhanced by the increasing human activities.The urban small-scale landscape water bodies(including landscape pond,lake),featured by small area and large quantity,are a crucial component of urban ecosystem and strongly influenced by human activities.However,greenhouse gases emissions from such artificial-dominated waters are rarely studied and have been badly neglected.In the present study,for exploring the spatiotemporal variations and controls of CO_(2)and CH_(4)emissions from urban small landscape waters,we selected eight landscape water bodies and two natural water bodies in Chongqing,and carried out four seasonal investigations of CO_(2)and CH_(4)concentrations and emissions from the surface water in January,April,July and October in 2019 through the static chamber-gas chromatography technique and headspace method.Meanwhile,the vegetated and non-vegetated zones in the sampling water were monitored separately to identify the hydrophyte's disturbance.The result showed that CO_(2)and CH_(4)concentrations in urban landscape waters in Chongqing were widely supersaturated with range of 10.75—116.25μmol/L(averaged(42.5±28.7)μmol/L)and 0.09—3.61μmol/L(average of(0.98±0.80)μmol/L),respectively;the average CO_(2)and CH_(4)fluxes measured by the floating box method were(72.7±65.9)and(2.3±3.5)mmol m-2 d-1 respectively,indicating that the urban landscape waters were the net CO_(2)/CH_(4)emission source.CO_(2)and CH_(4)emissions from the residential landscape waters were slightly higher than those from the landscape waters in campuses,but both were significantly h

关 键 词：城市 景观水体 CO_(2)与CH_(4)排放 时空特征 影响因素 

分 类 号：X52[环境科学与工程—环境工程] X16