| 引用本文: | 李文儒,陈财,万洁婷,唐剑锋.长三角典型城郊流域溶解性有机质的分子特征:以浙江樟溪为例.湖泊科学,2024,36(2):477-486. DOI:10.18307/2024.0225 |
| Li Wenru,Chen Cai,Wan Jieting,Tang Jianfeng.Molecular characteristics of dissolved organic matter in a typical peri-urban watershed in the Yangtze River Delta: A case study of Zhangxi watershed in Zhejiang Province. J. Lake Sci.2024,36(2):477-486. DOI:10.18307/2024.0225 |
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| 长三角典型城郊流域溶解性有机质的分子特征:以浙江樟溪为例 |
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李文儒1,2,3, 陈财1,2, 万洁婷4, 唐剑锋1,5
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1.中国科学院城市环境研究所城市环境与健康重点实验室, 厦门 361021;2.中国科学院大学, 北京 101408;3.福建农林大学生命科学学院, 福州 350002;4.上海应用技术大学生态技术与工程学院, 上海 201418;5.厦门市城市环境智慧管理重点实验室, 厦门 361021
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| 摘要: |
| 溶解性有机质(DOM)在流域水环境中广泛存在,参与各种生物地球化学循环过程。快速的城镇化过程和人类活动显著改变了流域水体DOM含量和特性,从分子层面上解析DOM在流域尺度上的时空分异特征对流域水质管控具有重要的理论和应用价值。以长三角地区樟溪流域为研究对象,依据土地利用和人类活动强度布设采样点,于2022年7月采集水样。结果表明,樟溪流域水体溶解性有机物主要的分子式元素组成为CHO、CHON、CHOS,其中木质素/富羧酸脂环分子类有机物相对占比最高。在子流域空间分布上,人类活动强的子流域CHON、CHONS类型化合物含量更高。选取采样点距城镇距离、距源头距离以及土地利用类型所占采样点缓冲区的比例来表征人类活动的影响。结果表明,流域内DOM杂原子受人类活动强度影响,距源头的距离与水体DOM分子中氮原子的强度加权平均值(Nwa)和CHON化合物百分呈显著正相关,与碳、氢原子和荷质比的强度加权平均值(Cwa、Hwa、m/zwa)呈显著负相关。CHON分子的相对丰度与林地面积比例呈显著负相关,与农业用地比例呈显著正相关。比较具有典型土地利用类型的水体DOM:典型农田、城镇土地利用类型DOM含有更多独特的CHON分子式,农田DOM在木质素/富羧酸脂环分子区域出现CHON分子式的富集,城镇DOM在脂肪类和木质素/富羧酸脂环分子区域均出现了CHON分子式富集。研究表明在城郊流域中,人类活动显著改变了水体DOM的分子特征,增加了分子多样性,促进了特定分子式的富集。 |
| 关键词: 地表水 城郊流域 溶解性有机物 傅里叶变换离子回旋共振质谱 樟溪流域 |
| DOI：10.18307/2024.0225 |
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| 基金项目:国家自然科学基金项目(31971489)资助。 |
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| Molecular characteristics of dissolved organic matter in a typical peri-urban watershed in the Yangtze River Delta: A case study of Zhangxi watershed in Zhejiang Province |
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Li Wenru1,2,3, Chen Cai1,2, Wan Jieting4, Tang Jianfeng1,5
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1.Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China;2.University of Chinese Academy of Sciences, Beijing 101408, P.R. China;3.College of Life Science, Fujian Agriculture and Foresty University, Fuzhou 350002, P.R. China;4.School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, P.R. China;5.Xiamen Key Laboratory of Smart Management on the Urban Environment, Xiamen 361021, P.R. China
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| Abstract: |
| Dissolved organic matter (DOM) is ubiquitous in aquatic environment and is of great significance in various biogeochemical cycling processes. Rapid urbanization coupled with intensified human activities has significantly altered the content and characteristics of DOM in surface water at watershed. It has importance of characterize the spatial distribution of DOM at the molecular level for effective watershed management. In this study, the spatial variation of molecular characteristics of DOM as well as its influent factors was analyzed in a typical peri-urban watershed (Zhangxi watershed) in the Yangtze River Delta. Water samples were collected in July 2022 from sites from various land use and intensity of human activities. Results showed that the molecular characteristics of DOM were dominated by CHO type compounds, with lignin/carboxylic-rich alicyclic molecules (CRAM)-like structures as the main proportion. Significant higher content of CHON and CHONS compounds were observed in sub-watersheds with higher intensive human disturbance. The intensity of human activities was indirectly assessed with three indices: distance to town (DT), distance to water source (DS) and proportion of land use types. Our results showed that human activities played a significant role in the spatial distribution of heteroatoms of DOM. A positive correlation was observed between DS and both the intensity weighted average of nitrogen atoms (Nwa) and the percentage of CHON compounds of DOM molecules, while a negative correlation was found with the intensity weighted average of carbon and hydrogen atoms, as well as the ratio of charge to mass (Cwa, Hwa, m/zwa). The relative abundance of CHON-containing formulae was positively correlated to the proportion of agricultural land use whereas negatively correlated to the proportion of forest. Compared with the DOM in typical land use types: unique CHON molecules exhibited relatively higher abundances in farmland and urban land use types than that in forest land. The CHON molecular formula was enriched in the lignin/CRAM-like structures region of the water samples in farmland land use types. The CHON molecular formula was enriched in fat and lignin/CRAM-like structures region of the water samples in urban land use types. In short, our results revealed that anthropogenic activities significantly altered the molecular characteristics of surface water DOM in peri-urban watersheds, augmenting molecular diversity and facilitating the enrichment of specific molecular formulas. |
| Key words: Surface water peri-urban watershed dissolved organic matter (DOM) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) Zhangxi Watershed |
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