Shifting of dissolved organic matter components and sources in precipitation into an intensified anthropogenic influenced embayment: Interpretation from spectral characteristics and dual stable isotopes
Shifting of dissolved organic matter components and sources in precipitation into an intensified anthropogenic influenced embayment: Interpretation from spectral characteristics and dual stable isotopes
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降水中溶解的有机物成分和来源转移到受人为影响加剧的海湾：光谱特征和双稳定同位素的解释
DOI：
10.1016/j.atmosres.2022.106089
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发表时间：
2022
影响因子：
5.5
通讯作者：
Xiaoping Huang
中科院分区：
文献类型：
--
作者：
Yunchao Wu;Jinlong Li;Zhijian Jiang;Songlin Liu;Xiaoping Huang
溶解有机质（DOM）是雨水中普遍存在的一类有机化合物，它构成了DOM池，在海洋生物地球化学循环中起着至关重要的作用。在此基础上，从δ13C-DOMSPE和δ15N-DOMSPE的角度分析了雨水DOM的组成和来源，并讨论了大气DOM沉积的生物地质效应。结果表明，DOM浓度以降水为主，存在明显的季节变化。此外，激发-发射矩阵光谱耦合平行因子分析（PARAFAC）结果显示，雨水DOM具有5种荧光成分（C1-C5）。C1和C5是类似蛋白质的DOM成分，来源于生物源排放物。C1和C5的荧光强度在雨季显著升高，而C2和C3则主要来源于化石燃料燃烧，是一种分子量更高、芳构化程度更高的腐殖质样物质。δ13C-DOMSPE和δ15N-DOMSPE结果表明，化石燃料在旱季降水中贡献了约80%的DOM，而由于南海气团的影响，在湿季降水中DOM的海洋排放贡献更高。然而，海上排放对雨水DOM的贡献仅为4%。溶解有机碳（DOC）和溶解有机氮（DON）的沉积通量分别为799mmol·C·m、46mmol·N·m，对大亚湾DOM输入通量（DOC和DON分别占28%和12%）起着重要作用。总体而言，我们的研究结果表明，大气湿沉积是沿海水域有机碳和氮的潜在关键来源，特别是在以季节间季风变化为特征的人为影响加剧的河口。
Dissolved organic matter (DOM) is a ubiquitous group of organic compounds in rainwater that contributes to DOM pools and plays a vital role in the marine biogeochemical cycle. Here, we presented the rainwater DOM components and sources attribution (in δ13C-DOMSPE and δ15N-DOMSPE perspective) to an intensified anthropogenic influenced embayment, and discussed the biogeological effects of atmospheric DOM deposition. The results showed an apparent seasonal variation in the DOM concentration dominated by precipitation. Moreover, the excitation-emission matrix spectroscopy coupled a parallel factor analysis (PARAFAC) results revealed that five fluorescent components (C1-C5) of the rainwater DOM. C1 and C5 are protein-like DOM components and derived from biogenic emissions. The fluorescence intensity of C1 and C5 were significantly higher in the wet season, whereas C2 and C3, which are humic-like substances with higher molecular weights and aromatization, were mainly derived from fossil fuel combustion. The δ13C-DOMSPE and δ15N-DOMSPE results indicated that fossil fuel contributed approximately 80% of the DOM in the precipitation in the dry seasons, whereas the marine emission contribution of DOM was higher in the wet seasons due to the influence of air masses originating from the South China Sea. However, the maritime emissions only contributed 4% to the rainwater DOM. The deposition fluxes of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) were 799mmol·C·m˗2·yr˗1 and 46mmol·N·m˗2·yr˗1, respectively, and they played a substantial role for the DOM input flux of Daya Bay (28% of DOC and 12% of DON, respectively). Overall, our results suggest that atmospheric wet deposition represents a potentially critical source of organic carbon and nitrogen for coastal waters, particularly in intensified anthropogenically influenced embayments characterized by substantial monsoon shifts between seasons.