摘要
为了探究曝气条件对城市水体温室气体排放的影响,选取南京市浦口滨江湿地公园湖滨带的表层沉积物开展室内培养实验。实验设置了表层曝气、中层曝气、底层曝气以及静置对照共4组处理,曝气头分别位于水–气交界面下1 cm、10 cm以及水–沉积物交界面处。在45 d的实验周期内,每天12︰00—15︰00进行3 h曝气,所曝气体为空气。实验期间,每天9︰00采集气体、水样和沉积物样品,测定温室气体排放速率、累计排放量,以及水体和沉积物的相关理化性质。研究结果表明,在CO_(2)排放方面,中层曝气处理对水体中CO_(2)排放的抑制效果最为显著,表层曝气、中层曝气和底层曝气处理组的CO_(2)累计排放量分别为对照组的67.7%、60.9%和76.7%。在CH_(4)排放方面,表层水体曝气处理下CH_(4)累计排放量在所有处理组中最高,表层曝气组、中层曝气组和底层曝气组的CH_(4)累计排放量分别为对照组的197.3%、106.7%和97.7%。在N_(2)O排放方面,中层水体曝气显著提高了N_(2)O排放,表层曝气、中层曝气以及底层曝气处理组的N_(2)O累计排放量分别为对照组的112.2%、146.4%和81.9%,而底层曝气处理能够有效抑制N_(2)O排放。此外,不同曝气深度显著影响了上覆水的理化性质及碳氮循环过程。溶解氧(DO)浓度随曝气深度增加而降低,底层曝气组实验末期的DO浓度显著低于对照组;pH呈先增后减的单峰趋势,表层曝气组初始阶段pH最高,但是实验末期对照组pH高于底层曝气组;溶解有机碳(DOC)和总碳(TC)浓度在对照组最高,中层曝气组最低。在氮元素转化方面,底层曝气组NH_(4)^(+)-N浓度最低,中层曝气显著提高了NO_(3)^(-)-N浓度,TN浓度在底层曝气组最低,且其碳氮比最高。溶解有机物质(DOM)荧光特性分析显示,各处理组DOM以陆源腐殖质为主,且腐殖化程度无显著差异。本研究明确了曝气处理技术对城市景观水体温室气体排放的影响,为城市景观水体管理及碳排放核算提供了重要的理论依据,有助于更好地理解曝气、水体环境和温室气体排放之间的复杂关系,对制定科学合理的城市水体管理策略和减少城市温室气体排放具有重要意义。
To explore the impact of aeration conditions on greenhouse gas emissions from urban water bodies,this study conducted indoor incubation experiments using the surface sediments from the lakeside zone of Nanjing Binjiang Wetland Park.Four treatment groups including surface aeration,middle-layer aeration,bottom-layer aeration,and a static control group were set up,with aeration heads placed at different depths(1 cm below the water-air interface for surface aeration,10 cm for middle-layer aeration,and at the watersediment interface for bottom-layer aeration).During the 45 d experiment,aeration with air was carried out from 12:00 to 15:00 every day.Samples of gas,water,and sediment were collected at 9:00 daily to measure greenhouse gas emission rates,cumulative emissions,and relevant physical and chemical properties.The results showed that in terms of CO_(2) emissions,the middle-layer aeration treatment had the most significant inhibitory effect,with the cumulative CO_(2) emissions of the surface,middle-layer,and bottom-layer aeration groups being 67.7%,60.9%,and 76.7%of the control group respectively;for CH_(4) emissions,the surface-water aeration treatment led to the highest cumulative emissions,with the cumulative CH_(4) emissions of the surface,middle-layer aeration and bottom-layer aeration groups being 197.3%,106.7%,and 97.7%of the control group respectively;regarding N_(2)O emissions,middle-layer water aeration significantly increased emissions,with the cumulative N_(2)O emissions of the surface,middle-layer,and bottom-layer aeration groups being 112.2%,146.4%,and 81.9%of the control group respectively,while bottom-layer aeration effectively inhibited N_(2)O emissions.Additionally,different aeration depths significantly affected the physical and chemical properties of the overlying water and the carbon-nitrogen cycling process.The DO concentration decreased with increasing aeration depth,with the bottom-layer aeration group having a significantly lower DO concentration at the end of the experiment compared to the control group.The pH value showed a single-peak trend of first increasing and then decreasing,with the surface-aeration group having the highest pH initially but the control group having a higher pH than the bottom-layer aeration group at the end of the experiment.The DOC and TC concentrations were highest in the control group and lowest in the middle-layer aeration group.In nitrogen transformation,the bottom-layer aeration group had the lowest NH_(4)^(+)-N concentration,the middle-layer aeration significantly increased the NO_(3)^(-)-N concentration,the TN concentration was lowest in the bottom-layer aeration group with the highest carbon-nitrogen ratio,and the DOM fluorescence analysis showed that the DOM in each treatment group was mainly terrigenous humus with no significant difference in humification degree.This study clarifies the impact of aeration treatment technology on urban landscape water body greenhouse gas emissions,provides an important theoretical basis for urban landscape water body management and carbon emission accounting,helps understand the complex relationships among aeration,water body environment,and greenhouse gas emissions,and is of great significance for formulating scientific urban water body management strategies and reducing urban greenhouse gas emissions.Moreover,the results can serve as a reference for similar studies in other regions,contributing to global climate change mitigation and sustainable urban water resource management.
作者
贾原
钱畅
杨伊琳
周旭东
于志国
Jia Yuan;Qian Chang;Yang Yilin;Zhou Xudong;Yu Zhiguo(School of Hydrology and Water Resources,Nanjing University of Information Science and Technology/Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,P.R.China;Jiaojiang District Meteorological Bureau,Taizhou 318000,Zhejiang,P.R.China;Nanjing Hydraulic Research Institute,Nanjing 210000,Jiangsu,P.R.China)
出处
《湿地科学》
北大核心
2025年第3期608-620,共13页
Wetland Science
基金
国家自然科学基金项目(32471702、41877337)
江苏省智库计划项目(JSKX24081)
国家级大学生创新创业训练计划支持项目(202410300072Z)资助。
关键词
温室气体排放
沉积物
城市水体
曝气技术
greenhouse gas emissions
sediment
urban water
aeration technology
作者简介
贾原(2001-),男,河南省郑州人,在读本科生,从事生态水文方面的研究。E-mail:875761232@qq.com;通信作者:于志国,教授。E-mail:002696@nuist.edu.cn。
