城市化地区典型水体的N2O排放通量特征——以南京市为例

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 城市化地区典型水体的N2O排放通量特征——以南京市为例 DOI: 10.5846/stxb202205061253 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然基金青年项目（42207268）；江苏省基础计划自然科学基金青年基金项目（SBK2022044914）；南京信息工程大学科研启动经费项目（1521052201006）；大学生创新训练项目（1514072101087） N2O emissions in typical urban waterbodies: example of Nanjing Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:内陆淡水水体是大气中N2O的重要排放源，然而目前对于内陆典型城市水体N2O排放通量的监测数据依然匮乏，典型城市水体的N2O排放特征及驱动因素尚不清楚。本研究选取了南京市江北新区的典型水体，包括湖库、河流、养殖池塘和景观池塘，在2020年5月-2021年4月利用漂浮箱法连续监测了不同水体类型的水-气界面N2O排放特征，并通过测定水环境特征，探究驱动水体N2O排放通量的关键因素。研究结果表明，典型城市水体整体均表现为N2O排放源，河流和养殖池塘的日平均排放通量最大，分别为（503±1236）μg m-2 d-1和（508±797）μg m-2 d-1，其次为景观池塘（（179±989）μg m-2 d-1），而湖库的N2O排放通量最小，仅表现为微弱的N2O排放源（（54±212）μg m-2 d-1）。水体的N2O排放呈现季节性差异，河流和养殖池塘夏季的N2O排放通量显著高于其他季节（P<0.01）。水体全年N2O排放数据与水体温度和溶解氧含量（DO）呈显著相关。而在温度较高的5月份-9月份（>20℃），氮输入成为影响N2O排放通量的关键因素（P<0.01），因此控制城市水体的氮输入尤其是在水温较高的夏季是减少N2O排放的有利措施。此外，由于水文化学条件差异等因素，小型封闭水体包括养殖池塘和景观池塘的N2O排放通量差异较大，未来应加强监测不同水体的水文化学特征和N2O的时空排放特征，探讨影响小型封闭水体水-气界面N2O排放通量的具体驱动因素。此研究为城市区域N2O排放的精准核算提供了数据支撑，为N2O排放模型的修正提供了科学依据。 Abstract:Even though inland freshwater waterbodies are important atmospheric N2O sources, but current N2O emission data from those waterbodies are still limited. Furthermore, it is unclear about N2O spatiotemporal emission characters in different urban waterbodies and corresponding drivers. This study applied floating chambers to in-situ measure N2O emission fluxes in typical urban waterbodies including reservoirs, rivers, aquaculture ponds and scenic ponds of Nanjing starting from May of 2020 to April of 2021. Furthermore, physical and chemical water parameters were also measured to elucidate main N2O emission drivers. The result revealed that all types of urban waterbodies generally showed as emission sources. Rivers and aquaculture ponds had the largest N2O flux, with average values of (503±1236) μg m-2 d-1 and (508±797) μg m-2 d-1, respectively, following by scenic ponds ((179±989) μg m-2 d-1), while reservoirs only showed as a weak N2O emission source ((54±212) μg m-2 d-1). N2O emissions from all waterbodies showed the seasonal pattern with higher N2O fluxes in summer, which is especially pronounced in rivers and aquaculture ponds (P<0.01). The annual N2O flux positively correlated with temperature and negatively correlated with dissolved oxygen (DO) (P<0.01), respectively. However, the nitrogen input was shown as the key driver for N2O emissions starting from May to September with temperature higher than 20℃. Therefore, controlling nitrogen input especially in the Summer season was an important measure for reducing N2O emissions. Furthermore, ponds showed large differences in N2O emissions resulting from different hydro-geochemical conditions and other factors. Monitoring of hydro-geochemical conditions and N2O emission fluxes for small waterbodies should be strengthened in further studies, and specific drivers for N2O emissions had to be explored. This study contributed to N2O emission estimations in the city, and provided the basis for updating N2O emission models. 参考文献 相似文献 引证文献